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Textile science

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Complete textile notes..

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Textile science

  1. 1. 1 1. Fiber Slide # 2 2. Spinning Slide # 81 3. Weaving Slide # 117 4. Knitting Slide # 166 5. Fabric Pretreatment Slide # 216 6. Dyeing Slide # 236 7. Printing Slide # 297 8. Finishing Slide # 404 9. Washing Slide # 466 10.Fabric Inspection Slide # 500 Textile Science : Index © 2007 www.vasantkothari.com
  2. 2. 2© 2007 www.vasantkothari.com
  3. 3. 3 FIBER ► A unit of matter characterized by Flexibility, Fineness and a high length to width ratio. Fiber Natural Man Made © 2007 www.vasantkothari.com
  4. 4. 4 Natural Fiber Mineral FiberAnimal FiberVegetable Fiber Jute Cotton Silk Wool Metal Glass Asbestos Linen © 2007 www.vasantkothari.com
  5. 5. 5 Natural Fiber Mineral FiberProtein FiberCellulosic Fiber Jute Cotton Silk Wool Metal Glass Asbestos Linen © 2007 www.vasantkothari.com
  6. 6. 6 Man Made Fiber Synthetic FiberRegenerated Fiber Acetate Viscose Nylon Polyester © 2007 www.vasantkothari.com
  7. 7. 7 Fiber Filament FiberStaple Fiber Polyester Cotton Nylon Silk © 2007 www.vasantkothari.com
  8. 8. 8 Primary Properties ► Length; length-width ratio ► Tenacity (strength) ► Flexibility (pliability) ► Acceptable extensibility for processing ► Cohesion ► Uniformity of properties © 2007 www.vasantkothari.com
  9. 9. 9 Secondary Properties ► Physical shape (cross-section, surface contour, etc. ► Specific gravity (influence weight, cover, etc.) ► Moisture regain and moisture absorption (comfort, static electricity, etc.) ► Elastic character - tensile and compression ►Thermoplasticity (softening point and heat-set character) ► Dyeability ► Resistance to solvents, corrosive chemicals, micro- organisms, and environmental conditions ► Flammability ► Luster © 2007 www.vasantkothari.com
  10. 10. 10 Fiber Cotton 4 2 2 1 4 4 2 2 4 4 4 2 2 3 0 4 3 4 0 2 4 2 59 Wool 3 3 0 4 4 2 1 2 4 4 0 4 2 4 0 2 3 4 3 2 4 4 59 Silk 4 4 4 4 4 4 0 2 4 4 2 2 4 4 1 4 3 4 3 2 2 4 69 Viscose 4 4 2 3 2 4 4 2 4 4 2 0 0 0 0 4 3 4 0 4 4 2 56 Acetate 4 4 0 3 2 2 4 0 2 2 4 2 4 4 2 4 2 2 2 0 4 4 57 Polymaid 4 4 4 4 4 2 3 4 2 2 4 2 4 4 4 2 2 2 2 4 2 2 67 Acrylic 4 4 3 4 4 0 3 4 0 0 2 4 4 2 4 4 0 2 1 2 4 4 59 Polyseter 4 4 4 4 4 0 3 4 0 0 2 4 4 4 4 0 2 2 2 4 4 4 63 Fineness Length Strength Elongation Elasticity WaterImbibition Price AbrasionResistance DyeAffinity Static Laundering BulkingPower DrapeandHandle CreaseResistance CreaseRecovery Pilling Wicking SofteningPoint Flammability FatigueResistance LightStability AestheticApparance GrandTotal Secondary FeaturesPrimary Features 0 - Poor ; 2 – Generally Acceptable ; 4 – Very Good © 2007 www.vasantkothari.com
  11. 11. 11© 2007 www.vasantkothari.com
  12. 12. 12 General Fiber Characteristics ► External Structure ●1. Length ■ (short staple 0.5 – 2.5 inches, long staple > 2 inches) ●2. Diameter ■ (natural 10-20 microns, manufactured 10 – 50 microns) ●3. Cross-sectional shape ●4. Crimp ●5. Color © 2007 www.vasantkothari.com
  13. 13. 13 General Fiber Characteristics ► Internal Structure ●1. Chemical Composition ■ Sequence and kind of atoms in structure ●2. Crystallinity ■ Polymer chains or sections packed together ●3. Orientation ■ Alignment of chains along fiber axis © 2007 www.vasantkothari.com
  14. 14. 14 General Fiber Characteristics ► Thermal Properties ●1. Melting Temperature ●2. Glass Transition Temperature ■ Most polymers are thermoplastic – they soften before melting © 2007 www.vasantkothari.com
  15. 15. 15 General Fiber Characteristics ► Physical Properties ●1. Breaking Strength ■ Force required to break a fiber ●2. Breaking Elongation ■ Amount of stretch before breaking ●3. Modulus ■ Resistance to deformation ●4. Toughness ■ Amount of energy absorbed ●5. Elasticity ■ Ability to recover after being deformed © 2007 www.vasantkothari.com
  16. 16. 16 General Fiber Characteristics ► Chemical Properties ●1. Density ●2. Moisture Regain ●3. Chemical Resistance ●4. Dyeability © 2007 www.vasantkothari.com
  17. 17. 17 Cotton © 2007 www.vasantkothari.com
  18. 18. 18 Cotton © 2007 www.vasantkothari.com
  19. 19. 19 Cotton: Advantages ► Absorbent. ► Cool. ► Comfortable to wear. ► Durable. ► Economical. ► Does not melt. © 2007 www.vasantkothari.com
  20. 20. 20 Cotton: Limitations ► Wrinkles unless treated. ► Susceptible to mildew and strong acids. ► May scorch. © 2007 www.vasantkothari.com
  21. 21. 21 ► Cotton is hypoallergenic since it doesn’t irritate sensitive skin or cause allergies ► Cotton’s softness makes it a preferred fabric for underwear and other garments worn next to the skin ► Cotton’s adaptability allows it to blend easily with most other fibres including synthetics such as polyester and lycra ► Cotton is one of the easiest fabrics to dye, making it very popular with fashion and homeware designers Cotton © 2007 www.vasantkothari.com
  22. 22. 22 Cotton ► Cotton can be given a coating or a finish. For example, cotton used in fire fighting uniforms is coated and finished with Proban®, a flame-retardant chemical treatment ► Durable press is a finishing treatment used in cotton garments to eliminate creasing and reduce the need to iron. It retains specific contours such as creases and pleats to be resistant to normal usage, washing or dry cleaning ► Cotton has a high absorbency rate and holds up to 27 times its own weight in water © 2007 www.vasantkothari.com
  23. 23. 23 Cotton ► Cotton also becomes stronger when wet ► Cotton’s strength and absorbency levels make it an ideal fabric for medical and personal hygiene products such as bandages and swabs ► Terry cloth is a cotton fabric used to make common items such as towels. It can be safely washed in very hot water and with strong bleach and/or detergent ► Cotton keeps the body cool in summer and warm in winter because it is a good conductor of heat © 2007 www.vasantkothari.com
  24. 24. 24 Cotton ► Cotton is often used in the manufacture of curtains, tents and tarpaulins as it is not easily damaged by sunlight ► Cotton breathes easily as a result of its unique fibre structure. This attribute makes cotton more comfortable to wear than artificial fibres unable to provide similar ventilation ► Unlike synthetic fibres, cotton is a natural product and contains no chemicals © 2007 www.vasantkothari.com
  25. 25. 25 Cotton Products ► Almost all parts of the cotton plant are used in some way, including the cottonseed, lint (raw cotton fibre), stalk and hull (shell) ► Popular uses for cotton fibre include clothing apparel, home furnishings and industrial/medical products such as tents, bandages and cotton swabs ► Well known cotton fibre products include denim jeans, socks, towels, t-shirts, bed sheets and underwear ► Cotton fibre can be woven or knitted into fabrics such as velvet, corduroy, chambray, velour, jersey and flannel © 2007 www.vasantkothari.com
  26. 26. 26 Cotton Products ► Linters are the very short fibres that remain on the cottonseed after ginning. Once removed and processed, linters are used to produce goods such as bandages, cotton buds, and x-rays ► The fibre from one 227 kg cotton bale can produce 215 pairs of jeans, 250 single bed sheets, 750 shirts, 1,200 t- shirts, 2,100 pairs of boxer shorts, 3,000 nappies, 4,300 pairs of socks or 680,000 cotton balls © 2007 www.vasantkothari.com
  27. 27. 27 Flex / Linen © 2007 www.vasantkothari.com
  28. 28. 28 Linen: Advantages ► Best wicking of natural fibers; therefore, cool to wear. ► Dries quickly. ► Natural, soft sheen. ► Strong and durable. ► Does not melt. © 2007 www.vasantkothari.com
  29. 29. 29 Linen: Limitations ► Wrinkles badly unless treated. ► Susceptible to mildew and strong acids. ► Color frosts on creases. ► May be weakened with repeated creasing in the same place. ► May scorch. © 2007 www.vasantkothari.com
  30. 30. 30 Silk © 2007 www.vasantkothari.com
  31. 31. 31 Silk © 2007 www.vasantkothari.com
  32. 32. 32 Silk © 2007 www.vasantkothari.com
  33. 33. 33 Silk: Advantages ► Luxurious. ► Lightweight. ► Dyes in beautiful, rich colors. ► Absorbent. ► Strong. ► Moderately wrinkle resistant. ► Resists mildew and moths. ► Does not melt. © 2007 www.vasantkothari.com
  34. 34. 34 Silk : Limitations ► Weakened by sunlight, perspiration and chlorine bleach. ► Absorbs body oils and grease stains. ► Water spots. ► Yellows and fades with age. ► Subject to attack by carpet beetles unless treated. ► Affected by high temperatures. ► Loses strength when wet. ► Should be pressed with a press cloth. ► Color damaged by hair spray. ► Damaged by perfumes. © 2007 www.vasantkothari.com
  35. 35. 35 Wool © 2007 www.vasantkothari.com
  36. 36. 36 Wool © 2007 www.vasantkothari.com
  37. 37. 37 Wool: Advantages ► Warm and comfortable to wear. ► Absorbent. ► Wrinkle resistant. ► Mold and shape easily when pressed. ► Water repellent. ► Flame resistant. ► Does not melt. © 2007 www.vasantkothari.com
  38. 38. 38 Wool: Limitations ► Subject to attack by moths and carpet beetles unless treated. ► May shrink and felt when laundered unless blended or especially treated. ► Damaged by chlorine bleach. ► Damaged by dry heat. ► Loses strength when wet. ► Sensitive to alkaline agents. ► Should be pressed with a press cloth. © 2007 www.vasantkothari.com
  39. 39. 39 Man Made Fiber © 2007 www.vasantkothari.com
  40. 40. 40 Melt Spinnig ► Typical Melt Spun Fibers ●Nylon ●Polyester ●Polypropylene ►Disadvantages ● Separate drawing step (unless spin draw) ►Advantages ●High speed (275 to 1500 yddmin); (4000 yddmin spin draw) ●No solvents ●No purification problems © 2007 www.vasantkothari.com
  41. 41. 41 Melt Spinning ► Melt Spinning ● simplest and economical ● melting the polymers ● molten polymer is extruded from spinneret ►ONLY limited to polymers which are stable to high temperatures. ► E.g., polyester, polyamides, polystryrene. etc © 2007 www.vasantkothari.com
  42. 42. 42© 2007 www.vasantkothari.com
  43. 43. 43© 2007 www.vasantkothari.com
  44. 44. 44 Dry Spinning ► Typical Dry Spun Fibers ●Acetate ●Spandex ► Disadvantages ●Flammable solvent hazards ●Solvent recovery ●Slow (200 - 400 yd/min) ► Advantages ●Yarn does not require purification © 2007 www.vasantkothari.com
  45. 45. 45© 2007 www.vasantkothari.com
  46. 46. 46© 2007 www.vasantkothari.com
  47. 47. 47 Wet spinning ► Typical Wet Spun Fibers ● Viscose ► Disadvantages ●Slow (70 - 150 yd/min) ●Washing to remove impurities ●Solvent and chemical recovery ► Advantages ● Large tows can be handled © 2007 www.vasantkothari.com
  48. 48. 48© 2007 www.vasantkothari.com
  49. 49. 49 Viscose © 2007 www.vasantkothari.com
  50. 50. 50 Viscose © 2007 www.vasantkothari.com
  51. 51. 51 Rayon: Advantages ► Dyes easily. ► Versatile. ► Relatively inexpensive. ► Absorbent. ► Does not melt. © 2007 www.vasantkothari.com
  52. 52. 52 Rayon: Limitations ► Wrinkles easily. ► Weaker when wet. ► Damaged by strong acids and mildew. ► May shrink or stretch unless treated. ► May scorch. © 2007 www.vasantkothari.com
  53. 53. 53 Nylon © 2007 www.vasantkothari.com
  54. 54. 54 Nylon: Advantages ► Extremely strong. ► Extremely durable. ► Can be heat set to retain pleats. ► Wrinkle resistant. ► Resists mildew and insect damage. ► Does not burn easily. ► High elasticity. ► Very resistant to abrasion. © 2007 www.vasantkothari.com
