Production of foamed polymer structures
US4897432A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 1988 |
| Grant date | Jan 30, 1990 |
| Priority date | — |
| Expiry date | Sep 26, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S521/915
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Described are ways of improving the yields of specification grade polyimide foam on a consistent basis from one run to the next by use of improvements in microwave-based foaming processes. While a body of polyimide precursor is exposed to microwave radiation, the body of polyimide precursor and of the foam structure as it is developing therefrom are kept under a substantially vapor-impermeable microwave-compatible shroud that does not substantially restrict or impede development of the foam structure. For this purpose use may be made of a shroud composed of a polymer film. Mechanisms by which the shroud produces the improved results are discussed, and methods based thereon are set forth.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.