Scouring blended fabrics

Other fibers blended with polyesters in numerous blended fabrics requke alternative methods of preparation. Generally, the scouring and bleaching procedures used for these blends are those employed for the primary component of the blended fiber or for the component that most influences aesthetic appearance. 

Solvent scour low foaming for jet, beck, and continuous scouring of polyester and polyester blend fabrics. 

SEQ 100 is used in preparation of cotton and cotton blend fabrics and also can be used in scouring synthetic fabrics when there is a substantial amount of interfering heavy metals on the fabrics. A concentration of 0.1% on the weight of the bath in the caustic scour prior to peroxide bleaching will remove calcium, magnesium and copper but very little iron as the metal or as the rust. If it is necessary to remove ron or rust, other products such as SEQ CF in strong caustic are recommended. 

A worsted polyester/wool blended fabric is prepared by crabbing or blowing and then Scoured Dry Heat-set (on pin stenter) -> Brushed and Cropped Press or Decatise. 

Polyester/wool blends are very popular, the most common blend ratios are 55 45 and 70 30 polyester wool. Polyester rich blends are normally constructed from a texturised polyester fibre warp and 55 45 polyester wool weft yams. The 20 80 polyester/wool is woven from 55 45 warp and a pure weft yam. Worsted polyester/wool blend yams may contain 2.5 - 3% solvent extractable oil, compared with 3.5- 5% for similar all wool yams. The oils have much greater affinity for polyester fibre than wool and after normal piece scouring, the blends contain residual oil content of 0.6 - 1.2% compared with 0.3% for wool. Oxidation of combing oil is influenced by exposure to light which should be avoided before scouring. Addition of surfactant to combing oil improves the scourability of the blend fabric [75]. 

The object of scouring polyester/wool blended fabric is not only to remove spin finishes, lubricating oils, sizes and contamination of all types, it also helps in fabric relaxation and parting the necessary compactness. Blended fabrics may also be pressed and flattened by any of the usual methods employed with all-wool cloth before scouring. 

Casein/cellulosic fibre blended fabric is first desized under mildly acidic conditions at 60-70 C for 30-60 min and then scouring is carried out in a fresh bath at pH 6 with 3-4 g/1 non-ionic detergent at 50-60°C for 30 min, and rinsed well, first in warm and then in cold water. 

A single stage combined scouring and bleaching of polyester/cotton blended fabric can also be done for economy. There are various approaches which include alkali treatment with detergent and peroxide hot bleach alkali treatment with detergent and sodium chlorite bleach sodium chlorite and peroxide bleach and peroxide cold and peroxide hot bleach. 

Many continuous processing machineries have been developed over the past few decades by which cotton and polyester/cotton blended fabrics can be desized, scoured and bleached in one single operation. 

Textile wastewaters can vary from slightly acid to highly alkaline depending on the individual processes carried out within the plant. They generally are alkaline when caustic scouring or mercerizing is involved. Heavy metals such as copper, chromium and zinc result from the use of certain dye carriers in the dyeing operation of synthetic fabrics and of blended fabrics, e.g., cotton and rayon. The pretreatment unit operations which may be necessary for various types of joint treatment facilities are listed in Table 6. 

Uses One-bath desizing agent, solvent scouring agent, and dyeing auxiliary for syn., natural and blended fabrics antiredeposition aid for soil and sizings Features Does not interfere with subsequent dyeing operations Properties Yel. cl. liq., mild aromatic solv.-type odor sp.gr. 0.935 g/cc dens. 7.8 lb/ gal flash pt. (COC) 106 F pH 7.0 0.2 Use Levei 2-4% ow Arosolve IWS [Arol Chem. Prods ]... 

Uses Scouring agent, penetrant, emulsifier, degreaser, cleaner for continuous desizing, scouring, and bleaching of cotton and cotton/polyester blended fabrics or yarns, and greige fabrics and yarns... 

