Composite for controlling oxygen flux into thermal cells
US5718955A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 12, 1996 |
| Grant date | Feb 17, 1998 |
| Priority date | — |
| Expiry date | Mar 12, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/1352
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A composite material for controlling oxygen flux into a thermal cell comprises a bottom sheet formed to have a pocket. The bottom sheet is impermeable to oxygen. A plurality of particles is placed in the pocket. The plurality of particles reacts exothermally when exposed to oxygen. A top sheet is sealed to the bottom sheet at a flange around the pocket to enclose the plurality of particles such that the particles cannot fall out of the pocket. The top sheet has a substrate which is highly permeable to oxygen. The substrate is coated with an oxygen permeable silicone based elastomer to a thickness which regulates an oxygen flux into the pocket when the top sheet is exposed to oxygen. The composite material further comprises an oxygen impermeable barrier film bonded to the top sheet by pressure sensitive adhesive for preventing exposure of the top sheet to oxygen until the body warmer is intended to be used. A method for making a top sheet material involves coating a silicone rubber layer onto a smooth surface, partially curing the silicone, pressing a porous substrate against the silicone rubber layer, and completely curing the silicone rubber such that it adheres to the substrate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.