Patent ID: 6884380
Filing Date: 2005-04-26
Classification: B29C

Abstract:
1. A method of injection molding of a thermoplastic resin, comprising: filling a mold cavity with a molten resin that preliminarily contains at least 0.2 wt % and not more than 10 wt % of carbon dioxide dissolved therein to lower its melt viscosity, while allowing the molten resin to foam at the flow front thereof; and then pressurizing the resin in the mold cavity to at least a pressure at which the resin does not foam; wherein a thermoplastic resin having an amount of carbon dioxide dissolved in its molten resin at the molding temperature, when carbon dioxide is supplied from a plasticizing cylinder of an injection molding machine to be dissolved in the molten resin, of not more than 0.3 wt %/MPa with respect to the pressure of the supplied carbon dioxide is used.