A molding condition setting method for an injection molding machine that molds a molded article includes: (a) adjusting a temperature and humidity around the injection molding machine; (b) acquiring a moisture content of a material used for molding the molded article; (c) setting a plurality of molding conditions for the molded article to be molded by the injection molding machine; (d) molding the molded article under the plurality of molding conditions by the injection molding machine injecting a plasticized material obtained by plasticizing the material into a mold under an environmental condition including the temperature and the humidity adjusted in (a) and the moisture content acquired in (b); and (e) determining an optimum condition in the molding conditions under the environmental condition based on quality of the molded article molded in (d). In (a), the temperature is adjusted to a temperature of a place where the molded article is to be produced, and the humidity is adjusted to humidity of the place where the molded article is to be produced.

A method for manufacturing an injection-molded article, preferably a preform (11) of a bottle (1), in particular an aerosol bottle, made of a crystallizable polymer material, this article having at least one crystallized part (3), in particular a neck, and preferably a tubular body (14) closed at one end (16), the method comprising the following steps: a) producing an injection-molded article, preferably an injection-molded preform (11), by injecting the crystallizable polymer into a mold, b) crystallizing said part (3) of the injection-molded article, in particular of the injection-molded preform, by heating and then cooling the latter, wherein, in said method, between step a) and step b), the injection-molded article, in particular the injection-molded preform (11), is held for a sufficient duration under storage conditions such that it undergoes moisture uptake of at least 0.4% by weight.