Contents

1 Introduction to polyester............................................................................................2

2 History of polyester....................................................................................................3

3 The Manufacturing Process.......................................................................................4

3.1 Polymerization....................................................................................................4

3.2 Spinning..............................................................................................................4

3.3 Drawing...............................................................................................................5

3.4 Variations on the Basic Polyester.......................................................................5

3.5 Making Yarns......................................................................................................6

3.6 Blends.................................................................................................................6

3.7 Weaving..............................................................................................................7

3.8 Finishing Processes............................................................................................7

4 Types of Polyester.....................................................................................................8

4.1 PET Polyester.....................................................................................................8

4.2 PCDT Polyester..................................................................................................9

4.3 PBT - Poly Butylene Terephthalate....................................................................9

5 Types of Polyester Yarns........................................................................................10

5.1 Filament Yarns..................................................................................................10

5.2 Textured Yarns.................................................................................................10

5.3 Spun Yarns.......................................................................................................10

5.4 Trademarked Fabrics........................................................................................11

6 Properties of Polyester............................................................................................13

7 Uses of Polyester....................................................................................................15

7.1 Use of polyester in garments............................................................................15

7.2 Industrial uses of polyester...............................................................................16

7.3 The Future........................................................................................................17

8 Bibliography.............................................................................................................18

POLYESTER

1 Introduction to polyesterPolyester is a chemical term which can be broken into poly, meaning many, and ester, a basic organic chemical compound. Polyester is a term often defined as “long-chain polymers chemically composed of at least 85% by weight of an ester and a dihydric alcohol and a terephthalic acid”. In other words, it means the linking of several esters within the fibers. Polyester is a synthetic fiber derived from coal, air, water, and petroleum. Developed in a 20th-century laboratory, polyester fibers are formed from a chemical reaction between an acid and alcohol. In this reaction, two or more molecules combine to make a large molecule whose structure repeats throughout its length. Polyester fibers can form very long molecules that are very stable and strong.

Polyester is used in the manufacture of many products, including clothing, home furnishings, industrial fabrics, computer and recording tapes, and electrical insulation. Polyester has several advantages over traditional fabrics such as cotton.

Today, polyester is largely regarded as a cheap fabric that is rather uncomfortable for sensitive human skin to wear.

However, the emergence of luxury fibers like polyester microfiber and various polyester blends the industry is experiencing resurgence. The Tennessee Eastman Company and the Man-Made Fiber Producers’ Association’s (MMFPA) Polyester Fashion Council played a significant role in the revival of polyester. The Tennessee Eastman Company started a YES campaign for polYESter and popularized it via radio and television. The idea was to focus on the wash and go properties of polyester rather than sell it as a cheap fabric.

Today, the biggest contributor to the appeal of polyester is the discovery of microfibers. Microfibers give polyester the feel of silk and are rapidly becoming the choice of fabric. With an expensive tag to match, the cheap image of polyester seems to be on it’s way out. Here’s to heralding a new era in the history of polyester!

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2 History of polyester

In 1926, United States-based E.I. du Pont de Nemours and Co. began research into very large molecules and synthetic fibers. This early research, headed by W.H. Carothers, centered on what became nylon, the first synthetic fiber

Soon after, in the years 1939-41, British research chemists took interest in the du Pont studies and conducted their own research in the laboratories of Calico Printers Association Ltd. This work resulted in the creation of the polyester fiber known in England as Terylene.

In 1946, du Pont purchased the right to produce this polyester fiber in the United States. The company conducted some further developmental work, and in 1951, began to market the fiber under the name Dacron. During the ensuing years, several companies became interested in polyester fibers and produced their own versions of the product for different uses.

Subsequent to the development of Terylene and Dacron, Kodel was developed by Eastman Chemical Products, Inc in 1958. The polyester market underwent rapid expansion and textile mills emerged everywhere. Many of the mills were located at small gas stations and produced cheap polyester apparel. The inexpensive and durable fiber became very popular and the industry expanded rapidly till the 1970s. Unfortunately, the infamous double-knit polyester image hit the industry and polyester soon came to be known as the uncomfortable fabric.

