Kohinoor Internship Report

University College of Textile Engineering, Bahauddin Zakariya University, Multan

Internship Report

INTERNSHIP REPORT

Kohinoor dyeing mills

A Division of Kohinoor Weaving Mills (L.t.d)

Submitted to: GENERAL MANAGER PRODUCTION

Kohinoor dyeing mills

Submitted by: Azhar Hussain Shahid Sheikh Arslan Shaukat Muhammad Ayyoob Omer Ali Bhatti

B.Sc. Textile Engineering With specialization in Wet Processing 7th semester (Final Year)

Date of submission: 12-08-2008

UNIVERSITY COLLEGE OF TEXTILE ENGINEERING

Bahauddin Zakariya University Multan.


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Dedicated to

Mr. Hafiz Muhammad Ali Jaan Manager Dyeing

And

Mr. Amir Abbas Sherazi

One of our favorite teachers and a good friend of us


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ACKNOWLEDGMENT

None, however great can lay claim to absolute originality in any branch of knowledge. No one can deny it. Every one is indebted to their precursors in the particular field in which they are working. We are indebted to many individuals within our branch of knowledge and outside it. At first, we are grateful to Almighty ALLAH, The most Beneficent and Merciful, Who gave us mind to think and all physical abilities to work out problems and obstacles faced in life, and for giving us enough courage and commitment to complete this internship successfully. At Kohinoor Dyeing Mills, we found people very cooperative. During our internship we learnt a lot and found it as an excellent learning place. We are very thankful to Mr. Asad-Ullah (GM Production) and Hafiz Muhammad Ali Jaan sb. (Dyeing Manager) who allowed us to work under their supervision. At this place I would also like to thank Ms. Mumtaz Zia (Manager HR Dyeing) for her guidance and warm support throughout the internship period. We would also like to thank Mr. Nouman Shamsi (Manager Finishing), Mr. Kamran Bashir (Manager Lab.), Mr. Nasir (AM Bleaching), Mr. Naveed (AM Finishing), , Mr. Nouman (DM Dyeing for helping us through thick and thin and guiding us in best possible way. We would specially like to thank Mr. Umer, Mr. Rehan, and Mr. Naveed Akbar for taking keen interest to help us out in problems. With best wishes and regards, Azhar Hussain Sheikh Arslan Shaukat Muhammad Ayyoob Omer Ali Bhatti B.Sc Textile Engineering, 7th Semester (2005-2009), University College of Textile Engineering, BZU, Multan


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PREFACE Bahauddin Zakariya University is one of the leading universities of the country. University College of Textile Engineering is the heart of this University. This institute is rendering invaluable services to the nation Pakistan by producing outstanding graduate engineers who have aims to change the world. We ourselves feel proud as being a part of that superb college and of our teachers because of their excellent style of teaching and vast knowledge, as well as their scholastic approach. Preparing students to face the world confidently and courageously, University College of Textile Engineering arranges an internship Programs during summer vacations. The purpose of this program is to give practical exposure to our field of studies. It is also helpful for understanding the organizational environment and to deal with the professionals. For that , We joined Kohinoor Dyeing Mills Limited, which is one of the largest textiles Export Company in Pakistan. During our internship span of 45 days we got chance to work in all the departments of Kohinoor Dyeing Mills. We tried best to include every thing which we learned and observed here. This report details the technical and the managerial aspects. This report is prepared to provide the reader with an overview of Kohinoor Dyeing Mills. Azhar Husaain Shahid Sheikh Arslan Shaukat Muhammad Ayyoob Omer Ali Bhatti


Internship Report

AREAS OF WORK DURING OUR INTERNSHIP During our internship at Kohinoor Dyeing Mills, we worked on the following areas of different departments

1. GREIGE INPUT Process Flow Inspection Procedures Introduction Of Faults And Samples Issuance Lab Testing

2. PRETREATMENT

Process Flow Machine & Steamers Specifications Block diagrams of Machine Procedures For Each Process And Machine Chemical Recipes Testing and Chemical Titration

3. DYEING

Process Flow and Machine Specifications Block Diagrams Of Machines Procedures For Each Process And Machine Machine Conditions Testing + Online Testing Process Types And Conditions

4. FINISHING

Process Flow + Machine Specifications And Usage Line Diagrams Of Machine Chemicals And Their Usage+ Chemical Making Machine Conditions Testing + Online Testing

5. QUALITY CONTROL AND R&D LAB

Online Inspection Online Testing

6. FOLDING

Inspection system and Inspection Procedure Packing & Labeling and Storage


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Internship Report GREY INPUT DEPARTMENT It is the first department in the textile-processing mill. It is called Greige Department because greige fabric (from weaving mill) is first brought in this department. As the cloth is received from weaving mills, it is given a “lot” number and other data in the receiving register. A computer record of the received cloth is made and the cloth is stored according to the lot number. When Production and Planning Department requires the specific quality and type of fabric, the desired quality and type of fabric is issued to the production department. TYPES OF PACKAGES The woven fabric comes in three types of packages which are as follows;

1. Bale form 2. Roll form

These types of packages differ in length, shape and type of packing. The outermost layer of the packing is composed of polypropylene sheet and under it is polythene sheet. INSPECTION OF GREY CLOTH Before the loom state or greige cloth is set for processing it has to go through a number of inspections which would help to overcome any defects and faults caused by inefficient weaving or mishandling of fabric during its course of life from Weaving shed to Processing zone. The greige cloth is inspected at two places

1. In weaving unit after weaving 2. In processing unit before processing

The purpose of inspections is the detection of faults and their removal (incase the faults are mendable) caused by inefficient spinning or weaving and mishandling of the fabric during the period from weaving to processing zone.


Internship Report It also help to estimate the fabric quality and grade and it also assists to consider the possible difficulties, which may come during the processing of the fabric. DEFECTS IN GREIGE FABRIC The defects in the greige or loom state fabric can be divided into the following categories.

1) Spinning faults

2) Weaving faults

3) Mechanical faults

4) Handling faults

5) Mending Faults

Faults can also be divided according to their mend ability.

1. Mendable Faults 2. Non-mendable faults

SPINNING FAULTS These are the faults, which are caused due to improper spinning e.g.

Fat yarn Slubby yarn Thick yarn Thin yarn Uneven linear density Count variation Over or under twisted Mixed yarn Contaminated yarn

WEAVING FAULTS The faults in the fabric, which are caused due to inefficient weaving

Short pick Miss pick Double pick Short end Loose end Reed marks


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Starting mark. HANDLING FAULTS These faults become the part of fabric during its weaving, transportation and storage e.g.

Water stains Color stains Oil stains Soil stains Holes

MENDING FAULTS

Hanging thread Mending Mark Course pick

MECHANICAL FAULTS

Temple mark Oil stain Oily yarn Selvedge defect Reed cut Let-off bar Loose weft (slub)

PURPOSE OF GREIGE DEPARTMENT The purposes of the greige department are

1. Receiving 2. Inspection 3. Storage 4. Issuance

Initially the fabric from all customers received here. Before it is stored, inspection is done and results from QC Lab are considered. If the inspection results of greige and quality control lab are satisfactory then it is stocked by given its all identifications, i.e., lot no., bin no. type of fabric total no of meters etc. and then according to the queries from PPC, fabric is issued.

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MACHINES IN GREIGE DEPARTMENT Inspection Frames No. of machines: 16 Rolling Machine No. of machines: 02 RECEIVING OF FABRIC First the fabric conducts into greige department, gate pass and list of packing is provided by the supplier for greige department. This list contains the whole information about fabric inside packing. It will be in the form of bales, rolls and pallet. Then bales and roles are counted measured and tally with the packing list. After clearance bin and lot no are allotted. RECEIVING REPORT Receiving report prepared against packing list is sent to marketing department. Here contract no is given to this report and sent back to greige department.

SUPPLIERS OF FABRIC FOR KDML

Lot no.

Contract no.

Quality Width Weave Blend Supplier

No. of B/R

Lot

Length

Ahmad Hassan KWML Suraj Cotton Mills Ahmed Fine Hamid Textile Roomi Fabrics Fazal Rehman Dimond Fabrics

Ltd. Qamar Fabrics IMMI Garments Fazal Cloth Shafi Texel Samin Textiles Fatima Enterprises ICC Textile Sapphire Textiles

Mills Sapphire Textile Quetta Textile

Mills Ltd.


Internship Report PROCESS FLOW

Merchandiser Customer

Procurement Manager

Sample From W i

Greige department Q.C Lab. Customer satisfaction

Order of Fabric

Receiving

Greige Department

Whole Inspection

Whole Treatment

Prepared Sample to Customer

Accepted or Rejected

Lot No. and Bin No. Given

Inspection

Rolling

Send to Stock

PPC

Issuance of Fabric as per PP Unrolling

Status Card

Pretreatment

Q.C Lab.


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SAMPLING When a lot is received in greige, samples are taken for Q.C lab and one for greige record also. No. of samples taken depends on type, quality and length of the fabric received.

INSPECTION The fabric comes in KDML is A grade as a whole so Inspection of about 10 to 15% of whole fabric takes place in greige department. Inspection percentage may vary depending upon the quantity of fabric. If the amount of fabric is less then inspection percentage may increases from 10% to 50%. There are five inspection frames out of which 3 in working form. The main purpose of inspection is to count faults in type of fabric. In Kohinoor Dyeing Mills 4 point grading system is used for inspection of fabric. 4 Point System

Length of fault Points 1-3 inches 1 3-6 inches 2 6-9 inches 3 9- above 4

This is called four point American systems. This system is considered as a best grading system all over the world. It was developed to create an understanding between customer and supplier. Average Point: Average point is calculated by following formula. (Total Points) X (3937) Total Average Points Per 100 Meter2 (Total length in Meters) X (Width) (Total Points) X 3600 Total Average Points Per 100 Yards2 (Total length in Meters) X (Width) Based on above calculation inspection report is prepared. If fabric contains fault less then 15 or equal to 15 faults /100m2 then it


Internship Report considers as ok or pass. If 18 faults/100m2 are detected in fabric then it is under discussion. If more then 18 points are found/100m2

then it is rejected and tagged as hold or rejected.

Inspection frame

Daily Inspection Report Then daily inspection report is made in which total fabric inspected, total faults, faults per 100m2, rejection or acceptance of fabric in the whole day is written and then feed it into the computer.

STORAGE OF FABRIC Re-Rolling After inspection, the whole fabric is re-rolled and put in the respective bin. Storage conditions

Fabric must be kept in dry place and away from rain, tog, acid, base, oil, and all other fiber damaging material.

Storage Capacity

Storage capacity of department is 6 to 7 lack meters. Bales or roles are placed up to 7 feet height approximately.

Identification

If we want to find any type of fabric we have to see the stock report. On the wall bin number and in front of each lot its lot


Internship Report number shade total meters etc. (STATUS CARD) are attached, so that it is identified easily. Status Card It is attached at one bale or roll in front of whole lot. It contains the lot number, construction (quality), and number of pieces, total meter, selvage type, party name, or textile mill name. Production planning (P.P.) Production planning comes from PPC department to greige department. It tells about the construction ,lot number, number of meters etc. so, according to PPC lot is taken out, then roles are un-rolled and fabric is stitched and loaded on trolleys having an identity number. During stitching keep in mind that stitching of different rolls should be on the same side so, front to front, and back to back. Stock Report It contains the whole information related to stock in greige department. It tells us the total number of lot, types of construction, weave type, contract number, supplier, total bales and roles, meters etc.

ISSUANCE According to PPC the fabric is issued. Daily issuance report contains the whole issuance record of the day. It also shows the balance and then it is fed in the computer, at the end side of report C or O is written which means commercial or own respectively. Then fabric is send to pretreatment department with its route card which contains the whole information of process which should be done on fabric. Unrolling Fabric from the store is un rolled with the unrolling machine in the trolley, before issuance. Stitching Procedure Stitching machine is used for this purpose. Two yarns are used for stitching in this stitching machine. During stitching keep in mind that front of fabric will stitch on the same side of other fabric. Also on every fabric piece, its quality and quantity is written by textile marker. Its ink is not removed during pretreatment process.

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Internship Report Dye: Dyes are colored compounds which are absorbed or adsorbed by the fiber from a solution or suspension where they are subsequently fixed and are thus used for the coloration of textiles. All dyes have following basic elements Chromophore: It is the color giving element in dyes for producing color. Colorants are sometimes classified on the basis of their chief chromophore, e.g. azo dyes contain the chromophore (-N=N-). The most important chromophores are azo, carbonyl, methane, anthraquinone and nitro groups. Auxochrome: This is the second most important group in constitution of dyes; which is responsible for increasing intensity of color. Common auxochromes include hydroxyl (OH-) group and amino group. Chromogen: A chemical compound that is either coloured or can be made colored by the attachment of suitable substituents is called as chromogen. The chromophore and the auxochrome(s) are part of the chromogen. Some Terms Used In Dyeing

Affinity: The quantitative expression of substantivity is called as affinity. It is the difference between the chemical potential of the dye in its standard state in the fiber and the corresponding chemical potential in the dye bath. Affinity is usually expressed in joules (or calories) per mole. Substantivity: It is the attraction between a substrate and a dye or other substance under the precise conditions of test whereby the latter is selectively extracted from the application medium by the substrate.


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Based on Application

Direct dyes

Reactive dyes

Sulphur dyes

Basic dyes

Acid dyes

Azoic dyes

Mordant dyes

Natural & regenerated cellulose Cotton, Viscose rayon)

Natural & Regenerated Cellulose Natural Protein/Synthetic (Nylon)

Disperse dyes

Vat dyes

Pigments

Natural and regenerated cellulose

Natural Protein (Wool & Silk) Man-made (Acrylic)

Natural Protein (Silk/wool/Mohair) Man-made (Nylon)

Natural and regenerated cellulose

Natural Protein specifically Wool Acrylic & Nylon

Man-made Specifically Polyester

Natural & regenerated cellulose

Mostly for cellulose

Classification of Dyes

Dyes can be classified in three categories • Based on Application Properties • Based on Ionic nature • Based on Solubility in Water


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Based on Ionic structure

Anionic Dyes Cationic Dyes Non-ionic Dyes

Direct dyes

Reactive dyes

Sulphur dyes

Vat dyes

Acid dyes

Azoic dyes

Mordant dyes

Basic dyes Disperse dyes

Pigments

Based on Solubility in Water

Water Soluble Dyes

Water Insoluble Dyes

Direct dyes

Reactive dyes

Basic dyes

Acid dyes

Azoic dyes

Mordant dyes

Disperse dyes

Vat dyes

Sulphur dyes

Pigments


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Solubilizing groups used in dye molecules


Internship Report Introduction of Some Dye Classes

Reactive Dyes

These dyes are water soluble and are anionic in nature. These dyes are used for dyeing of cellulosics and modified reactive dyes can be used on wool, silk, nylon etc. These dyes have good to excellent fastness properties and form covalent bong with the fiber.

