Mold and process for molding
US4351789A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 27, 1981 |
| Grant date | Sep 28, 1982 |
| Priority date | — |
| Expiry date | Jul 27, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/812
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
When molding rubber or plastic articles in a closed mold, a film of a liquid coating material having a boiling point above the ambient temperature of the work area and below the temperature at which the molding is to occur is applied to the surface of the mold cavity and/or the surface of the article to be molded just before the mold is closed. The mold cavity then is heated to a temperature above the boiling point of the liquid coating material. The pressure maintaining the mold closed is suddenly reduced exposing vapor release passages between mating surfaces of the mold segments. The liquid coating material at the elevated temperature and reduced pressure within the mold cavity rapidly vaporizes and exhausts through the vapor release passages flushing air entrapped within the mold cavity when the mold was closed from the mold cavity. The mold once again is closed before air can seep back into the mold cavity. Normal molding procedures thereafter are followed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.