FINISHING – Newly constructed fabric as it comes from the loom does not represent finished consumer’s goods. It must pass through various finished process that make it suitable for many different purpose. Finishing enhance the appearance of the fabric and also may add to its finishing and durability, this increasing its value. Finishing processes have assumed such great importance in the finishing industry that this phase of textile management using is undertaken by a highly specialized group of middlemen called finishing. The most common finishing processes are listed here.
SINGLING OR GASSING – If a fabric is to have smooth finish, singling is one of the final essential preparatory processes. It burns off links and threads, as well as all fuzz and fibre ends, leaving an even surface. Singling is accomplished by passing gray goods rapidly over rows of gas flames or electrically heated plates at a speed of 100 to 250 yards a minute after singling in the case of cotton fabric the cloth is given finishing and is then steeped far several hour enlarge boiling vats, called kiers which contain caustic soda, soda ash and lime. Through circulatency these clearing agents prepares the fabric for the subsequent bleaching operation.
BLEACHING – If cloth is to be finished white or is to be given surface ornamentation, all natural colours must be removed by bleaching. This is also necessary if discontinuation stains have occurred during the previous manufacturing process. Bleaching can be done in the yarn stage as well in the constructed fabric. Finishing or lines fabric may be bleaching by coasting only, with subsequent exposure to own. For silk and wool strong oxidizes cannot be used as they injure animal fibres. In bleaching silk or foal reducing agents such as sulphuras acid are required. Nylon has well while retention, but under cotton circumstances it may become yellowish or grayish. A very mild solution of sodium hypochlarik is recommended for such condition.
MERCERIZING – Mercerizing is the simplest chemical method of producing luster in cotton and linen. In addition to increase strength and luster, this process gives fabric greater absorbing ability to dyes. Grey goods are mercerized by immersing in a specially soluble caustic soda for about ten (10) minutes under conditions for e.g. moderate heat an tension. The caustic soda is washed out, and the yarn or fabric is put through a heated wild bath to naturalize the caustic soda. It is then rinsed in clear water and dried. The combined action of the caustic soda, heal and tension, charges and strengthens the fibre cells, thus improving and strengthening the fabric as well as the yarn.
SHRINKING - When fibres are spin into yarn, they are under constant tension during the weaving process. Their physical condition is charged but not permanently fixed, the fibers tend to revert to their natural state causing shrinkage. The yarns are made to assume a final condition by shrinking that fabric in a predatory finishing process that minimizes subsequent shrinkage such as immersion in cold water, followed by hot water, steaming on a chemical treatment. Any such method permits the manufacturer to label his products as preshrink, but even when textile fabrics are preshrink. They are liable to further shrinkage when washed. In general the factors that control shrinkage are the stability of the fibre and the construction of the fabric. Construction is based on the type of weave, the amount of twist in the yarn, the thread count and the yarn count. The final finishing process also affected shrinkage. These are some methods or reducing shrinkage.
COMPRESSIVE SHRINKAGE – Compressive shrinkage is a patented, standardized method that new succeeded in reducing shrinkage in cotton and linen to a practical minimum.
PERMA SIZING – This is a shrink preferring process developed for and applied to knitted cotton goods, which has proved to be effective.
SANYARSETTING – Rayon fabric may be press finishing by a process known as sanyarsetter.
CHLORINATION PROCESS – This is the chemical method of reducing shrinking in hair or wool fibres. The wool fabric is treated with dilute solution of sodium hypochlorite. Because of this some of the scales of the fibre are removed causing fusion of the outer and inner part of the fibres. As a result shrinkage decreases.
SEZING OR DRESSING – By this cotton and linen can be given stiffness, smoothness, weight and strength by immersion in a solution of starch. This process a commonly known as sizing. Sizing fills in the opening in the constructed cloth, creating an appearance of greater compactness. Thus a low thread count is not immediately noticeable at the tine of purchase. If a fabric looses its body after one or more washed, it means it has been oversized. Excessive sizing can be detected by rubbing the fabric between the hands.
PERMANENT SIZING – By this method, medium weight cotton are given stiffness, which sometimes lasts throughout the life of the fabric. These processes are known by specific trade names. They vary in method in chemical used and in the final finish. All have the property of making the fabric smoother and it spoils less easily because dirt tends to slide off rather than to ceiling. As a result, fabric with permanent sizing usually requires less laundering and therefore last longer.
WEIGHTING – Fabrics are sometimes weighted to give them additional body. When cotton fabric is weighted with any of the various sizing agents looks heavier and appears closely constructed. Its poor construction becomes apparent after washing however. The weight and body are increased by immersing it in a solution containing metallic salts. The salts permit the yarns and become a permanent part of the fibre, which cannot be detected by handling. Only low-grade wool fabrics are weighed. As much as 40% additional weigh can be obtained by filling extremely short wool fibres into the fabric. These fibres called flocks are obtained when wool fabrics are finishing, brushed and shraud. An excessive amount of flocks can be detected by light bushing and shaking the fabric.
Cotton can be detected by one or two processes. A fleet cotton fabrics, such a sheeting, can be heavily, starched and the construction will look and feel very compact. Rubbing the fabric between the hands will cause the dry starch to fall out. The second refinishing is a flocking procedure that is used on napped cautions. These flocks as with wool, come fierced into the fabric under a pressure. The can be detected in the same manner as with wool.