Basic Structure of Reactive Dyes There are many reactive groups that have been used in the manufacture of reactive dyes but most reactive dyes have the structural features, represented diagrammatically in Figure 1 and in the example of the dye CI Reactive Red 1 in Figure.

Structural Features of a Reactive Dye

• S is one or more solubilizing groups. • C is the chromophore of the dye. • B is a bridging group. • R is the reactive group. • X is a leaving group.

Typical Components of a Reactive Dye (CI Reactive Red 1)

Some or all of these features may be present more than once in the dye molecule, as in the case of bi- or poly-functional reactive dyes.


Internship Report The solubilizing groups are usually sulphonic acids and they typically range in number from one to four, depending on the starting materials used for the synthesis of the dye, the overall size of the dye molecule and the intended application method. Where high substantivity (the attraction between the dye and a substrate) for the fibre is desirable (e.g. in batch-wise exhaustion) a low number of solubilizing groups will be present within the dye structure; the reverse is found where low substantivity is required, for example, in continuous processes such as pad-bake. It is possible to use almost any chromophore group in the reactive dye class. The only structural features required are at least one sulphonic acid group to ensure adequate water solubility and a site that a bridging group (such as an amino group) can bond to in order to link in the reactive group. Therefore, reactive ranges can incorporate, for example, mono-azo, di-azo, metallised mono- and dis-azo, anthraquinone and phthalocyanine chromogens. Bridging groups attach the reactive group to the chromophore, but are not always necessary. Typical bridging groups are amino (-NH-), substituted amino and amide linkages (-NHCO-). The bridging group can bear some influence on the reactivity, substantivity and stability of the reactive dye.

Relative Reactivity of Major Reactive Groups

REACTIVE GROUPS

Dichlorotriazine: These dyes are highly reactive and can be readily fixed to cellulosic materials by a pad batch dyeing or by a batch-wise method at 30-40oC.These dyes are extremely suitable for bright dyeings but less satisfactory for deep tertiary hues. Such dyes are stable in neutral solution at ambient temperature, but subject to hydrolytic attack by hydroxide ions at an alkaline pH. A weakness with certain Dichlorotriazine dyes is that under acidic conditions the dye fibre bond is broken by acid-catalysed hydrolysis, leading to deficiencies in fastness to washing or to acid perspiration.


Internship Report Difluorochloropyrimidine: Dyeing temperatures for optimal fixation of these dyes are 40-50oC. The dye-fibre bond formed by reaction of cellulose with the highly reactive difluorochloropyrimidine system is more stable in acid conditions than that of the Dichlorotriazine system, but it does tend to undergo oxidative cleavage under the influence of light exposure in the presence of peroxy compounds. Monofluorotriazine: A fluorine atom is the leaving group in this system and they are therefore more reactive than the monochlorotriazine systems. Dichloroquinoxaline: This type of dye has one reactive group and an amide bridging link between the chromogen and the reactive system. Optimal fixation can be achieved by batch-wise dyeing at 50oC. The reactivity of this system is much higher than that of the corresponding dichlropyrimidine dyes and is comparable with that of the dichlorotriazine and difluoropyrimidine dyes. These dyes are readily hydrolysed under acidic conditions. Vinylsuphone or sulphatoethyl-sulphone: These dyes are intermediate in reactivity and are used in a number of batch wise and continuous processes. They can be used between 40oC and 60Oc depending on the pH. They tend to have low substantivity and the dye-fibre bonds are at their weakest under alkali conditions but this low substantivity makes washing-off easy. Monochlorotriazine: These dyes are of course less reactive than dichlorotriazine dyes and the monofluorotriazine dyes and require more energetic reaction conditions; therefore 80oC and pH 10.5 or even pH 11 are typically necessary for batch-wise application for efficient fixation on cellulosic fibres. Trichloropyrimidine: This is a pyrimidine unit with three chlorine atoms. The reactive system is made less active by the nitrogen atoms in the heterocyclic ring system and thus dyes of this type require batch wise application at the boil for fixation to the fibre. Dichloropyrimidine dyes are even less reactive than the trichloropyrimidine dyes.


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Classification of Reactive Dyes

Reactive dyes are versatile and allow a variety of different approaches for controlling the rate of dye adsorption, degree of dye migration and dye fixation. Salt additions, temperature variations and alkali additions are used alone or in combination to control the dye adsorption and fixation. Dyes are therefore often classified according to the most important controlling parameters. Classification by Application Method

Classification Description Examples Cold brand dyes or “M” dyes

Batch wise dyeing temperatures, for optimal fixation, of 30-400C. They are very reactive and show high fastness properties. These dyes require alkaline conditions for application. The required pH for dyeing is pH12.5. Caustic soda or sodium phosphate is required to achieve this pH.

Dichlorotriazine, Difluorochloro pyrimidine, Dichloro quinoxaline

Warm or medium brand dyes

Recommended dyeing temperature of these dyes for the maximum fixation for exhaust dyeing is 50-600C. The required pH for these dyes is pH 11.5

Vinyl sulphone, Sulphonamide, Monofluorotriazine groups

Hot brand dyes

The dyeing temperature for this type of dye is 800C or more.

Monochlorotraizine

High Exhaust or “HE dyes” (a sub-set of “Hot”)

Bis (monochlorotriazine) or Bis (mono nicotinotriazine)


Internship Report Classification by Parameters Classification Description Examples Alkali controllable reactive dyes

These dyes have optimal temperatures of fixation between 300C and 600C. They are characterized by relatively low exhaustion in neutral salt solution, before alkali is added. They have high reactivity and it is necessary to be careful when adding alkali to achieve level dyeing, preferably at a controlled dosage rate.

Dichlrotriazine, Difluorochloro pyrimidine, Dichloro quinoxaline and Vinyl sulphone reactive system

Salt controllable reactive dyes

Dyes in this group show optimal fixation in the range 80-1000C and comparatively exhibit high exhaustion in neutral pH, so it is important to add salt carefully to avoid uneven dyeing. Dyes with these properties typically have low reactivity systems, but they are sufficiently reactive for fixation at 800C or lower by batch wise application. Temperature is still important though and varies by reactive group.

Trichloropyrimidine, Monochlorotriazine or Monofluorotriazine reactive system

Temperature controllable reactive dyes

This group is represented by those dyes that react with cellulose at temperatures above 1000C in the absence of alkali although if desired they can be applied under the same conditions. Dyes in this group have self levelling characteristics so there is no need to use auxiliary products to facilitate level dyeing.

Bis (Mononicotinotriazine) reactive system

When selecting a dye it is important to know the reactive groups present in a particular brand. Typical brand names for certain reactive systems are therefore given in Table on next page.


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Some Important Points in Dyeing:

• The efficiency and therefore the cost effectiveness of dyeing can be greatly enhanced by knowing the type of dye being used, its compatibility with other dyes and the ideal conditions under which it should be applied (again). A reputable dye supplier should provide all this information to a dyer, although it is best practice to make systematic checks according to an agreed protocol.

• It is also necessary to know and continually monitor the quality of dye being received. This enables the dyer to make adjustments to the recipe to ensure the correct shade is achieved. Not doing this can result in the need to re-shade, which can be costly. Choosing less expensive dyes often means that the quality is poor or variable, which can ultimately result in the overall cost of dyeing increasing due to the need to use more dye, or to re-dye or re-shade.

• Fixation levels can be optimized and right first time dyeings can be achieved through an understanding of the dyes being used, the chemistry involved and having appropriate control over the factors influencing dye exhaustion and dye fixation levels. Choosing appropriate and compatible dyes for any particular shade is one of the most important factors.

• If the dyer is not satisfied with the quality of the dyes they receive they should discuss it with the dye supplier. In the longer term, it may be beneficial and cost effective to use a more reputable dye supplier that provides dyes of consistently good quality as this reduces the need to alter recipes or to re-shade.

• Dyestuff manufacturers should also be able to provide information that is of use to the dye manager regarding the dyes that they supply. Such information would include the:


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Recommended trichromate for each dye range; this is the standard, most compatible red, yellow and blue dye for the range.

Recommended application conditions for each dye range: application time-temperature profile; salt concentration; and pH (for covalent fixation).

Fastness data for each dye: light-fastness at 1:1 and 1/12 standard depth; wash-fastness; and rubbing fastness. This enables the dyer to select dyes with appropriate fastness characteristics for their purpose (linked to buyers’ specifications). This is the expected minimum data, though other fastness data would be of benefit to the dyer.

Percentage exhaustion and percentage fixation of each dye under standard dyeing conditions.

Material Safety Data Sheets (MSDS): these provide workers with details of the proper procedures for handling or working with particular substances.

• When buying dyes and selecting recipes many dyers and dye house managers focus on the cost of the dyes and select less expensive dyes. However, this may be a false economy because using cheaper dyes may increase the dyeing time or reduce the quality of the dyeing, leading to the need to re-shade and re-dye, and ultimately losing credibility with buyers. Full economic costing should therefore be used when calculating the cost of dyeing not just the cost of the dye. This means that cost calculations should include:

Man power - salaries including laboratory and factory floor

staff Energy - for heating water, operating machinery, pumping

water, lighting and cooling the factory Water - cost of purifying ground water Dyes Other chemical inputs, e.g. Dyeing auxiliaries Fabric Any penalties imposed by textile buyers for delayed delivery

of goods Cost of effluent treatment Costs associated with re-shading / re-dyeing Costs associated with testing/analysis Cost of depreciation


Internship Report VAT DYES Vat dyes constitute a very important class of dyes for dyeing cotton fabrics. Features of Vat Dyes

• Mainly applied on celluloses • Insoluble in water • Anionic in nature • Two or more reducible Keto (=C=O) groups are present • Vat dyes, although insoluble in water can be reduced in dyeing, to

water soluble leuco compounds, which successfully dye the fibre. The leuco form is then oxidised back on the fibre back into the original insoluble dye which is trapped inside fiber.

• Require great care during application • Have the highest standard to all-round fastness • Vat dyes have a very high fastness to washing. • Have high light fastness • Have good chlorine fastness. • Provide a wide range of shades from yellow to black. • Difficult to achieve bright shades. • Expensive • Used on high quality shirting, towelling, curtains and furnishings.

Types of Vat Dyes

• Strong Alkali Dyes • Weak Alkali Dyes

Strong Alkali Dyes

Vat dyes belonging to this class give maximum color value in the presence of high concentrations of NaOH (i.e 6g/l). Weak Alkali Dyes

Vat dyes belonging to this class give maximum color value in the presence of less amount of NaOH (i.e 2g/l).


Internship Report Controlling Parameters for Vat Dyes

• Time • Temperature • Ph (alkaline) • Reducing agent (sodium dithionite) • Electrolyte • Oxidizing agent (H2O2) • Soaping

Application of Vat Dyes

Application of vat dyes consists essentially of four stages.

VATTING

OXIDATION

IMPREGNATION

SOAPING

Vatting

To prepare the leuco form, the vat dye is pasted with warm water, often containing a suitable wetting agent, reduced by Sodium Dithionite solution, made alkaline with sodium hydroxide. The amount of sodium dithionite required for reduction is influenced by the number of carbonyl groups in each dye molecule. In practice this theoretical amount is well exceeded to allow for any oxidation which may arise through air dissolved in the dye liquor.


Internship Report The amount of sodium hydroxide required also depends upon the number of carbonyl groups. Vatting requires close control because a number of undesirable effects can occur. If there is insufficient alkali, the leuco may be subject to undesirable molecular rearrangements. Careful control o temperature is also important. If the temperature is too low reduction may be incomplete. And if too high, the reducing agent may react with dye in another way. Moreover, some conditions promote the loss of halogen atoms from those vat dyes which contain them. Thus for a given vat dye, there are well defined conditions of temperature, ph concentration of the reducing agent. Impregnation The leuco dye, once formed, is thus applied from a solution containing excess of alkali and excess of reducing agent. In many cases, sodium chloride is also present. The leuco form is anionic. Leuco dyes are, therefore, similar to direct dyes in that anions are absorbed by the cellulosic fibres. However the concentration of electrolyte in the dye bath is particularly high and consequently the adsorption of dye is often rapid. On the other hand migration is often slow. As with the application of direct dyes, electrolytes facilitate the approach of the leuco dye anions to the negatively charged cellulosics fibers, so that non-ionic forces of interaction becomes operative. Oxidation

Once the leuco form of the dye has been adsorbed, it is oxidised to the parent vat dye. In many instances, atmospheric oxygen is sufficient. However, some leuco forms are more difficult to oxidize and oxidizing agents such as potassium dichromate or hydrogen peroxide are required. Oxidizing agent may also be needed where the fibres are densely packed. Soaping

After oxidation of the leuco form, the fibers are treated with boiling soap or detergent solution. Soaping has a two fold function

• It removes vat dye particles adhering to the surface of the fibres • Modifies the shade of the dye

On soaping, larger, better defined crystals of dye are formed within the fibers, and indeed their lattice structure may be altered.


Internship Report Disperse Dyes

The disperse dyes are so named because these are almost insoluble in water and hence used as finely divided aqueous dispersion. Disperse dyes can be applied to Nylon, Cellulose Acetate, Acrylics and occasionally on other fibers. Disperse dyes are the only class generally accepted for dyeing of polyester and cellulose acetate. But the major consumption is for dyeing of polyester. Classification Of Disperse Dyes

The two most important types of disperse dyes are MONOAZO and ANTHRAQUINONE based dyes. Other structural type of disperse dyes include

DIAZO NITRODIPHENYL METHANE STRYL BENZODIFURANONE QUINOPHTHALONE

Developmental work on disperse dyes is going on, and new products and structures are frequently being introduced. Disperse dyes are non-ionic in nature which account for their low solubility in the water. However they do contain some polar groups which account for their solubility of the order of 0.2-2 %. These dyes are called as disperse because they are made into dispersion and then applied on the fibre. Characteristics Of Disperse Dyes

Non-ionic in nature Insoluble in water Possess small dye molecule

Fastness Properties Of Disperse Dyes

Fair to excellent light fastness Some colour change possible in hot pressing Stains wool badly


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Perspiration fastness is good Crocking fastness is good Fastness to sea water is good Excellent washing fastness

Nature of Attachment of Disperse Dyes

Mode of attachment of the dyes is “a Solution of Solid into Solid”. This theory explains that the disperse dye molecule is simply dissolved by the hydrophobic fibre. The dye distributes itself between the fibre and the dye bath in direct proportion to its solubility in these two phases. The resulting equilibrium absorption isotherm should be linear up to the limit of the dye solubility in either the dye bath or the fibre. Factors that effect “Rate of Dyeing”

The rate of dyeing primarily depends upon the rate of diffusion of the disperse dyes into the amorphous regions of the fibers. Factors affecting the rate of dyeing are;

Fiber morphology (nature of the amorphous regions, degree of available openings)

Molecular size of the disperse dye Degree of hydrophobicity of the fibre (degree of dye solubility in

fiber) Temperature in dyeing Use of dyeing assistants (dye carriers, swelling agent)

Methods of Creating Opening

For the fixation of disperse dyes, it is necessary to create opening in fibre structure. Opening can be created by following methods;

With the help of Carriers HT-Dyeing Thermo fixation process

Carriers

Dye carriers are small hydrophobic organic compounds. Carriers increase significantly the rate of dyeing of hydrophobic fibers and are used mainly for dyeing polyester and to some extent on triacetate. Normally the use of carrier is not feasible as it is;


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Expensive Toxic in nature Removing carrier by additional process Water repellent Bad smell

HT-Dyeing

High temperature dying is usually done for one hour and the temperature ranges from 125-130oC. Above 100oC, the swelling of fibre enhances and therefore more penetration of dye molecule inside the fiber results. Thermo fixation Process

In continuous dyeing millions of polyester-cotton are processed annually by thermo fixation process. The disperse dye is padded onto the fabric. The fabric is passed through IR-predrying section and then through intermediate drying section. The purpose is just to dry the fabric. The fixation of the dyestuff is done in curing chambers of the thermosoling machine for 90 sec at temperature of 180-220oC.


