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Dr bmn college special finishes for textiles

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Dr bmn college special finishes for textiles

  3. 3. INTRODUCTION The term finishing means completing the manufacture of cloth by surface treatment. In a broad sense it covers all the treatment it undergoes after leaving the loom for weaving/knitting machine till it enters the market and includes processes like bleaching ,mercerising ,dyeing and printing. But it is normally confined to the final stage in the embellishment of textile goods after dyeing and printing. Most of the fabrics required some finishing treatment or the other. Silk does not require elaborate finishing treatment other than smoothing and straightening process because of it natural beauty and luster. A bleached long cloth may not require any finishing treatment except calendering. Finishing treatments depend on various factors such as the nature of the fiber, texture of the fabric, its physical operations differ according to the type of fiber in the fabric and the properties to be imparted to it by mechanical or chemical method.
  4. 4. OBJECTIVES • To improve the appearance of the fabric, that makes it more attractive by operations like calendering, optical whitening etc. • To improve the feel of fabric by softening, stiffening. • To cover faults in the original fabric by starch finishing. • To increase the eight of the cloth by back filling with starch and china clay or by tin chloride treatment. • To improve wearing quality of cloth before making it shrink resistant.
  5. 5. Continue…… • To impart special properties to the fabric for specific end use such as water proofing, flame proofing moth proofing. • To make garment hold their shape and enable them to be worn without ironing by durable press finishing. • To set texture of certain fabric and make other dimensionally stable by crabbing or potting (wool) and heat setting (synthetic fabrics). • To produce strong and more durable fabrics such as seat covers of cars b coating, bonding and laminating. • To produce novelty effects. e.g. organdie fabrics by parchmentisin.
  6. 6. TYPES OF FINISHES • MECHANICAL FINISHES • CHEMICAL FINISHES Finishes that cause a physical change only Finishes in which a chemical reaction cause a permanent change in the fiber
  7. 7. Mechanical finishes 1)Simple : a series of hard and soft rollers. polished metal and soft bawls are made of compressed cotton or paper or wood. • Calendering: uses high temperatures and pressures to change the nature of the fabric. performed by a “stack” of rollers through which the cloth passes. hard metal rollers alternate with softer ,cloth wrapped rollers with solid paper rollers. Two metal rollers never run against each other. 2)Friction: used for finishing lining, shirting, and printed clothes. 3)Schreiner: metal roller engraved with 200 to 300 fine lines . 1957 it was produce the satine finish on nylon and polyester tricot jersey. 4)Embossing: produces either flat or raised designs on the fabric. consists of two rolls , one is metal roll heated from the inside by gas flame. other one is paper solid twice the design of roll.
  8. 8. 5)Pleating: the fabric is placed in a pleated paper pattern mold and another one is placed on top fabric is pleated between the two pleating papers 6)Tentering Clip tension can be exerted by the clip tenter , is also may damage fabrics.in which pin tenter is used. 7)Moire :passing by two layers of rib weave. watermark , woodgrain describe fabric finish. heat applied during thermoplastic properties Eg. Acetate , polyster 8)Napping: one or both side of the fabrics .produced only with spun yarns, as fibers cannot be pulled from filament yarns , wire hooks used to pull from low twist yarns. pin
  9. 9. Chemical Finishes Bleaching: improves whiteness by removing natural coloration and trace impurities from the cotton. (Oxidizing bleaching or reductive bleaching) Eg. white bed sheetings and medical applications(highest levels of whiteness, absorbency). Mercerization: discovered in 1853 by john mercer , a calico ptinter ,treated with caustic soda solution. Increases luster and softness . • Eg . cotton (tension , yarn and fabric),linen
  10. 10. Embossed finish on fabric Cotton and wool socks
  11. 11. Tentering • Tentering is the mechanical straightening and dyeing of fabrics. • For woven fabrics the tenter establishes the relationship between warp and filling yarns. • Properly tentered fabrics will be straight or 'on- grain' which means that warp yarns and filling yarns are at true 90 degree angle. • A tenter frame holds the fabric between two parallel chains with either clips or special pins. • The chains spread apart to the desired fabric width, move with the fabric through finishing or drying units, and release the fabric to be rolled or folded onto cylinders.