  55. 55. 55 Nylon: Limitations ► Builds up static electricity. ► Low moisture absorption. ► Grays and yellows with age and poor care. ► Picks up dye and soil in laundering. ► Absorbs and holds body oils and perspiration stains. ► Melts if too hot. ► Pills if spun. © 2007 www.vasantkothari.com
  56. 56. 56 Polyester © 2007 www.vasantkothari.com
  57. 57. 57 Polyester: Advantages ► Wrinkle resistant. ► Retains heat-set pleats and creases. ► Superior wash-wear performance. ► Strong. ► Resists damage from abrasion, strong sunlight, weather conditions, moths, mildew and most strong chemicals. © 2007 www.vasantkothari.com
  58. 58. 58 Polyester: Limitations ► Absorbs body oils. ► Accumulates static electricity. ► May pill and attract lint. ► Absorbs perspiration odor. ► Melts if too hot. © 2007 www.vasantkothari.com
  59. 59. 59 Spandex © 2007 www.vasantkothari.com
  60. 60. 60 Spandex: Advantages ► Provides strength without weight. ► Resists perspiration, cosmetic oils and lotions. ► Has elasticity; great stretch and recovery. © 2007 www.vasantkothari.com
  61. 61. 61 Spandex: Limitations ► Damaged by chlorine bleach. ► Absorbs little moisture. ► May yellow when exposed to light. ► Melts at relatively low heat. © 2007 www.vasantkothari.com
  62. 62. 62 Polypropylene © 2007 www.vasantkothari.com
  63. 63. 63 Fiber Strength © 2007 www.vasantkothari.com
  64. 64. 64 Specific Gravity © 2007 www.vasantkothari.com
  65. 65. 65 Thermal Properties © 2007 www.vasantkothari.com
  66. 66. 66 Thermal Properties © 2007 www.vasantkothari.com
  67. 67. 67 Absorbency © 2007 www.vasantkothari.com
  68. 68. 68 Sunlight Resistance © 2007 www.vasantkothari.com
  69. 69. 69 Fiber Blends - Some Reasons For Blending ► To facilitate processing ► To improve properties ● Abrasion resistance ● Strength ● Absorbency ● Hand ● Dimensional stability ● Resistance to wrinkling ► To produce multi-color fabrics ► To reduce cost © 2007 www.vasantkothari.com
  70. 70. 70 Summary Of Properties Desired For Textile Fibers ► Tenacity: 3 - 5 gram/denier ► Elongation at break: 10 - 35% ► Recovery from elongation: 100% at strains up to 5% ► Modulus of elasticity: 30 - 60 gram/denier ► Moisture absorbency: 2 - 5% ► Zero strength temperature (excessive creep and softening point): above 215' C © 2007 www.vasantkothari.com
  71. 71. 71 Summary Of Properties Desired For Textile Fibers ► High abrasion resistance (varies with type fabric structure) ► Dyeable ► Low flammability ► Insoluble with low swelling in water, in moderately strong acids and bases and conventional organic solvents from room temperature to 100' c ► Ease of care © 2007 www.vasantkothari.com
  72. 72. 72© 2007 www.vasantkothari.com
  73. 73. 73 Fiber Usage Customer Term Textile Property Comfort Moisture Character Flexibility Elasticity Thermal Character Appearance Optical Character Elasticity Durability Tensile Strength Toughness Flexibility Elasticity Easy Care Moisture Character Elasticity Dimensional Stability Safety Flammability Chemical Resistance © 2007 www.vasantkothari.com
  74. 74. 74 Fibers For Products ► Bed Shits ● The Consumer Expects the Soft and Warm Handle with Easy care Properties. ● Sheets are expected to be hard wearing and dimensional stable. ● The majority of bed sheets are manufactured from polyester / cotton blends. © 2007 www.vasantkothari.com
  75. 75. 75 Fibers For Products ► Shirting ● Shirts are expected to absorb perspiration as well as being non creasing and retaining their shape in wear. ● Easy care properties are essential and shirts must be hard wearing to give long service life. ● Like bed sheets, most shirts are made from polyester / cotton blends. © 2007 www.vasantkothari.com
  76. 76. 76 Fibers For Products ► Knitted Jumpers ● Jumpers are worn for warmth and need to be elastic so that they do not lose their shape in wear. ● Wool is often used, but its high cost is a disadvantage. ● Acrylic fibres are cheaper and have better easy care characteristic. ● Increasingly, cotton is used for jumpers and polyester / cotton for sweatshirts. © 2007 www.vasantkothari.com
  77. 77. 77 Fibers For Products ► Swimwear ● Swimwear needs to fit the body but also allow freedom of movement. ● The fibres must be resistance to salt water, as well as chlorinated water in swimming baths. ● almost exclusively, polyamids are used as the main fibres, with about % of Elastine to give stretch. ● This combination dries quickly since neither is water absorbent. © 2007 www.vasantkothari.com
  78. 78. 78 Fibers For Products ► Towels ● The most important characteristic of fiber for towels is the ability to absorb the water. ● It is useful that the towel will retain its shape in use and be soft to the touch. ● Cotton is the major fiber used although viscose could also be used. © 2007 www.vasantkothari.com
  79. 79. 79 Fibers For Products ► Tights ● Tights must fits to legs closely, yet be sufficiently elastic to allow moments. ● The fiber must be strong and extensible to give resistance to snagging, and highly elastic to prevent wrinkling. ● Polyamide is used for the main part of the tights while a small qty of elastane is used for the waisteband. © 2007 www.vasantkothari.com
  80. 80. 80 Fibers For Products ► Trousers ● The fibres used for the trousers can vary greatly according to consumer requirements. ● In all, easy care and dimensional stability for shape retentation are important. ● For warmth, polyester/wool is effective. This blend is less care. ● Summer trousers are often made from polyester/cotton and denim jeans are just 100% cotton. ● Jeans do not have easy care properties but are hard wearing; creasing in use is often a positive advantage to the consumer. © 2007 www.vasantkothari.com
  81. 81. 81© 2007 www.vasantkothari.com
  82. 82. 82 Spinning Spinning is the process where Fiber is Converted into Yarns Yarns are a grouping of fibres twisted together to form a continuous strand © 2007 www.vasantkothari.com
  83. 83. 83 Yarns Spun Filament Spun Yarns are composed of relatively short lengths of Fiber twisted or spun to hold them together Filaments yarns are composed of continuous strand of fibers which may be miles long © 2007 www.vasantkothari.com
  84. 84. 84 Spun Yarn © 2007 www.vasantkothari.com
  85. 85. 85 Blow Room Carding Draw Frame Speed Frame Ring Frame Combing Yarn Fiber © 2007 www.vasantkothari.com
  86. 86. 86 Blow Room Carding Draw Frame Speed Frame Ring Frame Combing Yarn Fiber Lap Card Sliver D/F Sliver Combed Sliver Roving © 2007 www.vasantkothari.com
  87. 87. 87 Yarn Fiber Lap Card Sliver D/F Sliver Combed Sliver Roving © 2007 www.vasantkothari.com
  88. 88. 88 Blow Room © 2007 www.vasantkothari.com
  89. 89. 89 Bale to Lap © 2007 www.vasantkothari.com
  90. 90. 90 Function ► Opening ► Cleaning ► Mixing © 2007 www.vasantkothari.com
  91. 91. 91 Mixing © 2007 www.vasantkothari.com
  92. 92. 92© 2007 www.vasantkothari.com
  93. 93. 93 Mixing © 2007 www.vasantkothari.com
  94. 94. 94© 2007 www.vasantkothari.com
  95. 95. 95© 2007 www.vasantkothari.com
  96. 96. 96 Carding © 2007 www.vasantkothari.com
  97. 97. 97 Carding ► Function ● Opening ● Cleaning ► Input ● Lap ► Output ● Card Sliver © 2007 www.vasantkothari.com
  98. 98. 98 Draw Frame © 2007 www.vasantkothari.com
  99. 99. 99 Drafting © 2007 www.vasantkothari.com
  100. 100. 100 Draw Frame ► Function ● To Parallel the Fibres ● Drafting ► Input ● 8-10 Card Sliver ► Output ● Drew Frame Sliver © 2007 www.vasantkothari.com
  101. 101. 101 Lap Preparation © 2007 www.vasantkothari.com
  102. 102. 102 Lap Preparation ► Function ● To prepare the Lap for Combing ► Input ● 8-10 Draw Frame Sliver ► Output ● Lap for Combing © 2007 www.vasantkothari.com
  103. 103. 103 Combing ► Function ● To remove the short Fibers ● To Parallel the fibres ► Input ● Lap ► Output ● Combed Sliver © 2007 www.vasantkothari.com
  104. 104. 104 Speed Frame ► Function ● To prepare the package for the R/F ● To impart the Twist ► Input ● Sliver ► Output ● Roving © 2007 www.vasantkothari.com
  105. 105. 105 Ring Frame © 2007 www.vasantkothari.com
  106. 106. 106 Ring Frame ► Function ● Twisting ● Drafting ● Winding ► Input ● Roving ► Output ● Yarn © 2007 www.vasantkothari.com
  107. 107. 107© 2007 www.vasantkothari.com
  108. 108. 108 Filament Yarn False Twist Stuffer Box Air Jet Knit de Knit © 2007 www.vasantkothari.com
  109. 109. 109 Yarn Twist Clockwise Anticlockwise © 2007 www.vasantkothari.com
  110. 110. 110 Yarn Count Direct Indirect Length is Constant Weight is Variable e.g. Tex Denier Weight is Constant Length is Variable e.g. English © 2007 www.vasantkothari.com
  111. 111. 111 Tex ► The Tex number is defined as the weight in grams of one thousand meters of the material. 10 gm 30 gm 40 gm 50 gm 1000 mtrs or 1 Km 1 g m 1 10 30 40 50 © 2007 www.vasantkothari.com
  112. 112. 112 English ►The English Count is defined as the numbers of hanks of 840 yds in length that weigh one pound in weight. 840 yds 4200 yds 8400 yds 16800 yds 3 3 6 0 0 y d s 1 lbs each 1 5 10 20 4 0 © 2007 www.vasantkothari.com
  113. 113. 113© 2007 www.vasantkothari.com
  114. 114. 114 Finer Yarn Coarser Yarn Direct System 1 5 10 20 25 30 40 50 60 70 70 60 50 40 30 25 20 10 5 1 Indirect System © 2007 www.vasantkothari.com
  115. 115. 115 Direct System Indirect System 1 5 10 20 25 30 40 50 60 70 © 2007 www.vasantkothari.com
  116. 116. 116© 2007 www.vasantkothari.com
  117. 117. 117© 2007 www.vasantkothari.com
  118. 118. 118 Winding ► To convert the smaller package in to bigger package ► To remove the faults of yarn ► To lubricate the yarn © 2007 www.vasantkothari.com
  119. 119. 119© 2007 www.vasantkothari.com
  120. 120. 120 Warping ► An operation where yarn is transferred from single packages of yam to an even sheet of yarn representing hundreds of ends and then wound onto a warp beam. ► To produce a beam which contains a large number of individual threads parallel to each other. © 2007 www.vasantkothari.com
  121. 121. 121 Sizing ► Around 8-10 Warper’s beams are passed through the Size paste which contains the Starch based adhesive. ► Sizing increases the Strength of yarn. ► It also reduces the hairiness. ► Make outer surface of yam smoother © 2007 www.vasantkothari.com
  122. 122. 122 Why Warp Yarns Need To Be Strengthened ?? ● Random variations in tension ■ due to large, badly shaped knot ■ yam and fiber entanglements ■ knot tails entangling ► To overcome weaknesses in the yam created by: ● Yam damage caused by the machine ● Weak places in the yam supplied ● Inadequate distribution of load over all warp ends ● Inadequate knotting or joining © 2007 www.vasantkothari.com
  123. 123. 123 Why Warp Yarns Need To Be Strengthened ?? ► To overcome tension levels in the warp ● Constant average tension determined by: ■ rate of take-up of cloth and let-off of warp ■ contraction of warp due to crimp ■ stretch of warp due to tension ● Cycling variations in tension ■ due to shedding ■ due to beat-up ■ higher level in dense fabric ■ highest tension in cycle is where a weak yam will break © 2007 www.vasantkothari.com
