| 摘要 |
PURPOSE:To obtain a molding with favorable external appearance having no sink mark by a method wherein dwell process is provided after the injection of reaction stock liquid. CONSTITUTION:As for reaction stock liquid, solution containing norbornene type monomer and catalyst as A-liquid and solution containing norbornene type monomer and activator as B-liquid are used. The reaction stock liquids, which are mixed in a mixing head, are firstly introduced through a three-way valve 5 into an accumulator 4 so as to store a given amount of the mixture of the reaction stock liquids therein. By changing-over the three-way valve 5, the mixture of the reaction stock liquids is injected from the mixing head 1 through a line 3 in a mold 2. Next, by changing-over the three-way valve 5 again, the mixture of the reaction stock liquids stored in the accumulator 4 is injected by means of nitrogen gas pressure in the mold 2 for dwelling. Though the cure shrinkage occurs in the mold and the sinkage develops in the mold, the mixture of the reaction stock liquids, the volume of which corresponds to the volume of sinkage, is secondarily shot in the mold under the constant pressure during the dwell process provided. Consequently, said secondary shot forcibly prevents the sink mark from developing. |
