Method for making and then removing a molded article of rigid polyurethane foam from a mold
US5728333A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 1996 |
| Grant date | Mar 17, 1998 |
| Priority date | — |
| Expiry date | Jun 26, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C33/46
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A molded article of rigid polyurethane foam is manufactured by using a mold of separable upper and lower mold sections mated to define a cavity therebetween. A film of polypropylene which is previously vacuum formed in conformity to the mold cavity is closely set within the cavity and secured to the lower mold section outside the cavity. A rigid polyurethane foam-forming raw material is introduced into the cavity and on the film and caused to foam and expand in place to mold an article of rigid polyurethane foam. Thereafter, the molded article is lifted together with the film from the mold cavity by a pneumatic pressure or ejector pin. The molded article is stripped from the film to remove only the molded article from the mold without taking the entire film out of the mold. The once lifted film is returned to the original shape by vacuum suction for replacing the film in the cavity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.