| 摘要 |
PROBLEM TO BE SOLVED: To produce an ethylene/vinyl acetate while reducing the deposition of scales on the inside wall of a polymerization kettle by copolymerizing ethylene with vinyl acetate in the presence of crotonaldehyde in a solvent. SOLUTION: Ethylene is copolymerized with vinyl acetate in the presence of, desirably, 0.0001-0.5 ppm, more desirably, 0.0002-0.005 ppm of crotonaldehyde in a solvent, desirably, a 4C or lower alcohol. The amount of the solvent used is desirably 1-60 pts.wt. per 100 pts.wt. vinyl acetate. It is desirable that the conversion (of vinyl acetate) is 20-90% in the case of batch wise polymerization and is 20-60% in the case of continuous polymerization. The ethylene content of the copolymer is, desirably, 15-60 mol.%, more desirably, 25-55 mol.%. A saponificate of this copolymer is advantageous in that it is less discolored and that it can give film of a low fisheye content. This copolymer is useful for adhesives, pressure-sensitive adhesives, coating materials, etc. |
