| 摘要 |
PROBLEM TO BE SOLVED: To obtain a uniformly and minutely foamed molded product having a beautiful surface by mixing a thermoplastic resin raw material with thermally expandable microcapsules, kneading and melting the mixture to expand the microcapsules, and subsequently molding the expanded mixture. SOLUTION: This method for foaming and molding a thermoplastic resin comprises simultaneously charging a thermoplastic raw material and thermally expandable microcapsules into a hopper, mixing the materials, and subsequently foaming and molding the mixture in a die or a mold by the use of an extruder or an injection molding machine. When the thermoplastic resin of raw material is thermally melted in the extrusion or injection molding process, the synthetic resin outer shells of the thermally expandable microcapsules are softened, and a liquid or gas charged in the microcapsules is thermally expanded. Thus, the outershells of the microcapsules are expanded to form the foamed state. The method enables to select the sizes of the thermally expandable microcapsules, mix the selected microcapsules, control the foaming state, and thereby easily obtain an objective specific gravity. |
