Process and apparatus for producing foamed synthetic resin bodies
US4487731A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 30, 1983 |
| Grant date | Dec 11, 1984 |
| Priority date | — |
| Expiry date | Sep 30, 2003 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/06
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A process for producing a foamed synthetic resin body comprising continuously extruding a foamable thermoplastic resin extrudate composition from an extruder die into a reduced pressure zone, subjecting the extrudate to an expansion molding step, a cooling-hardening step and a cutting step while transporting the extrudate through the reduced pressure zone to obtain a foamed piece of predetermined length, shutting off a portion of the reduced pressure zone surrounding the foamed piece from the other portion thereof when the foamed piece has reached a specified position to restore the foamed piece surrounding portion to a normal pressure, subsequently discharging the foamed piece into the atmosphere, and thereafter bringing the surrounding portion into communication with the reduced pressure zone again upon reducing the pressure. Foamed resin bodies of desired expansion ratio and shape can be prepared continuously with high cooling efficiency. An apparatus for practicing the process is also disclosed. Such apparatus includes means to form a continuous length of extrudate within a vacuum chamber and means to cut the extrudate to length and means to pass the cut extrudate into a second…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.