Increased throughput in melt fabrication and foaming of polyester
US5340846A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 1993 |
| Grant date | Aug 23, 1994 |
| Priority date | — |
| Expiry date | Dec 17, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2367/02
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Disclosed is a process for obtaining polyester articles, including foamed articles, containing low levels of extractable branching agent. The process comprises: (1) forming a molten mixture comprising (i) a major amount of a first resin composition comprising polyester and from 0 up to about 1 wt. % of a compound capable of branching the polyester, and (ii) a minor amount of a second polyester resin composition comprising at least about 50 wt. % polyester resin and greater than about 2 wt. % of a compound capable of branching the polyester, wherein the relative amounts of (i) and (ii) are such that said molten mixture comprises from about 0.1 wt. % to about 1 wt. % of said branching compound; (2) adding a blowing agent to the molten mixture; and (3) extruding the resultant mixture to obtain a foam. The invention is also directed to the second composition used in the above process, and foamed polyester articles obtained from the process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.