| 摘要 |
<p>PURPOSE:To improve the peelability from a film forming base material and to easily obtain a uniform and defectless protective dustproof body for a mask by using specific polyvinyl acetal having a fluorine-contained silyl group at the side chain. CONSTITUTION:The protective dustproof body consisting of the polyvinyl acetal which is expressed by the formula I, contains the silyl-substd. vinyl alcohol component expressed by x2/x1 at >=0.05 ratio, contains <=10mol.% vinyl acetate component and has >=60mol.% rate of acetalization. In the formula I, R<1>-R<3> denotes an alkyl group of 1-10C and a group in which the hydrogen atom of at least one group thereof is partly or wholly substd. with a fluorine atom; R denotes an alkyl group of 1-3C. The peelability from the film forming base material is thereby improved and the uniform and defectless protective dustproof body for the mask is produced at a good yield.</p> |
