METHOD AND APPARATUS FOR PRODUCING A BLOW MOLDED ARTICLE

摘要

A method for obtaining a relatively large-sized blow molded article superior in mold transfer properties such as surface gloss in a short forming cycle with good productivity by a blow molding using a simple facility. In particular, a method for producing a blow molded article comprising the steps of supplying between forming molds a molten parison formed from a crystalline resin, clamping the molds, blowing a pressurised fluid into the parison so that the parison is tightly secured to the forming surface of the molds and allowing the parison to be solidified, wherein the temperature of the forming surfaces of the molds when the parison is tightly secured thereto ranges from a temperature lower by 10 DEG C than a crystallizing temperature of the crystalline resin to a melting point of the resin, and wherein a coolant whose temperature is lower than a room temperature is introduced into the parison while the pressurised fluid is being blown in or after it has been blown in for cooling the parison, thereafter the parison being ejected from the molds. An apparatus for producing a blow molded article comprising a blow molding machine, forming molds for use with the blow forming machine for producing a blow molded article and each having gas vent holes with a diameter of 100 mu m or less and at a pitch of 50 mu m or less, and a means for introducing a coolant into the parison formed through the molds and discharging it from the parison.