MOLDING OF THERMOSETTING RESIN MOLDING MATERIAL

摘要

PURPOSE:To produce artificial marble improved in surface appearance and water resistance by preparing a molding material by compounding a specific amt. of a filler with unsaturated polyester and a vinyl monomer containing a specific amt. of substituted styrene and subjecting the same to pressure molding under pressure within a vacuum mold. CONSTITUTION:A molding material is formed by compounding 100-550 pts.wt. of a filler with 100 pts.wt. of a resin compsn. consisting of 80-60wt.% of unsaturated polyester and 40-20wt.% of a vinyl monomer with substituted styrene content of 40wt.% or more. This molding material is charged in a mold and pressurized under heating while the pressure in the mold is reduced to 400mmHg or less to form artificial marble. By this method, the artificial marble not causing the deterioration of water resistance and having good surface appearance can be obtained. Since substituted styrene has a high b.p., the air in the molding material is removed at the time of heat and pressure molding under vacuum and the artifical marble has no surface defect and high water resistance.