Internship Report Sulphur Dyes Sulphur dyes are compounds prepared by heating various nitrogenous organic materials with sulphur, Sodium sulphide, sodium polysulphide or other sulphurizing agents. These chemicals are described as countering thiazole, thiazone and thiantherene rings with polysulphide linkages. Characteristics of Sulphur Dyes

Anionic in nature Dissolved in alkaline solution Moderate to good fastness properties Good washing fastness Provide fair to good chlorine bleach fastness. Provide dull colours Very cheaper than other classes of dyes

Different types of auxiliaries are used in sulphur dyeing process. The main are as follows;

Reducing Agent----------Sodium Sulphide Oxidation agent----------Hydrogen peroxide Solubilizing agent-------NaOH

Application of Sulphur Dyes Sulphur dyes are applied to the cellulosic fabrics in the same way as vat dyes are applied.

Sulphur dyes are water insoluble substances. So these are brought into soluble form for dyeing. Sulphur dyes are solubilized using sodium sulphide. In solubilized form they become substantive to cellulosic fibers and hence can be applied by using padder. Application on fabric requires relatively strong dye bath. After application, the dyes are reoxidized in and on the fiber back to original insoluble dye. Since little is known about the constitution of sulphur dyes, they are usually classified according to the chemistry of their starting materials and in accordance with colour. On the basis of solubility we can classified these into three classes;


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Water insoluble sulphur dyes Ready to use liquid formulations-leuco sulphur dyes Water insoluble “bunte salts” solubilized sulphur dyes

Sulphur Black It is the most important member of the sulphur group. This is because of ease of preparation, cheap dyeing and fastness properties. Full black shades are obtained on cotton by air oxidation after dyeing from sodium sulphide bath. It is remarkably fast to light, acids, alkalis, scouring and milling. Disadvantages of Sulphur Dyes

Sensitive to chlorine bleaches Poor fastness to bleaching agents Very toxic in nature Bronzing: if dye does not penetrate inside the fiber perfectly and

remains on the surface of the fabric then surface of the fabric appears shiny.

Tendering: if the dyes fabric is not stored in neutral conditions,

then there are chances of the formation of sulphuric acid because the fibers absorb moisture from air. Hence strength of the fabric is weakened.


Internship Report DYEING FLOOR

Machines on Dyeing Floor

LINE # 1

Pad Thermosol

Manufacturer Monforts (Germany)

Working Width 180cm

Year of manufacture 2001

Padder

Company Kusters (Germany)

Pad Steam

Manufacturer Benninger (Germany)

Working Width 180cm


LINE # 2

Pad Thermosol

Manufacturer Monforts (Germany)

Working Width 180cm


Padder

Company Kusters (Germany)

Pad Steam

Manufacturer Brugman (Holland)

Working Width 180cm



Internship Report Pad Thermosol Machine There are two pad-thermosol machines in line # 1 and line # 2 installed at Kohinoor Dyeing Mills. If we stand in front of the dyeing lab then on our right hand side there is pad dry # 1 and on left hand side there is pad dry #2. Both the machines have similar parts.

1. Entry section a. Batcher unit b. Pull roll system c. J-Scray d. Cloth guiders e. Cooling drums f. PLEVA humidity sensor

2. Kusters padder 3. VTG 4. IR chambers 5. Drying and curing chambers 6. Outlet section

Inlet Section

Inlet consists of following parts. o Batcher unit o Pull roll system o J-Scray


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o Plaitor o Tensioner rollers o Cooling Drums o PLEVA humidity sensor o Cloth guiders

The fabric enters the machine from batcher/trolley or is continuously being fed from Pad-Thermosol machine through guide rollers. The fabric can either be stored for a short duration in the J-Scray incase of batcher/ trolley change. Fabric is pulled by the pull-roll system. Capacity of the scray depends on the quality of the fabric being processed. Light quality like 40 x 40 can be store 600 meters and heavy quality like 7 x 7 can be store about 250 meters. There are two cooling drums after the scray. Fabric from scray flows from these cooling rollers. Chilled water from chiller is fed through on side of the drums and slightly warm water is collected from the other end and sent back to the chiller. The function of these rollers is to reduce the temperature of the fabric, so that it cannot raise the temperature of trough. Incase of reactive dyes, if temperature of the trough is raised then there are chances that dye will react with OH- of water (Dye Hydrolysis). This exchange of heat may cause LCR problems. Padding Section Main parts included in this section are:

• Padder rollers (Kusters Swimming Roll technology) • Trough • Economizer rollers • Feeding nozzles • Level sensor • Chiller • Mixing and dosing station • Hydraulic system

The fabric after passing the cooling drums is guided through guide rollers into trough containing the dye liquor to impregnate the fabric.


Internship Report According to the lab dip recipe, the dye stuff made in the separate mixing station is fed to the trough. Mixing station consists of three recipe preparation tanks through which the dye liquor is pumped in the overhead dosing tanks. There are two dosing tanks. The liquor through the tanks is fed in the trough due to gravity. Line washing is some times done by hot water or with 2% hydro and caustic. Capacity of the trough is 60L. Trough is jacketed from outside. Fresh water from chiller enters from one side to maintain the constant padding temperature of 40oC. Slightly warm water is collected from other side of the trough jacket and is again fed to the chiller for cooling. There is a level sensor attached at one side of the trough and the sensing probe is dipped in the liquor. When the level of the trough is lowered down to a certain level it send signal to PLC and through automatic action the dye liquor is fed in the trough. The liquor level is decreased due to the pickup of the fabric, and hence to avoid the tailing, liquor is fed at intervals. There are small feeding nozzles throughout the width of the trough, from which the dye liquor is fed. The purpose of using a number of nozzles is to avoid the problem of concentration variation within the trough. Some times in case of dye liquors having impurities or un-dissolved dyes (especially incase of Vat dyestuff), pieces of fine meshing cloth (Organdi Cloth) at the tied mouth of each nozzle to filter the dye liquor. There is mechanism for the lowering and raising of the trough. The trough can be lowered for washing purposes. There is a drain pipe attached to the trough to drain the exhausted liquor. The fabric to be dyed is stitched with the leading cloth and the leading fabric is passed the trough. After that the trough is filled with dyestuff up to 55 to 60 liter. There are four economizer rollers (covered with soft rubber) in the trough to provide under liquor squeezing of the fabric. The fabric after passing through the trough comes to the nip of the padder rollers. The purpose of the padder rollers is to evenly squeeze out the excess liquor so that LCR problem by not occur. Kusters padder (installed at Kohinoor Dyeing Mills) is the best solution for the LCR problem. The


Internship Report center pressure at the padder is hydraulic while the pressure at the shafts of the padder rollers is pneumatic. There is a hydraulic system connected to the padder to provide the pressurized oil for the pressure in the padder roller. There is a heat exchanger in the hydraulic system. Chilled water from chiller exchanges heat with the warm oil in the hydraulic system. This is to cool down the temperature of the hydraulic oil so that its viscosity may not change and hence provide even pressure across padder width and work at maximum efficiency. A circulation pump then feeds it to the padder rollers.

There are three knobs at the named as L, C and R to adjust the pressure at left, center and right respectively. Central pressure is provided by the management and the operator adjusts the pressure of left and center


Internship Report accordingly so that no LCR problem is seen in the dyed fabric. This pressure adjustment is called as tuning. A graph is provided in the panel which shows that what pressure should be adjusted at left and right sides of padder with respect to central pressure. But this is not definite because the fabric may have varying absorbency in LCR. So tuning is done to avoid this problem. Mechanism of Kusters swimming rollers It is based on a mechanism where the roller floats on a hydraulic cushion. Oil pressure applied internally over the full width of the bowl counters the deflection of the outer shell. The oil pressure is directed towards the mangle nip and the oil occupies one half of the space inside the bowl. There is a danger that the deflecting internal mandrel will foul the internal surface of the swimming roller. A graph is therefore supplied with each machine, showing the permitted settings of air pressure to the bowl shafts and the internal oil pressure.

The outer boundaries of the polygon must not be breached; otherwise there is a danger of mechanical damage

The graph is specified to that particular machine and, although it is located on the control panel of that machine for all to see, over a period of


Internship Report time it tends to become contaminated with dirty oil and dyestuff, rendering it almost illegible. It is thus a wise precaution to keep another copy. The operation of the hydraulic chamber and the bearing pressure can deflect every S roller positively or negatively, or allow the flexible line of a conventional roller to be followed whilst applying even pressure. For example, if we have fixed the central pressure at 2 bar and then we adjust the left and right pressure by following the graph provided at panel. Then initial running of the fabric is done and fabric is checked for LCR variation at the exit of the machine. If there is no difference in LCR then it is ok. But if LCR problem is occurring then tuning of the left and right pressure must be done. The Kusters padder should be adjusted here in such away that pickup should be 60 to 80% (depending upon the shade depth and quality).

VTG Section It consists of vertically placed guide roller. Their purpose is to give aeration to fabric to some extent and to give reasonable penetration time of the dye into fabric. Also these rollers are Teflon coated to avoid stains on the fabric due to rusting and stickiness of chemicals. If these rollers are not placed in the flow of fabric and directly sent to IR chambers, the dye will remain at the surface of the fibers and will not be present at the center of the fibers. So migration problems and poor wash fastness will be resulted.


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Internship Report I.R Chambers There are two IR chambers in each pad thermosol machine at Kohinoor Dyeing Mills. These chambers help in the pre-drying of the padded fabric so that dye migration chances become negligible in subsequent processes. About 60-70 % of the moisture is removed I.R have more penetration power than an ordinary dryer and can evaporate water molecules from the inner core of fiber without coming out on surface. Thus in this way evaporation of water is done from inner side of fabric without coming out on the surface and thus die will remain inside the fiber. Drying is carried out at temperatures of 1000oC.

Heating System for IR Chambers I.R chambers at Kohinoor Dyeing Mills are gas fired. Air is sucked through atmosphere with the help of blower and is filtered. There is damper in the flow of air, which will control the vibration of this equipment. After damper, there is a butterfly valve, which regulates flow of air, and then ahead of it solenoid valve is present which indicates the air pressure by giving signal on the panel. Gas is carried through supply mains. The gas is filtered first and then ahead of filter there is a gauge which is showing pressure of gas in mbar. At this point pressure is 10 mbar. Then there is a pressure reducing valve,


Internship Report which reduces pressure which indicates on next gauge. At this point the pressure to 80 mbar then again pressure reducing valve reduces pressure from 80 mbar to 60 mbar. Then after this gauge there is a pair of solenoid valve which regulates the flow of fuel gas. There is an LPG vaporizer for vaporizing the LPG, incase LPG is being used as fuel gas.

Air and gas are mixed in MAXON mixing tube in a proper ratio. Air and gas are mixed in a ratio of 4/1. For proper mixing of the air and gas swill plates are present in mixing tube which mixed the gas and air properly. Then this gas air mixture is carried to the I.R chamber through main duct, where it is further divided into six parts i.e. three on each side of an I.R chamber. The gas-air mixture enters into the core of the heater from one side. An electric spark plug is on the other side of the heater for ignition. There are two thick ceramic plates in the heater and between the plates there is a narrow slit. The flame ejects through the narrow slit and also heats the ceramic plates. Ceramic plates radiate IR energy which is then used up in the evaporation of the water at a very high speed. The pressure of gas air mixture at burning point is 12 mbar. When this pressure reduces less then 10 mbar then the burner will automatically trip. The temperature range of I.R. chamber is 750ºC – 1200ºC. The burnt gases and water vapors are exhausted through rectangular exhaust holes in the roof of the IR-chamber. There is an exhaust pipe connected to the roof of IR chamber which takes away these gases and vapors. There is one exhaust fan to exhaust the gases from both IR-dryers. Drying and Curing Chambers There are three drying chambers and two curing chambers in both Pad-Thermosol machines (at line # 1 and line # 2) in Kohinoor Dyeing Mills. These chambers are having the same structure but vary in Cloth content and temperatures inside the chambers. Drying is performed at temperatures ranging from 100-140 oC, while curing is done at temperatures ranging from 180-230 oC.


Internship Report Each chamber consists of a series of rollers stacked vertically in a chamber. Fabric enters the chamber at one end and passes from the upper roller to the lower roller, threading in this way trough the chamber to the exit at other end. Hot air is circulated past the open sheets of fabric formed by the alternating pair of upper and lower rollers. This allows the fabric to be dried form both sides ate the same time. The tensions on the fabric are similar to dying cans, the major difference is that fabric-to-metal contact is minimal and water can evaporate from both sides of the fabric simultaneously. At thermosol machine, each chamber can be heated to different temperatures, so this arrangement would allow for lower temperature drying zones followed by higher temperature curing zones. For producing higher temperature inside the chambers there is a radiator in which Therm-Oil is flowing. Besides there is a Circulation Fan (Blower) which sucks air from the atmosphere by centrifugal action and throws it at the radiator. The air becomes hot by exchanging heat with the radiator pipes. This hot air is then circulated in whole chamber through nozzles. Therm-Oil is heated in the Therm-Oil boiler. The hot oil is then fed to the thermosol chamber via supply pipes. The used oil is then sent back to the boiler for further heating. To maintain a constant temperature inside the chamber, we have to control the air circulation rate (through circulation fan), air exhaust rate (through exhaust fan) and the temperature of the oil (through oil circulation pumps). In each chamber there is a dancer for compensating the tension of the fabric. In 2nd and 3rd chamber there is a special roller before the compensator, which is used to shutdown machine if there is problem in the machine i.e. whether the compensator is not working properly or tension is becoming out of order. There is an indicator attached to this roller and it will give signal to the panel when the roller changes its position and machine will shutdown. In 1st chamber, rollers are Teflon coated to avoid sticking of chemicals to the rollers which will affect the fabric.


Internship Report Also PLEVA humidity sensor is present in each chamber which shows %age humidity within the chamber on the panel. There is a gauge on each dryer which is showing the balance of air inside the chamber. If it is at 0 (neutral), it means air circulation in upper and lower side is same. If positive + , then it means air in upper side is more then lower side and if it is negative- it means air in lower side is more then air in upper portion. However, here the neutral condition is desirable. There is a knob in the machine which is used to adjust the air to be exhausted from the chamber. A Lint Sieve is present on the bottom of chamber above radiator, which filters the air from fluff. This sieve is removed from the chamber at intervals and is cleaned.

