| 摘要 |
PURPOSE:To obtain a film having improved electrical properties, heat resistance, mechanical strength and orientability by using a specified polyphenylene sulfide copolymer. CONSTITUTION:A polyphenylene sulfide block copolymer of a melt viscosity (at 300 deg.C and a shear rate of 20sec<-1>) of 500 to 200,000P, prepared by chemically combining a polyphenylene sulfide part containing at least 70mol% repeating units of formula I with a polyphenylene sulfide sulfone copolymer part containing 50 to 99mol% repeating units of formula II, is melted by heating to a temperature above the m.p. thereof and extruded through a slit die, and the extrudate is rapidly cooled to a temperature below the glass transition temperature on a rotary cooling drum to obtain an amorphous unoriented sheet. This sheet is uniaxially oriented at 70 to 130 deg.C in a draw ratio of 2 to 6, then oriented in a draw ratio of 1.5 to 6 in the direction perpendicular to that of the initial orientation and heat-treated at a temperature of 220 deg.C to the m.p. of the polymer under conditions of a limited shrinkage or elongation within 20% of of a constant length to obtain a polyphenylene sulfide copolymer film of a thickness of 0.5 to 200mum. |
