| 摘要 |
PURPOSE:To obtain a mold capable of molding a molded from showing good shielding effect for a long period of time without spoiling the appearance of the molded form by a method wherein a multitude of polyhedron type protuberances, having a crest line raised up so as to be opposed to the injection direction of composition, is provided protrudingly on the molding surface of the mold. CONSTITUTION:A multitude of polyhedron type protuberances, having a crest line raised up so as to be opposed to the injection direction of composition,is provided protrudingly on the molding surface of a mold, whereby a composition consisting of synthetic resin blended with fiberous electroconductive fillers can be molded by injection molding so as to be highly accurate and good in the appearance thereof. The height of the polyhedron type protuberance is preferable to be within the range of 80-40% of the thickness of a molded form and the number of the polyhedron type protuberance is preferable to be 1.5-3 pieces/cm<2>. A multitude of the polyhedron protuberance 1, formed so that one of the upright crest line 1a of the triangular pyramid thereof is opposed to the upstream side of the injection direction of the composition and the top surface of the same is slanted downwardly from the upstream side to the downstream side of the same, is protruded in the arrangement of mosaic and this arrangement is most preferable in the molding work of the composition. |
