Pigment Dyeing

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DEFINITION: Pigment is a substrate in a particulate form which is insoluble in water but which can be dispersed in this medium to modify its color and light scattering properties. They are organic or inorganic coloring materials. They have no affinity to textile materials. They are fixed on the textile material with the help of binding agent in form a thin invisible coating.

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2. Name : MAZADUL HASAN SHESHIR ID: 2010000400008 Batch: 13th Batch (Session 2009-2013) Department: Wet Processing Technology Email: mazadulhasan@yahoo.com Blog: www. Textilelab.blogspot.com Southeast University Department of Textile Engineering PREPARED BY right 3. PIGMENT DYE DEFINITION: Pigment is a substrate in a particulate form which is insoluble in water but which can be dispersed in this medium to modify its color and light scattering properties. They are organic or inorganic coloring materials. They have no affinity to textile materials. They are fixed on the textile material with the help of binding agent in form a thin invisible coating. In pigment auxochrome groups are absent. Pigment dyeing is not really "dyeing" in it's truest form because the pigments stick on the fabric with the help of binders.. Pigments are insoluble in water. They exist in the form of finely ground molecules, milled for garment dyeing purposes into a paste. When anionic dispersing agents are added, a slightly negative charge is present, thus the foundation for pigment dyeing is born. When a positively charged cationic pre-treat is added to the fiber a magnetic bond is formed. The process is complete when a cationic binder is added to "lock" the pigment into place.In pigment dyeing no actual chemical reaction takes place between the dye and the fabric. 4. ClASSIFICATION OF PIGMENT: 5. PIGMENT DYEING PROCESS: 6. TRADE NAMES: Trade Names Manufacturer Country Wintramin Winsol chem- Industries India Helizerine BASF Germany Neopralac Francolor France Acramin Bayer AG West Germany 7. PROPERTIES OF PIGMENT: 1. Insoluble in water. 2. Organic or inorganic compounds. 3. No auxochrome group. 4. No direct affinity towards textile materials. 5. Binder is required for fixation. 6. Applicable to all kinds of fibers or textile materials. 7. No after treatment is required after coloration process. 8. Rubbing fastness is poor. 9. Water, wash and light fastness is very good. 10.A wide range of bright shades can be produced for some physical properties- Particle size : 0.2-0.4 Specific gravity : 1.14-1.37 for most of the pigments Boiling points : Decompose at 190- 345c Melting points : Softeners ranges from the points 110-175c 8. CHEMICAL PROPERTIES: 1. Most of the pigments are azoic compounds. Besides that it may be inorganic oxide, inorganic salt phthalocyanine metal compounds etc. 2. Insoluble in water andother solvents like white spirit, per chloroethylene, trichloroethylene, CCl4 etc. 3. Pigments are toxic. Some are oral toxic, some are dermal toxic, some causes eye irritation etc. 9. REQUIRED PROPERTIES OF PIGMENTS: 1. Should have good covering power. 2. Should be chemically inert. 3. Should have freely mixing quality. 4. Should have good resistance to acid, alkali, bleaching agent etc. 5. Should have good fastness properties. 6. Should be applicable to all fibers and textile materials. 7. Should have well resistant to solvents. 10. DIFFERENCE BETWEEN DYES AND PIGMENTS: DYES PIGMENTS 1. Water solubility is 70% 1. 100% water insoluble 2. Dyes have direct affinity to textile material 2. They have no direct affinity to textile materials 3. Auxochrome groups are present 3. Auxochrome groups are absent 4. Most of the dyes are organic 4. Most of dyes are inorganic 5. Costly 5. Cheap 6. No binding agent is required 6. Binding agent is required 7. Dye diffusions in the fabric 7. Pigment diffusions on the fabric 11. EXAMPLE OF VARIOUS PIGMENTS: ORGANIC PIGMENT: 1. Dyes converted into pigment: a) Dyes made insoluble by precipitation on substrate: Peacok Blue Lake : CI pigment blue 24 ; Bronze red pigment : CI pigment 90 b) Vat dyes converted into pigment: Thio indigo red violet : Violet 36 Indanthrone blue : Blue 60 Perinone orange : orange 43 2. Quinacridone: Cinquasia blue B, Cinquasia red Y, Cinquasia violet R. 3. Azo pigments: a) Metal free water insoluble azo- compounds (Group- I): CI pigment red: Red 3; Fire red: Red 4; Red tonner: Red 6; Per matone orange : Orange 5 b) Metal containing water soluble azo compounds: Low solubility (Group- 2a): Lithol red: Pigment red 49 Lake red: CI pigment red 56 4. High solubility (Group- 2b): Precipitation of pigment from orange 11: CI acid orange 7 12. INORGANIC PIGMENT: I. White pigment: A. Barytes ( Barium sulphate), B. Gypsum ( CaSO4 .2H2O), C. Whitening (CaSO4), D. China clay, E. talc and silica. 