| 摘要 |
PURPOSE:To prevent accumulation of air on the surface of a molded article, by a method wherein a pressure reducing opening is provided on a runner part communicating with a gate of a mold, raw materials are injected within a cavity of the mold by closing the pressure reducing opening and pressure of the inside of a runner is reduced by opening the pressure reducing opening after completion of injection. CONSTITUTION:A mixed liquid is injected within a cavity 4 of a metal mold 1 through an aftermixer 7 and passing through a runner 6 and gate 5 further from a mixing head of a molding machine by closing a pressure-reducing opening 13 with a clogging member 14. After completion of injection of raw materials, the pressure-reducing opening 13 is opened by pulling out the clogging member 14 outward and a runner 6 is depressurized. With this construction, the surplus raw materials in the inside of the runner 6 is discharged outside of the same under blowing pressure at the time of reaction. Together with the above, reactive gas in the inside of the cavity 4 and remaining air in the inside of the mold 1 are discharged outside of them through the pressure- reducing opening 13 of the runner 6 from the gate 5 and the surface of a molded article is prevented from producing the accumulation or air. |