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3 The Manufacturing ProcessPolyester fibers, the synthetic fibers, are long chain polymers derived from coal, air, water, and petroleum. They are formed through chemical reaction between an acid and alcohol. In this reaction, two or more molecules combine to make a large molecule whose structure repeats throughout its length. These molecules are very stable and strong. There are variations in the compositions and therefore in the properties of polyester fibers.

3.1 Polymerization

Condensation polymerization occurs when the acid and alcohol are reacted in a vacuum at high temperatures. The polymerized material is extruded in the form of a ribbon onto a casting trough or cooling wheel. After the ribbon hardens, it is cut into chips.

3.2 Spinning

Polymer chips are melted at 500-518°F (260-270°C) to form a syrup-like solution. The molten polymer is then extruded through a spinneret and the filaments are subsequently

drawn into the desired polyester fiber. Variations are introduced to obtain desired end results. Spinnerets having hole of different shapes such as round, trilobal, pentalobal, hexalobal or octalobal can be used for special effects like opacity, luster or its suppression, wicking, comfort or feel. Hollow fibers may be produced to make it lightweight and for providing greater cushioning or insulative properties. Crepe effect can be obtained through crimps. Certain additives may also be combined with the spinning solutions for specific properties. Delusterant can be added to make the fiber dull, a flame retardant may be added or certain other antistatic substance may also be included.

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3.3 Drawing

After extrusion from the spinneret, the fibers are drawn or elongated, with the help of godet wheels. Depending upon the desired properties, the polyester fibers are usually drawn up to five times its original length. For higher tenacity, the filaments are drawn to a greater extent. When the fibers come in contact with the air, they solidify. Usually, the PET fibers are drawn hot as it produces more uniform fibers. PCDT fibers are drawn at higher temperature due to their higher melting point. During the drawing process itself, fibers may be textured which saves time, efforts and production cost and also gives greater quality control over the finished fibers. After the polyester yarn is drawn, it is wound on large bobbins or flat-wound packages, ready to be woven into material.

3.4 Variations on the Basic Polyester

Different fibers can be created by doing one or more of the following:

Adding a delusterant : Polyester is a naturally bright fiber, but can be made dull or semi-dull by the addition of a delusterant.

Changing the shape of the spinneret : The simplest and most common shape is a circle, but by changing ths shape of the spinneret, square, oval, and bean-shaped fibers can be formed. One can even create a hollow fiber. The different shapes affect the hand and strength of the fiber.

Drawing it out more: Drawing out the fiber to five times its orginal length is normal, but polyester can be stretched even further to create the now-popular microfiber. Drawing it out may also affect the strength, elasticity, and dyeability.

Adding dye: In its natural state, polyester is a slightly transparent off-white. Adding dye at the manufacturing stage can create brilliant colors like electric blue and atomic red.

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Crimping : When the fiber is drawn out it is long and smooth. Crimping can give the fiber more texture and bulk and can increase its insulation properties, as well as its elasticity.

3.5 Making Yarns

After the fiber itself is created, it is made into a yarn. There are two types of polyester

yarns: filament and spun. Filament yarns are made by taking the long polyester filaments, grouping them together, and then twisting them to make them thicker and stronger. A monofilament yarn has just one, long polyester fiber that is not twisted.

Spun yarns are produced in much the same way that a cotton or wool yarn is produced.

The long filaments are fist cut into short pieces called staples. These are then combined together and spun to create a yarn made up of thousands of short filaments.

3.6 Blends

At this stage, polyester can also be combined with other fibers to produce a variety of effects.

Polyester and cotton is probaby the most famous and popular blend. The polyester helps the fabric retain its shape and resist stains and wrinkles. The cotton makes the fabric more absorbent and comfortable.

