The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 07, 2006
Filed:
Mar. 12, 2003
Atsuo Teraoka, Hiroshima, JP;
Fumiaki Tsuda, Hiroshima, JP;
Hideo Ohyabu, Hiroshima, JP;
The Japan Steel Works, Ltd., Tokyo, JP;
Abstract
The present invention relates to the step of plasticizing a thermoplastic resin material by rotatably driving a screw (). Also included in the method is the step of injecting an inert gas into a screw cylinder () to permeate the melted resin and injecting the melted resin into a mold by driving the screw () 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 () are employed to drive the screw (). After the step of plasticizing the resin material has been completed, brakes are applied to the electric servomotors () to prevent the screw () from retreating. Alternatively, even after the step of plasticizing the resin material has been completed, the screw () is driven at low speeds in the direction of plasticization until immediately before the step of injecting the melted resin is initiated. This allows foaming inside the screw cylinder ().