GB1037169A - Stabilization of polymers - Google Patents

Abstract

Benzylidene malonic acid diesters may be prepared by reacting benzaldehydes with malonic acid diesters. In Example 1 p-methoxybenzaldehyde is reacted with diethyl malonate in benzene in the presence of piperidine. Corresponding products may be derived from benzaldehyde, o-methoxybenzaldehyde, p-hydroxybenzaldehyde, 2,4 - dimethoxybenzaldehyde, 2,5 - dimethoxybenzaldehyde, p - octyloxybenzaldehyde and p-dodecyloxybenzaldehyde, and from dimethyl, dioctyl, dibenzyl and diphenyl malonates.ALSO:Polymers are stabilized by incorporating therein a benzylidene malonic ester of formula <FORM:1037169/C3/1> where R and R1 are hydrogen, hydroxy, C1- 12 alkoxy, C1- 12 alkyl, C2- 12 alkanoyloxy, C2- 12 alkenyloxy or C3- 12 alkenoyloxy; and R11 and R111 are C1- 12 alkyl, aryl or aralkyl. The esters may be used together with phenolic antioxidants. Specified polymeric materials are cellulose acetate, polyethylene, polypropylene, polystyrene, polymethyl acrylate, polymetnyl methacrylate, polyvinyl chloride, polyvinylidene chloride, polyesters, polycarbonates and melamine resins. Specified phenolic antioxidants are 2,6-di-t-butyl 4-methyl-, 4-methylol-, 4 - ethyl- and 4 - octyl phenols, 2,6 - di - hexyl - 4 - methyl- and 4 - t - butyl - phenols, and 2,4,6-tri-t-butyl phenol. In comparative tests diethyl esters in which R1 is H and R is H or p-methoxy are incorporated in cellulose acetate, and in Examples (9) diethyl p-methoxybenzylidene, benzylidene, o-methoxybenzylidene, p-hydroxybenzylidene and 2,4-dimethoxybenzylidene malonates are incorporated in cellulose acetate; (10) diethyl p-methoxybenzylidene malonate and (11) diethyl 4-acryloxybenzylidene malonate, diethyl 4-octyloxybenzylidene malonate and dimethyl p-methoxybenzylidene malonate are incorporated in organo tin heat-stabilized polyvinyl chloride; (12) diethyl p-methoxybenzylidene, benzylidene, o-methoxybenzylidene, p-hydroxybenzylidene and 2,4-dimethoxybenzylidene malonates are incorporated in organo tin heat-stabilized vinyl chloride/vinyl acetate copolymers; (13) diethyl p-methoxybenzylidene, o-methoxybenzylidene, p-hydroxybenzylidene and 2,4-dimethoxybenzylidene malonates and (14) diethyl p-methoxybenzylidene malonate and 2,4,6-tri-t-butyl phenol are incorporated in polystyrene and (15) diethyl p-methoxybenzylidene malonate is incorporated in benzoguanamino - melamine - formaldehyde resins.