| 摘要 |
PURPOSE:To beautifully finish the appearance of a molded product and shorten the cycle time by coating a foamed material with a coating agent to make a double structure and kneading and dispersing a foaming agent for which required temperature and required retaining time to generate foaming action with molten resin. CONSTITUTION:A foamed material 17 is constituted with a coating agent 16 to make a double structure in a manner to be mixed with molten resin 13 without foaming reaction occurring in a heating cylinder 2 during plasticizing the resin, not foamed at the molten resin temperature of a section of fast cooling speed in a mold after being injected into the mold and foamed at the molten resin temperature of the slow cooling speed, and a foaming agent 14 for which required temperature and required retaining time are adjusted is kneaded and dispersed with the molten resin. The same is injected in this state into the mold through a heating cylinder 2, and the difference of foaming reaction is provided by the difference of the cooling speeds of the molten resin in the mold and molded. As the molding can be carried out in the non-foaming state just after filling into a product section in the mold in the process, a product of a thin wall or complicated shape of a projected section can be molded and the cycle time can be shortened because of the localized foaming. |
