| 摘要 |
PURPOSE:To obtain a saponified material, having improved melt moldability, particularly drawing moldability, and suitable to a laminate molding material, by copolymerizing ethylene with a vinyl acetate under conditions of specific two or more stepwise varied different methanol concentrations, and saponifying the resultant copolymer. CONSTITUTION:A saponified material, obtained by copolymerizing ethylene with vinyl acetate, and saponifying the resultant copolymer, and having 25-45mol% ethylene content and >=95% saponification degree of the vinyl acetate component. The copolymerization reaction of the ethylene with vinyl acetate is carried out by keeping the temperature and ethylene pressure within the region of formula I [P is ethylene pressure (kg/cm<2>G); T is temperature ( deg.C)] and formula II under conditions of two or more varied methanol concentrations and at least one of the differences between the adjacent above-mentioned concentration at >=5wt% while changing substantially the mutually different above-mentioned concentration conditions to give >=10wt%, based on the total amount of the based on the total amount of the copolymer, formed copolymer under the respective copolymerization conditions. |
