Resin and gas injection molding method with subsequent cohering
US6676867B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 10, 2001 |
| Grant date | Jan 13, 2004 |
| Priority date | — |
| Expiry date | Oct 7, 2021 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2045/1702
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The present invention provides an injection molding method for providing a molded product with excellent transcription and an excellent gloss level. In this method, immediately after a resin is filled in a cavity (1), a carbon dioxide gas is injected or the skin layer is moved back to form a space (13) between the resin and the die surface (1), so that growth of the skin layer is hold down, and at the same time the carbon dioxide is dissolved in the skin layer for lowering the glass transition point of skin layer. Then the skin layer is again closely cohered to a surface of the die by increasing the resin pressure and cooling the molded product for solidifying behind the holding pressure. With this method, products with excellent transcription and with an excellent surface gloss level can be obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.