2. Colored pigment: Ultramine: China clay 30% + Sodium carbonate 32% +Sulphur 30% +Silica 4% +Rosin 4% EXAMPLE OF VARIOUS PIGMENTS: 3. Cadmium Pigment: Color components Prime Rose CdS, ZnS Yellow CdS Orange Cds, 0.2 CdSe RedCdS, 0.4 CdSe Maroon CdS, 0.7 CdSe 4. Iron Oxide: i) - FeOOH of Fe2O3 . H2O ii) FeSO4. H2O (Red, Brown, Black) iii) FeO, Fe2O3 and FeOOH (Mixed crystal) 13. INORGANIC PIGMENT: REQUIREMENT OF WHITE PIGMENT: 1. Primary requirement is that it should not absorb any radiation in the visible part of electromagnetic spectrum (400-700nm). 2. Second requirement is that it should be in the form of particles fairly uniform in the size with the diameter of the order of 100 nm. 3. Third requirement is that it should have as high refractive index between 1.5- 2.3 throughout the visible spectrum as possible. Example of White Pigment: They includeBarytes(BaSO4), Gypsum(CaSo4.2H2O),Whitening(CaCO3), China clay, talc,& Silica. 14. No. Organic pigments Inorganic pigments 1 These are natural pigments like the Cadmiums, Cobalts, Earth Colors, etc. These are pigments created in the laboratory and include the Pthalocyanines, Quinacidrones, Dioxazenes, Napthols, etc. 2 The main source of organic pigments are plants and plant products The inorganic pigments are manufactured from topical cosmetic and also from dirt. 3 Carbon chains or carbon rings are always present in the molecules of the Organic Pigments. In the molecules of the Inorganic Pigments, the cat-ions of metal are found in an array form with the non-metallic anions. This arrangement doesn't allow these pigments to dissolve in the solvent and plastic 4 have a high refractive index have much lower values 5 most inorganic pigments are opaque organic pigments are transparent Difference 15. COlORED PIGMENTS: At past- Yellow lead chromates and iron blue. They are not used for lead poisoning. Colored pigments are used when organic pigments are unsuitable or cant match. ULTRAMIN: 1) Synthetic form of blue mineral Lapis Lazuli (Latin name) incorporated from China and India. 2) Higher light fastness (Grade : 7-8). 3) Attractive blue color with excellent resistance to alkalies and all organic solvents. 4) Easily dispersible. 5) Non toxic. 6) Poor resistance to acid. 16. INGREDIENTS: NOTE: 4-5 days at 8000c. Requires absence of iron impurities. 17. CADMIUM PIGMENTS: A range of mixtures containing CdS and varying amount of ZnS and CdSe can give following colors: COlOR COMPONENTS PRIME ROSE CDS, ZNS YEllOw CDS ORANGE CDS, 0.2 CDSE RED CDS, 0.4 CDSE MAROON CDS, 0.7 CDSE PROPERTIES: 1. Outstanding brightness 2. Higher heat stability than organic pigments (400c). 3. Better solvent fastness and high migration fastness. 18. BINDER: Binders are film forming polymers which play important roles in achieving optimum fastness properties. Pigments have no affinity towards textile materials. So actually pigment particles are sticked on the surface of fabric. Binders are those adhesive type coating forming polymeric materials which sticks pigment particle on fiber / fabric surface. It forms a very thin invisible film on fabric surface during curing. Under this film pigment particles are remain sticked. Binders with a particle size range of 0.05 to 2 microns are usually available. These contain about 6% by weight of reactive groups for cross linking of the binder to textile. Cross linking increases the rubbing, washing & dry cleaning fastness properties but it affects the handle of fabric. 19. TYPES OF BINDER: According to origin: 1. Natural: Glue, Gelatine etc. 2. Synthetic: Acramin binder. According to chemical groups: 1. IG binder: Emulsion copolymer of vinyl acetate & butyl acrylate with modified urea formaldehyde. 2. AG binder: Emulsion copolymer of olifinic unsaturated monomers in an aqueous medium. Monomers include: 1. Acrylic acid ester 2. Styrene 3. Acrylonitrile 4. Vinyl chloeid etc. 20. PIGMENT DYEING PROCESS: Dying Recipe: Pigment 2 gm/ lit Binder 20 gm/ lit Levelling agent 1gm/ lit Temp (Padding) Room to 60c PH 4-5 Drying 100c Curing 140-180c for 2-3 min for cotton 160-180c for 2-3 min for synthetic M:L 1:20 to 1:30 21. Standard Recipe: Binder 25cc/L Fixer 7cc/L Leveling Agent 3cc/L Acetic Acid 3cc/L Pigment 5% owf pH