METHOD FOR MANUFACTURING ALIPHATIC COPOLYESTER FILM

摘要

Prodn. of alphatic polyesters by T-die melt extrusion is effected using a polyester obtd. by (i)esterifying or ester-interchanging at below 220 deg.C a reaction mixt. of (a)succinic acid or anhydride or ester, (b) 1: 1.2-1.7 mol. % 1,4-butanediol, (c)1-25 mol. % 2,2-di-methyl-1,3-propane-diol and (d) 0.01-mol. % multifunctional cpd. contg. at least 3 OH and/of carboxy gps., and (ii) catalytically polycondensing the oligomer at 240-260 deg.C under a reduced pressure of not more than 1mm Hg. The aliphatic copolyesters have sufficiently high melt viscosity and melt strength to allow film extrusion.