Method of producing foamed thermoplastic resin articles having smooth and glossy surfaces free from swirl marks and hair cracks
US4096218A · kind A · utility
31Cited by
6References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 27, 1976 |
| Grant date | Jun 20, 1978 |
| Priority date | — |
| Expiry date | Jul 27, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/249989
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method of producing foamed thermoplastic resin articles having smooth and glossy surfaces free from swirl marks and hair cracks, which comprises melting a thermoplastic resin containing a condensable blowing agent and an organic chemical blowing agent, injecting, in full shot, the molten resin into a mold cavity to which a pressurized gas is being applied during said injection, terminating the application of the pressurized gas to the mold cavity, enlarging the volume in said molded cavity by movement of a mold wall, and thereafter cooling and solidifying the resin to form the foamed articles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.