1. Feeding section 2. Kusters Padder 3. Wetting unit 4. Thermex hot-flue 5. Measuring and control unit (chamber atmosphere) 6. Steam injection unit 7. Outlet section Cooling Drums There are 4 cooling drums at the exit if the fabric from the chambers. These are water circulated from inside. Cool water flows in from one side and slightly hot water exits from the other side. The purpose is to cool down the fabric to normal temperature before plaiting it into trolley or winding it in batch form. Outlet Section


Internship Report Fabric comes out of the machine and is wound to form batcher. The batcher is then sent to the next machine for further processing. Outlet section consists of following main parts:

• Pull roll system and J-Scray • Cooling drums • Static charge eliminator • Cloth guiders • Winder

Specifications of Pad-Thermosol machine

Model: Thermex C - C – C Fabric speed 6 – 120 m/min VTG 12m of fabric Gas air mixer pressure 60-80 mbar Drying chambers 3 Curing chambers 2 Rollers 40 + 40 + 40 = 120 Nominal width 200 cm Working width 180 cm Fabric (48+ 48 + 48) = 144m Width (among transport rollers of dryer) 960mm Diameter of transport rollers 140 mm


Internship Report Pad-Steam Machine There are two PAD-STEAM machines at Kohinoor Dyeing Mills.

• Benninger Pad-Steam (in dyeing line # 1) • Brugman Pad-Steam (in dyeing line # 2)

We will discuss now each machine separately. Benninger Pad-Steam Main sections of this machine are

• Entry Section

• Padding Section

• Booster

• Steamer

• Washing Boxes

• Drying Cylinders

• Exit Section Inlet Section

Inlet consists of following parts. o Batcher unit o Pull roll system o J-Scray o Plaitor o Tensioner rollers o Cloth guiders

The fabric enters the machine from batcher/trolley or is continuously being fed from Pad-Thermosol machine through guide rollers. The fabric can either be stored for a short duration in the J-Scray incase of batcher/ trolley change.


Internship Report Fabric is pulled by the pull-roll system. Capacity of the scray depends on the quality of the fabric being processed. Light quality like 40 x 40 can be store 600 meters and heavy quality like 7 x 7 can be store about 250 meters.

Padding Section Main parts included in this section are:

• Padder rollers (Benninger’s Bicoflex technology) • Trough • Economizer rollers • Feeding nozzles • Level sensor • Mixing and dosing station

Benninger Pad-Steam at Kohinoor Dyeing Mills is mainly being used for the developing, oxidation and washing of Vat dyestuffs or fixation of the reactive dyestuffs (PDPS route).

Fabric is led to the trough with the help of guide rollers. Trough has a capacity of about 40L. There are 3 economizer rollers for under liquor squeezing. The bottom roller in the trough is made up of Stainless steel while the other two are soft rubber coated. According to the lab dip recipe, the chemical solution made in the separate mixing station is fed to the trough.


Internship Report Mixing station consists of three recipe preparation tanks through which the dye liquor is pumped in the overhead dosing tanks. The recipe is prepared and fed at cold. For this purpose ice blocks are added to the mixing tanks. There are two dosing tanks. The liquor through the tanks is fed in the trough due to gravity. Line washing is some times done by hot water or with 2% hydro and caustic. Capacity of the trough is 40L. Trough is jacketed from outside. Fresh water from chiller enters from one side to maintain the constant padding temperature of 40oC. Slightly warm water is collected from other side of the trough jacket and is again fed to the chiller for cooling. There is a level sensor attached at one side of the trough and the sensing probe is dipped in the liquor. When the level of the trough is lowered down to a certain level it send signal to PLC and through automatic action the dye liquor is fed in the trough. The liquor level is decreased due to the pickup of the fabric, and hence to avoid the tailing, liquor is fed at intervals. There is a rod connected to the feed pipe from the dosing tanks. There are small holes in this rod throughout the length of the padder trough. This rod is connected to the trough and chemicals are fed through it. There is mechanism for the lowering, raising and tilting of the trough. The trough can be lowered for washing purposes or can be drained by moving it in a fixed path. There is also a drain pipe attached to the trough to drain the exhausted liquor. The fabric after passing through the trough comes to the nip of the padder rollers. The purpose of the padder rollers is to evenly squeeze out the excess liquor so that LCR problem by not occur. The BICOFLEX roll consists of a fixed load bearing axle with bearings at each end. Pressure pads are mounted across the full width of the load bearing axle and around its circumference.


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Each pressure pad is connected to a compressed air supply to provide individual pressure control against the articulated sleeve. Supported on rollers on top of the air-cushioned rubber pads is the flexible outer sleeve which carries the removable shrunk-fit rubber working sleeve. BICOFLEX rolls can also be retrofitted into existing padders. The BICOFLEX roll ensures a uniform application, even with changing fabric width. It is a convincing, technologically unique solution individual internal pressure zone adjustment over the whole fabric width as well as retracting cushions for avoiding selvedge pressing.

Side and end views of the BICOFLEX rollers

Benninger’s Bicoflex rollers help in minimizing variation in LCR and lengthwise shade variation. There is pneumatic pressure throughout the width of the padder. Bicoflex roller helps in using various nip profiles.


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Nip pressure profiles with a BICOFLEX roller system

Booster There is booster installed overhead after the Bicoflex padder. Chemicals can also be applied here onto the fabrics. The construction of the booster padding rollers offers uniform nip, such that it ensures equal and uniform liquor application. Liquor pick up can be adjusted from 70-130%. There is an economizer trough in it which contains the liquor. This trough can be raised or lowered when required. The liquor turnover in the trough is 14l/m. there is a swiveling roller in the trough. Because of the quick liquor turnover, possible errors in the initial filling have almost no effect and deviations over length are avoided. The displacement body can be pneumatically lifted for easy cleaning of the BOOSTER. This is used incase of vat dyeing or Sulphur dyeing for the application of reducing agent or alkali application incase of reactive dyestuff. But during our course of internship at Kohinoor Dyeing Mills, booster was not in operation.


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Steamer The fabric leaving the padding section r booster section enters into the steamer section. This is a Tight-strand roller steamer. The distance from the booster or the Bicoflex padder is very short to ensure that no air oxidation takes place.

1. Horizontal or vertical fabric entry with heated lips and exhaust fan

for excess steam 2. Section with 25 m fabric content


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3. Large roller diameter (193 mm) for creaseless fabric run 4. Lifetime lubricated bearings 5. Top rollers individually driven by AC-motors 6. Load cell to measure fabric tension for drive control 7. Roof heating 8. Water seal with small liquor content and uniform liquor

distribution 9. Temperature or volume controlled fresh 10. water flow to the water seal 11. Steam conditioning unit 12. Probe to measure the steam condition (below steamer bottom level) 13. Automatic cleaning system (option)

The fabric after passing through different guide rollers then comes to the main steaming section. There are three dancer rollers to compensate for the tension in the fabric, one at entry to steamer, one in the middle of the steamer and one at the exit of the steamer. At the exit side there is a water lock which serves as a seal for the steam to exit. This water lock is temperature controlled and also serves to cool down the dyes when necessary. There is an exhaust pipe for condensate in bottom of steamer entry side. In the Steamer, temperature required for the fixation of dyes is given to the fabric. This temperature is achieved by fully saturated steam. This saturated steam is supplied by steam saturator. Prior to entry into the steamer, the steam is saturated in a steam conditioning device. There is a controlled device for controlling the steam entering into the steamer. This helps to avoid loss of energy. Constant saturated steam conditions are the essential prerequisite for perfect dyeings and their reproducibility. Benninger Reacta has an arrangement to control for the humidity in incoming steam through a steam conditioning station.


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This saturator mixes steam and water under pressure. The purpose of using saturated steam is that the chemicals used for developing should not dry on the surface of fabric preventing fabric from stains. Its temperature is kept at 102ºC. The main purpose of steamer is to provide conditions for the fixation of the dyes stuff and chemicals on the fabric and give a proper time for fixation. The steam enters the REACTA dyeing steamer in perfectly saturated condition. The steamer design and the positioning of the steam condition monitoring ensure absolute absence of air in the steamer. Even minimal deviations in steam feed are automatically corrected. Geometry and drive system of the REACTA ensures crease free cloth run. The rollers are with large diameters of 193 mm, and are individually driven by maintenance free AC-motors. Very precise drive control is ensured via load-cell equipped measuring rollers and frequency converters. Tension differences caused by shrinking or stretching of the cloth in the steaming process are equalized immediately. There are steam heated lips (indirectly heated) at the entry of the fabric to steamer. This serves as a seal for the steam and steam cannot escape from this point. The ceiling of the steamer filled with glass wool is also indirectly heated with steam to avoid dropping. The steamer roof is heated; roof and front and back side are well insulated. The water lock at the steamer exit is a critical part of equipment for a successful process. The temperature is controlled via the water feed and low water volume ensures constant process parameters.


Internship Report The REACTA Steamer has good access through windows and can be cleaned easily.

The Benninger’s steamer at Kohinoor Dyeing Mills is mainly used to provide suitable conditions for the continuous fixation of vat, or reactive dyes on cotton and polyester/cotton blends. The operating principle is that the uniformly distributed dyes located mainly at the fiber surface diffuse quickly into the interior of the cotton fibers during treatment for 20 to 120 seconds in saturated steam. Reactive dyes of the low-reactivity classes require treatment for 60 to 90 seconds at 102°C for optimum fixation. Vat dyes require treatment in dry saturated steam at 102 to 105°C. The steam must be completely free from air when fixing the leuco forms of vat dyes.


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Washing Boxes After steamer, the fabric is guided to the washing section. The washing section of the Pad-Steam in the line # 2 at Kohinoor Dyeing consists of 9 Extracta washers. The liquor capacity in the washer is 1100L.

The EXTRACTA washer is constructed in such a way that the washing process is divided into stages that can be repeated with accuracy. This makes the whole washing process easier to follow it also makes it amenable to calculation of fresh water throughput. In each of the separate washing chambers the dirt or chemical liquor present in the cloth is exchanged 50 to 80% for wash liquor, which is loaded commensurately with dirt and chemicals. Entrainment of the contaminated liquor with this cloth is prevented by the EXTRACTA roller.


Internship Report In the next chamber the liquor exchange is repeated but with much lower dirt concentration in the wash liquor. The EXTRACTA washer has the advantage that fresh water throughput can be easily calculated. Minimal fresh water consumption leads to saving in water, effluent and energy costs. Capital investment and operating costs determine the economy of washing machines. The water consumption for a defined washing effect is depending on the type and number of washing compartments. A crease-free fabric run in EXTRACTA washing compartment is guaranteed through • Large guide roll diameters and adapted roll spacing that prevent the fabric from skewing and guarantee crease-free treatment from entry to exit of the range • Computer controlled tension force from

100–500 N with press rolls or, 200–600 N without press rolls

• Screw expanders with separate drive • Free running outer bearings with minimal friction on

bath rolls (Self-aligning ball-bearings, life-time lubricated, with carbon sliding ring seals)

upper rolls (Self-aligning ball-bearings; life-time lubricated, with

PTFE labyrinth seals)

press rolls (Self-aligning roller-bearings; life-time lubricated, with PTFE labyrinth seals)

EXTRACTA washer is equipped with drive control via swiveling compensators and load cells. Intermediate squeezers (pulling/squeezing device) are controlled via swiveling compensator and frequency converter in the next compartment. The upper roll single drive is controlled with a separate frequency converter. For the washers that have a pulling/ squeezing device, the upper roller drive is controlled through a measuring roll with a load cell.


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Load cell

For the washers without a pulling/ squeezing device, the upper roller drive is controlled through a swiveling compensator of the following compartment.

Angle detector of swiveling compensator for drive control

There is a counter flow system in all washers. First 4 washers have a separate water supply and are connected to first heat exchanger placed at the drive side of the machine near dosing station. Next 4 washers are connected to a second heat exchanger placed beside. All the washers are equipped with overflow valves, counter flow valves and drain valves. These are all automatically controlled through pneumatic system. Rollers in EXTRACA are extremely rigid and strong and due to the large diameter of the roller, the creasing of the fabric is minimized. Each roller is equipped with a special seal and bearing construction so that no leakage takes place.


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There are stainless steel plates having alternating gates in the bottom of each washer section which provide Counter current partitions for the water flow. Due to the counter current flow, turbulence is enhanced so efficient washing takes place. The fabric is squeezed at the exit of each washer with a squeezing unit. The top roller in squeezing unit is rubber covered while the bottom roller is made up of stainless steel roller. At the exit of the 9th washer there is a high extraction squeezing unit to extract maximum of water. So that minimum energy is consumed in drying cans. Each washer is equipped with temperature sensor, level sensor, steam pressure control, pneumatically operated steam valve. To drive top rollers in each washing unit, there are three AC-motors. There is single cloth threading system in each washer. Each washing compartment has strip rollers installed with top rollers. Each washing compartment is equipped with an intermediate squeezing unit. The module of EXTRACTA in Kohinoor Dyeing Mills is of plain EXTRACA washer of the type E7. The cloth content of each washer is 20m. There are two glass doors in a washer which provide good visibility and accessibility to the fabric. Due to easy accessibility, the machine can be cleaned easily. These glass doors have a special seal so that no leakage takes place.


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First two washers are used for washing of salt or chemicals which are being applied in trough of pad-steam padder. In 3rd and 4th washer oxidation is done if required. If oxidation is not required then soaping is done in 3rd and 4th washer. Further rinsing is carried out in next washers. In 9th washer acetic acid is added to control the pH of the fabric.

Drying Drums


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• At the last of Benninger Pad-Steam machine at Kohinoor Dyeing Mills, there are three groups of vertically stacked drying cylinders (made by WUMAG texroll) for the purpose of drying out the fabric

• Each group has 12 hot cylinders but last one has 10 hot and 2 cool cylinders.

• First two rollers in the first stack of drying rollers are Teflon coated. Remaining 34 rollers are made up of stainless steel. Steam is passed inside the cylinder through inlet pipe and the surface of the cylinder becomes hot. The condensate is also collected from the point of entrance of steam. There is a trap valves installed on each condensate return pipe to separate the steam from the condensate. Last two drums of the last stack of cans are water circulated from inside to reduce the fabric temperature to normal. The water is fed from one side and is drawn out from other side.

• There is a dancer installed after each stack of drying cans to compensate for the tension in the fabric.

• There is a steam exhaust hood at the top of the stacks of drying drums to exhaust the steam formed during the drying operation of the fabric. The hood has filling of glass wool and is also steam heated from inside to avoid from any chances of condensation of the steam back on the fabric. There are three exhaust fans installed above the hood to exhaust the steam.

• In each stack of drying rollers at Benninger’s pad-steam, there are 6 motor driven cylinders and remaining 6 are driven by pulling force.

