| 摘要 |
1,150,508. Fibre-reinforced polyurethanes. UPJOHN CO. 1 March, 1967 [19 April, 1966], No. 9721/67. Heading C3R. Fibre-reinforced polyurethanes comprise a fibrous reinforcing material of a kind inert to polyurethane reactants having bonded thereto a rigid, non-cellular polyurethane comprising the reaction product of an aromatic polyisocyanate and at least one aromatic polyol of OH number 75 to 750, the hydroxy groups of which are attached indirectly to an aromatic nucleus via a linking group, the polyisocyanate and polyol being employed in proportions such that the overall NCO: OH ratio is within the range 0À9:1À0 to 1À2:1À0. The polyisocyanate is suitably a mixture of polymethylene polyphenyl isocyanates containing 35 to 85% of methylenebis- (phenyl isocyanate), the remainder of the mixture being polymethylene polyphenyl isocyanates of functionality greater than 2À0. The aromatic polyols may be polyesters derived from aromatic polycarboxylic acids, adducts of alkylene oxides with primary aromatic amines, polyethers prepared by reacting alkylene oxides with polyhydric phenols and Mannich base polyols obtained by condensation of an alkanolamine, formaldehyde and a phenol and adducts of these Mannich base polyols with alkylene oxides. The fibrous reinforcing material may be glass, asbestos, mineral (including metal) fibres and fibres prepared from polyesters, boron, carbon, graphite and beryllium. Such fibres may be used in short pieces or chopped form and added to the reaction mixture or preferably they are employed in the form of non-woven mat or a woven fabric or mesh. An inert particulate filler may also be added to the reaction mixture. It is preferred to add a tertiary amine catalyst to the reaction mixture. |
