Abstract: The present invention relates to the step of plasticizing a thermoplastic resin material by rotatably driving a screw (20). Also included in the method is the step of injecting an inert gas into a screw cylinder (1) to permeate the melted resin and injecting the melted resin into a mold by driving the screw (20) in the direction of injection. Here, the inert gas has a pressure, at least in pressure, equal to or greater than a supercritical pressure or is under a supercritical state. To provide a thermoplastic resin foam by the method, electric servomotors (31, 32) are employed to drive the screw (20). After the step of plasticizing the resin material has been completed, brakes are applied to the electric servomotors (31, 32) to prevent the screw (20) from retreating. Alternatively, even after the step of plasticizing the resin material has been completed, the screw (20) is driven at low speeds in the direction of plasticization until immediately before the step of injecting the melted resin is initiated.

Abstract: The present invention relates to the step of plasticizing a thermoplastic resin material by rotatably driving a screw (20). Also included in the method is the step of injecting an inert gas into a screw cylinder (1) to permeate the melted resin and injecting the melted resin into a mold by driving the screw (20) in the direction of injection. Here, the inert gas has a pressure, at least in pressure, equal to or greater than a supercritical pressure or is under a supercritical state. To provide a thermoplastic resin foam by the method, electric servomotors (31, 32) are employed to drive the screw (20). After the step of plasticizing the resin material has been completed, brakes are applied to the electric servomotors (31, 32) to prevent the screw (20) from retreating. Alternatively, even after the step of plasticizing the resin material has been completed, the screw (20) is driven at low speeds in the direction of plasticization until immediately before the step of injecting the melted resin is initiated.

Abstract: The present invention relates to the step of plasticizing a thermoplastic resin material by rotatably driving a screw (20). Also included in the method is the step of injecting an inert gas into a screw cylinder (1) to permeate the melted resin and injecting the melted resin into a mold by driving the screw (20) in the direction of injection. Here, the inert gas has a pressure, at least in pressure, equal to or greater than a supercritical pressure or is under a supercritical state. To provide a thermoplastic resin foam by the method, electric servomotors (31, 32) are employed to drive the screw (20). After the step of plasticizing the resin material has been completed, brakes are applied to the electric servomotors (31, 32) to prevent the screw (20) from retreating. Alternatively, even after the step of plasticizing the resin material has been completed, the screw (20) is driven at low speeds in the direction of plasticization until immediately before the step of injecting the melted resin is initiated.

Abstract: A method of plasticizing a material for molding thermoplastic resin foam including the steps of: rotating a screw disposed in a screw cylinder such that rotation and axial movement are permitted to plasticize thermoplastic resin, one of penetrating inactive liquid in a super critical state to molten resin in said screw cylinder and injecting inactive gas having a pressure not lower than the super critical gas pressure into said screw cylinder in a hot state not lower than the super critical temperature to realize a super critical state in said screw cylinder to cause said inactive gas to penetrate said molten resin, and injecting said molten resin for molding a foam member to which said inactive liquid has penetrated into a mold by moving said screw in the axial direction so that thermoplastic resin foam is obtained.

Abstract: The present invention relates to the step of plasticizing a thermoplastic resin material by rotatably driving a screw (20). Also included in the method is the step of injecting an inert gas into a screw cylinder (1) to permeate the melted resin and injecting the melted resin into a mold by driving the screw (20) in the direction of injection. Here, the inert gas has a pressure, at least in pressure, equal to or greater than a supercritical pressure or is under a supercritical state. To provide a thermoplastic resin foam by the method, electric servomotors (31, 32) are employed to drive the screw (20). After the step of plasticizing the resin material has been completed, brakes are applied to the electric servomotors (31, 32) to prevent the screw (20) from retreating. Alternatively, even after the step of plasticizing the resin material has been completed, the screw (20) is driven at low speeds in the direction of plasticization until immediately before the step of injecting the melted resin is initiated.