Process for recovering vinyl polymers from emulsion polymerization latices

Claim 1

A process for producing polymers of vinyl and vinylidene halides and copolymers thereof with each other or either with one or more polymerizable unsaturated olefinic monomers which comprises forming a monomer premix containing an aqueous reaction medium, the monomer or monomers to be polymerized, a free radical yielding catalyst, and at least one emulsifier, homogenizing said premix and passing the same to a reaction zone, polymerizing said premix in said zone at a temperature in the range of about 30° C. to about 70° C. and at a pH of about 3 to about 12 to produce a vinyl polymer latex, passing said latex through a stripping zone to remove unreacted monomer(s) therefrom with steam, passing said stripped latex to a coagulation zone, adding a coagulating agent to said latex in said coagulation zone at a pH in the range of about 2 to about 8 to form a slurry of friable agglomerates of polymer particles in a serum, passing said slurry to a pressure filter zone wherein the serum is removed under pressure through a permeable membrane and a wetcake of polymer is formed, rinsing said wetcake to remove residual compounds therefrom, pressing said wetcake to a solids content in the range of about 65% to about 75% by weight, passing said wetcake to a crumbling zone and breaking the same to form friable polymer agglomerates and particles, passing said polymer agglomerates and particles into a fluid energy mill while injecting heated air into said mill under a pressure in the range of about 2.5 psig. to about 80 psig. thereby grinding and drying said polymer agglomerates and particles, and recovering the polymer from said mill in the form of discrete particles thereof.