| 摘要 |
1,253,108. Stabilized polyurethanes. FARBENFABRIKEN BAYER A.G. 25 Aug., 1969 [14 Sept., 1968 (2)], No. 42165/69. Heading C3R. Polyurethanes are stabilized by the addition thereto of 0-05 to 10% by weight based on the polyurethane, of an alkoxy substituted, sterically hindered phenol of the formula wherein T represents a tertiary alkyl radical, A is a primary or secondary alkyl radical containing 1 to 12 carbon atoms or the radical T, R represents a primary alkyl radical containing 1 to 12 carbon atoms or an aralkyl radical, Q is an OR radical, T or A and X is a hydrogen atom or a radical of the formula the group -CH 2 X being in the 6-position when Q is an alkyl radical and in the 5-position when when Q is in an OR group. The phenols may be added, if desired in solution, to solutions of the polyurethanes, to melts or plasticized polyurethane sheets, to elastomer threads by application to the surface together with the dressing or they may be added to the starting materials used in the production of polyurethanes. Suitably, 0-05 to 5% by weight based on the polyurethane of a stabilizer mixture is used. The mixture comprising a phenol as defined above and a 2-(21-hydroxyphenyl)-benzotri:.' azole. In a typical example polytetramethylene ether diol, N,N - bis - (# - hydroxypropyl) - N- methylamine and diphenylmethane-4,41-diisocyanate are reacted in chlorobenzene to form a prepolymer solution which is introduced into a solution of ethylene diamine in dimethylformamide, a stabilizer being added to the final elastomer solution or being dissolved in the dimethylformamide with the ethylene diamine, and being 4.methyl.2,6.bis. (2<SP>1</SP>.hydroxy-3<SP>1</SP>-tertiary butyl-51_methyl benzyl)-O-benzyl:phenol optionally mixed with 2-(21-hydroxy-3<SP>1</SP>-tertiary butyl - 5<SP>1</SP> - methyl - phenyl) - 5 - chlorobenzotriazole.
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