Patent ID: 8981212
Filing Date: 2015-03-17
Classification: B32B,C08J,H01L,Y02E,Y10T

Abstract:
1. A polyester film comprising particles and two kinds of crystalline polyester resins in which a sea-island structure is formed, wherein, if a crystallization temperature of a crystalline polyester resin A that forms a continuous phase or matrix phase in the polyester film is represented by TccA and a crystallization temperature of a crystalline polyester resin B that forms a dispersion phase or domain phase in the polyester film is represented by TccB, expression (1) below is satisfied, a degree of flatness of the dispersion phase is 3 or more, 70% or more of a total number of the particles present in the dispersion phase or are in contact with the dispersion phase, and the dispersion phase is 0.1/μm to 5/μm in terms of an average number of dispersion phases per unit of 1 μm in a length in a film thickness direction: