Process for injection molding a hollow plastic article
US5139714A · kind A · utility
Inventor
Key dates
| Filing date | Jun 3, 1991 |
| Grant date | Aug 18, 1992 |
| Priority date | — |
| Expiry date | Jun 3, 2011 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2045/1722
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A process for injection molding a hollow plastic article in which a low pressure heat-activated gas is injected in combination with a plastic material into a mold cavity of a plastic injection mold unit. When the plastic material and heat-activated gas enter the mold cavity, the gas expands to outwardly exert pressure on the plastic material thereby urging the plastic material towards the walls of the mold cavity to, in turn, form the hollow portions of the hollow plastic article. The gas remains within the hollow plastic article and continues to exert outward pressure until the plastic article has substantially cooled and hardened at which time the gas becomes dormant. Accordingly, no venting of the gas from the plastic article is necessary.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.