| 摘要 |
PURPOSE: To greatly improve the lowering of strength due to the internal stress of an insert-molding by a method wherein a elastic covering layer having molding strain-dispersing function is attached to the edge or the end of the tip part of an insert. CONSTITUTION: Machined steel plate as an insert main body is polished with sand paper and degreased. After that, the end part of the main body is immersed in a molten bath of moisture-curing urethane-based hot melt adhesive, immediately pulled up and solidified by forced air cooling so as to build up covering layer having the thickness of about 1mm by repeating the above-mentioned operation. Next, by being moisture-cured in a chamber of constant temperature and humidity, an insert 8, to which elastic covering layer 4' is attached. By injection-molding resin under the condition that the insert 8 is set in a mold, an insert-molding 5 is produced. Further, in order to improve the adhesion between the resin and the elastic covering layer, grooving, knurling, boring or the like and primer treatment with silane couping agent or the like may well be performed on the surface of the insert main body. |
