Synthetic suedes and process for preparing them.

摘要

1,178,240. Synthetic suede. SUEHIRO SEN-I KOGYO K.K. 21 Dec., 1967 [27 Dec., 1966], No. 58040/67. Headings D1B and D1P. Synthetic suede is made by impregnating a napped knitted fabric of double rib stitch structure or double rib stitch structure modified by the addition of a plain stitch structure and made from spun yarns of hydrophilic fibres with less than 15% by weight of a polyurethane elastomer. The fabric may be impregnated with a solution prepared by dissolving in a solvent a polyurethane elastomer having a molecular weight of 50,00-70,000 and a Durometer hardness of less than 82 at 20‹C and diluting the solution with a non- solvent for the elastomer to produce a liquor having a polyurethane elastomer concentration of 10% or less by wt and a viscosity of less than 200 centipoises at 25‹C, excess liquor removed from the fabric, and the fabric immersed under little or no tension in a first coagulation bath of water maintained at a temperature of 5-15‹C immersed under transverse tension in a second coagulation bath of water maintained at the same temperature as the first coagulation bath to stretch it in a direction transverse of its length, after coagulation removing at least some of the water from it, optionally subjected to a warm water treatment or softening treatment, dried at a temperature below 100‹C and polished e.g. by means of a roller wrapped with sand paper or a sanding paper. The fabric comprises at least 50% by weight of hydrophilic fibres and may be made from cotton, viscose rayon or wool fibres alone or in admixture with acrylic fibres. The polyurethane may be derived from methyl diphenyl diisocyanate, toluene diisocyanate or an aliphatic diisocyanate. The polyurethane elastomer may be dissolved in, dimethyl formamide, diethyl formamide, tetrahydrofurane, dimethyl sulphoxide, dioxan or diethyl dioxide and the solution diluted with acetone, methyl ethyl ketone, or an alcohol. The solution of the polyurethane elastomer may also contain a pigment. The synthetic suede may be used in the manufacture of overcoats, car clothes, golf gloves, household glass cleaning cloths, motor-car sheets and car polishing cloths.