| 摘要 |
1,144,979. Saponified ethylene-vinyl acetate copolymers. FARBENFABRIKEN BAYER A.G. 26 May, 1967 [29 July, 1966], No. 24589/67. Heading C3P. Saponified ethylene/vinyl acetate copolymers of particle size 0À1 to 0À7 mm. and in which at least 50% of the acetyl groups are saponified, which polymers originally contained ethylene and vinyl acetate in a molar ratio of 4: 1 to 50 1, are prepared by a process which comprises gelling the hot saponification solution by cooling below 60‹ C., extruding the gelled solution through a die plate to produce filaments of diameter 0À3 to 5 mm., breaking down the filaments in or with water to particles of length 0À1 to 5 mm., freeing the gel particles so obtained from organic solvents at 20‹ to 80‹ C. under reduced pressure, washing out any saponification catalysts present, isolating and if desired additionally grinding the copolymer. Apparatus suitable for carrying out the process of the invention is described and illustrated, and the products may be used for bonding textile fabrics at elevated temperatures. |
