Transparent polyurethane-hydrogel composition, method of making transparent polyurethane-hydrogel composition, and air-freshener application
US6960625B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 21, 2002 |
| Grant date | Nov 1, 2005 |
| Priority date | — |
| Expiry date | Feb 2, 2023 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G2650/50
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A transparent polyurethane-hydrogel composition includes a reaction product in aqueous solvent of a prepolymer and a water-soluble crosslinker in the substantial absence of organic solvent, and such a composition can be prepared by admixing a prepolymer and a water-soluble crosslinker in aqueous solvent and in the substantial absence of organic solvent. A prepolymer is present in an amount of no greater than about 5 weight percent based on total weight of all hydrogel components. The prepolymer is generally prepared from at least one water-soluble polyol and an isocyanate. A water-soluble crosslinker generally has a crosslinker functionality of at least 2 and is selected to provide a site ratio of initial isocyanate to crosslinker (i.e., moles NCO×functionality/moles crosslinker×functionality) of at least about 1.5 and no greater than about 2.6. In one embodiment, a crosslinker is effective to react with and solubilize residual isocyanate concurrently with the reaction between prepolymer and crosslinker. A transparent polyurethane-hydrogel composition has desirable gel physical properties and is useful for an air-freshener application.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.