Graft copolymers

Claim 1

A PROCESS OF COPOLYMERIZING IN AQUEOUS EMULSION BY GRAFT POLYMERIZAITON A MONOMER (A) HAVING A CONJUGATED DOUBLE BOND AND POSSESSING A VERY HIGH COPOLYMERIZATION PARAMETER (R-VALUE) WITH A MONOMER (B) HAVING A NON-CONJUGATED DOUBLE BOND AND POSSESSING A VERY LOW R-VALUE, THE R-VALUES OF SAID TWO MONOMERS (A) AND (B) DIFFERING FROM EACH OTHER BY A RATIO OF AT LEAST 50 TO 1, COMPRISING THE STEPS OF FIRST COPOLYMERIZXING IN AQUEOUS EMULSION A MONOMER (A) SELECTED FROM THE GROUP CONSISTING OF STYRENE AND METHYLEMETHACRYLATE WITH AT LEAST ONE ASMMETRIC MONOMER (CD) HAVING ONE CONJUGATED (C) AND ONE NON-CONJUGATED (D) DOUBLE BOND, SAID MONOMER (CD) BEING SELECTED FROM THE GROUP CONSISTING OF ALLYL ACRYLATE, ALLYL METHACRYLATE, METHALLYL ACRYLATE AND ALLYL STYRENE AND SECOND, FURTHER COPOLYMERIZING IN AQUEOUS EMULSION THE REACTION PRODUCTS OBTAINED IN SAID FIRST STEP WITH A MONOMER (B) SELECTED FROM THE GROUP CONSISTING OF VINYL ACETATE AND ALLYL ACETATE, THE TWO DOUBLE BONDS (C) AND (D) OF SAID MONOMER (CD) HAVING R-VALUES DIFFERING FROM EACH OTHER BY A RATIO OF AT LEAST 50 TO 1, THE GROUP (C) HAVING ABOUT THE SAME VERY HIGH R-VALUE AS THE MONOMER (A) AND THE GROUP (D) HAVING ABOUT THE SAME VERY LOW R-VALUE AS THE MONOMER (B), SAID MONOMER (CD) BEING USED IN QUANTITIES OF UP TO 10 MOLE PERCENT, CALCULATED ON THE BASIS OF THE QUANTITY OF SAID MONOMER (A), SAID AQUEOUS EMULSION POLYMERIZATION OF BOTH THE FIRST AND THE SECOND STEP BEING CARRIED OUT IN THE PRESENCE OF REACTION INITIATIORS WHICH REMAIN STABLE IN AQUEOUS SOLUTION, SAID INITIATORS BEING SELECTED FROM THE GRUOP CONSISTING OF WATER SOLUBLE AND OIL SOLUBLE INITIATORS, WHEREBY IN SAID FIRST STEP OF COPOLYMERIZATION THE GROUP (C) OF THE MONOMER (CD) COPOLYMERIZES WITH THE MONOMER (A), WHILE IN SAID SECOND STEP THE GROP (D) OF SAID REACTION PRODUCT FORMED IN THE FIRST STEP, COPOLYMERIZES NOW WITH THE MONOMER (B), TO OBTAIN A HIGH YIELD OF A SUBSTANTIALLY UNIFORM, HARD COPOLYMER OF HIGH RESISTANCE TO SHOCK AND IMPACT.