Polyester is combined with wool to give it wrinkle-resistance and shape retention in all kinds of weather. Since polyester is stronger than wool, it increases the durability and life of the fabric. The wool contributes good draping characteristics and elasticity.

Polyester and rayon is another popular blend fabric. Here again the polyester makes the fabric more resilient and durable, and helps it keep its shape. The rayon adds a different texture, has a good hand, is good for draping, and is absorbent.

Polyester and nylon produce a strong fabric because of nylon's strength and abrasion resistance and polyester's wrinkle-free properties. This combination produces a yarn that is strong, durable, stable, easy to launder, and resistant to mildew and insects. Problems with this blend, however, are that pilling may occur, and it does not have a very good hand. Furthermore, since neither nylon nor polyester is very absorbent, the fabric may feel wet and clammy in warm or humid weather.

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3.7 Weaving

After the yarns are made, they are shipped out to textile mills to be woven into fabric. Polyester can be made into both woven and knitted fabrics (such as the infamous double-knit!)

3.8 Finishing Processes

Finally, after the fabric is made, one or more of the following finishing processes is often used to improve the quality of the fabric:

Heat setting--creates a permanent shape Singeing--improves the hand, reduces pilling, and increases smoothness Anti-static finish--reduces static electricity Water and stain repellency--increases comfort and makes it easier to clean; also

used for rainwear Resin finishes--increases ease of care Calendering--increases smoothness and reduces pilling Embossing--creates a design and/or luster

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4 Types of Polyester

The polyester fibers are generally available in two varieties- PET (polyethylene terephthalate) and PCDT (poly-1, 4-cyclohexylene-dimethylene terephthalate). PET is the most common production. It is stronger than PCDT, while PCDT has more elasticity and resilience. PET can be used alone or blended with other fabrics for making wrinkle free and stain resistant clothing that can retain its shape. PCDT is more suitable for heavier applications, such as draperies and furniture coverings. Modifications can be introduced in each of these varieties for obtaining specific properties.

4.1 PET Polyester

The polymer usually used for textile fibres is polyethylene terephthalate, or PET, which is formed by reacting ethylene glycol with either terephthalic acid or dimethyl terephthalate. Antimony oxide is usually added as a catalyst, and high vacuum is used to remove the water or methanol by-products. High temperature (>250oC) is necessary to provide the energy for the reaction, and to keep the resultant polymer in a molten state.

PET molecules are regular and straight, so their inter-chain forces are strong but not strong enough to prevent melting. Thus, PET is a thermoplastic material; that is, it can be melted and then solidified to form specific products. Since its melting point is high, it does not soften or melt at temperatures normally encountered in laundering or drying.

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4.2 PCDT Polyester

This variation of polyester is made by condensing terephthalic acid with 1, 4-cyclohexane-dimethanol to form poly-1, 4-cyclohexylene-dimethylene terephthalate or the PCDT Polyester. As for PET Polyester, PCDT is processed for melt spinning.

4.3 PBT - Poly Butylene Terephthalate

• Raw materials: BD + PTA• PBT Characteristics:

Its melting point is 232 °C. Its chief application is in field of industrial plastics. Lately, it has also been used to manufacture carpet yarns and textile fibres. Base resin is widely used in compounding. Has good chemical & heat resistance and outstanding electrical properties. It is easy to make flame retardant and master batches.

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5 Types of Polyester Yarns

The polyester yarns have a wide range of diameters and staple lengths. The yarns are made basically as monofilament yarns, multifilament yarns and spun yarns.

5.1 Filament Yarns

PET Polyester is used to make filament yarns either in monofilament or multifilament forms. The direction and amount of twists are decided by the desired end use. The properties are also pre-determined. There are various types of such yarns. There is the bright, regular tenacity polyester yarn having light, stretch and sag resistance, used for sheer lightweight fabrics like tulle, voile and organdy. The regular tenacity semi dull yarn used for various apparels including lingerie. Its more dull version is used for shirts and blouses. Polyester yarns resistant to various chemicals, and micro organisms are produced from high tenacity fibers for such industrial uses as conveyor belts, ropes and nets etc.

