Dehydrochlorination of vinyl chloride resins followed by graft copolymerization with copolymerizable monomers

Claim 1

The method which comprises dehydrochlorinating a vinychloride resin selected from the group consisting of homopolyvinylchloride, a copolymer of vinylchloride and vinyl acetate containing up to about 50% by weight of vinyl acetate and a copolymer of vinylchloride and vinylidene chloride containing up to about 50% by weight of vinylidene chloride and mixtures thereof as finely divided particles suspended in water, by heating said resin in said water at from about 50 to 150 psi and at a temperature of from about 150° to 180° C. for from about 1 to 2 hours to remove not over about 3% by weight, or from about 1 to 2% by weight, of chlorine from said resin, said water containing dissolved therein from about 0.1 to 5 parts by weight per 100 parts by weight of said resin of a material to prevent agglomeration of said resin during dehydrochlorination and being selected from the group consisting of a solid water soluble electrolyte and a weak base, where said electrolyte is selected from the group consisting of the lithium, sodium, potassium, magnesium, calcium, strontium and barium bromide, chloride and iodide salts and mixtures of the same, ammonium chloride and the sodium, potassium, lithium and magnesium acetates and where said weak base is selected from the group consisting of the lithium, sodium and potassium carbonates and phosphates and mixtures of the same, and, in said water, free radical aqueous graft suspension polymerizing on said dehydrochlorinated vinylchloride resin a monomer containing a polymerizable ethylenically unsaturated double bond and being selected from the group consisting of maides, nitriles, acrylates, alkacrylates, dienes and vinyl benzenes and mixtures thereof, said monomer being used in the amount of from about 50 to 200 parts by weight per 100 parts by weight of said dehydrochlorinated resin.

Claim 2

The method which comprises dehydrochlorinating a vinychloride resin selected from the group consisting of homopolyvinylchloride, a copolymer of vinylchloride and vinyl acetate containing up to about 50% by weight of vinyl acetate and a copolymer of vinylchloride and vinylidene chloride containing up to about 50% by weight of vinylidene chloride and mixtures thereof as finely divided particles suspended in water, by heating said resin in said water at from about 50 to 150 psi and at a temperature of from about 150° to 180° C. for from about 1 to 2 hours to remove not over about 3% by weight, or from about 1 to 2% by weight, of chlorine from said resin, said water containing dissolved therein from about 0.1 to 5 parts by weight per 100 parts by weight of said resin of a material to prevent agglomeration of said resin during dehydrochlorination and being selected from the group consisting of a solid water soluble electrolyte and a weak base, where said electrolyte is selected from the group consisting of the lithium, sodium, potassium, magnesium, calcium, strontium and barium bromide, chloride and iodide salts and mixtures of the same, ammonium chloride and the sodium, potassium, lithium and magnesium acetates and where said weak base is selected from the group consisting of the lithium, sodium and potassium carbonates and phosphates and mixtures of the same, and, in said water, free radical aqueous graft suspension polymerizing on said dehydrochlorinated vinylchloride resin a monomer containing a polymerizable ethylenically unsaturated double bond and being selected from the group consisting of maides, nitriles, acrylates, alkacrylates, dienes and vinyl benzenes and mixtures thereof, said monomer being used in the amount of from about 50 to 200 parts by weight per 100 parts by weight of said dehydrochlorinated resin.