| 摘要 |
PURPOSE:To obtain a foamed molded body having excellent appearance by a method wherein a capacity of a mold cavity which can be contracted and enlarged is made to be above a shot capacity of a melting resin, the foaming agent-containing melting resin is injected by heating it to above dissolving temperature of the foaming agent by shear heating, the cavity is contracted and the surface of the resin is cured, then the cavity is enlarged and foamed. CONSTITUTION:Temperature of a foaming agent-containing melting resin is made to be below a dissolving temperature of a foaming agent in a cylinder 14 of an injecting unit. At injection, the resin is sheared with heat by, for example, a rotary valve 17 provided at a nozzle 12 so as to make it above the dissolving temperature of the foaming agent and is injected into a cavity 23 whose capacity is enlarged larger than a predetermined shot capacity of the melting resin. During the injection or after the injection is completed, the cavity 23 is contracted and details of the cavity 23 are also filled with the resin. Successively, the resin is pressed and the surface of the resin is cooled and fixed by a mold 22 so as to form a skin layer. Then, the mold 22 is moved in the direction where the cavity 23 enlarges and the resin is foamed, cooled, and a molded body is taken out. |
