| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyvinyl acetal film in which the fine-tuning of positions is facilitated on lay-up, shrinkage is not caused on lamination, and the flow-out of resin from edges parts of a member such as a glass plate or the like is not caused, a sealing material for a solar battery and an intermediate film for laminated glass formed of the polyvinyl acetal film, and a solar battery module and the laminated glass using the polyvinyl acetal film.SOLUTION: A polyvinyl acetal film is formed using polyvinyl acetal in which the content of a vinyl alcohol unit is 8 to 30 mass%, has a three layer structure where a core layer C is present between skin layers A, B at the outside, and satisfies the following inequalities (I), (II), (IV): ▵≥▵(I), ▵-▵≥0.1×10(II) and ▵<3.5×10(IV)(here, ▵,anddenote the birefringences in the mechanical flow directions of the skin layer A, the skin layer B and the core layer C, respectively). |
