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A method for manufacturing molded products of thermoplastic material by injection molding or extrusion molding a material containing a thermoplastic material as a primary component and a second polymer or a blend of the thermoplastic material and second polymer as a primary component and an inorgani

A method for manufacturing molded products of thermoplastic material by injection molding or extrusion molding a material containing a thermoplastic material as a primary component and a second polymer or a blend of the thermoplastic material and second polymer as a primary component and an inorganic material. The material is molded under the following mold conditions by a general type or vent type molding machine. The material is provided with a water content of less than about 1% by weight. The wall temperatures of the molding cylinder are controlled at different locations of the molding machine. The residence time of the molding material in the cylinder is controlled in response to the cylinder temperature so that the residence time is reduced as the temperature is increased whereby the residence time of said material in the cylinder is less than about 23 minutes. The temperatures of the discharge end is maintained within the range of plus 35°C. or minus 25°C. of the melting temperature of the material.

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A method of molding thermoplastic material comprising; a primary component selected from the group consisting of polyethylene, polypropylene, polystyrene, acrylonitrile-butadiene-styrene, polybutylene terephthalate, its isomer, and its similar polymer, polyamide 6, polyamide 66, polyamide 7, polyami

A method of molding thermoplastic material comprising; a primary component selected from the group consisting of polyethylene, polypropylene, polystyrene, acrylonitrile-butadiene-styrene, polybutylene terephthalate, its isomer, and its similar polymer, polyamide 6, polyamide 66, polyamide 7, polyamide 11, polyamide 12, and a combination of said above polymer; and a second polymer selected from the group consisting of polyethylene, polypropylene, polystyrene, acrylontrile-butadiene-styrene, polybutylene terephthalate, similar polymer, polyamide 6, polyamide 66, polyamide 7, polyamide 11, polyamide 12, cotton, hemp, and rayon, in an amount of from 5% to 60% by weight, or a blend of said above polymer as the primary component and an inorganic material selected from the group consisting of boron nitride, glass fiber, glass balls, glass powder, feldspar, quartz, carbon, aluminum oxide, ceramics, marble, metal fibers, metal powder and whiskers, and a mixture of said above thermoplastics as the primary components with said polymer component and said inorganic material, by one of injection and extrusion means in a molding machine having a screw conveyor cylinder provided with controllable heating means, a hopper at one end of said cylinder, and a discharge means at the other end of said cylinder selected from at least one of a nozzle, die, and adapter, comprising: (a) providing said material with a water content of less than about 1.0% by weight; (b) maintaining the inside wall temperature of said cylinder within a range of plus or minus 35°C. of said melting temperature of the material; (c) keeping the temperature of a first portion of the inside wall of said cylinder located adjacent said one end lower than the melting temperature of said material; (d) controlling the temperature of the second portion of said inside wall of said cylinder which extends from a position intermediate its opposite ends to said other end at a temperature higher than the melting temperature of said material, while controlling the temperature difference between said first and second portions of said inside wall below 70°C.; (e) bringing the temperature of said molding material to a predetermined maximum at the outlet zone adjacent said discharge means; (f) controlling the temperature of the inside of the cylinder by directly measuring the actual temperature of the molding material as it passes through the one of the nozzle, die and adapter of the molding machine; (g) controlling the residence time of said molding material in said cylinder in response to the cylinder temperature so that the residence time is reduced as the temperature is increased whereby the residence time of said material in said cylinder is less than about 23 minutes; and (h) maintaining the temperature of the nozzle or die of the discharge means within the range of plus 35°C. or minus 25°C. of the melting temperature of the material.