Stability improvement of carbon monoxide ethylene copolymer in pvc compound

A plastic composition having diminished tendency to discolor on heating at 180° C. in the presence of a carbon monoxide modified ethylene copolymer, comprising polyvinyl chloride, a carbon monoxide modified ethylene copolymer with an unsaturated ester softening monomer, and an amount, effective in diminishing said tendency to discolor, of at least one inorganic perchlorate salt selected from the group consisting of alkali metal perchlorates and alkaline earth metal perchlorates.

A masterbatch composition adapted for safe storage, transport, and compounding with a plastic composition whose major polymeric component is polyvinyl chloride, comprising carbon monoxide modified ethylene-vinyl acetate copolymer and at least one inorganic perchlorate salt selected from the group consisting of alkali metal perchlorates and alkaline earth metal perchlorates, said masterbatch containing from 7 parts by weight to 50 parts by weight of said perchlorate salt per 100 parts by weight of carbon monoxide modified ethylene-vinyl acetate copolymer.

A method of diminishing the tendency to cause discoloration on heating at 180° C. of a carbon monoxide modified ethylene-vinyl acetate copolymer containing plastic composition whose major polymeric component is polyvinyl chloride, comprising the steps of mixing polyvinyl chloride with carbon monoxide modified ethylene-vinyl acetate copolymer and with at least one inorganic perchlorate salt selected from the group consisting of alkali metal perchlorates and alkaline earth metal perchlorates, such that the composition contains from 5 parts by weight to 75 parts by weight of carbon monoxide modified ethylene-vinyl acetate copolymer per 100 parts by weight of polyvinyl chloride and from 0.03 parts by weight to 10 parts by weight of the inorganic perchlorate salt per 100 parts by weight of carbon monoxide modified ethylene-vinyl acetate copolymer.

In a carbon monoxide modified ethylene-vinyl acetate copolymer containing plastic composition whose major polymeric constituent is polyvinyl chloride, the improvement consisting of the diminishment of the tendency to discolor upon heating at 180° C. of said composition by the addition thereto of an amount, effective in diminishing said discoloration, of at least one inorganic perchlorate salt selected from the group consisting of alkali metal perchlorates and alkaline earth metal perchlorates.