PURPOSE: To enable a packing bag which is large in heat sealing strength to be manufactured by a method wherein a resin composition in which linear low density polyethylene and polybutene resin are mixed is inflation molded under a specific condition and heat-sealed.
CONSTITUTION: A resin composition composed by mixing 100 pts.wt. of linear low density polyethylene and at most 100 pts.wt. of polybutene resin, is inflation molded under conditions wherein a blow-up ratio is 0.9 to 2.0, a draft ratio is 10 to 40, and a cooling rate index is at most 30sec. The obtained cylindrical film is heat-sealed to be cut by taking a direction intersecting a receiving direction as a longitudinal direction. A melt index of the linear low density polyethylene is made 10g/1min or under and a melt index of polybutene resin is made 20g/10min or under.
KAWAI YUTAKA
YAMADERA MAKOTO