  124. 124. 124 Warp Preparation ► Drawing-In ● Provides each warp yam with its drop wire, heddle, and reed dent. ►Tying - In ● When mass producing the same fabric by simply typing each end of a new beam to its corresponding end of the old beam © 2007 www.vasantkothari.com
  125. 125. 125 Weaving ► Woven fabric consists of two sets of yarns at right angles to one another. ► Lengthwise yarns are the warp yarns (ends). ► Widthwise yarns are the filling yarns (picks). ► Fabric is woven on a machine called a loom. © 2007 www.vasantkothari.com
  126. 126. 126 Weaving © 2007 www.vasantkothari.com
  127. 127. 127© 2007 www.vasantkothari.com
  128. 128. 128 Weaving Warp Beam Warp Shuttle Reed Harness Healds Cloth Weft © 2007 www.vasantkothari.com
  129. 129. 129 Loom ► Essential features of a loom: ● Warp Bean - A roll containing all the warp yarns. For a 36 yarn per inch fabric woven at 36” wide, it would contain 1296 yarns. ● Harnesses - Controls the movement of warp yarns (i.e., up or down). This creates an opening or shed so that the filling yarn can pass through. ● Shuttle - A projectile that carries the filling yarn. The filling yarn is wound onto a bobbin. ● Reed - A frame with thin, vertical wires that separate the warp yarns after insertion of the filling yarns. It compacts each fill yarn into the fabric. © 2007 www.vasantkothari.com
  130. 130. 130 Motions of Loom ► Primary ● Shedding ● Picking ● Beating ► Secondary ● Let Off ● Take Up ► Auxiliary ● Warp Stop Motion © 2007 www.vasantkothari.com
  131. 131. 131 Shedding © 2007 www.vasantkothari.com
  132. 132. 132 Picking © 2007 www.vasantkothari.com
  133. 133. 133 Beating © 2007 www.vasantkothari.com
  134. 134. 134 Shedding © 2007 www.vasantkothari.com
  135. 135. 135 Shedding Motion ► Definition ● Shedding is a function of weaving involving the lifting of harnesses containing warp ends in order to provide a shed opening for filling insertion and to control design. ► Types Of Shedding ● Cam Shedding ● Dobby Shedding ● Jacquard Shedding © 2007 www.vasantkothari.com
  136. 136. 136 Jacquard Loom © 2007 www.vasantkothari.com
  137. 137. 137 Picking ► Shuttle ► Water ► Air ► Projectile ► Rapier ► Other © 2007 www.vasantkothari.com
  138. 138. 138 Woven Fabric Production © 2007 www.vasantkothari.com
  139. 139. 139 Shuttleless Looms ►Shuttleless Loom ● Filling yarn is supplied on cones at the side of the loom. ● Filling yarn is cut after each yarn insertion. ● Filling yarn is inserted by a projectile, rapier or jet nozzle. ● The rapier loom is often used to weave industrial fabrics. ● Shuttleless looms are 3 times faster than Shuttle types. © 2007 www.vasantkothari.com
  140. 140. 140 Shuttleless Looms ► Inserting the filling yarn for Shuttleless looms. © 2007 www.vasantkothari.com
  141. 141. 141 Rapier © 2007 www.vasantkothari.com
  142. 142. 142 Rapier © 2007 www.vasantkothari.com
  143. 143. 143 Air Jet © 2007 www.vasantkothari.com
  144. 144. 144 Air Jet © 2007 www.vasantkothari.com
  145. 145. 145 Projectile © 2007 www.vasantkothari.com
  146. 146. 146 Projectile © 2007 www.vasantkothari.com
  147. 147. 147 Terry Loom © 2007 www.vasantkothari.com
  148. 148. 148 Multiphase Weaving © 2007 www.vasantkothari.com
  149. 149. 149 Beat-Up Motion ► Functions of the reed ● Keep ends parallel and in the same position ● Beat the filling yarn into the fabric ● Provide some control for filling insertion ► Implications of increased beat-up ● Filling density ● Warp tension ● Noise and vibration ● Fabric structure and properties © 2007 www.vasantkothari.com
  150. 150. 150 Beat Up © 2007 www.vasantkothari.com
  151. 151. 151 Basic Weaves ► Plain Weave ► Twill Weave ► Satin Weave Plain Twill 2.2 Satin 8 © 2007 www.vasantkothari.com
  152. 152. 152 Plain ►Plain Weave - simplest and most common ►Each warp and fill yarn interlace with no floats. It makes one complete cycle on two ends and two picks. ►Only two harnesses are required on the loom. © 2007 www.vasantkothari.com
  153. 153. 153 Plain © 2007 www.vasantkothari.com
  154. 154. 154 Plain © 2007 www.vasantkothari.com
  155. 155. 155 Rib © 2007 www.vasantkothari.com
  156. 156. 156 Plain Basket Weave ►A popular version of the plain weave is the basket weave. ►Two or more warp yarns are woven with the same number of filling yarns. ►Basket weaves are used to increase tear strength and allow a higher yarn count vs. a plain weave. © 2007 www.vasantkothari.com
  157. 157. 157 Twill ►Twill Weave: ● Produce characteristic diagonal lines on the fabric. ● Can be right hand (diagonals upward to right), left hand (diagonals upward to left), or broken twill (herringbone or chevron). ● The angle of the twill can be varied. ● Twill weaves are infrequently used in industrial fabrics. Commonly used in denim jeans. © 2007 www.vasantkothari.com
  158. 158. 158 Twill © 2007 www.vasantkothari.com
  159. 159. 159 Twill Weave © 2007 www.vasantkothari.com
  160. 160. 160 Satin ► Satin Weave: ● Only one interlacing for each warp and fill yarn in each repeat. ● No two interlacings ever touch or are adjacent. ● Have a distinctive face side and back side to the fabric. ● Designation 5H Satin means there are only 5 interlacings in a repeat. 5 harnesses on the loom required to weave. ● Satins are know for the excellent hand a drapeability and are used extensively in rigid composites. © 2007 www.vasantkothari.com
  161. 161. 161 Satin © 2007 www.vasantkothari.com
  162. 162. 162 Satin © 2007 www.vasantkothari.com
  163. 163. 163 Sateen and Satin weft faced warp faced © 2007 www.vasantkothari.com
  164. 164. 164 Weave Variations are Produced By ► Different ply, count or texture of yarns ► Equal or unequal size and count for warp and filling ► Equal or unequal yam count for warp and filling ► Equal yarn size and unequal or dented spacing ► Equal yarn count for warp and filling and unequal yarn size ► Interlacing different patterns and weave effects ► Interlacing different colored yarns © 2007 www.vasantkothari.com
  165. 165. 165 Physical Properties of Fabric ► Weight ► Construction ► Strength - tensile and tear ► Abrasion resistance and pilling ► Dimensional stability (heat, washing, dry cleaning) ► Appearance &r washing ► Fastness (wash, light, gas) ► Stiffness and drape (handle) ► Sewability (seam strength and resistance to slippage) © 2007 www.vasantkothari.com
  166. 166. By Vasant Kothari © 2007 www.vasantkothari.com
  167. 167. Weaving is the intersection of two sets of straight threads, warp and weft, which cross and interweave at right angles to each other. Knitting is the interlooping of yarn(s), which are interlaced in a variety of ways to form a fabric. © 2007 www.vasantkothari.com
  168. 168. Woven Fabrics Knitted Fabrics Rigid (Inextensible), High Elastic Recovery. Weft Knit : Highly Extensible, Incomplete Elastic Recovery. Difficult to TearEasy to Tear Gets Crease And Wrinkled Highly Crease resistant Thinner Fabrics Thicker fabrics Stiffer Limb Air Permeability is Less Air Permeability is More Stronger Fabrics coz High Twist in Yarns Weaker Fabrics coz Less Twist in Yarns Tested by Loading or Extending fabrics in Warp/Weft Directions Tested by Multi-Directional fabric Bursting Strength Test © 2007 www.vasantkothari.com
  169. 169. : Courses are ROWS of loops across the width of fabrics, it is measured in units of (Courses / cm ) The number courses determine the LENGTH of fabric. : Wales are COLUMNS of loops across the length of the fabrics, it is measured in units of (Wales / cm ) The number of wales determine the WIDTH of fabric. © 2007 www.vasantkothari.com
  170. 170. Stitch Density : Stitch density refers to the total number of loops in a measured area of fabric. Stitch Density is the product of the courses and wales per unit length and is measured in units per square per centimeter. Stitch Length : Stitch length, measured in millimeters, is the length of yarn in one knitted loop. It is one of the most important factors controlling the properties of knitted fabrics. Generally, the larger the stitch length, the more open and lighter the fabric. © 2007 www.vasantkothari.com
  171. 171. NEEDLE LOOP The needle loop (H + L in Fig) is the basic unit of knitted structure. It consists of a head (H) and two side limbs or legs (L). At the base of each leg is a foot (F), which meshes through the head of the loop formed at the previous knitting cycle, usually by that needle. The yarn passes from the foot of one loop into the foot and leg of the next loop formed by it. Sinker Loop SINKER LOOP The sinker loop (S in Fig) is the piece of yarn that joins one weft knitted needle loop to the next. {The sinker is the second primary knitting element (the needle being the first). It is a thin metal plate with an individual or a collective action operating approximately at right angles from the hook side of the needle bed, between adjacent needles.} Functions: Loop formation, Holding-down, Knocking-over© 2007 www.vasantkothari.com
  172. 172. Knitting Notations A knitting notation is a simple, easily-understood, symbolic representation of a knitting repeat sequence and its resultant fabric structure that eliminates the need for time-consuming and possibly confusing sketches and written descriptions. Each point represents a needle in plan view from above and, after the thread path has been drawn, it also Represents its stitch. Each horizontal row of points thus represents adjacent needles during the same knitting cycle and the course produced by them. Point Paper The lowest row of points represents the starting course in knitting © 2007 www.vasantkothari.com
  173. 173. Graph/Squared Paper This method is developed by the Leicester School of Textiles for weft knitting only. In this method each square representing a needle or stitch. An ‘X’ symbol is placed in a square where a face stitch occurs and an ‘O’ where there is a reverse stitch. When notating each stitch, it is necessary to examine the intermeshing direction at the base of the loop because the intermeshing at its head determines the direction of the intermeshing of the new loop formed above it. © 2007 www.vasantkothari.com
  174. 174. TYPES OF NEEDLES Beard Needle Latch Needle Compound Needle Simplest, but requiring another element to control Self acting Two independent controlled part © 2007 www.vasantkothari.com
  175. 175. Beard Needle Head Beard Eye Stem Shank This is the simplest and cheapest It requires an additional element to close the beard during knitting A knitting section occupies a considerable amount of space, thus limiting productivity. Individual loop formation has to be achieved by a loop forming element. This leads to a more complicated knitting action but also provides for a more gentle and careful loop formation. © 2007 www.vasantkothari.com
  176. 176. The knitting action of the bearded needle © 2007 www.vasantkothari.com
  177. 177. LATCH NEEDLE 1 The hook 2 The slot or saw cut 3 The cheeks or slot walls 4 The rivet 5 The latch-blade 6 The latch spoon 7 The stem 8 The butt 9 The tail © 2007 www.vasantkothari.com
  178. 178. The knitting action of the latch needle © 2007 www.vasantkothari.com
