| abstract |
1291392 Partially neutralized ethylene-acid copolymers E I DU PONT DE NEMOURS & CO 9 March 1970 [7 March 1969] 11208/70 Heading C3P Aqueous dispersions of a copolymer with a solids content of at least 50% contain a copolymer of 65-97% wt. of ethylene and 35-3% wt. of an alpha, beta-ethylenically unsaturated acid or acid anhydride which is partially neutralized, up to 10%, in alkali metal salt form. The acid is acrylic, methacrylic, ethacrylic, itaconic, maleic, fumaric or a monoester or anhydride of a dicarboxylic acid. A third monomer, particularly vinyl acetate, may be present. The dispersion is formed by emulsifying a solution of the ethylene/acid copolymer in a hydrocarbon/polar solvent mixture with water in the presence of alkali metal base to neutralize less than 10% of the carbonyl groups and a volatile base followed by evaporating the solvent and the volatile base. The exemplified solvent mixture is cyclohexane/isopropyl alcohol and ammonia is used as the volatile base. |