POLYVINYL ACETAL FILM EXCELLENT IN TRANSPARENCY AND SUPPRESSING THERMAL CRACKING PHENOMENON

摘要

An object is to provide a polyvinyl acetal film which has excellent transparency and can suppress a thermal cracking phenomenon.;The above object is achieved by providing a polyvinyl acetal film in which a ratio between a composite modulus (GPa) of the highest part in a convex part and a composite modulus (GPa) of the lowest part in a concave part on a surface of a film on a side in contact with glass, calculated by a nanoindentation measurement using a scanning probe microscope, is 0.90 or less, when a laminated glass is formed. In addition, the above object is achieved by providing a polyvinyl acetal film in which a ratio between a hardness (GPa) of the highest part in the convex part and a hardness (GPa) of the lowest part in the concave part, calculated by the SPM nanoindentation measurement, is 0.90 or less.

主权项

1. A polyvinyl acetal film comprising a polyvinyl acetal and a plasticizer, wherein
at least one surface of the film has an uneven shape, and a ratio between a composite modulus (GPa) of a highest part in a convex part and a composite modulus (GPa) of a lowest part in a concave part, calculated by an SPM nanoindentation measurement, is 0.90 or less.