Foamable composition and process for making large cell size alkenyl aromatic polymer foam structure with 1,1-difluoroethane
US5286757A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 1993 |
| Grant date | Feb 15, 1994 |
| Priority date | — |
| Expiry date | May 24, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S521/91
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Disclosed is a process for making extruded, closed-cell alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters. The process comprises: a) heating an alkenyl aromatic polymer material having greater than 50 percent by weight alkenyl aromatic monomeric units to form a melt polymer material; b) incorporating into the melt polymer material at an elevated pressure a blowing agent comprising at least 50 percent by weight 1,1-difluoroethane (HFC-152a) based upon the total weight of the blowing agent to form a foamable gel; c) cooling the foamable gel to an optimum foaming temperature prior to extrusion through a die; and d) extruding the foamable gel through a die to form the foam structure. Further disclosed is a foamable gel capable of forming an alkenyl aromatic polymer foam structure having an average cell size of from about 0.3 to about 3.0 millimeters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.