Chlorination of polyvinyl chloride

Claim 1

IN THE METHOD FOR CHLORINATING PARTICULATE POLYVINYL CHLORIDE RESIN COMPOSED OF PARTICLES WITHIN THE RANGE OF FROM ABOUT 0.5 MICRON TO ABOUT 200 MICRONS COMPRISING THE STEPS OF PREPARING A SUSPENSION OF 100 PARTS BY WWEIGHT OF THE POLYVINYL CHLORIDE IN AT LEAST BOUT 130 PARTS BY WEIGHT OF LIQUID AQUEOUS MEDIUM, SAID SUSPENSION CONTAINING FROM ABOUT 15 TO ABOUT 100 PARTS BY WEIGHT OF HYDRO-CHLOROMETHYLENE COMPOUND TO SERVE AS A SWELLING AGENT FOR THE SUSPENDED POLYVINYL CHLORIDE RESIN, SUBSTANTIALLY SATURATING THE LIQUID AQUEOUS MEDIUM OF THE SUSPENSION WITH GASEOUS CHLORINE AND THE POLYVINYL CHLORIDE IN SAID SUSPENSION, MAINTAINING AN EXCESS OF DISSOLVED CHLORINE IN SAID SUSPENSION OVER THAT MOMENTARILY REACTING WITH THE SUSPENDED RESIN, TERMINATING THE REACTION WHEN THE DESIRED AMOUNT OF CHLORINATION OF THE RESIN HAS BEEN ACHIEVED, SEPARATING THE HYDRO-CHLOROMETHYLENE-SWOLLEN CHLORINATED POLYVINYL CHLORIDE RESIN PRODUCT FROM THE AQUEOUS MEDIUM NEUTRALIZING SAID PRODUCT, AND SEPARATING THE HYDRO-CHLOROMETHYLENE FROM SAID PRODUCT; THE IMPROVEMENT WHICH COMPRISES ADMIXING WITH SAID SUSPENSION OF POLYVINYL CHLORIDE RESIN IN LIQUID AQUEOUS MEDIUM PRIOR TO THE CHLORINATION THEREOF FROM ABOUT 0.1 PART TO ABOUT 5 PARTS OF AN ACRYLIC ACID POLYMER SELECTED FROM THE GROUP CONSISTING OF THE ESSENTIALLY LINEAR POLYMER OF AN ALPHA, BETA-MONOOLEFINICALLY TERMINALLY UNSATURATED MONOCARBOXYLIC ACID HAVING FROM 3 TO 4 CARBON ATOMS AND HAVING AN AVERAGE MOLECULAR WEIGHT BETWEEN ABOUT 5,000 AND ABOUT 500,000, THE CROSSLINKED INTERPOLYMER OF SAID MONOCARBOXYLIC ACID AND FROM ABOUT 0.5 TO ABOUT 2.5% BY WEIGHT OF A POLYUNSATURATED COMPOUND HAVING AT LEAST TWO ALKENYL GROUPS AND COPOLYMERIZABLE WITH SAID ACID HAVING AN AVERGE MOLECULAR WEIGHT GREATER THAN AZBOUT 200,000, AND THE AFORESAID POLYMERS AND INTERPOLYMERS CONTAINING UP TO 20 MOL PERCENT OF COPOLYMERIZED ALKYL ESTER OF SAID MONOCARBOXYLIC ACID WHEREIN THE ALKYL GROUP OF SAID ESTER HAS 1 TO 8 CARBON ATOMS.