Method for improving the heat stability of polyvinyl chloride

Claim 1

A method for improving the heat stability exhibited by shaped articles prepared using plasticized vinyl chloride polymer compositions consisting essentially of a. a vinyl chloride homopolymer or a copolymer wherein at least 50% of the repeating units are derived from vinyl chloride, the remaining repeating units being derived from one or more ethylenically unsaturated compounds which are copolymerizable with vinyl chloride; b. between 5 and 60%, based on the weight of said composition of a plasticizer for vinyl chloride polymers; c. between 0.5 and 5%, based on the weight of said composition, of an organic ester of phosphorous acid, said ester exhibiting the general formula P(OR 1 ) 3 or P(OR 1 ) 2 (OR 2 ) wherein R 1 and R 2 are each selected from the group consisting of alkyl radicals containing between 1 and 20 carbon atoms, cycloalkyl, aralkyl, aryl, alkaryl radicals and hydrogen atoms with the proviso that the number of hydrogen atoms is 0 or 1, the method comprising (1) adding to said polymer composition between 0.1 and 1%, based on the weight of said composition, of an organotin compound corresponding to the general formula R m 3 SnY 4-m , ##STR10##wherein m represents the integer 1, 2 or 3 and Y represents a radical exhibiting a formula selected from the group consisting of -SR 4 , ##STR11##R 3 and R 4 are each individually selected from the group consisting of alkyl radicals containing between 1 and 20 carbon atoms, cycloalkyl, aralkyl, aryl and alkaryl radicals and R 5 is a methylene or ethylene radical and R 6 is an alkylene radical containing between 1 and 8 carbon atoms, inclusive, with the proviso that the organotin compound constitutes between 3 and 45% of the combined weight of the organotin compound and the organic ester of phosphorous acid, and (2) subsequently converting said composition into a product selected from the group consisting of shaped articles, films and coatings, wherein the conversion is accomplished in the absence of significant amounts of shear.

Claim 2

A method for improving the heat stability exhibited by shaped articles prepared using plasticized vinyl chloride polymer compositions consisting essentially of a. a vinyl chloride homopolymer or a copolymer wherein at least 50% of the repeating units are derived from vinyl chloride, the remaining repeating units being derived from one or more ethylenically unsaturated compounds which are copolymerizable with vinyl chloride; b. between 5 and 60%, based on the weight of said composition of a plasticizer for vinyl chloride polymers; c. between 0.5 and 5%, based on the weight of said composition, of an organic ester of phosphorous acid, said ester exhibiting the general formula P(OR 1 ) 3 or P(OR 1 ) 2 (OR 2 ) wherein R 1 and R 2 are each selected from the group consisting of alkyl radicals containing between 1 and 20 carbon atoms, cycloalkyl, aralkyl, aryl, alkaryl radicals and hydrogen atoms with the proviso that the number of hydrogen atoms is 0 or 1, the method comprising (1) adding to said polymer composition between 0.1 and 1%, based on the weight of said composition, of an organotin compound corresponding to the general formula R m 3 SnY 4-m , ##STR10##wherein m represents the integer 1, 2 or 3 and Y represents a radical exhibiting a formula selected from the group consisting of -SR 4 , ##STR11##R 3 and R 4 are each individually selected from the group consisting of alkyl radicals containing between 1 and 20 carbon atoms, cycloalkyl, aralkyl, aryl and alkaryl radicals and R 5 is a methylene or ethylene radical and R 6 is an alkylene radical containing between 1 and 8 carbon atoms, inclusive, with the proviso that the organotin compound constitutes between 3 and 45% of the combined weight of the organotin compound and the organic ester of phosphorous acid, and (2) subsequently converting said composition into a product selected from the group consisting of shaped articles, films and coatings, wherein the conversion is accomplished in the absence of significant amounts of shear.