GB1001344A - Improvements in and relating to halogen-containing polymer compositions - Google Patents

Abstract

Compositions comprising a major proportion of chlorine-containing polymers sensitive to heat and/or light degradation are stabilized with a system comprising at least three distinct chemical compounds, at least one being drawn from each of the categories (a) organic metallic compounds of lithium, sodium, potassium, magnesium, calcium, zinc, strontium, cadmium, barium, aluminium, tin or lead or mixtures thereof provided that (a) is not solely barium laurate, cadmium laurate or dibasic lead phthalate and does not contain a mixture of barium, cadmium and tin compounds; (b) organic sulphur compounds having a boiling point not below 200 DEG C., not containing chains of more than two consecutive sulphur atoms, and having at least one sulphur atom having at least one lone electron pair, provided that (b) is not mercaptobenzimidazole, mercaptobenzothiazole or their salts; and (c) an organic anti-oxidant. Specified polymers are homopolymers and copolymers of vinyl chloride, vinylidene chloride, cis - 1,2 - dichlorethylene or trans-1,2-dichlorethylene e.g. emulsion, suspension or bulk polyvinyl chloride; emulsion, suspension or solution vinyl chloride-vinyl acetate copolymers; vinyl chloride-vinylidene chloride copolymers; after-chlorinated vinyl chloride polymers; and chlorine-containing graft copolymers. Many suitable stabilizer components are specified including (a) organo-tin and organo-thio-tin compounds, and organic compounds of barium, cadmium, calcium, magnesium and zinc; (b) alkyl or aryl sulphides; mercapto carboxylic acids or esters or polyesters thereof; monothio or dithio dicarboxylic acids or esters, polyesters or anhydrides thereof; thioglycols or esters, polyesters or ethers thereof; hydroxyalkyl or hydroxyaryl sulphides or esters or ethers thereof; aromatic thiols; thioureas; dithiocarbonates and dithiocarbamates; and (c) nuclear substituted phenol, aromatic primary or secondary amine, N-substituted p-amino phenol or nitrogen heterocyclic compounds in which the nitrogen atom bears a replaceable hydrogen atom. The compositions may also comprise processing aids, waxes, metal sequestering agents, e.g. triphenyl phosphite and epoxidized soya bean oil, and fillers and pigments, e.g. titanium dioxide and silica. Examples describe compositions comprising vinyl chloride-vinylidene chloride copolymers stabilized with dibutyl tin maleate prepolymer, 2,6-di-t-butyl-4-methyl phenol and (1) naphthalene thiol, (2) dilauryl b ,b 1 - thiodipropionate, (3) b ,b 1-dihydroxyethyl sulphide, (4) dibutyl-tin dithiodiglycollate, (5) dibutyl-tin bis-(diphenyl dithiocarbamate) and (6) dibutyl-tin bis-(diphenyl thiourea dithiocarbamate); dibutyl-tin maleate prepolymer, dilauryl b ,b 1-thiodipropionate and (7) pentaerythritol and (8) diphenylamine; compositions comprising polyvinyl chloride stabilized with dibutyl-tin maleate prepolymer and (9) dilauryl b ,b 1-thiodipropionate and resorcinol monobenzoate, (10) b ,b 1-dihydroxyethyl sulphide and p-octyl phenyl salicylate, and (16) zinc diethyl dithiocarbamate and N-lauroyl p-aminophenol; lauryl thioglycollate, calcium stearate, magnesium stearate, zinc stearate and (12) N-lauroyl p-amino phenol and (13) 2,2-methylene bis-(4-methyl-6-t-butyl phenol); and nonyl thioglycollate, barium stearate, cadmium stearate and (14) N-stearoyl p-aminophenol and (15) bisphenol A; and a composition comprising a vinyl chloride-vinyl acetate copolymer stabilized with dibutyl-tin bis-(2-ethylhexyl thioglycollate), dilauryl thiodipropionate and 2,6-di-t-butyl-4-methyl phenol.