  12. 12. Tentering • The fabric is held horizontally between the two chains , if filling yarns are not perpendicular to warp yarns an 'off-grain' situation develops. • Off-grain fabrics will not hang properly and may change shape after use and care and the consumer will probably be dissatisfied with product. • To reduce the frequency of off-grain fabrics, machinery like censors that stop the machine as soon as yarns are not in proper relationships
  13. 13. Tentering
  14. 14. Calendaring or pressing • It is a mechanical process of flattening or smoothening the surface of fabrics. • * Calendaring is applied to cotton linen silk rayon and other man made fabric. • *Pressing is the term used for wool fabrics and those made from blends of wool and other fibers. • *Calendaring or pressing uses heavy equipment that differ them from ironing the equipment used can create much greater pressure on fabrics than any iron • *Calendaring uses large metal rolls and a softer roll the hard roll is heated and it flattens the surface of fabrics. • *Pressing uses moisture to provide steam and reduce the possibility of damage to the fabric.
  15. 15. Calendering
  16. 16. SPECIAL FINISHES Special finishes are done on textile materials , it is a treatment that changes the appearance , handle and performance of the fibre , yarn or fabric. The main objective of finishes is to impart desired end use properties to the textile materials.
  17. 17. DEGUMMING • It is only done on silk. Degumming is the process of removing the sericin, or silk gum, from silk. Removing the gum improves the sheen, color, hand, and texture of the silk. Because the sericin [silk gum] can serve as a protective layer, little amount of sericin left over until it is ready
  18. 18. CARBONISING • It is specially done on wool . carbonising is a chemical finish which removes vegetables impurities such as seed, grass and burs which may remain on scoured wool. Woolen textile (yarn , fibre or fabric) can be carbonised before or after dyeing
  19. 19. RESIN FINISHING/WRINKLE FREE • Resin can be defined as a synthetic resins are complex organic products of high molecular weight. • It results when a number of simple molecular of low molecular weight join together and to form longer molecules which may be linear or linear molecules cross- linked.
  20. 20. RESIN FINISHING • Resin finishing was originally developed in the mid 1920s to improve the crease recovery problems associated with cellulosic materials. • Resin are the chemical group applied as wer finishes and used in many of the finishes.
  21. 21. PURPOSE OF USING RESIN • Resin are used for many purposes, primarily on cellulosic and cellulosic blends. • Resin are colorless.
  22. 22. CHEMICAL BONDS • It was found that urea and formaldehyde would react with the hydroxyl groups in cellulose to form a bon which gave the product both good recovery from creasing and improved dimensional stability
  23. 23. APPLICATION OF RESIN • It is applied to fabrics in liquid form, usually on a padder, then dried and finally treated at high temperature causing the resin to react chemically with the cellulosic component of the fabric.
  24. 24. RESIN AGENTS
  25. 25. PURPOSE OF RESIN FINISH • Minimize shrinkage. • IMRPOVE WRINKLE RESISTANCE • Improve fabric appearance. • Improve dimensional stability.
  26. 26. MODIFICATION OF RESIN • It add stiffness to fabric and thus used as stiffening agents or to create a firm hand. • Resin stabilize fabrics in the same shape or configuration as when the resin was cured. • Yarns in fabric will be stabilized and will resist shrinkage in laundering. • Fabric cured in a smooth, non wrinkled condition will return to that shape after being wrinkled in wear. • This reduction can be as high as 50%.
  27. 27. TYPES OF RESIN Resin are mainly of two groups: • Deposition type of resins. • Cross linking types of resins.
  28. 28. APPLICATION OF RESIN • Resin are applied in soluble form on the surface of cotton fabric using Padding Mangles with an acid catalyst. • If Dimethylo urea is padded and dried on cotton, then it is called as deposition type of resin, but after drying if curing is carried out, then it is called as cross linking type of resin. • Process : pad-Dry- Cure ( 1500 C for 5 min)
  29. 29. CROSS LINKING TYPE OF RESIN • It is reacted chemically with the fiber substance and cross link the fiber molecules. • This type of resin finishing is durable and is much better than deposition type of resin finish. • It is also known as N-Methylol compounds as the methylol groups(-CH2 OH) are attached to nitrogen. • It is also known as precondensates .
