Abstract: A polyester film includes a polyester (A) composed mainly of polybutylene terephthalate and a polyester (B) composed mainly of polyethylene terephthalate, wherein a mass ratio (A/B) between the polyesters (A) and (B) is 70/30 to 55/45, a dry heat shrinkage rate (B) through heat treatment at 200° C. for 15 minutes is 35% or less in any of four directions (0°, 45° 90° and 135°) on the film surface, a difference between a maximum value and a minimum value of these dry heat shrinkage rates is 5% or less, a thickness variation in the four directions is 10% or less, and a crystallization index shown in DSC measurement is 25 to 55 J/g.

Abstract: To provide a biaxially stretched polyester resin film that has excellent properties equal to or better than those of biaxially stretched polyester film that does not use recycled raw material, and in particular that has an excellent flexural resistance in low-temperature environments. A biaxially stretched polyester resin film that characteristically satisfies both of the following properties (1) and (2): (1) in differential scanning calorimetry (DSC), after heating from 25° C. to 300° C. at a heating rate of 20° C./minute and holding for 10 minutes at 300° C., the temperature of crystallization during cooling at a cooling rate of 40° C./minute is 160° C. to 180° C.; and (2) the number of pinholes after the execution of 200 repetitive cycles of a flexural fatigue test in a ?10° C. atmosphere using a Gelbo Flex Tester is not more than 10/500 cm2.

Abstract: A polyester film comprises a polyester (A) composed mainly of polybutylene terephthalate and a polyester (B) composed mainly of polyethylene terephthalate, wherein a mass ratio (A/B) between the polyesters (A) and (B) is 70/30 to 55/45, a dry heat shrinkage rate (A) through heat treatment at 160° C. for 30 minutes is 20% or less in any of four directions on a film surface (0°, 45°, 90° and 135®), a difference between a maximum value and a minimum value of these dry heat shrinkage rates is 5% or less, a dry heat shrinkage rate (B) through heat treatment at 200° C. for 15 minutes is 35% or less in any of the four directions, a difference between a maximum value and a minimum value of these dry heat shrinkage rates is 5% or less, and a thickness variation in the four directions is 10% or less.

Abstract: The present invention provides a mold release film including a resin layer provided on one surface of a polyester film, wherein the resin layer includes 100 parts by mass of a polypropylene-based modified polyolefin resin with the proportion of a modifying component of 1 to 10% by mass and 1 to 50 parts by mass of a cross-linking agent; the peel strength between the resin layer and a pressure-sensitive adhesive measured by bonding a rubber-based pressure-sensitive adhesive to the resin layer exceeds 3.0 N/cm; and the residual adhesion rate of a pressure-sensitive adhesive after bonding an acrylic pressure-sensitive adhesive to the resin layer is 80% or more.

Abstract: The present invention provides a mold release film including a resin layer provided on one surface of a polyester film, wherein the resin layer includes 100 parts by mass of a polypropylene-based modified polyolefin resin with the proportion of a modifying component of 1 to 10% by mass and 1 to 50 parts by mass of a cross-linking agent; the peel strength between the resin layer and a pressure-sensitive adhesive measured by bonding a rubber-based pressure-sensitive adhesive to the resin layer exceeds 3.0 N/cm; and the residual adhesion rate of a pressure-sensitive adhesive after bonding an acrylic pressure-sensitive adhesive to the resin layer is 80% or more.

Abstract: The present invention provides a mold release film including a resin layer provided on one surface of a polyester film, wherein the resin layer includes an acid-modified polyolefin resin with a proportion of an acid-modifying component of 1 to 10% by mass, polyvinyl alcohol and a cross-linking agent; the content of polyvinyl alcohol exceeds 200 parts by mass and is 1000 parts by mass or less, and the content of the cross-linking agent is 1 to 20 parts by mass in relation to 100 parts by mass of the acid-modified polyolefin resin; and the peel force between the resin layer and a rubber-based adherend measured by bonding the rubber-based adherend to the resin layer is 0.5 N/cm or less.