Abstract: Vinyl halide polymer is prepared by bulk liquid phase polymerization of vinyl halide monomer in the presence of a minor proportion, based on the weight of the polymerization reaction mass, of isobutane diluent followed by application of reduced pressure to remove diluent and unreacted monomer from the polymer.The product exhibits improved porosity and molten color stability compared to vinyl halide polymers prepared in bulk in the presence of conventional alkane hydrocarbon diluents.

Abstract: The present invention relates to production of vinyl halide-polyolefin graft copolymers by a liquid phase bulk polymerization process wherein the process is carried out in the presence of a diluent. Suitable diluents preferably have vaporization pressure characteristics, within 100 psi., and similar liquid state viscosity, as vinyl halide monomer. The diluents are soluble in vinyl halide monomer under reaction conditions and are inert to the polymerization mass. The diluents are straight or branched chain, or cyclic saturated hydrocarbons having from about 3 to about 15 carbon atoms and, more preferably, from about 4 to about 8 carbon atoms. Particularly useful diluents are n-propane, n-butane, isobutane or mixtures thereof. The diluents are utilized in amounts from about 0.2 to less than about 50.0 percent based upon the total weight of the reaction charge.

Abstract: An improved bulk polymerization of vinyl halide is disclosed wherein reactor scale formation is substantially reduced by polymerizing in a single or two stage bulk process a vinyl halide monomer containing up to 50% of a comonomer in contact with a combination of a polyolefin, water, and an inert fine particle size additive which is a solid at the reaction temperature, or water and said additive, optionally in the presence of a surface active agent. Compositions produced by the process of the invention are useful in making films, coated fabrics and molded objects.