Method for the preparation of a cellular foamed body of a vinyl chloride-based resin
US4402893A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 30, 1980 |
| Grant date | Sep 6, 1983 |
| Priority date | — |
| Expiry date | Apr 30, 2000 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/13
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The invention provides a novel and improved method for the preparation of a cellular foamed body of a vinyl chloride-based resin having a very fine and uniform cellular structure with high productivity in a continuous process. According to the inventive method, a vinyl chloride-based resin is admixed with a nucleating agent and a foam conditioning resin which is a specified acrylic resin or a styrene-based resin into a resin composition and the resin composition is first heated under pressure to be converted into an at least partly gelled mass, into which a volatilizable foaming agent which is an organic solvent having a boiling point not exceeding 90.degree. C. is injected under pressure so as that the resin composition is uniformly impregnated with the foaming agent. The foaming agent-impregnated and completely gelled resin composition is then brought under a reduced pressure to be expanded into foams with simultaneous cooling. The above process is most conveniently practiced by use of an extruder machine in which the volatilizable foaming agent is continuously injected into the cylinder where the heated and gelled resin composition is running.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.