| 摘要 |
PROBLEM TO BE SOLVED: To provide a PVAt-based (polyvinyl acetal) porous molded product and its manufacture wherein a satisfactory wear resistance is obtained along with improved dimensional accuracy, production efficiency and yield. SOLUTION: Separable upper and lower molds 5, 7 are matched to form spherical space compartments each opened at an injection hole 15 of the upper mold 5, followed by charging a reaction solution containing PVA and starch from the injection hole 15 into the space compartments, heating the upper and lower molds 5, 7 in the state where the reaction solution has been charged to cause the reaction of the reaction solution thereby forming a PVAt-based porous molded product, separating the upper and lower molds 5, 7 from each other to remove the PVAt-based porous molded products from the space compartments. The PVAt-based porous molded product has a film layer, which is formed substantially over the entirety of the exposed outer region and has a porosity lower than that of the inner region. |
