Method for injection foam molding
US4155969A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 25, 1977 |
| Grant date | May 22, 1979 |
| Priority date | — |
| Expiry date | Oct 25, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/83
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method for the manufacture by foam molding of plastic products by first injecting into a mold non-cellular plastic resin and then injecting a foamed plastic resin of the same basic composition as the non-cellular plastic resin. The process and apparatus consisting of a single extruder and single injection chamber wherein the non-cellular and foamed plastic resin are extruded from the same extruder and stored in an accumulator until shot into the mold by a hydraulic cylinder. Controls are provided for the correct amount of each type of resin to be extruded and stored and the process can be adapted so that the sprue portion of the final product will be solid resin. By a simple addition, coloring of the resin may be accomplished so that the basic resin, method or apparatus will not require changes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.