In textile manufacturing, finishing refers to the processes that convert the woven or knitted cloth into a usable fabric or any material and more specifically to any of the processes performed after dyeing the yarn or fabric to improve the look, performance, or "hand" (feel) of the finish textile or clothing. Some finishing techniques such as bleaching and dyeing are applied to yarn before it is woven while others are applied to the grey cloth directly after it is woven or knitted. Some finishes, such as fulling, have been in
use with hand-weaving for centuries; others, such as mercerization, are byproducts
of the Industrial Revolution.
Special finishes for natural fibers Bio-polishing removes the protruding fibers of a
fabric through the action of an enzyme. Enzymes, such as cellulose for cotton,
selectively remove protruding fibers. These enzymes can be deactivated by an
increasing the temperature. Mercerization makes woven cotton fabric stronger,
lustrous; to have better affinity to dyes and abrasion will be reduced. Raising lifts
the surface fibers to enhance softness and warmth, as in flannelette. Peach Finish
subjects the fabric (either cotton or its synthetic blends) to emery wheels, making
the surface velvet-like. This is a special finish commonly used in garments.
Fulling or waulking is a method of thickening woolen fabric to make it more
water- resistant.
Anti-microbial finish makes a fabric to inhibit the growth of microbes. The humid
and warm environment found in textile fibers enhances the growth of the microbes.
Infestation by microbes can cause cross infection by pathogens and the
development of odor where the fabric is worn next to skin. In addition, stains and
loss of fiber quality of textile substrates can also take place.
Special finishes for synthetic fibers
Heat-setting: Heat setting of synthetic fabrics abolishes the internal tensions within the fiber, generated during manufacturing, and the new state can be fixed by rapid cooling. Heat setting can be fixed in the fabrics at the relaxed state, and it eliminates subsequent shrinkage or creasing of the fabric. Presetting of goods makes it possible to use higher temperature for setting without considering the sublimation properties of dyes and also has a favorable effect on dyeing behavior and the running properties of the fabric.
Anti-pilling finish: It alleviates pilling, an unpleasant phenomenon associated with spun yarn fabrics, especially when they contain synthetics. Synthetic fibers are more readily brought to the surface of a fabric due to their smooth surface and circular cross-section, and due to their higher tensile strength and abrasion resistance. With knit “picking” also occurs: by abrasion, individual fibers work themselves out of yarn loops onto the surface, and the garment will get caught on a pointed or rough object. Knitting is susceptible to these effects due to the open weave and bulky yarn.
Anti-static finish: It eliminates dust from clinging to the fabric. Anti-static effective chemicals are highly inert chemicals and require thermasol or heat treatment for fixing on polyester fabrics. Polyether agents are likely useful but it should not affect the dye- equilibrium on fiber, lest they impair the rubbing fastness.
Non-slip finishes: give the filaments a rougher texture on fabric surface. Synthetic warp and weft threads in loosely woven fabrics are particularly prone to slip because of their smoothness on the surface when the structure is disturbed and appearance is not attractive. Silica gel dispersions or silicic acid colloidal solutions are used in combination with latex polymer or acrylates dispersions to get more permanent effect, along with simultaneous improvement in resistance to pilling or snagging. These polymer finishes are also contributes in imparting a softer and smoother handle to synthetic fabric without making it water repellent. Fire Resistant or Flame Retardant finish: reduces flammability.
Garment Finishing
Garment finishing through garment wet processing will add value to the garment and the additional effects become the clear differentiator. Garment finishing can be used for various applications, be it shirts, t-shirts or trousers, but majority of the effects are most popular in casual wear and denim segments. Garment finishing
Functional Finishes: AquaTex Finish: Traditional finishing processes for these fabrics typically require the addition of chemicals, in reality; however, these chemical compounds decrease the life span of such fabric’s performance, and exclude the of recycling possibilities, and frequently engage appreciably higher additional expenses for wastewater treatments. The AquaTex system or for the enhancement of woven and some knit fabrics has been developed In lieu of these chemicals, which frequently are environmentally objectionable, the AquaTex system only uses regular water at ambient temperature to attain adequacy of such fabrics in the trade and also makes them more profitable.
