Cross-Linked Silicone Films as Wash-Wear, Water-Repellent Finishes for Cotton1

Abstract

A variety of silicones substituted with hydrogen, methyl, amyl, or cyanoethyl groups have been deposited as cross-linked films on cotton fabric without cross-linking the cellu lose. The films surrounded individual fibers, leaving the air-permeability of fabric un changed. Insolubilization of silicone occurred in 1-5 min with an efficiency as high as 70-90% on curing with organic peroxides at 100-180° C. Dimethyl silicone imparted a wash-wear rating of 3, along with 240-260° crease recovery, unchanged tearing strength, and, in favorable cases, 70% to 80% retention of breaking strength and flex abrasion resistance. Application from organic solvents and aqueous emulsions, with and without a conventional cellulose cross-linking agent present, was demonstrated on fabrics of native, slack-mercerized, and tension-mercerized cotton. Little crease recovery was imparted by the silicone or benzoyl peroxide applied indi vidually. A mechanism for crease recovery based on cross-linked polymer films sur rounding unaltered cotton fibers is indicated. From the variation in efficiency with molecular weight, it was possible to estimate cross-linking densities in the silicone under different curing conditions. Methyl hydrogen silicone imparted high water repellency, increased flex abrasion resistance, and moderately increased wrinkle resistance, without loss of tearing strength, when cross-linked on cotton. Mixtures of silicones gave properties intermediate to those imparted separately.