  179. 179. COMPOUND NEEDLE Compound needles consist of two separately- controlled parts – the open hook and the sliding closing element (tongue, latch, piston, plunger). It is most popular in Warp Knitting m/c. Strain is not put on the yarn. Both members of Compound Needle have a straight moment, thus the knitting speed can be increased. These are very expensive to manufacture. Compound Needles are also consist of Hallow steel tube of finer guage in which a hook closing element, which is also a steel tube of fine guage, is inserted© 2007 www.vasantkothari.com
  180. 180. The loops are formed across the width of fabric It possible to knit with ONE thread e.g. Circular Knitting machine The loops are formed vertically down the length of fabric Warp beam is used e.g. Tricot & Raschel machine © 2007 www.vasantkothari.com
  181. 181. © 2007 www.vasantkothari.com
  182. 182. Staple as well as Filament yarns can be worked Successfully. Filament Yarn can be worked Successfully. (Staple: Size  Fluff) Costlier To Produce Latch Needles are used Latch, Beard or Compound Needles are used. Less Versatile M/c. Versatile M/c Speed reduces with Design change in Cams Change in Pattern does not affect the Speed of M/c Fabric Quality is not Consistent Fabric Quality is Consistent Loops are not Uniform Loops are Uniform Stretch in Both Direction Stretch in Widthwise Direction Less Dimensional Stability More Dimensional Stability Cheaper To Produce© 2007 www.vasantkothari.com
  183. 183. WEFT KNITTING ♣ In weft knitting, the loops are formed across the width of the fabric, and each weft thread is fed, more or less, at right angles to the direction in which the fabric is produced. ♣ It is possible to knit with only one thread or cone of yarn, though production demands have resulted in circular weft knitting machines being manufactured wit up to 192 threads (feeders). ♣ Compared to Warp knitting, Weft knitting is more versatile method of fabric production in terms of both the range of fabric structures that can be produced and the yarn types that can be utilised. ♣ Weft knitting is the simplest method of converting a yarn into a fabric. © 2007 www.vasantkothari.com
  184. 184. WEFT KNITTING MACHINE Straight bar Machines V-Bed Machines Circular machines Θ The simplest weft knitting machinery has one set of needles, arranged either in a straight line or around cylinder. These machines are capable of producing single jersey fabrics and can use a combination of knit, miss or tuck stitch. Θ With two needle beds, double jersey fabrics such as rib & interlock can be produced on both flat bar and circular machines. In the case of circular m/cs this second needle bed takes the form of a dial, a flat disc placed on the top of cylinder. In case of v-bed m/cs, the two beds forms an inverted ‘v’ shape. Θ In the case of purl machines, two needle beds are used. They can be flat or circular and use special double hooked needles. In the circular version, the second set of needles is in the form of a second cylinder positioned above the first.© 2007 www.vasantkothari.com
  185. 185. WEFT KNITTING FABRICS In woven fabric structures, three weaves, are called basic Weaves viz. PLAIN, TWILL & SATIN. It is considered that in single layer fabrics all other modifications of the structures are derivatives of PLAIN, TWILL & SATIN. In a similar way in a weft knit structures the following four structures are considered as basic Weft-knit structures.. 1 Plain Single Jersey Fabric 2 Rib Fabrics 3 Interlock Fabrics 4 Purl Fabrics© 2007 www.vasantkothari.com
  186. 186. Plain Single Jersey Fabric The three-dimensional structure of plain weft knitting magnified x130 by a stereo scan electron microscope. The arrows indicate the direction in which the fabric will tend to curl if it is cut.© 2007 www.vasantkothari.com
  187. 187. Plain single jersey is the simplest weft knitted structure that it is possible to produce on one set of needle. Plain is the base structure of ladies’ hosiery, fully fashioned knitwear and single-jersey fabrics. The production rate is very high because of stitch simplicity and its cost is low because of machine simplicity. If the yarn breaks, needle loops successively unmesh down a wale and sinker loops unmesh up a wale. The stitch length can be varied with cam setting giving more courses per unit length with short stitch length and vice versa. The properties such as rigidity, air permeability, weight per unit area, bursting strength changes with the stitch length. The fabric may appear thick of flimsy if the stitch length is reduced or increased. The fabric can be unroved from either end and if a stitch is broken, the wale will disintegrate causing the stitches in that line to undo or ladder. © 2007 www.vasantkothari.com
  188. 188. THE KNITTING ACTION (a) Tucking in the hook or rest position. The sinker is forward, holding down the old loop whilst the needle rises from the rest position. (b) Clearing. The needle has been raised to its highest position clearing the old Loop from its latch. © 2007 www.vasantkothari.com
  189. 189. (d) Knock-over. The sinker is fully withdrawn whilst the needle descends to knock-over its old loop on the sinker belly. (e) Holding-down. The sinker moves forward to hold down the new loop in its throat whilst the needle rises under the influence of the upthrow cam to the rest position where the head of the open hook just protrudes above the sinker belly. (c) Yarn feeding. The sinker is partially withdrawn allowing the feeder to present its yarn to the descending needle hook and also freeing the old loop so that It can slide up the needle stem and under the open latch spoon. © 2007 www.vasantkothari.com
  190. 190. Rib Fabrics The term Rib is used to describe a knitted fabric with vertical rows (wales) of loops meshed in the opposite direction to each other. © 2007 www.vasantkothari.com
  191. 191. Rib fabrics are generally produced on V-bed or Circular machines. In both the cases, loop formation is effectively same, with V-bed machines having a front bed and a back bed, while Circular machines have a cylinder and dial It is a reversible structure, i.e. face and back side has the same appearance in 1 x 1, 2 x 2, 3 x 3, ribs. It is heavier and thicker structure than the plain knit structure with similar gauge used. The rib machine also requires finer yarn than a similar gauge plain machine. Rib fabrics are extensively used in the production of outwear garments. The fabric does not curl at the edges due to its balanced nature. This property of rib structure is particularly useful in cutting and sewing operation. Like all weft-knitted fabrics, it can be unroved from the end knitted last by drawing the free loop heads through to the back of each stitch. It is a more expensive fabric to produce than plain. © 2007 www.vasantkothari.com
  192. 192. The Knitting Action of the Circular Rib Machine (a) Clearing The cylinder and dial needles move out to clear the plain and rib loops formed in the previous cycle. (b) Yarn Feeding The needles are withdrawn into their tricks so that the old loops are covered by the open latches and the new yarn is fed into the open hooks. (c) Knocking-over The needles are withdrawn into their tricks so that the old loops are cast off and the new loops are drawn through them. © 2007 www.vasantkothari.com
  193. 193. Interlock Fabrics Interlock is a popular double jersey structure produced on a cylinder and dial circular weft knitting machine. Interlock is a interlocking of two 1 x 1rib structures in such a way that the face wale of fabric “1” is directly in front of the ‘reverse wale’ of the rib fabric “2”. © 2007 www.vasantkothari.com
  194. 194. Interlock is a reversible fabric, which has a similar smooth appearance on each side. It does not curl at the edges. The fabric is firm i.e. less extensible due to interlocking structures knitted in two separate planes by the sinker loops. Fabric is thicker, stronger, less elastic and hence is nearer to the woven structure so that cutting and sewing operations are easier. It unroves from the course knitted the last. Due to complicated mechanisms cam tracks and short and long needles operating on the machine, the speed and number of feeds are reduced and thus affecting the production. The fabric becomes costlier due to thickness and less production. Interlock is used for outwear fabrics (dress wear and skirts), often using wool, acrylic and polyester yarns, while cotton and polyester/cotton blends are used for the production of underwear fabrics. © 2007 www.vasantkothari.com
  195. 195. Purl Fabrics 1 x 1 Purl fabric has loops knitted to the front and back on alternate courses, in the contrast to a 1 x 1 rib fabric which is knitted to the front and back on alternate wales. © 2007 www.vasantkothari.com
  196. 196. Interlock is a popular double jersey structure produced on a cylinder and dial circular weft knitting machine. In the simplest purl structures each wale consists of face and reverse loops. It is reversible in appearance and has soft hand with full cover. Its thickness is theoretically double to that of plain knit. Like the jersey knit fabric, it can be unroved from either end. As the link machine has a horizontal bed for the needles to reciprocate, the speed of the machine and the production is much less. It does not curl at the edges and because of alternate face and reverse courses it is a balance structure which property is useful in cutting and sewing. © 2007 www.vasantkothari.com
  197. 197. 1 Engagement of the head of the receiving slider with the needle hook that was originally knitting from the opposing bed. 2 Cam action causing the head of the delivering slider to pivot outwards from the trick and thus disengage itself from the other hook of the needle. 3 Sufficient free space to allow the heads of the sliders to pivot outwards from their tricks during engagement and disengagement of the needles. 4 A positive action which maintains the engagement of the head of a slider with a needle hook throughout its knitting cycle by ensuring that it is pressed down into the trick.© 2007 www.vasantkothari.com
  198. 198. Circular Fabric Knitting Machine © 2007 www.vasantkothari.com
  199. 199. WARP KNITTING  Warp knitting forms fabric by interlacing loops of yarn, but vertically down the length of the fabric in contrast to weft knitting.  Each needle in the knitting width must be fed by at least one yarn and in line with the direction of fabric production.  It is the fastest method of fabric production using mainly continuous filament yarns. Construction Beams supply the warp sheets in parallel form to the guide bars, whose pattern control determines the timing and configuration of the lapping movements in the form of overlaps and underlaps. The needles intermesh the new overlaps through the old overlaps to form the intermeshed loop structure. © 2007 www.vasantkothari.com
  200. 200. WARP KNITTING MACHINES Tricot Machine Raschel MachineCompound-Needle Warp Knitting Machine © 2007 www.vasantkothari.com
  201. 201. Tricot Machine Raschel Machine Needles Beard Latch or Compound Machine Gauge Finer Gauge 24s-40s Common Gauge 30,40 & 56 No. of Guides bars Two, Three, Four bars Between 4 and 36 Yarn Used Finer continuous Filament Yarn Coarser Filament or Coarser, Decorative Staple Spun Yarn Weight of fabrics Light Weight Heavy Weight Properties More Resilient, Better Drape, Higher Bursting Strength, Better Dimensional Stability. Soft Hand & Even. Opaque & Tight Less Resilient, Poor Drape, Lower Bursting Strength, Poor Dimensional Stability. Hard Hand & Uneven. & Loose Cloth Take up The fabric comes off the machine at 90o to the needle bed The fabric comes off the machine at 170o to175o the needle bed Speed Higher Less Versatility Less Versatile More Versatile © 2007 www.vasantkothari.com
