COPOLYMERS OF VINYLESTERS

1,249,390. Vinyl ester copolymers; electrocoating compositions. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. 6 April, 1970 [3 July, 1969], No. 33543/69. Headings C3P and C3R. [Also in Division C7] The invention comprises novel interpolymers obtained by copolymerizing in one or more stages, a monomer mixture consisting of (a) 20- 80% by wt. of a vinyl ester of one or more saturated aliphatic monocarboxylic acids of 5-20 carbon atoms in which acid, the carboxyl group is attached directly to a tertiary or quaternary carbon atom, (b) 2-20% by wt. of an alpha, beta-ethylenically unsaturated carboxylic acid of 3-5 carbon atoms, (c) 5-40% by wt. of a monovinyl aromatic compound of 8-9 carbon atoms, (d) 5-35% by wt. of a 2- hydroxyalkyl ester or an amide of an alpha, beta-ethylenically unsaturated carboxylic acid and (e) 0-25% by wt. of a C 1 to C 4 alkyl ester of acrylic or methacrylic acid. Monomers (a) specified are vinyl esters of commercially available "branched" aliphatic monocarboxylic acids of 9-11, preferably 10, carbon atoms from the cracking of paraffin hydrocarbons. Monomers (b) specified are acrylic, methacrylic, maleic, fumaric, aconitic and itaconic acids. Monomers (c) specified are styrene and vinyl toluene; monomers (d), 2-hydroxyethyl acrylate, 2- hydroxyethyl methacrylate (preferred), 2-hydroxypropyl acrylate and methacrylate, mono- and di-2-hydroxyethyl esters of maleic or fumaric acids, acrylamide, and N-hydroxymethyl acrylamide, and monomers (e), methyl methacrylate. Polymerization may be by any of the standard methods, but solution is preferred. A preferred process involves charging a reactor with all of monomer (a) and 5-15% by wt. of the other monomers and polymerizing, whilst adding the rest of the monomers in one or more subsequent stages. In the examples, interpolymers are made by the "staged" process from (1) a mixture of vinyl esters of saturated aliphatic monocarboxylic acids of 9-11 carbon atoms, branched at the alpha carbon ("Veova" -Trade Mark), acrylic acid, styrene, 2-hydroxy ethyl methacrylate and methyl methacrylate using as an initial initiator, di-t-butyl peroxide, and as further initiator with the subsequent addition of monomers (b) to (e), benzoyl peroxide, in a solvent mixture of ethylene glycol monobutyl ether, and benzyl alcohol, and (3) "Veova", methacrylic acid, styrene, and 2- hydroxyethyl methacrylate, polymerized in stages in a mixture of 2-methoxy ethanol and tetrahydrofurane, using benzoyl peroxide as the sole