Vinyl monomer polymerization process

Claim 2

The process of claim 1 wherein said agglomeration inhibitor is in the range of 0.5 to 2.5 weight per cent, based on the weight of monomer charge.

Claim 3

The process of claim 3 wherein said agglomeration inhibitor is hydrogenated butadiene-styrene copolymer.

Claim 4

In a process for preparing polymers of vinyl chloride comprising contacting in a first stage a monomer charge comprising liquid vinyl chloride or a liquid mixture of a major amount of vinyl chloride and a minor amount of at least one compound copolymerizable with vinyl chloride and a polymerization initiator under polymerization conditions while maintaining the contents of the polymerization zone in an agitated condition induced by a high speed mixing device to convert up to 15 per cent of said monomer charge to polymer and thereafter continuing said polymerization in a second stage in an agitated condition induced by a mixing device operated at a speed substantially slower than the mixing speed in said first stage, the improvement wherein said first stage polymerization is effected in the presence of from about 0.2 to 4 weight per cent, based on the weight of monomer charge, of an agglomeration inhibitor selected from the class consisting of hydrogenated butadiene-styrene copolymer, methyl methacrylate-styrene-acrylonitrile terpolymer, poly(vinyl acetate) and mixtures thereof said agglomeration inhitor being soluble in said monomer charge.

Claim 5

A process for preparing vinyl polymers comprising the steps of: polymerizing under liquid phase polymerization conditions in a substantially solvent-free environment a monomer charge comprising from 75 to 100 weight per cent of liquid vinyl chloride and from zero to 25 weight per cent of at least one compound copolymerizable with vinly chloride under the polymerization conditions, in the presence of a vinyl monomer polymerization initiator and at least one agglomeration inhibitor in the range of 0.2 to 4 weight per cent, based on the weight of monomer charge selected from the class consisting of hydrogenated butadiene-styrene copolymer, methyl methacrylate-styrene-acrylonitrile terpolymer, poly(vinyl acetate), and mixtures thereof, said agglomeration inhibitor being soluble in said monomer charge, to form a reaction mixture comprising polymer of vinyl chloride; and contacting said polymer of vinyl chloride under vapor phase polymerization conditions in a substantially solvent-free environment with a vaporized monomer charge comprising from 75 to 100 weight per cent vinyl chloride and 25 to zero weight per cent of at least one compound which is copolymerizable with vinyl chloride under vapor phase polymerization conditions to form additional reaction product comprising polymer of vinyl chloride.

Claim 6

A process according to claim 6 wherein said reaction mixture comprising polymer of vinyl chloride is present in an amount ranging from 15 to 60 weight per cent, based on weight of total polymer product. Pg,19

Claim 7

A process according to claim 6 wherein said vapor phase polymerization is effected in the presence of a polymer of vinyl chloride prepared according to the process of claim 2.