Polystyrene/polyethylene oxide copolymer for enhancing water vapor permeability in thermoplastic foam
US8378001B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 2010 |
| Grant date | Feb 19, 2013 |
| Priority date | — |
| Expiry date | Jan 24, 2031 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2425/00
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Polymeric foam and polymeric foam products that contain a foamable polymer material, at least one blowing agent, a polystyrene/polyethylene oxide copolymer, and optionally, an infrared attenuating agent, are provided. In exemplary embodiments, the blowing agent includes at least one hydrofluorocarbon blowing agent. The maleic anhydride-styrene copolymer grafted with polyethylene oxide provides a water vapor permeability of 1.1 perm inch or greater in the extruded foam product without detrimentally affecting physical or thermal properties of the product. Additionally, the copolymer of maleic anhydride-styrene grafted with polyethylene oxide has a positive affect on the processability of the blowing agent(s) in the composition by both widening the process window and enhancing the solubility of the blowing agent in the polymer melt. Thus, the polystyrene/polyethylene oxide copolymer present in the inventive composition acts as a cell enlarger, a plasticizer, and a processing aid. A method of forming an extruded foam product is also provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.