| 摘要 |
PURPOSE:To obtain the titled molded article for surface defect-free artificial marble, etc., by adding two kinds of polymerization initiators different in the half-life temperatures between each other in a composition made up of filler and a syrup consisting of methyl methacrylate polymer and methyl methacrylate monomer to effect polymerization to a specific conversion point followed by compression molding. CONSTITUTION:A composition made up of (1) 70-20pts.wt. of a syrup consisting of, based on the total amount of the syrup, (i) 0-50wt% of methyl methacrylate polymer and (ii) 100-50wt% of methyl methacrylate monomer and (2) 30-80pts. wt. of filler is incorporated with (A) a radical polymerization initiator with a 10hr half-life temperature <=50 deg.C and (B) a second radical polymerization initiator with a 10hr half-life temperature >=70 deg.C to perform polymerization on heating, of part of said monomer by the initiator (A) to adjust the conversion of the system between 30% and 80% by raising the conversion by >=10% to prepare a molding material. This material is them packed in a mold to carry out compression molding and curing mainly by the initiator (B), thus obtaining the objective molded article. |
