摘要:
The present invention provides a method for producing a polyester sheet, including melt-extruding a polyester having a half-value width of a crystallization temperature on cooling of 25° C. to 50° C.; and cooling the melt-extruded polyester such that a surface temperature of the polyester is lowered at a rate of 350° C./min to 590° C./min, wherein the polyester sheet has a thickness of 3 mm to 5 mm.
摘要:
Provided is a method for producing a polyester film, including: subjecting a polyester raw material resin, which contains a titanium compound and has an intrinsic viscosity of from 0.71 to 1.00, to melt extrusion using a twin-screw extruder which includes a cylinder; two screws disposed inside the cylinder; and a kneading disk unit disposed in at least a portion of a region extending from a 10%-position to a 65%-position of screw length with respect to an upstream end of the screws in a resin extrusion direction as a starting point, at a maximum shear rate generated inside the twin-screw extruder of from 10 sec−1 to 2000 sec−1; forming an unstretched film by cooling and solidifying the melt extruded polyester resin on a cast roll; subjecting the unstretched film to biaxial stretching in a longitudinal direction and a lateral direction; and heat fixing the stretched film formed by biaxial stretching.
摘要:
A biaxially oriented polyester film having: an equilibrium moisture content of from 0.1% by mass to 0.25% by mass; a difference between moisture contents measured at 10 cm intervals of from 0.01% by mass to 0.06% by mass; a degree of crystallinity of from 30% to 40%; a concentration of terminal carboxyl groups of from 5 equivalents/ton to 25 equivalents/ton; and a thickness of from 100 μm to 350 μm.
摘要:
An optical film comprising a thermoplastic resin, which is such that the slow axis direction in the film plane differs from the film tilt direction and the birefringence of a sliced section of the film that contains the tilt direction and the thickness direction in the plane varies in the thickness direction of the film.