Abstract: In a method of injection-molding a thermoplastic resin wherein a weld is formed in the mold cavity by the fusion of separate resin streams, use is made of a mold provided with a resin well protruding from the molded cavity or a runner on at least one of the separate resin streams at a point between where the injected molten resin is separated into streams and the weld. The resin is poured into the resin well after the formation of the weld from the feed of the molten resin into the mold cavity to cause migration of the resin at the weld, thus forcing the resin on one side of the weld into the resin of the other side of the weld to thereby strengthen the weld.

Abstract: In a method of injection-molding a thermoplastic resin wherein a weld is formed in the mold cavity by the fusion of separate resin streams, use is made of a mold provided with a resin well protruding from the molded cavity or a runner on at least one of the separate resin streams at a point between where the injected molten resin is separated into streams and the weld. The resin is poured into the resin well after the formation of the weld from the feed of the molten resin into the mold cavity to cause migration of the resin at the weld, thus forcing the resin on one side of the weld into the resin of the other side of the weld to thereby strengthen the weld.

Abstract: A resin composition of a thermoplastic resin and long fiber is injected into a molded article having good physical properties by molding the composition in the form of a pellet having a length of 3 mm or more and containing 10 to 80% by weight, based on the composition, of a fiber having a length substantially equal to that of the pellet and arranged in the lengthwise direction of the pellet, characterized by using an injection molding machine having a nozzle diameter of 6 mm or more.