Fabric Finishing

in the textile industry one of the basic operations in the final processing of materials (fabrics and knits), as a result of which they gain several valuable characteristics, which include increased durability, water repel-lency, and resistance to shrinkage, wrinkles, mildew, and fire. In certain instances yarn is finished when it is put on the market as a commodity output (thread products).

Cotton and especially linen fabrics are treated with a starch finish. This increases durability and improves the fullness and appearance of the fabric. It also facilitates in cutting the cloth when it is to be sewn. Aside from starch itself and dextrin, which is a product of its hydrolysis, starch finishes include softening substances (fats, oils, soaps), hygroscopic substances (glycerine, common salt), substances which impart a sheen (wax, paraffin, etc.), and antiseptics (Formalin, salicylic acid, copper salts). In finishing woolen and silk fabrics, hide glue, gelatin, and gum arabic are used instead of starch.

However, starch and other glue substances are not retained in fabric with any degree of stability, and they wash out with the first laundering. Moreover, starch is a food product, and its application in fabric finishing is undesirable. In foreign practice use is made of various cellulose esters, in particular hydroxyethyl ester, as permanent finishing agents. However, the technological process is relatively complex. In the USSR wide use is made of latexes of polyvinyl chloride, polymethylmethacrylate, polystyrene, and others. Such treatment increases the fabric’s resistance to wear and tear and improves its appearance.

In order to make cotton, linen, and viscose staple fabrics wrinkle resistant, products are used from the initial condensation of a number of synthetic resins. The use of synthetic resins and special calender rolls produces a figured fabric, which resembles jacquards; it also may effect glossing, moires, and so on.

An important task in treating certain fabrics—for example, those used in rainwear—is making them water-repellent. For this purpose the fabric surface is subjected to a waterproofing process. At first this was accomplished with the aid of paraffin-stearin emulsions which were bonded to the fabrics with aluminum acetate. With wear, however, the waterproof qualities of the fabrics are gradually lost. There are now more improved methods, based on the use of new synthetic materials, such as “chromolan velan,” “preparation 246,” silicones, and so on. Many of these preparations are firmly bonded chemically to the fibers; because of this the articles do not lose their water-repellency when used.

Most textile materials, primarily cellulose fibers, are subject to destruction by microorganisms—that is, bacteria and mold fungi. In order to increase the durability of goods which are subjected for an especially long time to heat and moisture, they are treated with antiseptics (antirot treatment). The most widespread method of antirot impregnation is the bonding of tanning extracts to the fabrics by means of copper and chromium salts. There are also other methods of protecting fibers from the action of microorganisms; in particular there are extremely effective antirot preparations such as salicylanilide(Shirlan), dioxydichlorodiphenyl-methane (Preventol), and others.

In order to make fabrics noncombustible, they are subjected to fireproofing impregnation. Formerly, fabrics used to be treated with solutions of phosphorous salts, a mixture of borax and boric acid, and so forth. After a thorough soaking, however, its fire-resistant quality would be completely lost. More effective is the application of salts of antimony, titanium, and tin with their subsequent change to insoluble compounds, as well as of chlorinated hydrocarbons—for example, chloronaphthalene. One of the new and effective methods of fireproofing fabric is the formation of cellulose esters by the action on it of phosphoric acid in the presence of dicyandiamide, as well as by “preparation TNRS.”

In order to protect woolen fabrics from moths, they are treated with solutions of fluoride salts and also by various organic preparations, containing at the same time chlorine atoms, hydroxyl and sulfo groups (“eilans”), as well as sul-famide groups and chlorine atoms.

in the broad sense, the bleaching, dyeing, and printing of fabrics, as well as the final finishing operations on fabrics. In a narrower sense, finishing only includes dressing, drying and simultaneous stretching to eliminate misalignment along the warp and weft, shearing, ironing, decating, softening, and shrinkproof processing. These processes improve the appearance and quality of the fabrics and increase their resistance to laundering and wear.

The operations involved in fabric finishing vary depending on the texture and the purpose of the fabrics. In some cases, particular operations may be eliminated (for example, calendering, decating, and softening).