5.2 Textured Yarns

These yarns are made of PET multifilaments. Texturizing is either done along with the drawing process or afterwards during throwing or texturizing process.

5.3 Spun Yarns

They are made of staple or cut PET or PCDT polyester fibers. The staple may be bright, semi dull or dull and tenacity may be regular, mid or high. It may be polished to reduce crimp and increase luster. It may either be spun alone or blended with other staple such as cotton, wool or rayon and then spun into yarn.

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5.4 Trademarked Fabrics

Every manufacturer has its own registered trademarks which appear on labels and tags for its products. Within the group of variants of the types of polyesters ,the properties are essentially similar, but with modifications for specific characteristics.The difference in quality among polyesters depends upon the quality of the fiber and yarn production as well as the fabrication of the final product. The following table gives the details of the various trademarks of polyester fibres.

TRADEMARK MANUFACTURER TYPESPECIAL CHARACTERISTICS

USES

A.C.E. Allied Corp. Multifilament   Industrial fabrics, tire cord,rope

Crepesoft American Enka Co.

Multifilament   Apparel

Dacron E.I.du Pont de Nemours & co.

Multifilament , staple,tow.

Types vary according to desired purpose

Apparel, home furnishings, industrial fabric

Enron American Enka Co.

Multifilament Types vary according to desired purpose

Apparel,home furnishings

Enka polyester

American Enka Co.

Multifilament Types vary according to desired purpose

apparel, home furnishing, industrial fabrics

Fortrel Celanese Fibers Marketing Co.

Multifilament, staple,tow

Types vary according to desired purpose

Apparel, home furnishings, industrial fabric,tire

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cord

Fortel Pcp Celanese Fibers Marketing Co.

staple Producer-coloured Home furnishings.

Golden Touch

American Enka Co.

Multifilament fine denier Apparel, home furnishings

Hanover Polyester

Hanover Mills, inc.

Monofilament, multifilament

  Apparel, home furnishings, industrial fabrics

KodOfill Eastman Chemical Products, Inc.

Staple Hollow apparel, home furnishings

Lambda Celanese Fibers Marketing Co.

Multifilament Spunlike characteristics

Apparel

Matte touch American Enka Co.

Multifilament Octolobal apparel, home furnishings

Newton polyester

Newton filaments, Inc

Multifilament Industrial fabrics

Polyfyre Johnsons filament

Monofilament Flame retardent Industrial fabrics

Spectran Monsanto textiles Co.

staple Apparel

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6 Properties of Polyester

Strength – Polyester fibre is relatively strong and durable than other fibres. High tenacity – PET polyester filaments used for and industrial purposes. Abrasion resistance of polyester fibre is being exceeded only by nylon fibres. The strength, abrasive nature, and stability make polyester very suitable for

sewing thread where adequate tension is ensure without losing the shape of the garment.

PET polyester is superior in all regards of strength as compared to PCDT.

Elasticity – polyester do not shape as it has low degree of elasticity.(PCDT>PET ; elasticity)

Resilience – polyester fibre have high degree of resilience. it resist wrinkling when dry and even when wet.

Drapibility – polyester yarns are more flexible and softer thereby fabric have good draping quality

Heat conductivity – polyester fabric have average heat conductivity. polyester filament fibre is round and when converted into fabric it has fewer air spaces and less insulation.

Polyester fabric are less warm as compared to acrylic, silk and wool and more as compared to cotton, linen and rayon.

Absorbency – polyester is one of least absorbent fibre.It has advantages – it will dry rapidly(suited for water repellant purposes) It does not stain easily easy to clean and dry

It has disadvantage also. it is uncomfortable in humid weather as it does not absorb perspiration.

