| 摘要 |
<p>1,260,580. Microporous polyurethane coating. KURARAY K.K. 16 Dec., 1969 [16 Dec., 1968; 19 Dec., 1968; 15 March, 1969], No. 61172/69. Heading B2E. [Also in Divisions B4, B5, C3, D1 and D2] Leather substitutes are prepared by coating solutions of polyurethanes onto substrates such as polypropylene sheets or microporous sheets previously obtained by coagulating similar polyurethanes within non-woven webs of nylon or polystyrene/nylon fibres, the layer obtained by such coating step being subsequently treated in a coagulation bath to develop microporous properties. The polyurethane used is an elastomer derived from an organic diisocyanate, a C 2-4 aliphatic diol chain extender and a polymer polyol consisting essentially of a polyester polyol of molecular weight 800 to 5,000 obtained by reacting an aliphatic dicarboxylic acid with a mixture of 20 to 80 mole% of 2-ethylhexane-1,3-diol and 80 to 20 mole % dipropylene glycol, ethylene glycol, a propylene glycol or a butylene glycol. Solvent mediums for the coating composition are dimethyl and diethyl formamides and dimethyl sulphoxide; aqueous or methanolic solutions containing such solvents being used for the coagulation baths. Softeners such as sorbitan monostearate and stearyl alcohol, and other materials such as carbon black may be incorporated in the polyurethane impregnant solution. The coated substrates may be further coated with colouring agents and embossed using a roller having the pattern of natural leather.</p> |
