| abstract |
An aqueous dispersion of at least one ethylene α,β-unsaturated carboxylic acid copolymer is produced by contacting a branched ethylene α,β-unsaturated carboxylic acid interpolymer such as ethylene-acrylic acid (EAA) or ethylene-methacrylic acid (EMAA) containing at most 30wt% acid, having a melt flow index (MFI) of at most 100 (g/10 min at 190°C, 2.16Kg), a melting point in the range 75° to 90°C a percent adjacency of the acid groups in the range 2-15%, a polydispersity in the range 2-7 and a branching parameter of at least 0.6 but less than 1, in an aqueous medium at a temperature above the melting point of the copolymer but not exceeding 100°C and at atmospheric pressure. The aqueous medium can be a single base selected from sodium hydroxide, potassium hydroxide and ammonium hydroxide. |