| 摘要 |
The purpose of the present invention is to provide a polyvinyl acetal film that has outstanding transparency and can suppress the phenomenon of heat cracking. The foregoing is achieved by providing a polyvinyl acetal film in which, when laminated glass is being formed, the ratio of the compound elasticity (GPa) of the highest part of a convex section and the compound elasticity (GPa) of the lowest part of a concave section, both of the surface of the film on the side touching the glass, is 0.90 or less as calculated by scanning probe microscopy nanoindentation measurement. Furthermore, the foregoing is achieved by providing the polyvinyl acetal film in which the ratio of the hardness (GPa) of the highest part of the convex section and the hardness (GPa) of the lowest part of the concave section is 0.90 or less as calculated by scanning probe microscopy (SPM) nanoindentation measurement. |
