| 摘要 |
<p>1531641 Polyurethane foam MINNESOTA MINING & MFG CO 18 Jan 1977 [19 Jan 1976] 1953/77 Heading C3R [Also in Divisions B1-B2] The open cell polyurethane backing for a pressure sensitive adhesive tape (see Divisions B1-B2) is rendered gasoline and water repellent by incorporating therein foam stabilizing fluoroaliphatic substance containing a plurality of fluoroaliphatic radicals having at least three fully fluorinated carbon atoms, one of which is terminal and at least one solubilizing moiety to impart a degree of solubility to the fluoroaliphatic substance in the polyurethane foam forming mixture. The fluoroaliphatic substance is free of active hydrogen containing functional groups. The fluoroaliphatic substances, many of which are specified, are added to 100 parts isocyanate prepolymer prepared from castor oil, phthalic anhydride and tolylene diisocyanate, 5À9 parts glycerine, 4À24 parts of a poly(oxypropylene)diol chain extender together with catalysts and blowing agents to form the foamable mixture.</p> |
