MOLD, HOLLOW MOLDING, AND MOLDING METHOD

摘要

PROBLEM TO BE SOLVED: To obtain the aimed shape of a molding even when the cooling time of a plastic molding process is shortened by a method wherein the difference between the maximum one and the minimum one of the ratio of the dimension of the cavity part of a mold to the outer dimension of a molding at the cylindrical part of the molding is set to a percentage within a specified range. SOLUTION: The difference between the maximum one and the minimum one of the ratio of the dimension of the cavity part of a mold 1 for blowmolding a bottle as a blown thermoplastic resin molding to the outer dimension of the molding at the cylindrical part of the molding is set to be 0-18.0%. In this case, when a high density polyethylene is employed as the thermoplastic resin, the difference between the maximum one and the minimum one of the ratio of the dimension of the cavity part of the mold 1 to the outer dimension of the molding at the cylindrical part of the molding is set to be 1.4-18.0%. Further, when a polypropylene is employed as the thermoplastic resin, the difference between the maximum one and the minimum one of the ratio of the dimension of the cavity part of the mold 1 to the outer dimension of the molding at the cylindrical part of the molding is set to be 0-8.0%.