  202. 202. TRICOT MACHINE The main parts of TRICOT MACINE are :  The warp beam carrying warp threads.  The sley bars which space the warp threads.  The tension bar which maintains tension in the warp threads, one bar foe each warp.  The knitting element, comprising the warp guides, sinkers, needles & presser bar.  The fabric take up rollers which take the fabric from the rollers at a constant rate.  The batch roller which winds up the fabric on a large rolls &  The crank shaft drive within a case which holds the mechanism for driving the knitting elements. © 2007 www.vasantkothari.com
  203. 203. Cross-section of a bearded needle tricot machine© 2007 www.vasantkothari.com
  204. 204. © 2007 www.vasantkothari.com
  205. 205. © 2007 www.vasantkothari.com
  206. 206. © 2007 www.vasantkothari.com
  207. 207. © 2007 www.vasantkothari.com
  208. 208. APPLICATIONS © 2007 www.vasantkothari.com
  209. 209. © 2007 www.vasantkothari.com
  210. 210. RASCHEL MACHINE The main Parts of the RASCHEL MACHINE are :  The ground beams and pattern beams having an access from front, top and back  The tension bar (one for each warp) which maintains tension in the warp threads.  Guide bars and guide bar levers and the sley bar.  The knitting elements comprising guides, sinkers, needles, latch needles and trick plates.  The fabric tension rollers, situated close to the knitting elements.  The fabric batch roller &  Main drive for the cam shaft. © 2007 www.vasantkothari.com
  211. 211. © 2007 www.vasantkothari.com
  212. 212. © 2007 www.vasantkothari.com
  213. 213. © 2007 www.vasantkothari.com
  214. 214. © 2007 www.vasantkothari.com
  215. 215. Compound-Needle Warp Knitting Machine  Compound Needle (main Body)  Compound Needle (Closing Element)  Trick Plate  Sinker  Yarn End  Yarn Guide  Fabric For increasing the productivity of the warp knitting machines a compound needle has been used instead of a beard ar latch needle on modern machines. © 2007 www.vasantkothari.com
  216. 216. 216© 2007 www.vasantkothari.com
  217. 217. 217 Pretreatment Before, Prior to A manner of dealing with something artistically ►“Pre” ►“Treatment” © 2007 www.vasantkothari.com
  218. 218. 218 Pretreatment ► The term "Preparation" has two implications in textile processing. ● In Greige manufacturing ■ In greige manufacturing it is used to describe the processes which prepare yarns for weaving and knitting. ● In Wet Processing ■ In Wet Processing, the term is used to describe those processes that ready fabrics for the steps that follow, coloration and finishing. © 2007 www.vasantkothari.com
  219. 219. 219 Fabric Pretreatment ► “Pretreatment can be defined as a series of cleaning processes / steps / operations that make the fabric fit for the preceding process e.g. Dyeing or Printing and Finishing” ► The steps that follow, dyeing or printing and finishing, are greatly influenced by how the fabric is prepared. ► Improper preparation is often the cause of problems encountered in the dyeing and finishing steps. © 2007 www.vasantkothari.com
  220. 220. 220 Fabric Pretreatment Singeing Desizing Mercerizing Scouring Bleaching Heat Setting © 2007 www.vasantkothari.com
  221. 221. 221 Singeing ► Definition ● Singeing is the burning off of loose fibers sticking out of textile goods. It is usually the first step carried out after weaving ► Purpose ● Clean fabric surface ● Reduce pilling ● Increased wettability ● Improved visibility of the fabric structure ● Decreased contamination through removal of fluff and lint. © 2007 www.vasantkothari.com
  222. 222. 222© 2007 www.vasantkothari.com
  223. 223. 223© 2007 www.vasantkothari.com
  224. 224. 224 Singeing © 2007 www.vasantkothari.com
  225. 225. 225 Desizing ► Definition ● Desizing is the process of removing the size material from the warp yarns in woven fabrics ► Types of Sizes ● Starch ● Poly (Vinyl Alcohol) or PVA ● Carboxy Methyl Cellulose or CMC ► Purpose ● Removal of added impurities like starch ● Weight loss ● Improved wettability © 2007 www.vasantkothari.com
  226. 226. 226© 2007 www.vasantkothari.com
  227. 227. 227 Scouring ► Definition ● Remove Dirt, Grease, Wax and Oil Impurities ► Two types of Systems ● Aqueous (water) Based ● Solvent ► Problems ● Uneven Dyeing, Spots, Blotches ● Fastness ● Yellowing ● Smoke ● Redeposition (Polyester) © 2007 www.vasantkothari.com
  228. 228. 228© 2007 www.vasantkothari.com
  229. 229. 229© 2007 www.vasantkothari.com
  230. 230. 230 Contents Of Cotton Fibers After Ginning ► Cellulose 95% ► Proteins 1.3% ● Hydrolyzed to soluble fragments ► Pectic Substances 0.9% ● Soluble in alkaline bath ► Ash (Ca, Mg, K, Na, phosphates, carbonates) 1.2% ● Soluble in water ► Organic Acids 0.8% ● Soluble in alkaline bath ► Wax ● Converted to soap © 2007 www.vasantkothari.com
  231. 231. 231 Contents Of Cotton Fibers After Ginning ► Wax ● Converted to soap ►Sugars 0.3% ● Soluble ► Other(Dirt) 0.9% ● Removed hy suspension or emulsification ►Scouring removes residual size and ruptures primary wall to increase absorbency ► Bleached cotton is > 99% Cellulose © 2007 www.vasantkothari.com
  232. 232. 232 Bleaching Systems ► Definition ● Bleaching is the process of removing natural pigments and vegetable impurities ► Purpose ● Improved whiteness ● Level dyeing properties ► Hydrogen Peroxide (H202) ● Cotton, Silk, Wool, Jute, ► Sodium Hypo chloride (NaOCl) ● Cotton © 2007 www.vasantkothari.com
  233. 233. 233 Mercerization ► Definition ● Mercerization is a treatment for cotton fabric and thread mostly employed to give cotton a lustrous appearance ► Purpose ● Improve dye finity and yield ● Improve breaking strength ● Improve dimensional stability ● Improve chemical reactivity ● Improve fabric smoothness ● Cover immature cotton fibers © 2007 www.vasantkothari.com
  234. 234. 234 Mercerization Before After 1-5 Swelling process in an alkaline solution 6 Removal of alkali by water substitution 7 After drying © 2007 www.vasantkothari.com
  235. 235. 235 Heat Setting ► Definition ● Heat treatment of fabrics containing thermoplastic synthetic fibers. Stabilizes fabric by reducing shrinkage and distortion ► Purpose ● Thermoplastic fibers are undergo through the process of heat setting and results in: ■ Stabilization of fabric structure © 2007 www.vasantkothari.com
  236. 236. © 2007 236www.vasantkothari.com
  237. 237. 237 ► Coloring of Textile Material is called as Dyeing ► Coloration of Dyeing involves the use of Dye Stuff which are capable of reacting and combing with the Textile fiber molecule, usually when in a water solution, and usually with other auxiliary chemicals to enhance the process. ► Depth of Shade: The Darkness or Lightness of Color in Dyeing is known as the depth of the shade, this depend on the quantity of the Dye used in the ratio to the fiber weight. Dyeing Definition © 2007 www.vasantkothari.com
  238. 238. 238 Dye Definition ► Colorant which is homogeneously dispersed in the dye medium ► Usually soluble ► Naturally occurring or synthetic organics ► Categorized by... 1. Method of Application 2. Chemical Structure ► The application of color to the whole body of a textile material with Some degree of fastness. © 2007 www.vasantkothari.com
  239. 239. 239 Principle of Dyeing ► The Textile material is moved in a solution of a Dye, then the dye is attracted to the material and it is seen that the dye liquor gradually looses its color whilst the Textile material becomes more deeply Dyed. © 2007 www.vasantkothari.com
  240. 240. 240 Dye Expectations ► Dyeing is a craft, not a pure science, and like all crafts there is a learning curve and many nuances that affect the outcome... ► The color, evenness (or lack thereof) and total effect produced depends on several factors that you control: the amount of dye used, ... the temperature of the water of the dye bath,… the fabric, whether pre-washed or not,… particular water chemistry, the type of fabric, does the fabric have any treatments on it, time for the process, etc., etc. © 2007 www.vasantkothari.com
  241. 241. 241 ► The color and evenness depends on the factors above and more, most of which you can control, some of which you cannot. Colors also can vary from dyelot to dyelot because the pure primary colors used for mixing can vary a little from the original manufacturer, which can affect the mixes made with them. ► To repeat a color exactly, you need to use the same dyelot, and you need to do everything exactly the same as you first did it. Dye Expectations © 2007 www.vasantkothari.com
  242. 242. 242 Objectives Of Dyeing ► Shade ► Fastness Properties ► Cost © 2007 www.vasantkothari.com
  243. 243. 243 Keys To Good Quality ► Consistency ► Uniformity ► Knits - Low Tension ► Woven - Penetration © 2007 www.vasantkothari.com
  244. 244. 244 Types Of Dyeing Systems ► Aqueous - in water ► Non-aqueous - in organic solvents ► Sublimation - thermosol, heat transfer © 2007 www.vasantkothari.com
  245. 245. 245 Types of Fibers ►Hydrophilic Fibers Cotton, Rayon, Wool, Silk, etc.. ►Hydrophobic Fibers Acetate, Polyesters, Polyamides, etc… © 2007 www.vasantkothari.com
  246. 246. 246 Basic Steps In Dyeing ► Dissolve or Disperse dye ► Diffuse the dye to the surface of the fiber ► Adsorb the dye "onto" the fiber surface ► Diffuse dye "into" the fiber © 2007 www.vasantkothari.com
  247. 247. 247 Causes Of Non-Level Dyeing ►Too little agitation ►Too low liquor ratio ►Rate of dyeing too high ►Uneven pick-up in padding ►Uneven moisture penetration ►Migration during drying ►Chemical or mechanical bard in the fabric ►Dyebath Instability ►Construction © 2007 www.vasantkothari.com
  248. 248. 248 Factors In Selecting Dyes ►Economy ►Shade (brightness or dullness) ►Fastness Requirements ►Level Dyeing Properties ►Barre Control ►Ease of Dispersed Dissolving ►Dusting ►Environmental Concerns © 2007 www.vasantkothari.com
  249. 249. 249 Dyes for Cellulose Fibers ►These are your choices if you want to dye a t-shirt. Cellulose fibers include cotton, linen, rayon, hemp, ramie, and tencel. ►Fiber Reactive Dyes (best choice) ►Direct Dye (hot water dye, less washfast) ►Vat Dyes (more complex method) ►Naphthol dyes (more hazardous, less available) ►All purpose Dye (hot water dye, less washfast) © 2007 www.vasantkothari.com
  250. 250. 250 Dyes for Protein Fibers ►Protein fibers include all fibers made by animals: wool, angora, mohair, cashmere, as well as silk. Silk is the only non-hair animal fiber, and can be dyed like wool or like cellulose fibers, above. The high-pH recipes used for most cellulose dyes will ruin animal hair fibers. ► Dyes that can be used for protein fibers include the following: ►Acid dyes ►Reactive dyes used as acid dyes ►Natural dyes (these work better on wool than on cotton) ►Vat Dyes © 2007 www.vasantkothari.com
