Process for preparing a graft of dienestyrene-acrylate interpolymer with a vinyl carboxylic acid

Claim 1

A PROCESS FOR PREPARING FREEZE-THAW MECHANICAL STABLE LATEX WHICH COMPRISES ADDING A MINOR PORTION OF A MONOMER MIXTURE CONSISTING ESSENTIALLY OF FROM 10% TO 20% OF A CONJUGATED DIENE, FROM 2% TO 55% OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF STYRENE AND RING-SUBSTITUTED SSTYRENE, FROM 20% TO 87.5% OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALKYL ACRYLATES HAVING FROM 4 TO 12 CARBON ATOMS, ALKYL METHACRYLATES HAVING FROM 8 TO 16 CARBON ATOMS AND MIXTURES THEREOF, AND FROM 0.5% TO 5% BY WEIGHT OF THE MONOMER MIXTURE OF AN ALPHA-BETA VINYLIDENE CARBOXYLIC ACID TO AN AQUEOUS EMULSION COMPRISING AN EMULSIFIER AND A FREERADICAL INITIATOR, AND THEN ADDING INCREMENTALLY DURING THE POLYMERIZATION THE MAJOR PORTION OF SAID MONOMER MIXTURE WHILE MAINTAINING THE TEMPERATURE OF THE REACTION MIXTURE BETWEEN ABOUT 15*C. AND 100*C. UNTIL AT LEAST 70% CONVERSION BUT LESS THAN 95% CONVERSION IS ACHIEVED, THEN ADJUSTING THE EMULSION TEMPERATURE TO FROM 20*C. TO 60*C. AND ADDING FROM 0.05 TO 10 PARTS PER 100 PARTS OF MONOMER OF AN ALPHA-BETA VINYLIDENE CARBOXYLIC ACID, THEN ALLOWING THE POLYMERIZATION TO PROCEED TO SUBSTANTIAL COMPLETION.