Method of forming hollow blow-molded foam and such hollow blow-molded foam

摘要

An object of the present invention is to provide a method of forming a hollow blow-molded foam and also provide such a hollow-molded foam, which are capable of improving a flow-rate efficiency of a fluid that flows through the inside of the hollow blow-molded foam. A foaming resin is sandwiched between molds so that a hollow blow-molded foam having a ventilation path is molded, and a fluid for use in cooling the hollow blow-molded foam is allowed to flow through the ventilation path so that the hollow blow-molded foam is cooled.

主权项

1. A method of forming a blow-molded foam duct comprising the steps of:
preparing a foaming parison or resin sheets with its value of MFR MT, which is a multiplication value of MFR (g/10 minutes) and MT (cN), being set to 13 or more at 200° C., sandwiching the foaming parison or resin sheets with molds to mold a completed blow-molded foam duct having a ventilation path through which a cooled or warmed air current is supplied when said duct in use having an inlet side through which said cooled or warmed air current enters said duct and an outlet side through which said cooled or warmed air current exits said duct; blowing a cooling fluid from a blow-in needle by inserting the blow-in needle into a portion constituting said inlet side of the duct, and discharging a compressed fluid from a blow-out needle by inserting the blow-out needle into a portion constituting said outlet side of the blow-molded foam duct, and allowing the cooling fluid to flow through the ventilation path so as to cool the blow-molded foam duct, wherein the cooling fluid flows in the same direction as a flow path direction in which the cooled or warmed air currant flows through the ventilation path when the blow-molded foam duct is in use, and the blow-molded foam duct is formed as one having a closed cell structure and smooth surface of the ventilation path so as to have less pressure loss when the cooled or warmed air current flows through the ventilation path from the inlet to the outlet than that in the case when the cooled or warmed air current flows through the ventilation path in a reversed direction.