  251. 251. 251 Dyes for Synthetic Fibers ► Polyester requires the use of disperse dyes. ► Nylon, which is a truly synthetic fiber, happens to dye quite well with the same acid dyes that work on wool and other animal fibers. Nylon can also be colored with a type of fabric paint called 'Pigment dye'. ► Acetate, also known as rayon acetate, requires the use of disperse dye. ► Acrylic can be dyed with disperse dyes or with basic dyes. © 2007 www.vasantkothari.com
  252. 252. 252 Dyeing blends ► Most cotton/polyester blends are best dyed as for cotton, using fiber reactive dyes, leaving the polyester undyed. Cotton/nylon blends may be dyed with all-purpose dye, first with soda ash at room temperature to dye the cotton, then in hot water with vinegar to dye the nylon. © 2007 www.vasantkothari.com
  253. 253. 253 Coloring Matter Dyes Pigment Readymade Ingrain Water Soluble Azoic, Oxidation, Mineral Water Insoluble Direct, Acid, Basic, Reactive Vat, Sulphur, Dispersed Vat, Azoic, Mineral © 2007 www.vasantkothari.com
  254. 254. 254 Fiber Type Application Cellulose Protein Polyamide Polyester Acrylic Acetate Direct Reactive Vat Sulphur Azoic Acid Mordant Basic Disperse © 2007 www.vasantkothari.com
  255. 255. 255 ►Direct dyes: used for cotton, linen, regenerated cellulose fibers, and some synthetics ►Mordant dyes: wool, silk and nylon ►Sulphur dyes: cotton ►Vat dyes: cotton and cellulose fibers ►Soluble vat dyes : cotton, viscose rayon, wool, and silk ►Basic dyes : wool, slik and other protein fibers, and some synthetics ►Dispersed dyes: acetate and some other synthetics ►Azoic dyes: cotton and viscose rayon, acetate and some other synthetics, and silk ►Acid dyes: wool, silk, and some synthetics © 2007 www.vasantkothari.com
  256. 256. 256 Dye Type Fiber Affinity End Use Direct Cellulosics Low quality Apparel Fabrics/Lining/Curtains Acid Protein Fibres Carpet Yarns / Dress Goods Vat Cellulosics High Quality Curtains, furnishings, shirts, towels, sewing threads Reactive Cellulosics Curtains, furnishings, apparel fabrics, towels, sewing threads Basic Acrylics Furnishings, apparel fabrics Disperse All Synthetics Apparel fabrics, bed sheets, carpets © 2007 www.vasantkothari.com
  257. 257. 257 Dye Type Light Fastness Washing Fastness Direct Poor / Good Poor Acid Good/Moderate Poor Vat Excellent Excellent Reactive Good/Excellent Excellent Basic Good/Moderate Good Disperse Good/Moderate Good © 2007 www.vasantkothari.com
  258. 258. 258 Dye Type Comments Direct Cheap, After treatment can improve fastness Acid Bright Colors, Vat Expensive, Bright color often difficult to achieve Reactive Excellent Shade range, Good Fastness Basic Bright Shades Disperse Best Fastness on polyester © 2007 www.vasantkothari.com
  259. 259. 259 Direct Dyes ► Direct dyes are a class of dyes for use on cellulose fibers, such as cotton. ► The colors of most direct dyes are duller than those provided by fiber reactive dyes, and the wash fastness is poor. ► One small advantage is that direct dyes are, in just a few cases, a little more lightfast, that is, resistant to fading in the light, than a few of the fiber reactive dyes. ► Without an appropriate after-treatment, direct dyes bleed a little with every washing, losing their brightness and endangering other clothes washed in the same load. © 2007 www.vasantkothari.com
  260. 260. 260 Disperse Dyes ► These dyes derive their names from their insoluble aqueous properties and the need to apply them from an aqueous dispersion. ► Polyester requires the use of disperse dyes. ► Disperse dyes on fabric are more likely to cause allergies than other textiles dyes. ► Wash Fastness varies with the fibers. ► Fastness to Crocking is Good to Excellent. ► Light Fastness is Fair to Good. © 2007 www.vasantkothari.com
  261. 261. 261 Acid Dyes ► Acid dyes are water soluble anionic dyes which are applied to fibers such as silk, wool, nylon & modified acrylic fibers from neutral to acid dye baths. ► Bright Colors. ► Most are non fast to washing. ► Excellent Fastness to Dry Cleaning. © 2007 www.vasantkothari.com
  262. 262. 262 Azoic Dyes ► Azoic dyes are so called because their molecule contain an Azo group. ► It is suitable for Man Made and Natural Cellulose fibers such as Cotton, Viscose, etc. ► Bright Shades, mostly deep Red, Yellow, Orange, etc. ► Light Fastness Fair to Good. ► Washing Fastness Good to Excellent. ► Heavy shades may have poor fastness to Crocking. © 2007 www.vasantkothari.com
  263. 263. 263 Reactive Dyes ► Reactive Dyes are so called because their molecules react chemically with the fiber polymers to form a covalent bond. ► The dyestuff thus becomes a part of the fibre and is much less likely to be removed by washing than are dyestuffs that adhere by adsorption. ► Suitable for Man made and Natural Cellulose Fibers, Synthetic Fiber and Natural Protein Fiber. ► Difficult dye with which to attain close shade matching. ► Bright Shades. ► Generally good to excellent fastness to light & washing. © 2007 www.vasantkothari.com
  264. 264. 264 Sulphur Dyes ► These dyes contain Sulphur atom in their molecules. ► Sulphur dyes are insoluble in water ► Suitable for the Man Made and Natural Cellulosic fibers ► Dull Shades, predominantly navy, black, brown ► Excellent Fastness to Light and Washing ► Relatively Low cost for Dark colors. © 2007 www.vasantkothari.com
  265. 265. 265 Vat Dyes ► Vat dyeing" means dyeing in a bucket or vat. ► Vat dyes are insoluble in water and incapable of dyeing fibers directly. ► Both cotton and wool, as well as other fibers, can be dyed with vat dyes ► Vat dyes have excellent wash and light fastness properties. ► It is usually very bright and will hold up better when bleached than most other dyes. © 2007 www.vasantkothari.com
  266. 266. 266 Solvent Dyes ► Solvent dye is a dye which is soluble in an organic solvent and is mostly introduced in the form of a solution in an organic solvent. ► It is very expensive method. ► It’s a alternative method as the use of water and its disposal in a non polluting form has become more expensive. ► Still it is relatively untied and uneconomical as compared to conventional dyeing techniques. © 2007 www.vasantkothari.com
  267. 267. 267 Basic Dyes ► Basic dyes ('basic' as in the opposite of acidic, not as in 'back to basics') are said to be very bright, and particularly washfast on acrylic. ► Basic dyes can be used to dye wool or cotton, but they do not perform well, tending to fade in sunlight quite badly. ► Characterized by Brilliance and Intense hue. ► Very Poor fastness to washing for Cellulosic and Protein ► Excellent fastness to light. © 2007 www.vasantkothari.com
  268. 268. 268 Pigment Dyes ► Pigments are colored organic materials in the form of insoluble powders, which are mixed with various resins, solvents and additives to manufacture plastics, rubbers & allied products. ► The pigment lays on the surface and becomes part of the dry film. ► Heavy Shade tends to stiffen fabric. ► Mostly excellent fastness to light. © 2007 www.vasantkothari.com
  269. 269. 269 Mordant Dyes ► Mordant dyes are those dyes which require a mordant in their application and which upon combination with the mordant deposit insoluble color on the substrate, e.g., dyes with metal chelating groups. ► The mordant substances include such acids as tannic acid, sumac, gall nuts, bark extracts, oleic and stearic acids, and Turkey red oil; and metallic substances such as various combinations or soluble salts of chromium, aluminum, iron, copper, and tin. ► Suitable for Wool ► Relatively Dull Colors ► Good to Excellent Fastness to Light and Wash. © 2007 www.vasantkothari.com
  270. 270. 270 Natural Dyes ►Natural dyes are, in most cases, acid dyes, which is why they will bond to wool and other animal fibers, but not to cotton. A way to improve attachment to wool, and to make some weak attachment to cotton possible, is to use metal ions, sometimes including toxic heavy metal ions, to form a bridge between the dye and the fiber; this is called mordanting. Cotton is typically mordanted with tannins in addition to metal ions Indigo is a natural dye, but it is quite different from other natural dyes, in that it is a member (the very first member) of the class of dye known as vat dyes, see above. © 2007 www.vasantkothari.com
  271. 271. 271 Textile Material may be dyed as… ► Fiber …… Stock Dyeing and Top Dyeing ► Yarn …... Skein, Package and Beam Dyeing ► Fabric ……Winch, Jet, Jig, Aerodynamic, Pad & Beam ► Garment …… Paddle © 2007 www.vasantkothari.com
  272. 272. 272 Stock Dyeing ► It refers to the dyeing of fibers, or stock, before it is spun into yarn. ► It is done by putting loose, unspun fibers into large vats containing the dye solutions, which are heated to proper temperature. ► 500 to 3000 pounds of fiber are dyed at one time. ► Usually result in excellent penetration of the dye into fiber and evenness of color throughout. © 2007 www.vasantkothari.com
  273. 273. 273 Stock Dyeing ►There is 10-15% Waste of dyed fiber through subsequent manufacturing of Spinning and Weaving. ► There is a strong element of Fashion risk in stock dyeing because as to the final color of a fabric has to be made at the earliest stage in its manufacturing. ► It produces soft, heather like color effect. ► Production is relatively Low. ► It is most costly method for dyeing. © 2007 www.vasantkothari.com
  274. 274. 274 Top Dyeing ► Top dyeing is also the dyeing of fiber. ► The term TOP refers to fibers of Wool from which shorter fibers have been removed, thus it select long fibers. ► The top in the form of Sliver is dyed, then later blended with the other colors of dyed top to produce desired blended heather shades. ► It would be waste of money if all the fibers, both the short and long, were dyed before being made into sliver. © 2007 www.vasantkothari.com
  275. 275. 275 Skein Dyeing ► It consists of immersing large, loosely wound hank of yarn. ► Soft, lofty yarns, such as hand knitting yarns, are usually skein dyed. ► Skein dyeing is the most costly yarn dyed method. © 2007 www.vasantkothari.com
  276. 276. 276 Package Dyeing ► In this about a pound of yarn is wound on a small perforated spool or tube called package. © 2007 www.vasantkothari.com
  277. 277. 277 Beam Dyeing ► Beam Dyeing is simply a much larger version of package dyeing. ► An entire warp beam is wound onto a perforated cylinder, which is then placed in the beam dyeing machine where the flow of the dye bath alternates as in package dyeing. ► Beam dyeing is more economical than Skein and Package dyeing. © 2007 www.vasantkothari.com
  278. 278. 278 Winch Dyeing ► Also know as Beck Dyeing or Box Dyeing. ► The fabric, in a rope like form, is dyed in a relaxed condition (without tension). ► It retains much of its original softness of hand and fabric fullness. ► Widely used for Knitted fabrics, woolen and worsted woven cloths. ► Capacity of around 1000 yds © 2007 www.vasantkothari.com
  279. 279. 279 Jet Dyeing ► In this the fabric is being dyed is circulated through the dyeing machine on a jet flow of a dye bath. ► Compared to Winch dyeing uses much less water, energy and chemical, and has shorter dyeing cycle time. ► The capacity is around 1400 lbs of material. © 2007 www.vasantkothari.com
  280. 280. 280 Jet Dyeing © 2007 www.vasantkothari.com