Outlet Section Fabric comes out of the machine and is wound to form batcher. The batcher is then sent to the next machine for further processing. Outlet section consists of following main parts:

• Pull roll • J-Scray • Static charge eliminator • Cloth guiders • Winder

Block diagram of pad steam


Internship Report Brugman Pad-Steam Main sections of this machine are

• Entry Section • Cooling drums

• Padding Section

• Steamer

• Washing Boxes

• Drying Cylinders

• Exit Section

Inlet Section Inlet consists of following parts;

o Batcher unit o Pull roll system o J-Scray o Plaitor o Tensioner rollers o Cloth guiders

The fabric enters the machine from batcher/trolley or is continuously being fed from Pad-Thermosol machine through guide rollers. The fabric can either be stored for a short duration in the J-Scray incase of batcher/ trolley change. Fabric is pulled by the pull-roll system. Capacity of the scray depends on the quality of the fabric being processed. Light quality like 40 x 40 can be store 600 meters and heavy quality like 7 x 7 can be store about 250 meters.


Internship Report There are two cooling drums after the scray. Fabric from scray flows from these cooling rollers. At the Brugman Pad-Steam in Kohinoor Dyeing Mills, these rollers are disconnected from water supply so we will not discus them here. Padding Section Main parts included in this section are;

• Padder rollers (Kusters Swimming Roll technology) • Trough • Economizer rollers • Feeding nozzles • Level sensor • Chiller • Mixing and dosing station • Hydraulic system

The fabric after passing the cooling drums is guided through guide rollers into trough containing the dye liquor to impregnate the fabric. According to the lab dip recipe, the dye stuff made in the separate mixing station is fed to the trough. Mixing station consists of three recipe preparation tanks through which the chemical liquor is pumped in the overhead dosing tanks. There are two dosing tanks. The liquor through the tanks is fed in the trough due to gravity. Line washing is some times done by hot water or with 2% hydro and caustic. Capacity of the trough is 60L. Trough is jacketed from outside. Fresh water from chiller enters from one side to maintain the constant padding temperature of 40oC. Slightly warm water is collected from other side of the trough jacket and is again fed to the chiller for cooling. There is a level sensor attached at one side of the trough and the sensing probe is dipped in the liquor. When the level of the trough is lowered down to a certain level it send signal to PLC and through automatic action the dye liquor is fed in the trough. The liquor level is decreased due to the pickup of the fabric, and hence to avoid the tailing, liquor is fed at intervals.


Internship Report There is a rod connected to the feed pipe from the dosing tanks. There are small holes in this rod throughout the length of the padder trough. This rod is connected to the trough and chemicals are fed through it. There is mechanism for the lowering and raising of the trough. The trough can be lowered for washing purposes. There is a drain pipe attached to the trough to drain the exhausted liquor. In Sulphur dyeing (on Pad-Steam-Line # 2), the fabric to be dyed is stitched with the leading cloth and the leading fabric is passed the trough. After that the trough is filled with dyestuff and chemical up to 55 to 60 liter. There are four economizer rollers (covered with soft rubber) in the trough to provide under liquor squeezing of the fabric. The fabric after passing through the trough comes to the nip of the padder rollers. The purpose of the padder rollers is to evenly squeeze out the excess liquor so that LCR problem by not occur. Kusters padder (installed at Kohinoor Dyeing Mills) is the best solution for the LCR problem. The center pressure at the padder is hydraulic while the pressure at the shafts of the padder rollers is pneumatic. There is a hydraulic system connected to the padder to provide the pressurized oil for the pressure in the padder roller. There is a heat exchanger in the hydraulic system. Chilled water from chiller exchanges heat with the warm oil in the hydraulic system. This is to cool down the temperature of the hydraulic oil so that its viscosity may not change and hence provide even pressure across padder width and work at maximum efficiency. A circulation pump then feeds it to the padder rollers.


Internship Report

There are three knobs at the panel named as L, C and R to adjust the pressure at left, center and right respectively. Central pressure is provided by the management and the operator adjusts the pressure of left and center accordingly so that no LCR problem is seen in the dyed fabric. This pressure adjustment is called as tuning. A graph is provided in the panel which shows that what pressure should be adjusted at left and right sides of padder with respect to central pressure. But this is not definite because the fabric may have varying absorbency in LCR. So tuning is done to avoid this problem. Mechanism of Kusters swimming rollers It is based on a mechanism where the roller floats on a hydraulic cushion. Oil pressure applied internally over the full width of the bowl counters the deflection of the outer shell. The oil pressure is directed towards the mangle nip and the oil occupies one half of the space inside the bowl. There is a danger that the deflecting internal mandrel will foul the internal surface of the swimming roller. A graph is therefore supplied with each machine, showing the permitted settings of air pressure to the bowl shafts and the internal oil pressure.


Internship Report

The outer boundaries of the polygon must not be breached; otherwise there is a danger of mechanical damage

The graph is specified to that particular machine and, although it is located on the control panel of that machine for all to see, over a period of time it tends to become contaminated with dirty oil and dyestuff, rendering it almost illegible. It is thus a wise precaution to keep another copy. The operation of the hydraulic chamber and the bearing pressure can deflect every S roller positively or negatively, or allow the flexible line of a conventional roller to be followed whilst applying even pressure. For example, if we have fixed the central pressure at 2 bar and then we adjust the left and right pressure by following the graph provided at panel. Then initial running of the fabric is done and fabric is checked for LCR variation at the exit of the machine. If there is no difference in LCR then it is ok. But if LCR problem is occurring then tuning of the left and right pressure must be done. The Kusters padder should be adjusted here in such away that pickup should be 60 to 80% (depending upon the shade depth and quality).


Internship Report

Steamer The fabric leaving the padding section enters into the steamer section. This is a Tight-strand roller steamer. There are steam heated lips (indirectly heated) at the entry of the fabric to steamer. This serves as a seal for the steam and steam cannot escape from this point. The ceiling of the steamer filled with glass wool is also indirectly heated with steam to avoid dropping. Brugman Dyeing Steamer is completely insulated by 80mm of insulation material, clad by stainless steel sheets. The fabric after passing through different guide rollers then comes to the main steaming section. There are three dancer rollers to compensate for the tension in the fabric, one at entry to steamer, one in the middle of the steamer and one at the exit of the steamer. At the exit side there is a water lock which serves as a seal for the steam to exit. This water lock is temperature controlled and also serves to cool down the dyes when necessary. There is an exhaust pipe for condensate in bottom of steamer entry side. In the Steamer, temperature required for the fixation of dyes is given to the fabric. This temperature is achieved by fully saturated steam. This saturated steam is supplied by steam saturator. Prior to entry into the


Internship Report steamer, the steam is saturated in a steam conditioning device. There is a controlled device for controlling the steam entering into the steamer. This helps to avoid loss of energy.

Steam conditioning unit

This saturator mixes steam and water under pressure. The purpose of using saturated steam is that the chemicals used for developing should not dry on the surface of fabric preventing fabric from stains. Its temperature is kept at 102ºC. The main purpose of steamer is to provide conditions for the fixation of the dyes stuff and chemicals on the fabric and give a proper time for fixation.

Brugman dyeing steamer

This is mainly used to provide suitable conditions for the continuous fixation of vat, Sulphur or reactive dyes on cotton and polyester/cotton blends.


Internship Report The operating principle is that the uniformly distributed dyes located mainly at the fiber surface diffuse quickly into the interior of the cotton fibers during treatment for 20 to 120 seconds in saturated steam. Reactive dyes of the low-reactivity classes require treatment for 60 to 90 seconds at 102°C for optimum fixation. Vat or Sulphur dyes require treatment in dry saturated steam at 102 to 105°C. The steam must be completely free from air when fixing the leuco forms of vat or Sulphur dyes. Washing Boxes After steamer, the fabric is guided to the washing section. The washing section of the Pad-Steam in the line # 2 at Kohinoor Dyeing consists of 9 Brubo-Matic washers. The liquor capacity in the washer is 1100L. First to four washers are used for washing of salt or chemicals which are being applied in trough of pad steamer. In 5th, 6th washer, oxidation is done if required. If oxidation is not required then soaping is done in 5th, 6th washers. Otherwise soaping is done in 8th washer. In 9th washer acetic acid is added to control the pH of the fabric. There is a counter flow system in all washers. First 4 washers have a separate water supply and are connected to first heat exchanger placed at the drive side of the machine near dosing station. Next 4 washers are connected to a second heat exchanger placed beside. All the washers are equipped with overflow valves, counter flow valves and drain valves. These are all automatically controlled through pneumatic system. Each washer has 25m cloth content. The rollers in the washing unit have a diameter of 200mm. these rollers are ‘foam’ filled from inside (patented rollers by Brugman) and thus are extremely rigid and strong and due to the large diameter of the roller, the creasing of the fabric is minimized. Each roller is equipped with a special seal and bearing construction so that no leakage takes place. The seal is constructed of a flexible mounted seal ring (high polymer composite) and spring loaded SS counter ring. This special seal offers extremely low friction during roller rotation.


Internship Report There are stainless steel plates having alternating gates in the bottom of each washer section which provide Counter current partitions for the water flow. Due to the counter current flow, turbulence is enhanced so efficient washing takes place. The fabric is squeezed at the exit of each washer with a squeezing unit of 30kN. The diameter of top rubber covered roller in the squeezing unit is 265mm with a Journal diameter of 60mm. while the diameter f the bottom stainless steel roller in this squeezing unit is 250mm with a Journal diameter of 60mm. At the exit of the 9th washer there is a ‘Unipad’ high extraction squeeze unit of 50N/mm. The diameter of each of rubber covered top roller and stainless steel bottom roller in this squeezing unit has a diameter of 300mm with a journal diameter of 90mm. Each washer is equipped with temperature sensor, level sensor, steam pressure control, pneumatically operated steam valve There is single cloth threading system in each washer. There are two glass doors in a washer which provide good visibility and accessibility to the fabric. Due to easy accessibility, the machine can be cleaned easily. These glass doors have a special seal so that no leakage takes place. Drying Drums

• At the last of Brugman Pad-Steam machine at Kohinoor Dyeing Mills, there are three groups of vertically stacked drying cylinders for the purpose of drying out the fabric. The frame of each stack consists of I-beams with interconnections.

• The diameter of each cylinder is 800mm. • There are inspection holes and vacuum valves on the sides of the

cylinders • Each group has 12 hot cylinders but last one has 10 hot and 2 cool

cylinders. • These cylinders are steam circulated from inside. The operation

side of a stack has a vertical steam distribution pipe with a T-piece at the upper end. This piece is connected to the steam supply and a safety valve. The distribution pipe has a steam trap at the bottom end. There is a stainless steel flexible steam hose connected to each individual cylinder. This steam hose has a long life. There is a ‘Johnson’ rotary joint through which steam is fed inside the cylinder and the condensate returns. ‘Johnson’ rotary joint is a specially designed joint through which no leakage of steam or


Internship Report

condensate takes place. The condensate is returned back through condensate-return pipes.

• First 4 rollers in the first stack of drying rollers are Teflon coated. But fabric is not being threaded from first two rollers as the surface of these rollers is contaminated with fluff and dyes. Threading is started from lower two Teflon coated rollers. Remaining 32 rollers are made up of stainless steel. Steam is passed inside the cylinder through inlet pipe and the surface of the cylinder becomes hot. The condensate is also collected from the point of entrance of steam. There is a trap valves installed on each condensate return pipe to separate the steam from the condensate.

• There is a dancer installed after each stack of drying cans to compensate for the tension in the fabric.

• There is a steam exhaust hood at the top of the stacks of drying drums to exhaust the steam formed during the drying operation of the fabric. The hood has filling of glass wool and is also steam heated from inside to avoid from any chances of condensation of the steam back on the fabric. There are three exhaust fans installed above the hood to exhaust the steam.

• Each stack of drying rollers at Brugman’s pad-steam is driven by one AC-motor at the drive-side of the machine. Drive mechanism is belt-pulley system.

• Last two drums of the last stack of cans are water circulated from inside to reduce the fabric temperature to normal. The water is fed into the cylinder through ‘Johnson’ rotary joint and slightly hot water is also retrieved from the same point.

• How much drying is required, depends upon

Initial moisture Fabric weight Machine speed Residual moisture

• Actual drying capacity depends upon Machine speed Number of active drying cylinders; it can be

controlled by shutting-off pairs of drying cylinders Steam supply; can be controlled by measurement of

fabric temperature and moisture content or the temperature of the condensate.

Outlet Section


Internship Report Fabric comes out of the machine and is wound to form batcher. The batcher is then sent to the next machine for further processing. Outlet section consists of following main parts:

• Pull roll • J-Scray • Static charge eliminator • Cloth guiders • Winder

Block diagram of Brugman’s pad steam


Internship Report APPLICATION PROCESSES Various methods depending upon type of fabric, type of dyes and their interaction and properties can be applied. In Kohinoor Dyeing Mills following application processes are being used.

PDPS PDC PS

DYEING OF 100 % COTTON FABRICS

At Kohinoor Dyeing Mills; Reactive, Vat or Sulphur dyestuff is applied on 100 % cotton fabrics depending upon customer requirements. Dyeing With Reactive Dyes Pad-Dry-Chemical Pad-Steam method For dyeing of 100 % cotton fabrics with reactive dyes first the dyes and alginate solution are padded onto the fabric at the thermosol padder. The fabric is then led to the IR pre-dryer chamber at a temperature ranging from 700-1000 oC. The fabric is then led to the thermosol chambers at the temperature ranging from 110-150 oC. After that the fabric is guided to the PAD-STEAM, where it is initially padded with the dye fixing agents and auxiliaries (NaCl, Na2CO3, NaOH, Detergent and wetting agent) and then the fabric is led to the steamer where fabric is steamed for 60-90 sec. After that the fabric is washed at the washer first with normal then hot water at 80-95 oC. At last the fabric is dried at the drying cans and then wound on the batcher or stored in pile form.

PADDING WITH DYE SOLUTION

PRE-DRYING AT IR

CHAMBERS

DRYING AT THERMOSOL

RINSING, SOAPING,

NEUTRALIZINGSTEAMING

PADDING WITH

FIXATION CHEMICALS

FINAL DRYING AT

DRYING CANS


Internship Report Pad-Dry-Cure method 100 % cotton fabrics can also be dyed with reactive dyes by Pad-Dry-Cure method. For this process, the dyes along with all auxiliary chemicals (NaCl, Na2CO3, NaOH, alginate and wetting agent) are padded onto the fabric at the thermosol padder. The fabric is then led to the IR pre-dryer chamber at a temperature ranging from 700-1000 oC. The fabric is then led to the series of thermosol chambers for drying and fixation of the dyestuff. The drying temperature at the first thermosol chamber can be 120 to 135 oC and that of the last can be 165-170 oC depending upon the fabric quality and type of the dye and shade depth required. After that the fabric is guided to the PAD-STEAM, where the fabric is not steamed but just washed at the washers first with normal then hot water at 80-95 oC. At last the fabric is dried at the drying cans and then wound on the batcher or stored in pile form.

