Abstract: In injection-molding a conductive material, prolongation of an injection molding cycle and occurrence of defective appearance of a molded article are reduced, and the molded article is given uniform conductivity. An injection molding apparatus has a heating injection means which heats a conductive material to a temperature that allows the conductive material to melt and flow, and which injects the conductive material to a mold. The mold has a plurality of conductive portions at least at a portion of a surface defining a cavity, the conductive portions being insulated from each other. A predetermined voltage is applied to the conductive portions. A static mixer is provided in an area including a tip portion of the heating injection means and a flow path of the conductive material.

Abstract: An injection-foaming molding process for manufacturing a formed article by injecting a molten resin containing a foaming agent into a cavity of a mold being retained in an openable state and then expanding the cavity by opening the mold to allow the resin to foam includes: i) a step of discontinuing a cavity of a mold from a resin-reserving section located at front end of a screw immediately after the completion of injection of a molten resin containing an expandable resin into the mold cavity; and ii) a step of keeping the resin-reserving section under pressure at least equal to back pressure for charging during a period from the completion of injection to start of charging the molten resin containing the expandable resin for next shot, decreasing pressure in the resin-reserving section to back pressure for charging, and then starting the charging.

Abstract: An injection-foaming molding process for manufacturing a formed article by injecting a molten resin containing a foaming agent into a cavity of a mold being retained in an openable state and then expanding the cavity by opening the mold to allow the resin to foam includes: i) a step of discontinuing a cavity of a mold from a resin-reserving section located at front end of a screw immediately after the completion of injection of a molten resin containing an expandable resin into the mold cavity; and ii) a step of keeping the resin-reserving section under pressure at least equal to back pressure for charging during a period from the completion of injection to start of charging the molten resin containing the expandable resin for next shot, decreasing pressure in the resin-reserving section to back pressure for charging, and then starting the charging. According to the process, a molding cycle can be shortened and a lightweight formed article by foaming having high rigidity and good appearance can be obtained.

Abstract: A stationary platen (14) and a movable platen (18), which are connected with each other by tie rods (28), to which metallic molds are respectively attached, are opened and closed by an electrically driven ball screw mechanism. The movable platen is composed of a platen body and a pressure plate (304) attached to the platen body which can be contacted with and separated from the platen body. Between the movable platen and the pressure plate, clamping is conducted by the expansion and contraction of a bladder (318) into which hydraulic oil for clamping can be introduced. The bladder houses an insert die (320), the shape of which is identical with an internal shape of the bladder, and a hydraulic oil path is formed in the insert die. While a ball screw member (102) of an electrically driven ball screw mechanism is being supported being capable of moving in the axial direction, a brake means (130) for restricting rotation is provided, and a mold releasing cylinder mechanism (116) is connected.

Abstract: A stationary platen (14) and a movable platen (18), which are connected with each other by tie rods (28), to which metallic molds are respectively attached, are opened and closed by an electrically driven ball screw mechanism. The movable platen is composed of a platen body and a pressure plate (304) attached to the platen body which can be contacted with and separated from the platen body. Between the movable platen and the pressure plate, clamping is conducted by the expansion and contraction of a bladder (318) into which hydraulic oil for clamping can be introduced. The bladder houses an insert die (320), the shape of which is identical with an internal shape of the bladder, and a hydraulic oil path is formed in the insert die. While a ball screw member (102) of an electrically driven ball screw mechanism is being supported being capable of moving in the axial direction, a brake means (130) for restricting rotation is provided, and a mold releasing cylinder mechanism (116) is connected.

Abstract: A laminating blow molding method for making a hollow article includes the steps of forming 1 to 500 fine, holes per an area of 100 cm.sup.2 in a resin sheet by punching to thereby form projections as burrs on one side of the resin sheet, the diameter of the holes being between 0.1 mm and 1 mm; disposing the resin sheet between an outer surface of a parison extruded from a die and a mold so that the one side with the projections faces a cavity face of the mold; closing the mold so that the resin sheet is held between the cavity face of the mold and the outer surface of the parison; and heating the mold to a temperature exceeding a softening temperature of the resin sheet and simultaneously blowing the parison to perform blow molding. Thereafter, the mold is cooled and a molded article is taken out. In the method, the molded article with smooth outer surface can be obtained.

Abstract: An improved process and apparatus for blow molding of engineering plastic materials, using a mold and an extrusion machine with a die for producing a hollow plastic parison to be partially received in the mold. An extrusion operation and a preblowing operation with air from the die into the parison are concurrently commenced at a high extrusion speed and a low air pressure, with a material remaining in the die being integrated with an upstream portion of a preceding parison prepared in a preceding blow molding run, to complete the downstream parison. The upstream portion has a closed and free lower end prepared in the preceding run. The apparatus is provided with a pinching and cutting device for self-adhering and separating the completed parison above and in the vicinity of the mold to prepare the above mentioned closed free end.

Abstract: A polyamide resin composition for fusible core molding which comprises (a) 100 parts by weight of a polyamide resin, (b) 1 to 150 parts by weight of a reinforcing agent and (c) 0.1 to 2.5 parts by weight of a polyvalent alcohol represented by the formula: HO--CH.sub.2).sub.n OH wherein n is an integer of 1 to 6, or polyethylene glycol or polypropylene glycol and a molded product obtained by molding the polyamide resin composition.