High melt index polystytene foam and method
US5356944A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 14, 1994 |
| Grant date | Oct 18, 1994 |
| Priority date | — |
| Expiry date | Jan 14, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2325/04
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A polystyrene resin in foam form having a basis weight of less than about 20 g/100 in.sup.2 and a density of about 6 lbs./ft.sup.3 or less, the foam precursor of which is either a polystyrene having a melt index of about 8 or more or a polystyrene in combination with a minor proportion of any other material which will result in a melt index of about 8 or more. A method of forming such a polystyrene resin foam structure includes combining the resin in molten form under pressure with the blowing agent of at least approximately 100% carbon dioxide and extruding the mixture through a die into an atmosphere of reduced pressure to form the foam structure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.