  281. 281. 281 Jig Dyeing ►It involves treating the fabric in open width. ►The fabric is not passed through the dye bath but rather passed through the dye bath. ► Upon completion of the first pass, the fabric reverses and is passed again through the dye bath. ► It places the certain degree of tension. ► It is more economical. ► Chances of shade variation are there due to variation in tension. © 2007 www.vasantkothari.com
  282. 282. 282 Pad Dyeing ► In this, fabric in open width first passed through the dye bath, then through rollers where the dye solution is squeezed into the fabric. ► Pad Dyeing places the tension on the fabric. ► Pigment may be applied to achieve solid color fabric. ► It is continuous dye system where quantities of fabric are run continuously run through a pad, then into heat steam chambers, then into washers, rinsers and dry and finally emerging as completely dyed fabric. © 2007 www.vasantkothari.com
  283. 283. 283 Beam Dyeing ► It is practically identical beam dyeing used for yarns. ► Used to dye fabrics of light weight, open construction. ► Tricot is a typical type which is dyed on Beam Dyeing. ► It is rapid and economical. ► Beam Dyed fabric is not subject to the stresses and tensions. ► 10000 yds or 4000 lbs of fabric could be wound on the beam. © 2007 www.vasantkothari.com
  284. 284. 284 Aerodynamic Dyeing ►The fabric transport takes place by means of a separate gas circuit through humid air or through an air-steam- mixture so that also an injection-free transport, i.e. a fabric passage without liquor is possible. i.e. the fabric is constantly moved from loading to the batch end, also during the discharge and filling processes. ► Dye­stuffs, chemicals and auxiliaries are dissolved in the processing liquor and injected directly into an air stream. ► In such a way, the liquor is atomized and evenly distributed on the surface of the textile material. The penetration of the fibers and consequently, the liquor exchange in the textile material are optimal. © 2007 www.vasantkothari.com
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  286. 286. 286 Aerodynamic Dyeing Process technological advantages: ► Short heating times by efficient heat exchanger ► Safe fabric run and good load capacity also for lighter articles ►No unwelcome formation of crease marks ►High speed of fabrics ►The dyeing machine can be used as tumbler © 2007 www.vasantkothari.com
  287. 287. 287 Aerodynamic Dyeing Economical advantages: ►Extremely low water consumption ►Considerably reduced consumption of chemicals and auxiliaries ►Savings in dyestuff are possible ►Significant savings in time by hot drop ►Extremely easy to operate ►Application of ecological dyeing processes © 2007 www.vasantkothari.com
  288. 288. 288 Garment Dyeing ► Garment Dyeing is the dyeing of the garment dyeing. ► It is done by placing a suitable number of garments into a large nylon net bag in a loose form. ► The most important advantage of garment dyeing is the fact that materials need not be dyed until shortly before the actual sale of merchandise. ► It requires that the initial size of the garment be adjusted during design and manufacture to account for the shrinkage ► It is an inexpensive. © 2007 www.vasantkothari.com
  289. 289. 289 Imperfections of Dyed Fabrics ► Imperfections of Dyeing may be due to faulty or improper dyeing procedures, faulty or improper preparation of the fabric prior to dyeing, or to imperfications in the material itself. © 2007 www.vasantkothari.com
  290. 290. 290 Barre ► In woven fabrics, a horizontal band of off-shaded yarns extending from selvedge to selvedge. ► Caused by differences in filling yarn size or differences in tension of warp or filling yarn. Color Crocking ► Color in a dyed fabric which rubs off rather easily onto other fabric surface. ► Caused by inadequate scouring at the completion of the dyeing cycle. © 2007 www.vasantkothari.com
  291. 291. 291 Color Bleeding ► Loss of color from a dyed fabric when immersed in a liquid. ► The liquid subsequently becomes colored. © 2007 www.vasantkothari.com
  292. 292. 292 Off Shade ► An expression referring to the fact that the color of the dyed fabric does not match the standard color or reference sample. © 2007 www.vasantkothari.com
  293. 293. 293 Shade Bar ► A shade change in a fabric that appears as a horizontal selvedge to selvedge change. ► Caused by a filling change or loom stop and subsequent start up. © 2007 www.vasantkothari.com
  294. 294. 294 Stained Cross Bar ► In cross dyed fabric, usually of one color and white, where the dye of the colored portion stains the white portion sometimes called unclear cross dye. ► In solid color fabric, the term refers to specks of foreign fiber that have been caught in the material and do not become dyed. © 2007 www.vasantkothari.com
  295. 295. 295 Stained / Streaked ► A discolored area on the cloth. ► Caused by foreign matter such as dirt, grease, oil or residue of sizing on the fabric being dyed. © 2007 www.vasantkothari.com
  296. 296. 296 Tender Spots ► Places in the fabric that have been excessively weakened, actually by exposure to processing of chemicals. Uneven Shade ► Differences in the shade of a fabric from edge to edge or one end of the fabric to the other. © 2007 www.vasantkothari.com
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  298. 298. 298 Textile Printing ► The application of color to a fabric in a design or pattern (localized dyeing) ► Modern printing generally incorporates one of the following techniques: ● Flat-bed screen printing ● Rotary screen printing ● Engraved roller printing ● Heat transfer printing © 2007 www.vasantkothari.com
  299. 299. 299 Steps In Printing Process ► Preparation of print paste ► Printing of fabric ► Drying ► Fixation of dyestuff ► Washing - off © 2007 www.vasantkothari.com
  300. 300. 300 Preparation Of Printing Pastes Type of specific formulation used depends on the fiber, the colorant system used and, to some extent, the type of printing machine. ► Typical Ingredients Used Include: ● Dyes or pigments ● Thickeners ● Binders, cross-linking agents ● Dispersing agents - surfactants ● Water-retaining agents (humectants) ● Adhesion promoters ● Defoamers ● Catalysts ● Hand modifiers © 2007 www.vasantkothari.com
  301. 301. 301 Block Printing © 2007 www.vasantkothari.com
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  303. 303. 303 Hand Screen ► Important Features and Advantages ● Best method for low yardage; samples; exclusive, limited quantity designs. ● Large repeat sizes (upto 120 in.) possible. ● Wet-on-dry print effects possible. ● Better color definition than roller print due to heavier lay-on of color. ● Acceptable to all woven and knitted constructions. ● Rapid preparation of Screen and pattern change over is possible. ● Ability to print cut garment parts and small items. © 2007 www.vasantkothari.com
  304. 304. 304 Hand Screen ► Limitations and Disadvantages ● Half tone designs not possible. ● Fine line paisley prints not possible. ● Lengthwise stripe designs not possible. ● Slow production. Uneconomical for large production yardages. © 2007 www.vasantkothari.com
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  309. 309. 309 Automatic Screen (Flat Bed) ► Important Features and Advantages ● Large repeat size (upto 120 in.) possible. ● Faster than Hand. ● Better Color definition than roller print; equal to hand screen. ● Adaptable to all woven and knitted construction. ● Rapid changeover of design possible. ● Best machine registration. © 2007 www.vasantkothari.com
  310. 310. 310 Flat Screen Printing ► In flat screen printing, a screen on which print paste has been applied is lowered onto a section of fabric. ► A squeegee then moves across the screen, forcing the print paste through the screen and into the fabric. ► Flat screen machines are used mostly in printing terry towels. © 2007 www.vasantkothari.com
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  319. 319. 319 Flat-Bed Screen Printing ► Mechanization of hand screen process ► Fabric glued to blanket ► Screens rise and fall ► Printing done while screen in down position ► Rod or blade squeegee system ► Up to four strokes possible ► Slow process © 2007 www.vasantkothari.com
  320. 320. 320 Automatic Flat Screen Printing ► Approximately 17% of printed goods ► Advantages ● Large repeats ● Multiple strokes for pile fabrics ► Disadvantages ● Slow ● No continuous patterns © 2007 www.vasantkothari.com
  321. 321. 321 Automatic Screen (Flat Bed) ► Limitations and Disadvantages ● Cost of Screen preparation and special mounting more costly than hand screen. ● Not adaptable to low yardage. ● Half tone designs are not possible. ● Fine-Line paisley prints not possible. ● Lengthwise stripes not possible. © 2007 www.vasantkothari.com
  322. 322. 322 Roller Print ► Important Features and Advantages ● Requires long production runs of same pattern (10000 yds) ● Best method for fine line patterns and Paisley Prints. ● Can produce half tones and fall on effects. ● Can print woven fabrics, knitted fabrics requires special handling. © 2007 www.vasantkothari.com
  323. 323. 323 Roller Print ► In the roller printing process, print paste is applied to an engraved roller, and the fabric is guided between it and a central cylinder. ► The pressure of the roller and central cylinder forces the print paste into the fabric. ► Because of the high quality it can achieve, roller printing is the most appealing method for printing designer and fashion apparel fabrics. © 2007 www.vasantkothari.com
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  327. 327. 327 Roller Print ► Limitations and Disadvantages ● Except for special machines, size of pattern repeat limited to 16 inches maximum for apparel pattern and 22 inches for home furnishings. ● Uneconomical for short runs. ● Long production delays in pattern changeovers engraving is expensive. © 2007 www.vasantkothari.com
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  332. 332. 332 Engraved Roller Printing ► Approximately 26% of printed goods ► Advantages ● High design capability ● Finedetail ● Multiple tones ► Disadvantages ● Copper cylinders very expensive ● Not economical for short runs ● Requires highly skilled workers © 2007 www.vasantkothari.com
  333. 333. 333 Rotary Screen ► Important Features and Advantages ● Oven 40 inch repeat size possible; larger than roller printing, but smaller than flat screen. ● Lengthwise stripe effect possible. ● Fall on designs possible. Adaptable to all woven and knitted constructions. ● Cleaner and brighter colors than on roller prints. ● Excellent color definitions, but less than flat screen methods. ● Rapid change over of design possible. ● Efficient for long runs and moderately small (1000yds) runs. © 2007 www.vasantkothari.com
  334. 334. 334 Rotary Screen ► In rotary screen printing, tubular screens rotate at the same velocity as the fabric. ► Print paste distributed inside the tubular screen is forced into the fabric as it is pressed between the screen and a printing blanket (a continuous rubber belt). ► Rotary screen printing machines are used mostly but not exclusively for bottom weight apparel fabrics or fabric not for apparel use. ►Most knit fabric is printed by the rotary screen method, because it does not stress (pull or stretch) the fabric during the process. © 2007 www.vasantkothari.com
