| 摘要 |
PURPOSE:To form a molded item, on which no sinking develops and which has a shape as designed, by a method wherein unsaturated monomer mainly consisting of filler-containing methyl methacrylate is poured in a mold under the condition that a favorably releasable sheet, which is shaped so as to lie parallel with at least a part of the molding surface for forming the rear side of a product, is lain parallel with said part of the molding surface. CONSTITUTION:The loadings of filler is 20 - 80wt% on the basis of the gross weight of polymer mainly consisting of methyl methacrylate and the filler. In addition, the sheet concerned prevents sinking, which is developed from developing through the separation of the front side of said monomer from the molding surface in the midway of polymerization due to the separation of its rear side from the molding surface for forming its rear side during the shrinkage of the polymer. Accordingly, the sheet must be soft and easily deformable. The thickness of the sheet depends upon its material and its normal and favorable thickness is 0.01 - 2mm. Further, the peeling strength between a product and the sheet is 2kg/cm or less. The shaped sheet must be arranged so as to come into close contact with the molding surface without gap caused by wrinkle, floating and the like. |
