Patent ID: 7238411
Filing Date: 2007-07-03
Classification: B29C,B29K,B32B,Y10S,Y10T

Abstract:
1. A multilayer polyester film comprising a layer A and a layer B which are laminated alternately, the layer A constituting the outermost layer on both sides of the film, wherein (1) the layer A comprises a polyester A, and the layer B comprises a polyester B, (2) the melting point of the polyester A is higher than the melting point of the polyester B by at least 15° C., (3) the layer A is a layer having an oriented structure, and the layer B is a layer having a substantially unoriented structure, (4) the ratio (a/b) of the total thickness (a) of the layer A to the total thickness (b) of the layerBis 0.01 to 3, and (5) the in-plane tensile strength of the multilayer polyester film is 50 MPa or lower at a maximum, and the difference between its maximum value and minimum value is 20 MPa or smaller, said multilayer polyester film having a thickness unevenness of 10% or lower and a haze value of 10% or lower.