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Shrinkage – once set polyester fabric have excellent dimensional stability.

Resistant to insect – polyester is detestable to insects.

Affinity for dyes – dye friendly polyester gives variety of colours to the fabric.

Effect of bleaching – polyester fabric can be easily bleached owing to good resistance to deterioration.

Effect of heat – polyester fabric get sticky at 227-242 centigrade so ironing should be done at lower temperature.

Effect of light – polyester fabric has resistance to degradation by sunlight. This quality suited for use as curtains.

Effect of chemical – polyester fiber has resistance to medium acid-base treatment.

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7 Uses of Polyester

Polyester is the choice of fiber and fabric for many industries. It can be applied to a wide variety of useful purposes.

7.1 Use of polyester in garments

Polyester is used in the manufacturing of all kinds of clothes and home furnishings like bedspreads, sheets, pillows, furniture, carpets and even curtains. The disco clothing of the 70s with all its jazz and flash was made of polyester.

Hydrophobic nature: High tenacity and good durability makes polyester the choice of fabric for high stress outdoors use. Polyester is also a strong fiber that is hydrophobic in nature. It is thus ideal for clothing to be used in wet and damp environments. The fabric is also coated with a water-resistant finish and further intensifies the hydrophobic nature.

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Being the most heavily recycled polymer worldwide, it is also used by climbers. Climbing suits, parkas, sleeping bags and other outdoor gear are using the new insulating polyester fiberfill products. One can also do winter windsurfing wearing dry suits lined with polyester fleece.

Creating insulation: By creating hollow fibers it is also possible to build insulation into the polyester fiber. Air is trapped inside the fiber, which is then warmed by the heat of the body. This keeps the body warm in cold weather. Another method to build insulation is to use crimped polyester in a fiberfill. The crimp helps keep the warm air in. Polyester is an ideal fabric for this kind of insulation because it retains its shape. Cotton and wool tend to flatten over a period of time and loose the warming effect.

Wrinkle resistant: Polyester is also wrinkle resistant and is used very often in everyday clothing like pants, shirts, tops, skirts and suits. Used either by itself or as a blend, it is also stain resistant and hence very popular.

7.2 Industrial uses of polyester

While clothing used to be the most popular use of polyester and which made it a household name worldwide, there are many other uses polyester is put to.

PET: The most common use of polyester today is to make the plastic bottles that store our much beloved beverages. Shatterproof and cheap these bottles are an absolute boon to the beverages industry.

Mylar: An unusual and little known use of polyester is in the manufacturing of balloons. Not the rubber kind that you use for water balloons but the really pretty decorated ones that are gifted on special occasions. These are made of Mylar – a kind of polyester film manufactured by DuPont. The balloons are made of a composite of Mylar and aluminum foil.

Miscellaneous: Polyester is also used to manufacture high strength ropes, thread, hoses, sails, floppy disk liners, power belting and much more in industries.

 

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7.3 The Future

Following its introduction to the United States in 1951, polyester quickly became the country's fastest-growing fiber. Easy care of the permanent press fabric made polyester double knits extremely popular in the late 1960s. However, polyester has suffered an "image problem" since that time, and clothes made out of polyester were often devalued and even ridiculed. Several new forms of polyester introduced in the early 1990s may help revitalize the image of polyester. A new form of polyester fiber, called microfiber, was introduced to the public in 1991. More luxurious and versatile than traditional polyester, microfiber fabrics are difficult to tell apart from silk fabrics. Clothing designers

such as Mary McFadden have created a line of clothes using this new form of polyester. Textile researchers at North Carolina State University are developing a form

of polyester that may be as strong as Kevlar, a super fiber material used to make

bulletproof vests. This type of polyester may eventually be used as composite materials for cars and airplanes.

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8 BibliographyTextiles – Fiber to Fabric

www.texmin.nic

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