| 摘要 |
1,242,170. Polyurethanes. E.I. DU PONT DE NEMOURS & CO. 9 April, 1969 [10 April, 1968; 31 May, 1968], No. 18306/69. Heading C3R. Polyurethanes contain in the polymer chain tertiary N atoms bound to two non-carbonyl carbon atoms which are not part of an aromatic ring and which are further bound to a t-butyl radical. They have repeating units in which R and R<SP>1</SP> are divalent aliphatic, cycloaliphatic or araliphatic radicals (M.W. < 400) at least one of which contains the said tertiary amine nitrogen. The polymers have an inherent viscosity of 0.07-0.6 measured in dimethylacetamide at 25‹ C. at a concentration of 1 g. per 100 ml. of soln. In preferred polymers R<SP>1</SP> is where R<SP>11</SP> is a C 2-3 alkylene group. R may be 4,4<SP>1</SP>-methylenedicyclohexyl or hexamethylene. The polymers may be prepared by reacting a diol containing the required tertiary N atom with a diisocyanate. The polymers are useful for stabilizing segmented polyurethanes (e.g. those of Specification No. 1,102,819) against discoloration by light and smog. The polymer should be present in an amount to provide at least 0À014% of tertiary amine nitrogen bonded to t.-butyl per kg. of the segmented polyurethane. |