  30. 30. STEPS INVOLVED IN RESIN FINISH drying washing curing drying padding
  31. 31. DEFINITION OF SOFTENING • Softening refers to the process of modifying the handle or feel of textiles for better comfort, better wear and performance under defined conditions of use. • It is the process associated with modification of surface properties of textile described in terms to handle, volume, softness and drape.
  32. 32. SOFTENING • Softness of a fabric is a subjective sensation felt by the skin when a textile fabric is touched or gently compressed. • Often exposure to various process and chemicals, for instance, heat setting or crease resistant finish imparts stifness to the fabrics, which adversely affect for handling. • Softening forms a very important part of the chemical processing.
  33. 33. DISADVANTAGES OF SOFTNING • Reduced crock fastness. • Yellowing of white goods • Change in the hue of dyed goods and fabric structure slippage.
  34. 34. SOFTENING • Softeners are applied on knit fabrics in the final rinse after the wet treatments to restore their handle. • It consist of molecules with both a hydrophobic and hydrophilic part. • Which contain long alkyl groups with 16-12 carbon atoms. • Most of the softeners have low water solubility. • Glycerin and Turkey Red Oil(TRO) are commonly chemicals used to impart softness.
  35. 35. CLASSIFICATION OF SOFTNERS • Softeners are classified according to their ionic nature into cationic, anionic, non-ionic, amphoteric and silicone softeners.
  36. 36. 1) CATIONIC SOFTNERS • Cationic softners are the most preffered • class of softners for industrial applications.
  37. 37. CATIONIC SOFTNERS ADVANTAGE DISADVANTAGE High softening efficiency. Render a hydrophobic surface and poor rewetting properties because hydrophobic groups are oriented away from surface. Substantivity to most most fibres and good lubricant properties. Example quarternary ammonium salts.
  38. 38. 2) ANIONIC SOFTNERS • Anionic softeners are the compounds which have anionic groups oriented towards outside. • They are stable to heat during textile processing and are compatible with other components of dyes and bleaching baths. • Provides good antistatic and rewetting properties and can be used in combination with anionic fluorescent brightening agents. • Example: Turkey Red Oil ( TRO ).
  39. 39. 3) NON-IONIC SOFTNERS • Non-ionic softeners are generally less efficient than anionic and cationic softeners, but they can withstand the effect of hard water and extreme PH conditions. • Examples : ethers and polyglycol esters, oxiethylates products, paraffin's and fats.
  40. 40. 4) AMPHOTERIC SOFTNERS • Amphoteric softeners have strong ionic character and hence provide good softening effect, low permance to washing and high antristatic effect. • Example: compounds based on betaine and amine oxide.
  41. 41. SILICONE-BASED SOFTNERS • Silicone-based softeners are generally polysiloxane derivatives of low molecular weight. • They are insoluble in water and therefore must applied on fabrics after dissolution in organic solvents / in the form of disperse products. • They create a lubricating and moderately waterproof film on the surface and give fabric a velvety silky handle.
  42. 42. SILICONE-BASED SOFTNERS • They can be used for velvets, upholstery fabrics and emerised fabrics. • Enzymes such as cellulose have also been used in the softening of cotton. • Bio-polishing, treatments removes protruding fibers and slubs from fabrics, which reduce the diameter of the yarn and leads to softening of handle and smoothing of the surface.
  43. 43. REFERENCES 1)Title: Essentials of textiles Publisher: Holt Rinehart and Winston Publication date: October 1987 2) Title: textile finishing Author: R.S. Prayag Publication date: 1994 Web refences: • https://www.indiamart.com/proddetail/anionic-softener- 10683786762.html • https://in.pinterest.com/pin/656188608193004499/?lp=true • https://www.textileschool.com/228/ways-to-finish-fabrics/ http://www.daeper.com/en/Products/45.html • https://textilelearner.blogspot.com/2012/03/raising-or-napping- finishing-working.html • https://www.indiamart.com/silverart/