| 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. |
