Polyurethane molding process with siloxane internal release agent
US4379100A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 20, 1981 |
| Grant date | Apr 5, 1983 |
| Priority date | — |
| Expiry date | Mar 20, 2001 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2075/00
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An improved polyurethane RIM process using a polycarboxy-functional alkyl siloxane as an internal release agent characterized by: PA0 (1) Tool break-in or preconditioning with siloxane treatment of the surfaces; PA0 (2) Supplying the siloxane to the mix head as a third stream when necessary to prevent undesired side reactions; PA0 (3) Using a minimal amount of siloxane that is inadequate for mold release in the absence of the tool preconditioning; PA0 (4) Adjustment of catalyst package to counter the inhibiting effects of the siloxane. The use of a bare minimal amount of siloxane prevents excess siloxane from appearing in the surface of the article and causing subsequent paint wet-out and like difficulties. The third stream isolating of the siloxane prevents its carboxy-functional groups from reacting with the prepolymer or with other ingredients that may be carried in the polyol blend.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.