Molding expandable thermoplastic resins
US4108934A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 23, 1976 |
| Grant date | Aug 22, 1978 |
| Priority date | — |
| Expiry date | Mar 23, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/18
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Shaped articles of organic polymer resins having cellular (foamed) structure are made from heat-expandable normally solid thermoplastic resin compositions in permeable molds particularly characterized by flooding the mold cavity and the expandable material therein with molten salt as heating medium. For example, a permeable mold, charged with pieces of polyethylene containing azobisformamide and crosslinked by electron irradiation, is immersed into a molten salt eutectic mixture of KNO.sub.3, NaNO.sub.2 and NaNO.sub.3 at about 264.degree. C, removed, cooled and washed with water, thereby forming a coherent, unitary cellular resin molded article completely filling the mold cavity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.