Durable water-repellent cotton fabrics prepared by low-degree substitution of long chain alkyl groups

Three kinds of water-repellent cotton fabrics, A, B, and C, are produced by alkylation with only 0.07 alkyl units per glucose unit. Sample A is prepared by alkylation by means of acetylation without mercerization, B is by direct alkylation after mercerization, and C is by alkylation by means of allylation and bromination. The merits of the methods are compared by contact angle measurements and spray tests after repeated laundry cycles. Sufficient water-repellency is attained with an alkyl length of over C-12. These samples retain a fabric hand, water-vapor permeability, and biodegradability similar to those of untreated cellulose fabric. The end-use properties of alkylated fabrics before and after laundering are also tested.