Injection molding process and injection molding apparatus for thermoplastic resin molded articles
US6949208B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 6, 2000 |
| Grant date | Sep 27, 2005 |
| Priority date | — |
| Expiry date | Jun 14, 2021 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C44/3446
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An object of the invention is to provide an injection molding process for preparing thermoplastic resin molded articles and an injection molding apparatus for use in practicing this process, the process and the apparatus being adapted to supply a blowing agent, especially a nonreactive gas such as carbon dioxide or nitrogen gas, to a thermoplastic resin continuously at a relatively low pressure with good stability to incorporate the agent or gas into the resin. As shown in FIG. 3, a resin in a cylinder (2) of an injection molding machine (1) as melted by rotating a screw (3) is mixed and dissolves carbon dioxide which is supplied to the molten resin from a gas supply opening (5) formed in the screw (3). An amount of the gas-incorporating molten resin is measured out and injected into a mold cavity to obtain an expansion-molded article. To incorporate carbon dioxide into the molten resin, the gas is supplied from a gas inlet (11) formed in a rear end portion of the screw to a portion (4a) not fed with the resin and positioned between front and rear screw flights and closer to the front flight, through a gas supply channel 6 extending through the screw and via the supply opening (5).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.