| 摘要 |
PROBLEM TO BE SOLVED: To obtain a uniaxially stretched aliphatic polyester film molded by using polycondensed aliphatic polyester and excellent in transparency, mechanical strength and product dimensional stability. SOLUTION: Aliphatic polyester mainly synthesized from 1,4butanediol and succinic acid and characterized by that melt viscosity at 190 deg.C and a shearing speed 100 (sec<-1> ) is 4,000-100,000 poise, an m.p. is 80-120 deg.C and a number average mol.wt. is 30,000 or more is molded by an extrusion film forming method. Subsequently, the formed film is longitudinally stretched by 3-8 times at temp. lower than the m.p. of the resin by 35-50 deg.C to obtain a uniaxially stretchred aliphatic polyester film with haze of 2.0-10.0% and impact strength of 2kg.cm or more. |
