| 摘要 |
PROBLEM TO BE SOLVED: To improve (1) the melting extrusion stability and (2) the melting moldability and to reduce (3) the development of coloration and (4) the development of gel in the production of an ethylene-vinyl acetate copolymer saponified material (EVOH). SOLUTION: In the production of an ethylene-vinyl acetate copolymer (EVA) having the ethylene content of 5-60 mol% by copolymerizing an ethylene and a vinyl acetate using a polymerization initiator, an aliphatic alcohol of 4C or less is used as a polymerization solvent, the contents of acetaldehyde and a saturated ester acetate with respect to the vinyl acetate are 200 ppm or less and 10-1,500 ppm, respectively, and the polymerization is carried out at 30-150 deg.C. |
