Fabrics cotton

Cotton dyes Cotton fabric Cotton gin trash Cotton linters... 

Improved Com fort Properties. Wear comfort generally means cotton-like properties. The abiUty to absorb moisture from the skin and the softness of cotton fabrics are considered to be the two key properties for comfort. The extremely fine denier of cotton fibers accounts for its softness. 

Commercially, elastomeric fibers are almost always used in combination with hard fibers such as nylon, polyester, or cotton. Use levels vary from a low of about 3% in some filling stretch cotton fabrics to a high of about 40% in some warp-knit tricot fabrics. Raschel fabrics used in foundation garments normally contain 10—20% spandex fiber. 

A significant advance in flame retardancy was the introduction of binary systems based on the use of halogenated organics and metal salts (6,7). In particular, a 1942 patent (7) described a finish for utilizing chlorinated paraffins and antimony(III) oxide [1309-64-4]. This type of finish was invaluable in World War II, and saw considerable use on outdoor cotton fabrics in both uniforms and tents. 

THPC—Amide—PoIy(vinyI bromide) Finish. A flame retardant based on THPC—amide plus poly(vinyl bromide) [25951-54-6] (143) has been reported suitable for use on 35/65, and perhaps on 50/50, polyester—cotton blends. It is appUed by the pad-dry-cure process, with curing at 150°C for about 3 min. A typical formulation contains 20% THPC, 3% disodium hydrogen phosphate, 6% urea, 3% trimethylolglycouril [496-46-8] and 12% poly(vinyl bromide) soUds. Approximately 20% add-on is required to impart flame retardancy to a 168 g/m 35/65 polyester—cotton fabric. Treated fabrics passed the FF 3-71 test. However, as far as can be determined, poly(vinyl bromide) is no longer commercially available. 

Bis(azol-2-5l)stilbenes (2(i]ll such as (4) have been prepared. 4,4 -Dihydrazinostilbene-2,2 -disulfonic acid, obtained from the diamino compound, on treatment with 2 moles of oximinoacetophenone and subsequent ring closure, leads to the formation of (4) [23743-28 ]. Such compounds are used chiefly as washing powder additives for the brightening of cotton fabrics, and exhibit excellent light- and hypochlorite-stabiUty. 

Miscellaneous. Flame-resistant cross-linked polyethylene can be made with a number of fluoroborates and antimony oxide. This self-extinguishing material may contain the fluoroborates of NH, Na", K", Ca ", Mg ", Sr ", or Ba " in amounts of 4—20% (76). Magnesium fluoroborate cataly2es the epoxy treatment of cotton fabrics for permanent-press finishes (77) (see Textiles). 

Solutions of fluorosihcones impart oil and water repeUent finishes to nylon—cotton fabrics. One series of C-1 through C-9 perfluoroalkyl substituents with varying stmctures were attached to siHcon through amide or ether linkages. The fluorosihcones having perfluorinated straight-chain... 

Fabric-Based Grades. Grade C is made from cotton fabric weighing over 140 g/m (4 oz/yd ). The maximum thread count in any ply is 28/cm (72/in.) in the fiU direction, and the maximum total thread count in the warp and fiU directions is 56/cm (140/in.). Heavier fabrics provide higher impact strength but rougher machined edges. Its use for electrical apphcations is not recommended. 

As in dry compounding, acid acceptors must be incorporated into neoprene latices because of the wide use of these latices in coating fabrics and metals. The hydrochloric acid that forms during service life has a particularly destmetive effect on coated cotton fabrics that are not adequately protected. High zinc oxide concentration (ca 15 parts) and use of 0.4 parts AJ-phenyl-AT(p-toluenesulfonyl)-/)-phenylenediamine (Aranox, Uniroyal) as an antioxidant provides adequate protection. 

Textiles. Sorbitol sequesters iron and copper ions in strongly alkaline textile bleaching or scouring solutions (see Textiles). In compositions for conferring permanent wash-and-wear properties on cotton fabrics, sorbitol is a scavenger for unreacted formaldehyde (252) and a plasticizer in sod-resistant and sod-release finishes (253). 

An important chemical finishing process for cotton fabrics is that of mercerization, which improves strength, luster, and dye receptivity. Mercerization iavolves brief exposure of the fabric under tension to concentrated (20—25 wt %) NaOH solution (14). In this treatment, the cotton fibers become more circular ia cross-section and smoother ia surface appearance, which iacreases their luster. At the molecular level, mercerization causes a decrease ia the degree of crystallinity and a transformation of the cellulose crystal form. These fine stmctural changes iacrease the moisture and dye absorption properties of the fiber. Biopolishing is a relatively new treatment of cotton fabrics, involving ceUulase enzymes, to produce special surface effects (15). 

The ease of hydrolysis of a DMEU-treated fabric has been used to produce bicolored cotton fabrics. This was accompHshed by applying a thickened DMEU solution in a print configuration to the pile of fabric, curing the resin, and dyeing the fabric. The DMEU-treated areas resisted dyeing because of the cross-links. Subsequendy, the DMEU-crosslinks were removed via an acid hydrolysis and the entire fabric was overdyed to achieve the desired bicolored effect (69). 

Several factors were utilized in bringing formaldehyde release down. In particular, resin manufacturer executed more careful control of variables such as pH, formaldehyde content, and control of methylolation. There has also been a progressive decrease in the resin content of pad baths. The common practice of applying the same level of resin to a 50% cotton—50% polyester fabric as to a 100% cotton fabric was demonstrated to be unnecessary and counter productive (89). Smooth-dry performance can be enhanced by using additives such as polyacrylates, polyurethanes, or siUcones without affecting formaldehyde release. 

A number of flame-retardant finishes have been developed for outdoor cotton fabrics. Various experimental and commercial finishes have been compared (149). Most noteworthy is that THPOH—NH finishes do not perform as well outdoors as the THPOH—NH precondensate finishes. Likewise, antimony oxide—halogen finishes perform exceptionally well on outdoor fabrics. 

Another fire-related problem that has seen some research effort is that of smolder resistance of upholstery and bedding fabrics. Finishing techniques have been developed to make cotton smolder-resistant (152—156), but the use of synthetic barrier fabrics appears to provide a degree of protection. Work also has provided a means of producing cotton fabrics that have both smooth-dry and flame-retardant performance (150,151). In this case, the appHcation of FR treatment should be performed first, and DP treatment should be modified to accommodate the presence of the FR polymer on the fabric. 

Empirical attempts have been made to relate strip and grab test results, particularly for cotton fabrics, so that if one strength is known, the other can be calculated. The relationship is complex, depending on fiber strength and modulus, yam size and crimp, yam-to-yam friction, fabric cover factor, weave, weight, and other factors (19). 

CP esters are generally prepared as the ammonium salt [9038-38-4] by the reaction of cellulose with phosphoric acid and urea at elevated temperatures (130—150°C). The effects of temperature and urea/H PO /cellulose composition on product analysis have been investigated (33). One of the first commercially feasible dameproofing procedures for cotton fabric, the Ban-Flame process (34,35), was based on this chemistry. It consists of mixing cellulose with a mixture of 50% urea, 18% H PO, and 32% water. It is then pressed to remove excess solution, heated to 150—175°C for 5—30 minutes, and thoroughly washed (36). 

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