Foamable resins process
US4226942A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 15, 1978 |
| Grant date | Oct 7, 1980 |
| Priority date | — |
| Expiry date | Aug 15, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S521/918
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
This invention relates to an improved process for the production of a particulate foamable polyvinyl aromatic resin of the type wherein a vinyl aromatic monomer is polymerized in an aqueous suspension system to produce beads of thermoplastic polyvinyl aromatic resin, separating the beads and incorporating a volatile liquid blowing agent in the separated beads at a temperature above the resin softening point under such conditions that foamable resin particles are produced, cooling said beads followed by separating and drying said beads, the improvement comprising: drying said beads under vacuum conditions at normal temperatures, removing residual water from said beads while retaining said blowing agent in said beads. Also included in the invention are foamable particles when produced by the above process and foamed articles made from the foamable particles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.