Process for the production of a continuous sheet of foamed synthetic, thermoplastic polymer by extrusion
US4435345A · kind A · utility
11Cited by
13References
4Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 29, 1981 |
| Grant date | Mar 6, 1984 |
| Priority date | — |
| Expiry date | Oct 29, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/13
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The density of the foam is reduced and the thickness of the sheet obtained by extrusion/expansion is increased by grasping the sheet between confining walls which are permeable to gas and movable together with the sheet, and which diverge from each other in the direction of advance of the sheet, and by applying a subatmospheric pressure to the faces of the sheet and through the said walls while the sheet is in its thermoplastic state, after which the foam is gelled by cooling to stabilize the thickness achieved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.