PADDING WITH DYES

AND CHEMICALS

PRE-DRYING AT IR

CHAMBERS

DRYING AT THERMOSOL

MACHINE

RINSING, SOAPING,

NEUTRALIZING

CURING AT THERMOSOL

MACHINE

FINAL DRYING AT

DRYING CANS

Dyeing With Vat Dyes For dyeing of 100 % cotton fabrics with vat dyes first the dyes, urea and alginate solution are padded onto the fabric at the thermosol padder. The fabric is then led to the IR pre-dryer chamber at a temperature ranging from 700-1000 oC. The fabric is then led to the thermosol chambers at the temperature ranging from 110-150 oC. After that the fabric is guided to the PAD-STEAM, where it is initially padded with the vat dyes developing solution (Sodium Sulphite and Caustic Soda) and then the fabric is led to the steamer where fabric is steamed for 60-90 sec. After that the fabric is led to the washers, where at first the fabric is oxidized with NaOH and H2O2 (H2O2 for dark shades) after that the fabric is washed with normal then hot water at 80-95 oC. At the last washer the fabric is neutralized with acetic acid (along with some buffer). At last the fabric is dried at the drying cans and then wound on the batcher or stored in pile form.


Internship Report

PADDING WITH DYES

PRE-DRYING AT IR

CHAMBERS

DRYING AT THERMOSOL

MACHINE

COLD WASHING STEAMING

PADDING DEVELOPING CHEMICALS

OXIDATION OF

DYESTUFF

HOT WASHING NEUTRALIZING

FINAL DRYING AT

DRYING CANS

Dyeing With Sulphur Dyes Pad-Steam process In this process, the dyes with other additive auxiliaries are padded on the fabric at the Pad-Steam padder. Padding is done at room temperature and pick-up is adjusted about 70-80 %. Fixation of the dyestuff is done in an atmosphere of saturated steam (102oC) at Steamer for 1-2 min. After that the fabric is led to the washers. Initial washers are for cold rinsing. At the forth washer oxidation process is done. Soaping is being done in 5th and 6th washer. 7th washer is for rinsing purposes while neutralization is being done in 8th washer with acetic acid. At last the fabric is dried at the drying cans and then wound on the batcher or stored in pile form.

PADDING WITH DYES

AND CHEMICALS

STEAMING RINSING COLD

RINSING, SOAPING,

NEUTRALIZINGOXIDATION

FINAL DRYING AT

DRYING CANS


Internship Report

DYEING OF POLYESTER/COTTON BLENDED FABRICS

At Kohinoor Dyeing Mills; Pigment, Disperse-Reactive or Disperse-Vat dyestuff is applied on PC blended fabrics depending upon customer requirements. Dyeing With Disperse-Reactive Combination Two-bath process is used in Kohinoor Dyeing Mills Ltd. Dyeing of PC blended fabrics is completed in two steps.

• Dyeing of Polyester portion • Dyeing of cotton portion

Dyeing of Polyester Portion Disperse dyes are used to dye polyester portion. The process would be Pad-Dry-Cure. First the disperse dye is padded along with other auxiliary chemicals (Dispersing agent, Anti-Migrating agent, Anti-Foaming agent, Acetic acid etc.). The fabric is dried at IR Pre-dryers and intermediate drying chambers while fixation of the dyestuff is done in the curing chambers at a temperature of 180-230 oC. After that Reduction-Clearance of the fabric is done at Pad-Steam where RC chemicals are padded at the padder and washing out of the extra chemicals and dyestuff is done in series of washers.

PADDING WITH DYES

PRE-DRYING AT IR

CHAMBERS

DRYING AT THERMOSOL

MACHINE

WASHING STEAMING

PADDING REDUCTION CLEARANCECHEMICALS

DRYING AT DRYING

CANS

Fabric back to Pad-Thermosol

Entry


Internship Report Dyeing of cotton portion At the second step, the cotton contents are dyed with reactive dyes by using Pad-Dry-Pad-Steam or Pad-Dry-Cure process at the same conditions used for dyeing of 100 % cotton fabrics.


PRE-DRYING AT IR

CHAMBERS

DRYING AT THERMOSOL

RINSING, SOAPING,


PADDING WITH

FIXATION CHEMICALS

FINAL DRYING AT

DRYING CANS

PDPS PROCESS

PADDING

WITH DYES AND

CHEMICALS

PRE-DRYING AT IR

CHAMBERS

DRYING AT THERMOSOL

MACHINE

RINSING, SOAPING,

NEUTRALIZING

CURING AT THERMOSOL

MACHINE

FINAL DRYING AT

DRYING CANS

PDC PROCESS

Dyeing With Disperse-Vat Combination Two methods can be employed

• One Bath • Two Bath

One bath process In the one bath process both disperse and vat dyestuffs are padded onto the fabric at the Pad-Thermosol padder. Fixation of the Disperse dyes is done in


Internship Report Pad-Dry-Cure process. After that in the Pad-Steam padder, fabric is padded with developing chemicals for vat dyes and steamed in the steamer. After that the fabric is led to the washers. Initial washers are for cold rinsing. At the forth washer oxidation process is done. Soaping is being done in 5th and 6th washer. 7th washer is for rinsing purposes while neutralization is being done in 8th washer with acetic acid. At last the fabric is dried at the drying cans and then wound on the batcher or stored in pile form.

PADDING WITH

DISPERSE + VAT DYES

PRE-DRYING AT IR

CHAMBERS

DRYING + CURING AT

THERMOSOL MACHINE

RINSING STEAMINGPADDING

DEVELOPINGCHEMICALS

OXIDATION HOT WASHING NEUTRALIZING

FINAL DRYING AT

DRYING CANS

Two Bath process In the two bath process, first the disperse dye is padded along with other auxiliary chemicals (Dispersing agent, Anti-Migrating agent, Anti-Foaming agent, Acetic acid etc.). The fabric is dried at IR Pre-dryers and intermediate drying chambers while fixation of the dyestuff is done in the curing chambers at a temperature of 180-230 oC. After that Reduction-Clearance of the fabric is done at Pad-Steam where RC chemicals are padded at the padder and washing out of the extra chemicals and dyestuff is done in series of washers.


Internship Report


PRE-DRYING AT IR

CHAMBERS

DRYING AT THERMOSOL

RINSING, SOAPING,


PADDING WITH

FIXATION CHEMICALS

FINAL DRYING AT

DRYING CANS

Dyeing Polyester Portion

After that the fabric is brought back to the Pad-Thermosol where the fabric is padded with Vat dyestuff. The fabric is then led to the IR pre-dryer chamber at a temperature ranging from 700-1000oC. The fabric is then led to the thermosol chambers at the temperature ranging from 110-150 oC. After that the fabric is guided to the PAD-STEAM, where it is initially padded with the dye developing recipe and then the fabric is led to the steamer where fabric is steamed for 60-90 sec. After that the fabric is led to the washers. Initial washers are for cold rinsing. At the forth washer oxidation process is done. Soaping is being done in 5th and 6th washer. 7th washer is for rinsing purposes while neutralization is being done in 8th washer with acetic acid. At last the fabric is dried at the drying cans and then wound on the batcher or stored in pile form.

PADDING WITH VAT

DYES

PRE-DRYING AT IR

CHAMBERS

DRYING AT THERMOSOL

MACHINE

RINSING STEAMINGPADDING

DEVELOPINGCHEMICALS

OXIDATION HOT WASHING NEUTRALIZING

FINAL DRYING AT

DRYING CANS

Dyeing Cotton Portion


Internship Report Pigment Dyeing PC blended fabrics can also be pigment dyed. For pigment dyeing we have to prepare dispersion of the pigment by using dispersing agent, binder, wetting agent and humectants. The process would be Pad-Dry-Cure. The fabric is then led to the IR pre-dryer chamber at a temperature ranging from 700-1000 oC. The fabric is then led to the series of thermosol chambers for drying and fixation of the dyestuff. The drying temperature at the first thermosol chamber can be 120 to 135 oC and that of the last can be 165-170 oC depending upon the fabric quality and type of the dye and shade depth required. At last the fabric is cooled down at the cooling drums and then wound on the batcher or stored in pile form. Note: Pigment dyed fabric is not washed

PADDING WITH

PIGMENT DISPERSION

PRE-DRYING AT IR

CHAMBERS

DRYING + CURING AT

THERMOSOL MACHINE


Internship Report

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Internship Report

Dyeing & Physical Testing LAB

Lab Manager: Kamran Bashir Sb.

Purpose of lab:

• The purpose of the lab is to determine the physical properties of the fabric at different stages during production.

• Color matching to provide exact recipe to the dyeing section. • Cost calculation. • Evaluation of the incoming materials regarding dyes and

chemicals. Physical testing section: Following tests are performed in the physical testing lab during processing of fabric Grey Fabric Testing:

• Size % • Lycra % • Width ASTM D 3774 • Construction ASTM D 3775 • pH BDH INDICATOR • Fabric GSM ASTM D 3776 • Width • Tear strength ASTM D 1424 • TENSILE Strength ASTM D 5034/5035 • Ends and picks per inch. • Selvedge testing • TEGEWA

Pretreatment testing:

• Tear strength ASTM D 1424 • Tensile Strength ASTM D 5034/5035 • Width testing ASTM D 3774 • H2O2 test


Internship Report

• Hydrophilicity • pH by extraction AATCC 81 • GSM ASTM D 3776 • Whiteness By spectrophotometer • TEGEWA test • Absorbency AATCC 79 • pH by drop method BDH INDICATOR

Post dyeing fabric testing:

• Washing Fastness (612A) AATCC(612A) • Washing Fastness (614A) AATCC(614A) • Water Fastness AATCC 107 • Dry And Wet Rubbing AATCC 08 • TEAR Strength ASTM D 1424 • TENSILE Strength ASTM D 5034/5035 • pH by Extraction AATCC 81

Post finishing fabric testing:

• WEIGHT ASTM D 3776 • WIDTH ASTM D 3774 • SHRINKAGE AATCC 135 • SKEWNESS AATCCC 179 • TEAR strength ASTM D 1424 • TENSILE strength ASTM D 5034/5035 • SEAM SLIPPAGE ASTM D 434 • ELONGATION AND GROWTH TTM074/TTM 077 • SMOOTHNESS APPEARANCE AATCC 124 • TEFLON TESTING AATCC 22 • SOIL RELEASE AATCC 30 • FLEX ABRASION ASTM D 3885 • ABRASION ASTM D 4966 • PILLING ASTM D 4970/3512 • EXTRACT PH AATCC 61 • FROSTING TEST ASTM D 3886 • DYE-STUFF ANALYSIS • CONSTRUCTION ASTM D 3775 • FIBRE ANALYSIS AATCC 20 • CREASE RECOVERY ANGLE AATCC 66


Internship Report Machines in Quality Control Testing Lab Machine Company Model Test Method

Crock Meter Atlas Chicago CM-5

AATCC 08 AATCC 165 BS 1006 D02 ISO 105 X 12 ISO 105 D02

Random Tumble Pilling Tester Atlas Chicago PT-2 ASTM 3512

Universal Wear Tester Atlas Chicago PT-2

ASTMD 3885-3886, AATCC 119, ASTM D 3514 (Frosting flat Abrasion Screen wire), AATCC 120

Weather-O-meter Atlas Chicago Ci 3000+

AATCC 16 E AATCC 169(s) ISO 105 B-06 ISO 105 B-02 ISO 105 B-04 ISO 11341 G 26(A) G 26(C) ISO 4892-02

Crease Recovery Angle Tester

James H. Heal England

AATCC 66 BS EN 22313 ISO 2313, M&S P22

Wrinkle Recovery Tester

James H. Heal England AATCC 128

ISO 9867, M&S P123

Tear Tester Thwing Albert’s USA Pro Tear ASTMD 1424

Tensile Strength Tester

Thwing Albert’s USA EJA-1000

ASTM 5034, ASTM 5035, ASTM D5733, ASTM D751, ASTM 2594, ASTM D3107, MTL S1005-1995, BS4162, BS25776, ISO 90733, BHS1, ISO 5081, ISO 5082, ASTM 1683, ASTM D4034, BHS 4a, BHS 4b, BS 3320, ISO 13963-1, ISO 13963-2, ASTM D2261, BS4303, BS-ISO 9073-4, BS 2062, ASTM D1335A

Nu. Martindale Abrasion & Pilling Tester

James H. Heal England 406

ASTM 4970 ASTM 4966 BS 3424 BS 5690 M&S P19/P1913

Delta Moist with Roller Probe

James H. Heal England 345


Internship Report Machine Company Model Test Method

Launder O meter ATLAS LEF

AATCC 61 AATCC 86 AATCC 132 AATCC 151 ISO 105 C01-C06, M&S C4, M&S C10A

Wrinkle Recovery Tester

James H. Heal England AATCC 128

ISO 9867, M&S P123

Wascator James H. Heal England

FOM 71 MP. Lab 316

AATCC 135 BS EN 26330 ISO 6330 BS4923 M&S P1A

Quick Wash Plus Raitech Partner of ATLAS AATCC 1870-2000

Whirlpool Washing Machine


AATCC 135 AATCC 88B AATCC 88C AATCC 124 AATCC 130 AATCC 142

Prespirometer ATLAS

AATCC 15 AATCC 107 AATCC 106 BS 1006 ISO 105 E01 ISO 105 E03 ISO 105 X 10

Tumble Dryer Whirl Pool, James H. Heal England

AATCC135 AATCC88B AATCC124 AATCC88C AATCC130 AATCC142 AATCC143 AATCC150 AATCC179

Steam Press James H. Heal England Fast

Incubator 1 Large 1 Small



Internship Report

EXPLANATION OF SOME TESTS: Standard Test method for the determination

of Ends per Inch and Picks per Inch Ends and picks per inch are determined to check the quality of fabric up to the Standard. Procedure:

• First of all make sure the warp and weft direction of the fabric before determination of ends or picks per inch

• If the fabric is more elastic in one direction then that direction is weft of fabric and other is warp of the fabric, the warp of fabric has crimps as well size material on it that is applied on yarn during weaving process.

• If we take the fabric along warp wise then its mean that we are going to determined ends per inch and vice versa.

• after this the fabric is placed on the fabric analysis cabinet for accurate vision of the of the threads

• Then place the pick glass on the fabric • This pick glass has one inch square area and a small needle is

present along with it. This needle helps in counting the no of threads in one inch square.

• After this count the no of threads and note it repeat this process 2 or 3 times. To get the average value.

• Same process is repeated with picks determination • We performed this practical and found that no of threads are

100*80


Internship Report Standard test method for the determination

of residual size % (TEGEWA test)

This test helps us to determine the effectiveness of the Desizing process Apparatus:

Scissor Fabric sample Iodine solution Violet scale

Procedure:

• Desized fabric is tested to check the remaining size material on the fabric

• The prepared solution of Tegwa is put on the desized fabric in the form of a single drop

• The Tegwa solution's drop turns into yellowish or into another color depend on the amount of size material present on the fabric

• Greater the size material present on the fabric darker will be the shade of TEGEWA drop and vice versa.

