Patent ID: 7943809

Claim:
A method for inhibiting polymer growth of a polymer present in ethylenically unsaturated monomers, said monomers selected from the group consisting of styrene, α-methylstyrene, styrene sulfonic acid, divinylbenzene, polyvinylbenzene, alkylated styrene, butadiene and isoprene monomers, said process comprising (A) providing the polymer to the ethylenically unsaturated monomers; and (B) adding to the ethylenically unsaturated monomers, an inhibitor composition consisting of: (i) at least one first inhibitor consisting of a hydrogen donor of the structure wherein R 104 , R 105 , R 106 , R 107 , R 108 , and R 109 are independently selected from the group consisting of hydrogen, alkyl, aryl, cycloalkyl, heterocyclic, substituted alkyl, substituted aryl, OR 110 , —SR 110 , NO, NO 2 , CN, COR 112 , halogen, and/or any two adjacent groups can be taken together to form ring structure(s), respectively of five to seven members, provided that at least one of R 104 , R 105 , R 106 , R 107 , R 108 , and R 109 is OH; R 110 and R 111 are independently selected from the group consisting of hydrogen, alkyl, aryl, benzyl, cyclic, heterocyclic, substituted alkyl or aryl where the substituents are C, O, N, S, or P, and COR 102 , or R 110 and R 111 can be taken together to form a ring structure of five to seven members; R 112 is R 102 , OR 102 , or NR 102 R 103 , R 102 and R 103 are independently selected from the group consisting of hydrogen, alkyl, aryl, benzyl, cyclic, heterocyclic, and substituted alkyl or aryl where the substituents are C, O, N, S, or P, or R 102 and R 103 can be taken together to form a ring structure of five to seven members, and (ii) at least one second inhibitor having the following structural formula: wherein R 1 and R 4 are independently selected from the group consisting of hydrogen, alkyl, and heteroatom-substituted alkyl, R 2 and R 3 are independently selected from the group consisting of alkyl and heteroatom-substituted alkyl, and X 1 and X 2 (1) are independently selected from the group consisting of halogen, cyano, amido, —S—C 6 H 5 , carbonyl, alkenyl, alkyl of 1 to 15 carbon atoms COOR 7 , —S—COR 7 , —OCOR 7 , wherein R 7 is alkyl or aryl, or (2) taken together, form a ring structure with the nitrogen; and (iii) N-phenyl-N′-(1,4-dimethylpentyl)-para-phenylenediamine and wherein the polymer's growth is decreased by the presence of the inhibitor composition.