Case-hardened gelatin-grafted polymer particles
US5248558A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 20, 1991 |
| Grant date | Sep 28, 1993 |
| Priority date | — |
| Expiry date | Jun 20, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2998
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
It has been shown by Photon Correlation Spectroscopy than when additional hardener is added to below saturation gel-grafted polymer particles, the gel layer shrinks due to hardening, as there is no free gel left in solution. In films, such case-hardened gelatin-grafted soft polymer particles can act as highly elastic stress absorbing fillers. This is because the dry case-hardened shell is expected to form a thin hard shell around the soft polymer particles. It is shown that gelatin-grafted soft polymer particles and case-hardened gelatin-grafted soft polymer particles, incorporated in the emulsion layers of pressure sensitive photographic products, produce coatings with highly reduced pressure sensitivity without any developability or delamination concerns. In this invention the case-hardened gelatin-grafted polymer particles are preferred over the simple gelatin-grafted material. The core polymer particle can have diameters anywhere between 10 to 10.sup.8 nm with a monolayer of gelatin shell that is chemically bonded to its surface and the gelatin shell is further cross-linked with each other to hydrated thicknesses of between 5 to 20 nm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.