Molded foam resin, process for forming the same and speaker diaphragm consisting of the same
US6334504B1 · kind B1 · utility
Assignees
Inventors
Key dates
| Filing date | Mar 6, 2000 |
| Grant date | Jan 1, 2002 |
| Priority date | — |
| Expiry date | Mar 6, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2307/029
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A molded foam resin, surface of which can be designed easily at low cost, a process for forming a molded foam resin, and a speaker diaphragm made of molded foam resin are provided, in which a molded foam resin is formed by injection molding of foaming agent-containing resin and has a foamed zone having a three layer-structure consisting of a foamed layer inside and a non-foamed layer outside and a non-foamed zone having a single layer-structure consisting of a non-foamed layer. The process for forming the molded foam resin according to the present invention includes the steps of injecting a foaming agent-containing resin into a mold and opening the mold after a lapse of a designated period of time after the completion of the injection, in which a cavity of the mold contains a thick space corresponding to the foamed zone and a thin space corresponding to the non-foamed zone, and the designated period of time is chosen so that a curing of the resin filled into the thin space is completed and a curing of the resin filled into the thick space is not completed. Thus, a molded foam resin and a speaker diaphragm according to the present invention can be thinned, designed with different to…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.