• Then this shade of the solution is then matched with standard scale • Then ratings are allotted to the desized fabric according to the scale

and shade of drop comparison • Rating is done according to violet scale having scales from 1 to 9 • 9 means good desized fabric and 1 means poor desized fabric.



of whiteness (Using Spectrophotometer)

• Check the whiteness of the fabric by spectrophotometer and note

reading. • After pretreatment whiteness must be 70 C.I.E or more. • Whiteness of the fabric after pretreatment must be same for side-

center-side. • The bleached fabric was tested against the CIE whiteness standard

from the data color and it was found to be 80-90 CIE



of absorbency Apparatus: • Stop watch • Stamp and pad • Scissors • Solution of turquoise dye • Hanger, pin and clip • Iron Procedure: • Take a fabric sample to be tested • Mark it with a stamp 13cm*3cm at three places (left, center and

right) parallel to warp direction • Cut the strips of fabric and attach one end of these strips onto a

smooth wooden bar • Tale 1000ml, 5g/l solution of Drimarene PCO dye in a beaker. • Place the wooden bar with fabric strips on the beaker in such a way

that 1cm lower edge of each strip should be immersed in the solution.

• The dye liquor rises through capillary action. When it touches a specific marked line 1cm we start the stop watch

• When the dye liquor covers 2cm distance (up to a marked line) we note the time and immediately remove the sample form the beaker and dry it with hot iron



of pH of the fabric Two methods are being used to check pH;

• Drop Method (for surface pH) • Extraction method (for core pH)

Drop Method (BDH indicator):

This method is used for direct and measuring surface pH of the fabric sample. Detection is made by comparing the spotted fabric with standard BDH scale. Apparatus:

Scissor Fabric sample BDH indicator BDH assessment scale

Procedure:

• Take the appropriate fabric sample for testing. • Take the standard BDH Indicator solution. • Put a drop of indicator on the fabric surface. • Then compare the reading on the BDH scale. • Give appropriate rating to the drop mark by using scale. • pH range for the fabric must be 6.5-8.5


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Extraction method (by boiling) AATCC 81

Usually this method is used for dyed and finished fabric. Apparatus:

Conical flasks Stove • Scissor Ph meter Beakers

Procedure:

• Takes piece of 10g fabric, • Check the pH of distilled water suppose it is A. • Cut the fabric sample into small pieces. • Take 250ml distilled water in a conical flask and raise its

temperature up to the boiling temperature in 10 minutes. • Also the 250ml distilled water in another conical flask and

boil it with other flask containing fabric sample. • Then add fabric pieces in boiling water and treat it for 10

minutes. • Then cool down the temperature of the conical flask

containing the fabric pieces and distilled water. • Then check the pH of the boiled sample solution with the

help of ph meter and note down the PH suppose it is B. • Also check the ph of boiled distilled water suppose it is C . • SUBTRACT DISTILLED WATER’S INITIAL AND

FINAL Ph as difference D= A-C then fabric PH will be; Core PH = D-B.


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Standard Test Method for Determination of Dimensional change

(AATCC 135)

APPARATUS:

Fabric sample Automatic washing machine

Procedure:

• Cut ¾ yard fabric specimen with full width. • Times mark 50 cm apart parallel to warp and 3 times mark 50

cm apart parallel to weft leaving at least 5 cm from each side (in case of smaller sample take 38 cm * 38 cm specimen and mark 25 cm apart.)

• Put the marked specimen into the automatic washing machine and add ballast to make a total load of 1.8 kg

• Add 30 g of AATCC referred detergent. • Set temperature at 27oC and start the machine for 15 minutes. • After washing transfer the fabric for drying in tumble dryer. • After drying condition the sample and note the shrinkage. • Repeat the process to complete three washes and note the

shrinkage after each wash followed by conditioning. Calculate the % dimensional change by using the following formula; % D.C = 100 * (B-A)/A Where; D.C = Dimensional change A = Original dimension B = Dimension after washing


Internship Report Standard Test Method for the Determination

of Dimensional Change (Skewness) Of Fabrics (AATCC 179)

APPARATUS:

Indelible ink marking pen Measuring tape in mm. Whirlpool washer Ballast load Automatic tumble dryer

Preparation:

• Cut a specimen 38cm * 38cm. • Mark face length wise • Mark two 25cm pair of bench parallel to length and two similar

marks parallel to width. • Each mark should be 5cm from each end • Draw a line through each four sides in square form. • Label corners A,B,C,D in clock-wise direction with lower corner

on left side • Draw a line A to C, and B to D. • PUT THE SPECIMEN and ballast in the machine to make a total

load of 1.8 Kg • Add water and 30 g of AATCC standard detergent to the whirlpool

washer • Turn ON the machine and allow to run for 15 minutes followed by

automatic rinsing and spin-drying • Transfer the specimen and ballast to the tumble dryer for drying at

60c. • Repeat the same procedure to complete the three washings • After third wash and drying condition the specimen at 21+-1c and

65+-2% RH. For one hour. • Then calculate the % skew in the fabric using the following

formula; X=100*{2(AC-BD)/(AC+BD)}

Where X = % SKEWNESS


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Standard Test Method for the Determination

of Tear Strength of Fabrics (ASTM D 1424)

Apparatus:

Elmendorf tear tester Fabric sample SS ruler Ball pan scissor

Procedure:

• Take a sample of 10cm*6.3cm dimensions in each (warp and weft) direction.

• Turn on the tester and adjust the pendulum in its starting position. • Press clamp button to clamp the specimen. • Make a cut of 2cm in clamped sample. • Press start to start the test. • When specimen got torn note down that reading. • Repeat the same procedure for the other specimen.



of fabric weight (GSM) (ASTM D 3776)

Apparatus:

Gsm cutter Rubber pad Weighing scale Calculator

Procedure:

• A GSM cutter is used to cut the specimen • Gsm cutter is placed on the rubber pad • First of all a paper is placed on the rubber pad to avoid cutting of

the rubber pad • Then place the fabric in appropriate position to cut it accurately • Place the GSM cutter on it • Press the cutter with suitable pressure also rotate it in clockwise

direction • The specimen will be cut in the form of circle • Weight the sample on the balance • Then weight of the specimen is multiplied with 100. i.e.

GSM = Wt of specimen * 100. • The weight was found to be = 1.04 • The GSM will be = 1.04 * 100 =104 GSM


Internship Report Standard Test Method for the Determination

of Tensile Strength of Fabrics (ASTM D 5034)

Apparatus:

Tensile strength tester SS ruler Fabric Ball pen Scissor

Procedure: • Cut samples of 4’’*6’’ dimensions, 5 for warp and 8 for weft. • Turn on the tensile testing machine. • Place warp sample first in upper clamp jaws keeping the previously

drawn line adjacent to the side edge of smaller jaw and turn ON the upper air control switch.

• Apply a small tension on the specimen in the downward direction just to align it. And clamp jaws by turning ON the lower Air control, switch keeping the previously drawn line adjacent to the side edge of smaller jaw.

• Click start button to start the test. The jaws will move apart and will return after the sample is broken.

• Repeat the same procedure for weft. And note the value of breaking force for the specimen


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Color Fastness Tests The resistance of a dyed or printed textile to various types of influences, to which they are normally exposed in textile manufacturing and in practical use, is known as Color Fastness. In color fastness tests, changes to the color of the sample and staining of undyed adjacent fabrics tested at the same time are visually assessed using the Grey scale and these are then given as fastness values. It is a basic concept of the tests that they are of a high level of reproducibility in result, may be carried out in a relatively short time and have a good degree of relevance to the demands of textile manufacture and use. Grey Scale for Assessing Change in Color This Grey Scale is for assessing changes in color of leather in color fastness tests, for example, wash fastness, perspiration fastness, etc. The scale consists of nine pairs of grey color chips each representing a visual difference and contrast. The fastness rating goes step-wise from:

Note 5 = no visual change (best rating) To Note 1 = a large visual change (worst rating). The grey scale has the 9 possible values:

5, 4-5, 4, 3-4, 3, 2-3, 2, 1-2, 1


Internship Report Grey Scale for Assessing Staining

This Grey Scale is for assessing the degree of staining caused by dyed textile material in color fastness tests. For example, the staining of wool and cotton fabrics in the wash fastness, perspiration fastness, etc. The scale consists of nine pairs of grey color chips each representing a visual difference and contrast. The fastness rating goes step-wise from:

Note 5 = no visual change (best rating) to Note 1 = a large visual change (worst rating).

The grey scale has the 9 possible values:

5, 4-5, 4, 3-4, 3, 2-3, 2, 1-2, 1.


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Standard test method for color fastness to crocking

(AATCC-08) The crocking test is of two types;

Dry rubbing Wet rubbing

Dry Rubbing Test

• In this test the pieces of white fabric was taken for crocking staining

• Then take the dyed fabric whose crocking has to be tested • Dyed fabric is then placed on the crock meter bed downward • Place the white fabric on the crock meter hand upward for rubbing

with the help of clip • Set the 10 revolutions on the meter • Then turn on the machine • When all the revolutions completed then draw out the white fabric • Then match the colored stain on white fabric piece with the

standard scale and give ratings Wet Rubbing Test

• In this test the pieces of white fabric was taken for crocking staining is in wet form

• The white fabric piece should be 60 - 70 % wet


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• Then take the dyed fabric whose crocking has to be tested • Dyed fabric is then placed on the crock meter bed downward • Place the white fabric on the crock meter hand upward for rubbing

with the help of clip • Set the 10 revolutions on the meter • Then turn on the machine • When all the revolutions completed then draw out the white fabric • Then match the colored stain on white fabric with the standard

scale and give ratings • The rating is ranges from 5-1, 5 for excellent crocking and 1 for

poor crocking


Internship Report Standard Test Method For Color Fastness To

Washing (AATCC 61-2A)

Apparatus:

Launder-ometer Stainless steel cylinder(9cm*20cm) having

1200ml capacity Stainless steel balls (0.6 cm in dia. ) Detergent WOB Multifibre strip Fabric sample to be tested Gray scale for color change Gray scale for staining

Procedure:

• Cut the fabric specimen of 5cm*15cm with longer dimensions parallel to warp.

• Stitch the Multifibre strip to the fabric face to face along its one edge keeping woolen strip first from right.

• Prepare 150g/l sol. Of WOB and take 150 ml of this solution in SS cylinder.

• Put fabric specimen into it. And close the lid. • Turn ON the laundr-o-meter set its temperature at 49oC. • Give treatment time of 45 minutes. • Thoroughly wash the specimen and dry it. • Compare the specimen with gray scale for assessment of

staining under d-65 illuminant.


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Standard Test Method for Determination Of Color Fastness To Sea Water

AATCC 106 Apparatus

Perspirometer Acrylic plates Gray scale for staining and color change

TEST SOLUTION:

SODIUM CHLORIDE 30g/l. Magnesium chloride 5g/l. Distilled water 1 liter.

PROCRDURE: • Cut a fabrics sample 5.7cm * 5.7 cm. • Attach Multifibre strip face to face with the test sample with wool

on the right side • Immerse the test specimen in the solution for 15 minutes at room

temperature with occasional agitation for through wetting • After 15 minutes squeeze the specimen to remove extra liquor • Weight of the wet specimen should be 3 times it dry weight. • Place the specimen between the acrylic plates (11.5 cm *6.4 cm *

0.3 cm ) of perspirometer • Adjust the perspire meter to adjust a pressure of 10 lbs on the test

specimen • Heat the loaded perspirometer at 38 c in the incubator for 18 hours • After the completion of time dry the sample by hanging it into the

air at room temperature • Don’t iron the specimen

EVALUATION:

• After drying, condition the specimen at 21+- 1 c and 65+-2 RH%. For 1 hour. • After conditioning check the shade and staining and shade change with the help of gray scale for staining and color change

respectively.


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Standard Test Method for Determination Of Color Fastness To Water

(AATCC 107) Apparatus:

Perspirometer Acrylic plates Gray scales (for assessing staining and color

change)

Test solution: Freshly boiled distilled water Procedure:

• Cut fabric specimen 5.7cm*5.7cm • Attach it with Multifibre strip parallel to the warp direction. • Immerse the fabric into the sol. At room temperature for 15 min. • After 15 min. squeeze the specimen to remove excess liquor. • Weight of the specimen should be 3 times its dry weight. • Place the specimen between the acrylic plates (11.5cm*6.4cm*

.3cm) of perspirometer. • Adjust the perspirometer at a pressure of 10lbs, on the test

specimen. • Heat the specimen for 18 hours at 38c.


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Standard Test Method for Color Fastness To perspiration

AATCC 15 (ACIDIC)

Apparatus: Perspirometer Acrylic plates pH meter Grey scale for staining and color change

Test Solution Prepare the perspiration solution by using the following recipe

Sodium chloride 10g/l di-sodium hydrogen phosphate 1g/l l-histidine 0.25g/l lactic acid 1g/l

Put all the chemicals in a flask and add 1 liter distilled water to make 1 liter solution

The pH of the solution should be 4.3. If not so then discard the solution and make anew one and weigh

chemicals accurately

Procedure: • Cut the fabric specimen 5.7 cm * 5.7 cm. • Attach it with Multifibre strip face to face with wool on the right. • Immerse the specimen in the solution at room temperature for 30

minutes, with occasional agitation to ensure maximum wetting. • After 30 minutes squeeze the specimen to remove extra liquor. • Weight of the specimen should be 2.25 times its dry weight. • Place the specimen between the acrylic plates (11.5 cm *6.4 cm *

0.3 cm ) of perspirometer • Adjust the perspire-o-meter to adjust a pressure of 10 lbs on the

test specimen by placing 8 lbs weight on the top of the perspirometer.

• Heat the loaded perspirometer at 38 c in the incubator for 6 hours • After the completion of time dry the sample by hanging it into the

air at room temperature • Don’t iron the specimen

Evaluation:


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• AFTER DRYING, CONDITION THE SPECCIMEN AT 21+- 1 oC and 65+-2 RH% For 1 hour.

• After conditioning check the shade and staining and shade change with the help of gray scale for staining and color change respectively.

Standard Test Method for Determination Of Color Fastness To Dry Cleaning

(AATCC 132) Apparatus:

Perspirometer Launder-o-meter SS container; 7.5 cm dia * 12.5 cm high, 500

ml capacity SS disk 30.5 mm dia * 3 mm thick, weighing

20 g each. Perchloroethylene


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Needle and thread for stitching. Grey scale for staining and color change

Procedure:

• Cut a specimen 5 cm * 10 cm with long dimensions parallel to warp

• Prepare a bag with outer size12 cm * 12 cm and inside 10 cm * 10 cm by sewing three sides and keeping twill weave inside.

• Place the sample and 12 disks in the bag from the upper end. • Place the bag in SS cylinder and add 200 ml Perchloroethylene. • Close the container and agitate it in launder-o-meter for 30

minutes at 30 c • Remove the container and the bag from it. • Open the bag, remove the specimen and dry it in the air at

temperature not exceeding 65oC Evaluation:

• AFTER DRYING, CONDITION THE SPECCIMEN AT 21+- 1 c and 65+-2 RH. For 1 hour.