Feather touch & ultra soft touch: Feather touch & ultra soft touch finishes are commercial names produced by treating with amino, carboxy, or epoxy silicones alone or in successive treatments. Amino Silicones are widely available in market are widely used in softening. They impart excellent softness with bounciness when used in concentration 2.5 3% on weight of fabric in garment finishing. Yellowing and some level of hydrophobicity are the disadvantages. Epoxy silicones, which are most compatible with most of the other finishing chemicals, impart softness without yellowing and improved fabric strength. They also play a vital role in wrinkle free finishes by imparting better tear strength.
Rubbery touch: Rubber latex provide lustrous, brittle handle with characteristic rubbery effect, which are hard-wearing. In leather finish, it is applied as final finish treatments which are after enzyme or stone wash or after mechanical abrasion and enzyme treatments. Many catching names such as bio polished & rubbery touch finish, enzyme bio polish & rubbery touch finish, are quite universal.
Non-stick Teflon spray: This is a new generation multi-use lubricant based on poly tetra fluoro ethylene (PTFE). In service this lubricant forms a tenacious non-stick coating of the fluoro-polymer, which does not permit dirt and dust to settle on the fabric surface. This makes the product ideal for cement plants, textile mills and industries etc. where constant flow of dust and contaminants affect the conventional lubricants.
Stone wash: Pre-washed, abraded, faded either regular or irregular looks are produced by subjecting the dyed garments to harsh washing treatments commonly known as stone wash garments. In order to speed up the garment wash effect and to give garments an even more exclusive appearance and softer hand; abrasive stones were introduced to the wash bath. There are variety of natural synthetic stones are available for stonewashing with perhaps the most broadly used being pumice or volcanic rock. As the stones are used, they slowly disintegrate, reducing the severity of the stonewash effect over a period of time. The stones not only abrade the fabric but also steadily corrode the inside of the rotary drum. A machine used for stonewashing should not be used to dye when abrasion would be detrimental to the fabric.
Nanotechnology and Nano-coatings in Textile Finishing: Nanotechnology is the utilization of structure and energies inherent in materials at the atomistic level, at the dimension of 10-9 nm, to build novel materials with enhanced performance properties. As in other fields of study, the use of nanotechnology in textile finishing has helped in improving quality and performance of textile materials by giving new and more sophisticated functionalities to textile substrates as well as enhancing the existing functionalities such as durability that sustains the fabric’s feel and texture. This comes with a very small amount of chemicals and wet treatment. The science and technology of use of some of the profitable nano-finishes that give antimicrobial, hydrophobic, super-hydrophobic and self-cleaning properties have been studied. The ability of metal oxide and metal nanoparticles to interact with microorganisms and light has impacted desired effects in textile materials. In the same vein, zinc oxide (ZnO) nanoparticles of average particle size 38±3nm, have been applied variously in the surface modification of textiles. In their work, Yadav and co. 2006 (Yadav et al., 2006), studied the effect of ZnO nanoparticles made from sodium hydroxide and zinc nitrate with soluble starch as the stabilizing agent, on UV blocking and air permeability of cotton fabrics. Bleached plain weave cotton fabrics were coated with the synthesized ZnO nanoparticles. And it was found that the coated fabrics appeared to be more capable of being permeated by active UV blockers and air.
Low or ultra low formaldehyde easy care finishing: Washing of cured fabric reduces the chances of released formaldehyde from the finished fabric. Washing removes free formaldehyde as well as untreated N-mehylol groups which may decompose to form formaldehyde. The PH during washing plays an important role in the formaldehyde release properties of finished fabrics. Generally the PH range for best formaldehyde release properties is between PH 4 to PH 5. The temperature of the wash bath has little or no effect on the amount of formaldehyde released from DMDHEU finished fabrics, consequently a low temperature or room temperature washing is preferable. A considerable amount of water and heat energy is needed to redry the fabric after washing which increases the production costs and this is the major draw-back of the process.
To decrease the amount of formaldehyde of the fabrics finished with N-methylol compounds, a process which is based on the spraying of urea on to the cured fabrics has been developed. The process is called the BASF fog-chamber technique. This technique is very efficient for reducing the amount of formaldehyde liberated during the storage of finished fabrics. In most cases a 10-30% solution of urea has proved satisfactory, while an atomized spray for low wet pick-up of 5-10% is sufficient .
