The invention is to ensure that in injection molding a molten resin having carbon
dioxide dissolved therein as a plasticizer, a sufficient amount of carbon dioxide
to achieve satisfactory improvement in flowability is dissolved in the molten resin
so that the flowability of the molten resin is significantly improved while enabling
the production of a non-foamed molded article.
Specifically, in the invention, a molten resin having dissolved therein
a sufficient amount of carbon dioxide to improve its flowability is filled into
a mold cavity while allowing to foam at the flow front of the molten resin, and
the resin in the mold cavity is then pressurized to at least a pressure at which
it does not foam.
