Process for halogenation of synthetic resins

Claim 1

IN THE PROCESS FOR CHLORINATING A POLYVINLY CHLORIDE RESIN SELECTED FROM THE GROUP CONSISTING OF HOMOPOLYMERS OF VINLY CHLORIDE AND COPOLYMES OF VINLY CHLORIDE WITH A COPOLYMERIZABLE MONOMER SELECTED ROM THE GROUP CONSISTING OF VINYLIDENE CHLORIDE, VINYL ACETATE, ISOPROPENYL ACETATE, METHYL ACRYLATE, ETHYL ACRYLATE, 2-ETHYL HEXYL ACRYLATE, METHYL METHACRYLATE, ETHYL METHACRYLATE, ACRYLONITRILE, ETHYLENE AND PROPYLENE, WHEREIN AT LEAST 75% BY WEIGHT OF THE COPOLYMER IS POLYMERIZED VINYL CHLORIDE UNITS, COMPRISING THE STEPS OF PREPARING A SUSPENSION OF THE POLYVINYL CHLORIDE RESIN COMPOSED OF MACRO-GRANULAR PARTICLES WITHIN THE RANGE OF FROM ABOUT 0.5 MICRON TO ABOUT 200 MICRONS IN A LIQUID AQUEOUS MEDIUM CONTAINING, AS A SWELLING AGENT FOR THE POLYVINYL CHLORIDE RESIN, A SATURATED CHLOROHYDROCARBON HAVING FROM 1 TO 4 CARBON ATOMS AND CONTAINING AT LEAST ONE CHLORINE AND AT LEAST ONE HYDROGEN SUBSTITUENT, SUBSTANTIALLY SATURATING THE LIQUID AQUEOUS MEDIUM OF THE SUSPENSION WITH GASEOUS CHLORINE, INDUCING THE CHLORINATIONREACTION BETWEEN THE CHLORINE AND THE POLYVINYL CHLORIDE RESIN IN SAID SUSPENSION BY PHOTO-ILLUMINATION, MAINTAINING THE REACTION AT A TEMPERATURE NO GREATER THAN ABOUT 65*C. AND MAINTAINING AN EXCESS OF DISSOLVED CHLORINE IN SAID SUSPENSION OVER THE MOMENTARILY REACTING WITH THE SUSPENDED RESIN, TERMINATING THE REACTION WHEN THE DESIRED AMOUNT OF CHLORINATION OF THE RESIN HAS BEEN ACHIEVED BY EXTINGUISHING THE PHOTO-ILLUMINATION, SEPARATING THE CHLOROHYDROCARBON-SWOLLEN CHLORINATED POLYVINYL CHORIDE RESIN PRODUCT FROM THE AQUEOUS MEDIUM, NEUTRALIZING SAID PRODUCT, AND SEPARATING THE CHLOROHYDROCARBON FROM SAID PRODUCT; THE IMPROVEMENT WHICH COMPRISES CARRYING OUT SAID CHLORINATION IN THE PRESENCE OF A CATALYTIC AMOUNT OF AT LEAST ONE REDUCING AGENT SELECTED FROM THE GROUP CONSISTING OF