| 摘要 |
<p>1464505 Polyurethane elastomers UPJOHN CO 7 July 1975 [29 July 1974] 28517/75 Heading C3R A thermoplastic polyurethane elastomer having a hardness of from Shore A 70 to Shore D 80 comprises the reaction product of (i) 4,4<SP>1</SP>-methylene bis-(phenyl isocyanate); (ii) a polyethylene glycol having a molecular weight of 600-3000; and (iii) an extender selected from (1) aliphatic straight chain diols of the formula where n is 3 to 6, (2) dihydroxyalkylated aromatic compounds of the formula wherein A is selected from HOCH 2 -, HOCH 2 CH 2 O-, and HOCH 2 CH 2 OCH 2 -, and (3) mixtures thereof, wherein the ratio of the weight of the polyethylene glycol to the total weight of extender and diisocyanate is 1 Œ 0À1, and the ratio of the number of equivalents of diisocyanate to the total number of equivalents of extender and polyethylene glycol is 0À99 to 1À05. Suitable aromatic compounds (2) are m- or p-xylene-α,α<SP>1</SP> diol, and the bis(2-hydroxyethyl) ethers of hydroquinone, resorcinol, and p- or m-xylene a,α<SP>1</SP> diol. The elastomers may be prepared by a preferably continuous one-shot procedure or by a prepolymer procedure. A catalyst, e.g. an organotin compound or a tertiary amine may be used. In the Examples elastomers are prepared by the one-shot procedure from 4,41-methylene bis-(phenyl isocyanate), polyethylene glycol and either bis-(2- hydroxyethylether)-hydroquinone or 1,4-butane diol, in the presence of stannous octoate. The resulting elastomer is chopped, granulated and dried and then injection moulded to form a test sheet which is post-cured first at elevated temperature then at room temperature.</p> |
