FREMGANGSMAATE FOR INHIBERING AV POLYMEROPPBYGGING PAA INNERFLATENE I ET POLYMERISASJONSKAR

1477270 Preventing polymer scale formation during polymerization CONTINENTAL OIL CO 16 Oct 1975 [29 Oct 1974] 42505/75 Heading C3P Polymer build-up on the interior surfaces of a polymerization vessel during the aqueous dispersion polymerization of a water-insoluble monoethylenic monomer which is liquid under the polymerization conditions, is inhibited by adding benzotriazole and/or tolyltriazole and/or 2 - (21- hydroxy - 51 - methylphenyl)benzotriazole to the dispersion prior to polymerization. Build-up may be further inhibited by additionally including (1) an alkylated copolymer of an N-vinyl lactam of the formula wherein n is an integer of 1 to 3 and R and R 1 are independently, H, CH 3 or C 2 H 5 ; and an at least C 2 alpha olefin, and/or (2) an alkali- or alkaline earth metal salt of an aminocarboxylic acid of formula (R) n -N-(A-COOH) 3-n wherein R is -CH 2 CH 2 OH or -CH 2 CH 2 CH 2 OH, A is C 1 _ 3 alkylene and n is zero, 1 or 2, or of the formula wherein Z is C 1-4 alkylene; X is zero, 1, 2, 3 or 4; Y and Y1 are independently H, -CH 2 COOH or hydroxyalkyl and Y11 is H or -CH 2 COOH. The preferred amino carboxylic acid salt is the tetra sodium salt of E.D.T.A. The examples relate to vinyl chloride polymerization.