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  344. 344. 344 Rotary Screen Printing ► Continuous screen printing process ► Fabric glued to blanket ► Fabric moves under rotating screens ► Rod or blade squeegee system ► Fine adjustments easily made ► Speeds up to 100 yd/min © 2007 www.vasantkothari.com
  345. 345. 345 Rotary Screen ► Limitations and Disadvantages ● Fine Line paisley prints not possible. ● Half tone designs not as effective as in roller printing. ● Screen do not last as long as rollers. © 2007 www.vasantkothari.com
  346. 346. 346 Rotary Screen Printing ► Approximately 50% of printed goods ► Advantages ● Fast ● Quick changeover of patterns ● Continuous patterns ►Disadvantages ● Design limitations ● Small repeats © 2007 www.vasantkothari.com
  347. 347. 347 Heat Transfer ► Important Features and Advantages ● Produces bright, sharp, clear fine line designs. ● Ability to print cut garment parts and small items. Adaptable to long and short yardages runs. ● Rapid pattern changeover possible. ● Simple, low investment installation possible. Steamers washers, dryers etc not required. ● Fewest seconds of all print process. ● Heat setting also accomplished. © 2007 www.vasantkothari.com
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  349. 349. 349 Heat Transfer ► Limitations and Disadvantages ● Lead time for paper preparation can cause problems in high fashion markets. ● Limited to fabrics having minimum 50% man made fibers. Cellulosic and protein (100%) fibres cannot be printed. ● Overprint only on pastels or else will not completely cover the original color. © 2007 www.vasantkothari.com
  350. 350. 350 Heat Transfer Printing ► Approximately 7% of printed goods ► Advantages ● High quality prints ● Fewer seconds ● Economical for short runs ● Practically pollution free ► Disadvantages ● Slow ● Primarily only for polyester © 2007 www.vasantkothari.com
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  353. 353. 353 Direct Prints ► A direct Print is one in which the design is printed directly onto a white cloth or over a previously dyed fabric. ► The Latter is called an over print and the printed design must be considerable darker than the dyed background. © 2007 www.vasantkothari.com
  354. 354. 354 Identification of Direct prints ► The background is white, or has large portions of white background. ► The printed design is lighter in shade on back of the fabric than on the face. This may not be evident on lightweight fabrics because of the strike-through of the print paste. ● If the fabric is over print. ► If the background color is the same shade on the face and back (piece dyed), and the print design are substantially darker than the background. © 2007 www.vasantkothari.com
  355. 355. 355 Discharge Print ► Discharge prints are fabrics which are dyed a solid color prior to printing. ► When printing is done, the design is applied by screen or roller with a chemical (Sodium Sulphoxylate Formaldehyde, a reducing agent) which removes the color of the originally dyed fabric. ► Production is more costly than direct prints since it is necessary to dye the fabric prior to printing. ► Very careful and precise process control is required. © 2007 www.vasantkothari.com
  356. 356. 356 Identification of discharge prints ► The background removing is the same shade on the face and back of the fabric (piece dyed). ► Print design area is white or a different removing or shade than background. ► Back of the print design reveals traces of the background removing. © 2007 www.vasantkothari.com
  357. 357. 357 Discharge Print © 2007 www.vasantkothari.com
  358. 358. 358 Resist Print ► Resist Prints involve a two step procedure: ● Printing a pattern design on a white fabric with chemical or Wax like resinous substance that will prevent or resist the penetration of dyes; and ● Piece Dyeing the fabric. ► It is used where background colors in fabric cannot be discharged. ► It is usually not possible to distinguish by ordinary visual examination between discharge prints and resist prints, since both types of prints produce the same results. © 2007 www.vasantkothari.com
  359. 359. 359 Resist Print © 2007 www.vasantkothari.com
  360. 360. 360 Printed PrintedPre Dyed Overdyed After Fixation and Wash off © 2007 www.vasantkothari.com
  361. 361. 361 Pigment Print ► Pigment Prints are direct prints made with Pigments. ► The process is frequently called Dry Printing as distinguished from Wet Printing. ► The Pigment area will be slightly stiffer and perhaps a bit thicker than the nonprint area. ► Pigment prints are the least costly type of Print. ► Pigment produce bright, rich colors, and are applied to all Textile fibres. ► It has good to excellent fastness to light and dry cleaning. © 2007 www.vasantkothari.com
  362. 362. 362 Identification of Pigment Prints ► Comparing the differences in fabric stiffness between a designs printed portion and a non-printed portion of the same fabric. ► The pigment print area will be slightly stiffer and a bit thicker than the non-print area. ► Deep shades are stiffer than light shades. © 2007 www.vasantkothari.com
  363. 363. 363 Blotch Prints ► Background has been obtained by printing rather than piece dyeing; Direct Print; The print and pattern design color are printed on to a white fabric in one printing operation; Imitates discharge or resist print effects. ► Identification: - The blotch print background color is lighter on backside of the fabric. ► Possibilities of large background color areas of the print are not covered with full depth of colors; Precious control is necessary; If pigment prints, fabrics very often result in objectionable stiff hand. © 2007 www.vasantkothari.com
  364. 364. 364 Flock Printing ► Tiny particles of fibers (1/10” – 1/4”) are made to adhere to a fabric surface in according to a particular design; printing the design with adhesive; exposing the fibre flock to the fabric. ► There are two methods of adhering the flock to the adhesive treated fabric surface: ● Mechanical Flocking. ● Electrostatic Flocking. © 2007 www.vasantkothari.com
  365. 365. 365 Warp Prints ► Warp Prints involve printing the warp yarns of a fabric before it is placed on the loom for weaving, then, the fabric is woven with a solid color weft usually white or contrast color. ►The result is a soft, shadowy design on the fabric; Producing warp prints require careful and skilled labor; these prints are found almost exclusively on high quantity and expensive fabrics. © 2007 www.vasantkothari.com
  366. 366. 366 Burn-out Prints ► Printing with chemical substance (sulfuric Acid) that will destroy the fibre in the pattern design print area; ► Fabrics are used in low-cost summer blouses and cotton lingerie; ► Interesting designs can be created with blends. © 2007 www.vasantkothari.com
  367. 367. 367 Duplex Prints ► Fabrics in which both sides of the fabric have been printed; ► Imitate Jacquard & Dobby woven design fabric; ► Very expensive printing © 2007 www.vasantkothari.com
  368. 368. 368 Engineered Prints ► Prints that have two or more distinct designs, ► Each located in separate areas of the fabric, and each designed to become a specific part of the garment; ► Printed by hand screen or heat transfer methods. © 2007 www.vasantkothari.com
  369. 369. 369 Wet Prints Dry Prints Heat Transfer Fiber Applied All Fibres fiber / dye affinity req. Can applied to all fibres Polyester/Nylon /Acetate Nature of Appl Chemical Physical Sublimation Application Method Roller / Screen Roller / Screen Transfer Paper Fabric Hand None Stiff and Thick Stiff on Acetate Light fastness Depend on Dye Good to Excell Good to Excell Rubbing Depend on Dye Fair in Light Shade & Poor in Dark Shade Excellent Laundering Depend on Dye Excellent on Polyester Cost Highest Lowest Second Highest © 2007 www.vasantkothari.com
  370. 370. 370 Printing Method Productivity Down Time Capital Cost Space Engraved Roller High High Very High Low Hand Screen Very Low Low Very Low Low/Mod Flat Bed Screen Low/Moderate Low Very High Very High Rotary Screen Very High Low High Low/Mod © 2007 www.vasantkothari.com
  371. 371. 371 Printing Method Skill Design Cost Design Durability Engraved Roller Highly Skilled High High Hand Screen Low/High Low Low Flat Bed Screen Semi Skilled Low Low Rotary Screen Semi Skilled Mod/High Moderate © 2007 www.vasantkothari.com
  372. 372. 372 Printing Method Design Limitations Complexity Pattern Repeat Engraved Roller Very Good- Fine Detail, tone Eff Limited Max 41 cm Hand Screen Can be Good High Flat Bed Screen Very Good High Rotary Screen Very Good Moderate 100cm © 2007 www.vasantkothari.com
  373. 373. 373 Printing Method Fabric Limitations Eff of Dye Engraved Roller Width Lim., Diff for Delicate Duller, Crush Effect Hand Screen Width Limitations Bright Prints Flat Bed Screen Wide width possible Bright Prints Rotary Screen Wide width possible Bright Prints © 2007 www.vasantkothari.com
  374. 374. 374 Flipped Yarn ► The arrows show the part that looks like scratches because the warp and weft yarns have been turned upside down. This failure of finishing is called, flipped yarn. Basically, the cause of this trouble is due to the insufficient penetration of color paste, and it often happens when the treatment after printing is carried out inappropriately. © 2007 www.vasantkothari.com
  375. 375. 375 Blebbiness ► A part of the printed surface became blebby with a rough appearance like that of sharkskin. This is often caused by such factors as unsuitability of color paste viscosity and screen mesh, and uneven adhesion. © 2007 www.vasantkothari.com
  376. 376. 376 Bleeding ► A printed motif blurs, and as a result the outline of the design appears unclear. When bleeding occurs, it is possible to think of the following reasons: the viscosity of color paste is too low; the concentration of dyestuff in print paste is too high and the amount of color paste printed or the amount of hygroscopic agent used is too large. © 2007 www.vasantkothari.com
  377. 377. 377 Staining During Steaming ► Stains are transferred when a poorly washed printing table is used, the printed cloth is piled up after insufficient drying or a part of the cloth touches another during steaming. In Japan, some factories carry out complete washing of finished cloth applying tensionless rope washers. © 2007 www.vasantkothari.com
  378. 378. 378 Stains (Non-Cleaned Printing Table) © 2007 www.vasantkothari.com
  379. 379. 379 Uneven Printing ► Color tone gaps appear horizontally at the same distance from each other. Bad screen frame, a poorly installed squeegee and uneven squeegee pressure can cause such a problem. © 2007 www.vasantkothari.com
  380. 380. 380 Slight Touching ► Some area in a motif has pale spots. This is caused by such factors as the slow replenishment of color paste, uneven squeegee pressure, choosing a squeegee with inappropriate hardness, bad squeegee relay, uneven surface of printing table, inappropriate viscosity of color paste and inappropriate use of thickener. © 2007 www.vasantkothari.com
  381. 381. 381 Poorly Adjusted Screen ► Disfigured designs or overlapped motifs. The problem occurs when the belt-drive and point adjustments, etc are not properly done. © 2007 www.vasantkothari.com

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