• After conditioning check the shade and staining and shade change with the help of gray scale for staining and color change respectively.


Internship Report DYEING LAB Purpose of Dyeing Lab Following are some important purposes of dying lab.

• To make lab dips as per requirements of customer. • To analyze new dye stuff i.e. its tone, METAMERISM and color

fastness etc. • To calculate the cost of every shade on any specific fabric. • To maintain Lab/ Dying production record customer and shade

wise. • To dye the fabric on small scale and observes its hue and matching

before bulk production on dyeing floor. • matching the color and shade developing the recipes for lab scale

and bulk dyeing Equipment in Dyeing Lab Machine Qty

. Company Model Test Method

Contact Heat 1 James H. Heal England AATCC 117

Padder 1 Roaches England EVP 350 Padder 1 Roaches England EHP 350

Pad Steam 2

Roaches England For color matching / Lab dips

Pad-dry-Thermosol 1

Roaches England For color matching / Lab dips

Soapy machine 2 Mathis Washing box

Color Matching Software

Data Color

DCI Match Standard Level, Color Tools – QC Software For Textile

Color Matching Software

Spectrophotometer 1 Data Color

SF600 plus CT

Color prediction and matching

Spectrophotometer 1 X-Rite Color Eye Color prediction and matching

Light Box 2 Verivide, Macbeth

CAC-150(1), CAC-60(4), Spectralight III(1)

Assessment cabinets for color matching.


Internship Report Working Process Flow

Selection Of Dyes To make a shade of any type following points should be taken in account:

1. First we have to know the customer’s requirements mentioned in the ‘Inquiry’ i.e. type of dyeing, fastness requirements and the light sources. This information will help us to choose the dyes, e.g. a customer want to dye the fabric in reactive dyes and require very good light/washing fastness then we will select the proper dyes from the range which will full fill the requirements.

2. Usually the customers require light fastness between 3-4, Washing fastness around 4 and crocking 3 to 5 from light to dark shades.

3. Another case when the customer not mentioned the type of dyes but only the fastness requirements then the lab in-charge will to select the dyes according to the shade depth, dullness/brightness and which will fulfill the fastness requirements, e.g. for light shades like Khaki, Light Grey, light pink etc. Vat dyes are first

Standard receiving

Fabric arrangement

Dye stuff selection

Chemical selection

Recipe Prediction With the help of Spectrophotometer

Selection of best option from the prediction

Lab dip

Application of finish

Sample to Customer


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priority because their washing fastness is very good and the light fastness is better.

4. Light fastness of orange is better than red. Running behavior of orange in production is better than red because red will create problems above 10 g/l. Red has also very poor crocking value.

5. Crocking of Reactive dyes better than vat. 6. Light fastness is better in Vat. Light fastness is an issue in case of

light pink shade. 7. Rem. Navy RGB has very poor light fastness so avoid it to use. 8. In navy shades of Black B washing fastness is an issue. 9. We have to know the running behavior in production of every dye

e.g. Rem. Black B will create problem below 15 g/l recipe. 10. Remember avoid to select opposite dyes (different tones) like Red

& Turq. Blue, Red and Green, Red and Lemon Yellow. 11. In Vat dyes secondary & tertiary dyes are preferred and to avoid

primary dyes e.g, we can use Brown in place of Red, Olive in place of Yellow and Grey in place of Blue.

12. For navy shades avoid to use Rem. Black B in recipes below 15 g/l because in small quantity its behavior in production is not good.

13. Rem. Navy RGB has poor light fastness so it is used conditionally. 14. If the customer’s requirement is to dye the fabric in Pigments then

we first develop 50% shade in reactive dyes and then apply pigment on the remaining shade.


Internship Report Methods of Application For the application of different classes of dyes to the fabric different application methods are used which are as listed below,

1. Reactive 2. Vat dyes 3. Sulfur dyes 4. Disperse dyes 5. Disperse and Reactive (one bath). 6. Disperse + reactive/vat (two bath).

Complete details of these application methods are given as follows;

Dyeing With Reactive Dyes Reactive dyes are applied by two ways

1. PDC (Pad+ Dry+ Cure) 2. PDCPS (Pad+ Dry+ Chemical Pad Steam)

1. PDC (for Reactive Ciba P Dyes) This process is only used for cibacron-P dyes. For P class dyes a typical recipe is as given

1. Dye x g/L 2. Urea 100 g/L 3. Wetting Agent (penetrant EH) 1.5 g/L 4. Anti-migrating Agent (sod. alginate) 20 g/L 5. Soda Ash 20 g/L

Process Conditions 1. Pad: Pad pressure 1.5 bar, speed 2.8 m/min. 2. Dry 3.0 min at 150oC 3. Cure 160-170oC for 1.5 min. 4. Wash with water in Soapy Time 2min Temperature 90oC Soaping agent (Decol SNS) 3g/l


Internship Report 2. PDPS (for Remazol, Levafix, Ciba.C, &Drimarene)

This process is used for all reactive dyes except Ciba P. Recipe for reactive dyes

1. Dye x g/l 2. Wetting agent (Penetrant EH) 1.5 g/l 4. Anti-migrating Agent (Sodium Alginate) 20 g/l

Process Conditions 1. Padding Pad pressure 1.5 bar

Speed 1.5 m/min. 2. Drying 3 min. at 150oC Developing on pad steam can be carried out by two ways.

• By using sodium silicate 50 % • By salt method as given,

1. Glauber’s salt 250 g/L 2. Caustic soda 6 g/L 3. Soda ash 20 g/L 4. Lyoprint RG 15g/L

After developing, Soapy is used for washing and soaping. Dyeing with Vat Dyes Recipe for vat dyes is as;

1. Dye x g/l 2. Penetrant EH (Wetting Agent) 2 g/l 3. Anti-migrant 10-15 g/l 4. Dispersing agent 2 g/l


Internship Report Process conditions: Padding:

Pressure 1.5 bar Speed 2.5 m/min

Drying: 2.0 min at 150 o C

Developing: For this purpose pad-steam is used for developing chemical padding. And the process conditions are

Padder pressure 2bar Speed 2 m/min Time 1min

Developing Recipe for Vat Dyes:

DYES (g/l)

<1 5 15 30 45 60 70 90 100>

Hydro (g/l)

30 35 40 45 50 55 60 70 72

Caustic (g/l)

38 44 50 57 63 69 76 85 88

Oxidation: For oxidation always Soapy machine is used in KDML.

H2O2 50ml Water 9LTR Time 3min Temperature 50oC


Internship Report Dyeing With Sulphur Dyes Recipe for Sulphur dyes

1. Dye x g/l 2. Sodium sulphide y g/l 3. Wetting Agent 2g/l 4. Soda Ash 10-20g/l 5. Sodium Chloride 10g/l 6. Urea (not necessary) 40-60g/l

Process conditions padding: Pad pressure 1.5 bar,

speed 1.5 m/min.

Drying:

3.0 min at 150 o C The ratio between dye and sodium sulphide should be 1:1.5 respectively and we have to use nearly boiled water to dissolve the recipe. Complete the process and then oxidize the sample with hydrogen peroxide and then wash it with hot and cold water.

Dyeing With Pigment Colors Recipe for pigment dyeing

1. Pigment color x g/l 2. Binder 5-25 g/l 3. Wetting Agent 2 g/l 4. Anti-migrating agent 10-15 g/l

Process conditions 1. Padding Pad pressure 1.5 bars,


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Speed 1.5 m/min. 2. Drying: Time 3.0 min Temperature 150oC 3. Curing: 160-170oC, for 1.5 min.

Dyeing With Disperse Dyes These dyes are only use for the polyester fabric

Recipe of disperse dyes 1. Dye x g/l 2. Wetting Agent 2 g/l 3. Anti-migrating Agent 10-15 g/l 4. Dispersing Agent 2g/l

Process condition 1. Padding: Pad pressure 1.5 bar, Speed 1.5 m/min. 2. Drying 3.0 min at 150 o C (IR Dryers) 3. Curing 160-170 o C for 1.5 min After curing the reduction clearing is done with the help of,

1 Sodium hydrosulphite = 20-30 g/l 2 Caustic(48°Be) = 20-30 g/l

Dyeing With Disperse/Reactive Or Vat (One Bath) This process is used for PC (Polyester Cotton Blend) dull &light shade. Take the recipes of disperse and reactive/vat in single bath and pad the fabric after padding first we develop disperse dye for polyester portion


Internship Report which is mentioned above then we use PDCPS for development of reactive/vat for cotton portion which is also discussed earlier then skeleton out polyester part. For this purpose we use sulphuric acid. Sulphuric acid dissolves cotton, but polyester fiber remains un-affected. Now dry the sample and check the shade manually and on data color program if it is not ok then retrial with revised recipe and if ok then proceed further Dyeing With Disperse/Reactive Or Vat (Two Bath) This process is used for PC (Polyester Cotton Blend) bright & dark shades. Recipes of disperse reactive and vat are discussed earlier so first prepare disperse recipe and proceed for polyester as mentioned above then skeleton out polyester part and match the shade if yes then proceed for cotton fiber and if not ok then retrial for polyester fiber by another sample. When polyester will ok according to shade then we evaluate at least 10 samples and do complete process as above and then make the recipe of reactive/vat, which discussed earlier and develop the shade of the cotton fibers. If we are working on reactive then the two processes PDCPS or PDC any one is applied depending on dye type and if we are working on vat then we use vat PDCPS. For both reactive and vat we complete the process then check the shade manually and data color program if not ok then retrial with change of recipe and if ok then proceed further. Padder

Padders are used for application of dye on the fabric .Speed and pressure of padders is adjusted according to required pickup of fabric.

There are two types of padders

Vertical Padder Horizontal Padder

Manufacturer ` ROACHES


Internship Report How to use Padder?

1. Switch on the padder. 2. Adjust speed 4.5 m/min. 3. Adjust the pressure 3 Bar. 4. Switch ON the pressure. 5. Adjust the padder on single mode. 6. Press the start Button (fabric Run). 7. Wash the padder with water. 8. Rotate the padder Roller at Vertical Position. 9. Attach dye Bath Larger OR Smaller Trough. 10. Rinse the padder 11. Dye your dip and proceed it. 12. Open the outlet from lower side of padder. 13. Wash the padder with shower. 14. Stop the padder from button fabric Run.

‘DATACOLOR’ Spectrophotometer The practice of color measurement with instruments is called spectrophotometery. Although the instruments used may be very different, the basic principles of visible spectrophotometry are the same as those applicable to infrared, near infrared, ultraviolet, microwave and other type of spectrophotometry. Spectrophotometers have three essential parts, a light source, a monochromator, and a detector. An output device such as a chart recorder, CRT or printer is often present. This ‘DATACOLOR’ Spectrophotometer is internationally acceptable shade evaluator system which follows the computer software of CIE Color Order System and gives us the deviation of shade from L*, a*, b*, C*, h*, which will explain latter. Some customers checked the shade visually and some demand “PASS” report of the DATACOLOR spectrophotometer. There are three options when we evaluate any shade:

1. Pass Report when the *CMC DE is below 0.5 2. Warn Report when the CMC DE is less than 1. 3. Fail Report when the CMC DE is above 1.


Internship Report *CMC DE (Color Measuring Committee Deviation) 444 By the help of this instrument, we can get some major advantages like

1. We select a range of dyestuff and the light sources under which we want to evaluate the shade, and then this equipment will give us different options with different set of dyes under recommended light sources with minimum metamerism value. Therefore, we have to select one of these options.

2. Another advantage of this equipment is that we can evaluate two samples of same shade and the color difference (CIE L*a*b* Color Difference) between these two can get. This difference is shown numerically and graphically and we can print out easily by printer.

Metamerism When two object, fabrics for example, match in color under one set of lighting conditions but fail to match under other lighting conditions, the object are said to be a metameric pair. This means that the two objects have different spectrophotometric curves. Metamaric pair has different spectrophotometric curves but identical color space coordinates for one set of conditions. Conversely, nonmetamaric pair has identical spectrophotometric curves. Metamerism is a common problem in textile because the dye used to formulate color usually has different light absorbing characteristics from the colorants in the object being matched. Therefore, formulating an exact, nonmetamaric match of the desired color in a textile material may not always be possible. The problem of metamerism cannot be removed completely but can be minimized by selecting a set of such dyes which have close spectrophotometeric curves.

How to use DATA Color Spectrophotometer?

1. Switch on spectrum 2. Switch on computer, enter pass word. 3. Double click on Data Color Tools. 4. Small window appear. Enter dci and press OK. 5. A window of Data Color Tools appears click ON. 6. “CIE P/F” and click on “CMC P/F” a small window open. 7. Click on List Std. 8. Select your required Std. 9. Place the STD in front of aperture according to size of specimen.


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10. Select your light source from Illum/Obs option. 11. Click on [Batch Insert] option OR press F8 from the key board. 12. DE values and l, a, b, values appear on the screen. 13. Observe them and take decision about your addition.

How to feed New Standard?

1. Place the Standard at the aperture of spectrophotometer. 2. Be sure no crease or effected fabric in front of aperture area. 3. Click on new standard I.con. 4. Write name of new standard with shade and customer

identification. 5. For example if you want to feed standard shade: Raven

Customer Springs and quality 60.60/180.106. 6. >>>…. “Raven SPG 60.60/180.106”……...<<<<< 7. Now click on Std: Inst.

How to Store standard?

1. Click on store std Icon. 2. Window open Select folder in which you want to store standard. 3. Click OK.

How to store Batch?

1. First of all store standard 2. Click on store all Batches 3. Select folder in which you stored standard. 4. Click Ok. 5. How to Retrieve Standard 6. Click on Retrieve Std 7. A window open move your mouse and click on Browse

Data. 8. Select folder. 9. Select sample. 10. Click Ok and then Click Ok.

How to Use Light Box?

1. Switch on the Light Box. 2. Switch off all other lights in dark room. 3. Remove all things from Light Box.

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4. Press Button to require light source (CWF, D-65, UV etc).

5. Place the Sample in light Box and observe it at 45 angles.

6. After use press button to Light off.

Various Light Sources There are various standard light sources under which a shade(object) can only reflect light waves which shine on the object, the color of the object depends on the intensity of the various wavelengths which are present in the light source. The Commission International de I’Eclairage (CIE) defines several light sources. Having standard light sources is important so that standard conditions can be established for viewing, comparison, acceptance and rejection of colors in commerce. CIE sources A, B and Care all incandescent. Source A is a tungsten filament lamp operating at a color temperature of 2854 oK. Source B & C are filtered tungsten filament sources operating at color temperature of 4800 o K and 6500 o K respectively. Source B is intended to simulate noon sunlight while source C is intended to stimulate over-cast sky daylight. Various Light sources which are commonly used are:

1. D65 (color temp. of 6500 o K) Day Light 2. F02 (CWF) Cool White Florescence 3. TL84 or Horizon Tube Light 4. A or INCA Bulb Light 5. UV Ultra Violet 6. U3000 (TL 83)

F11 (TL 84)

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