Scouring may be conducted on jigs, boil-off machines, or kettles, depending on fabric weight, constmction, and crease tendency ia the rope form. A combination of a synthetic detergent and soda ash is usually used and scouring is conducted at 85—100°C. Certain nylon blends may require less stringent conditions and the use of less alkaline builders, such as tetrasodium pyrophosphate. 

Trichloroethylene is an excellent extraction solvent for greases, oils, fats, waxes, and tars and is used by the textile processing industry to scour cotton, wool, and other fabrics (lARC 1979 Kuney 1986 Verschueren 1983). The textile industry also uses trichloroethylene as a solvent in waterless dying and finishing operations (McNeill 1979). As a general solvent or as a component of solvent blends, trichloroethylene is used with adhesives, lubricants, paints, varnishes, paint strippers, pesticides, and cold metal cleaners (Hawley 1981 lARC 1979 McNeill 1979). 

In a recent detailed evaluation of Cl Fluorescent Brightener 393 on polyester, this product was incorporated into the polymer melt. The prebrightened fibre was blended with cotton and fabric knitted from these yarns was scoured and bleached. It was demonstrated... 

PENTEX FR is a nonlonic/anlonic blended surfactant that is a biodegradable product for textile wet processing operations. Typical uses are in preparation of fabrics (bleaching), boil-off, and scouring of yarns and fabrics, soaping of fast dye yarns and fabrics particularly when dyed with fiber reactive dyes. 

Boll-off and scouring of yarns and fabrics (synthetics and blends)... 

BURCO SCOUR VAR-DF3 is particularly effective for J-Box and Kler bleaching, and for prescouring, of 100% cotton and polyester/cotton blends. It combines the solvents and emulsifiers to penetrate and remove troublesome oils and waxes by holding them in suspension, thus preventing any redeposit on the fabric. 

SCOUR DR is a nonionic surfacant blend which is especially useful for removing oil spots and stains from fabrics during preparation. 

Alkaline fulling/scouring agent for wool fabrics and blends. SYNTERGENT DMC ... 

Is a strongly hydrophilic emulsifier, dispersant, solubilizer and detergent. It is used as a stabilizer and anticoagulant for natural and synthetic latices and dye pastes, as a dyeing assistant for wool/acrylic blends, and as a detergent and lubricant for fiber/fabric scouring. TRYCOL 5972 is also used as an emulsifier for waxes used in coating citrus fruits. HLB 15.8... 

The ICI Markal process is used for desizing and scouring by using suspension of enzyme in trichloroethylene and surfactant solution. The fabric is padded through the solvent formulation, steamed to remove the solvent and to activate the enzyme. A wash-off with water completes the process. The Markal processes are suitable for polyester/cotton, polyester/rayon and other blends as well as for cotton. 

Acrylic/wool blended fibre fabrics may be prepared according to established practice for wool, except that precautions are taken to allow for the thermoplastic properties for the acrylic fibres. Relaxation is done to remove the inherent strain. Worsted fabrics are crabbed and then scoured in either a Dolly at temperature not exceeding 40 C or in winch. 

Diacetate and triacetate are both used in blends with wool. Scouring and milling can be conducted with the minimum quantity of alkali at temperatures not exceeding 50 C and care should be taken to avoid excessive mechanical friction on the fabric. Fabrics made from triacetate/wool blends should be given a crabbing treatment before dyeing. 

Scouring of knitted goods, wool and blended woven fabrics in discontinuous rotary-drum washing machines has been established in many countries for a number of years. Equipment for continuous preparation and dyeing from non-aqueous solvent have been developed by several companies (Table 5.1). 

Polyester/long-staple fibres are used in the linen industry, where yams may be of either the stretch broken or unbroken type, but more commonly of the latter. The linen component of the blend may be of bleached or unbleached fibre and yams spun from unbleached fibre may be bleached before weaving. Most fabrics in this blend are woven on sized (singles) warps. Unmodified warp sizes are removed by enzyme treatment and non-cellulosic matter is removed by an alkaline scour. 

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