US5026632A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Use of gelatin-grafted and case-hardened gelatin-grafted polymer particles for relief from pressure sensitivity of photographic products
Assignee: Eastman Kodak Co
•
Filing: 1990-03-22
•
Granted: 1991-06-25
•
Expires: 2010-03-22
Abstract
Abstract It has been shown by Photon Correlation Spectroscopy that 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.
Inventors
- 👤 Pranab Bagchi
- 👤 William L. Gardner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 02:17
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/04; G03C1/047; G03C1/053; G03C1/76; G03C1/95; Y; Y10; Y10S; Y10S430/00; Y10S430/151; Y10S430/162
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
81 words
A silver halide photographic element comprising radiation sensitive silver halide grains, gelatin and a composite polymer particle comprising a soft polymer core having a mean diameter from about 10 nm to 500 nm in diameter covered with a gelatin shell that has been cross-linked with a conventional hardener to form a hard case particle with a case thickness less than 10 nm wherein the hard case particle is incorporated into at least one layer comprising gelatin and said silver halide grains.
Claim 2
Dependent Claim
81 words
A silver halide photographic element comprising radiation sensitive silver halide grains, gelatin and a composite polymer particle comprising a soft polymer core having a mean diameter from about 10 nm to 500 nm in diameter covered with a gelatin shell that has been cross-linked with a conventional hardener to form a hard case particle with a case thickness less than 10 nm wherein the hard case particle is incorporated into at least one layer comprising gelatin and said silver halide grains.
Claim 3
Dependent Claim
23 words
The element of claim 1 wherein the soft core of said composite polymer particle is between 10 nm and 200 nm in diameter.
Claim 4
Dependent Claim
23 words
The element of claim 1, wherein the soft core of said composite polymer particle has a glass transition temperature less than 25° C.
Claim 5
Dependent Claim
33 words
The element of claim 1, wherein said soft polymer core comprises of either butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate or propyl acrylate in weight percent from 40 to 98% of the total polymer.
Claim 6
Dependent Claim
27 words
The element of claim 1, wherein said soft polymer core contains at least 0.1 mole percent of a monomer with at least one pendent carboxylic acid group.
Claim 7
Dependent Claim
19 words
The element of claim 1, wherein the soft polymer particles contain at least 0.1 mole percent methacrylic acid monomer.
Claim 8
Dependent Claim
28 words
The element of claim 1, wherein the soft polymer particle core is bonded to gelatin by a grafting agent selected from carbamoylonium compound, dication ethers and carbodiamide compounds.
Claim 9
Dependent Claim
23 words
The element of claim 1, wherein said soft polymer core is bonded to gelatin by using grafting agent 1-(4-morpholinocarbamoyl)-4-(2-sulfoethyl) pyridinium hydroxide inner salt.
Claim 10
Dependent Claim
23 words
The element of claim 1, wherein said soft core comprises a polymer particle capable of directly bonding to gelatin without a grafting agent.
Claim 11
Dependent Claim
37 words
The element of claim 1, wherein said soft polymer core comprises a polymer that contains at least 0.1 mole percent of monomers selected from monomers containing active halogen containing groups, aldehyde groups, azindine groups or isocyanate groups.
Claim 12
Dependent Claim
20 words
The element of claim 1, wherein the ratio of gelatin to the soft polymer core is between 1:2 and 2:1.
Claim 13
Dependent Claim
28 words
The element of claim 8, wherein said grafting agent utilized per g of gelatin is between 6.0×10 -2 and 10.4×10 -2 to obtain case-hardened gelatin-grafted soft polymer particles.
Claim 14
Dependent Claim
17 words
The element of claim 1, wherein said hardener is selected from bis(vinylsulfonylmethyl) ether, bis(vinylsulfonyl) methane or glutaraldehyde.
Claim 15
Dependent Claim
22 words
The element of claim 1, wherein said soft polymer core comprises butyl acrylate and methacrylic acid in the weight ratio of 95:5.
Claim 16
Independent Claim
120 words
A method of forming pressure resistant photographic materials comprising forming a soft polymer particle dispersion in water, incorporating a gelatin grafting agent into said polymer particles by adding said grafting agent to said dispersion, adding a gelatin solution to said polymer particle dispersion to form a gelatin-grafted case-hardened particle, incorporating said case hardened particle dispersion into a gelatin emulsion of silver halide photosensitive particles, and coating said emulsion containing said case hardened particles onto a suitable substrate to form a photographic element wherein the shell of said case-hardened particle comprises a shell of cross-linked gelatin up to 10 nm thick and the soft polymer core of said case hardened particle is between about 10 nm and 500 nm in diameter.
Claim 17
Independent Claim
120 words
A method of forming pressure resistant photographic materials comprising forming a soft polymer particle dispersion in water, incorporating a gelatin grafting agent into said polymer particles by adding said grafting agent to said dispersion, adding a gelatin solution to said polymer particle dispersion to form a gelatin-grafted case-hardened particle, incorporating said case hardened particle dispersion into a gelatin emulsion of silver halide photosensitive particles, and coating said emulsion containing said case hardened particles onto a suitable substrate to form a photographic element wherein the shell of said case-hardened particle comprises a shell of cross-linked gelatin up to 10 nm thick and the soft polymer core of said case hardened particle is between about 10 nm and 500 nm in diameter.
Claim 18
Dependent Claim
20 words
The method of claim 15 wherein color coupler is present in said melt and a color photographic material is formed.
Claim 19
Dependent Claim
14 words
The method of claim 15 wherein a black and white photographic element is formed.
Claim 20
Dependent Claim
18 words
The method of claim 15 wherein said case-hardened particle is between about 10 and 200 nm in diameter.
Claim 21
Dependent Claim
13 words
The element of claim 1 wherein said case thickness is about 5 nm.
Claim 22
Dependent Claim
13 words
The method of claim 15 wherein said shell is about 5 nm thick.
References Cited (Backward Citations)
US3576628A
Cited
UST969005I4
Cited
US4840881A
Cited
US4614708A
Cited
US4499179A
Cited
DD223264A1
Cited
US4822727A
Cited
US4714671A
Cited
US4940653A
Cited
EP0307856A2
Cited
EP0307855A2
Cited
US4855219A
Cited
US4920004A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-24 | 1994-12-24 | 1995-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-24 | 1998-12-24 | 1999-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-24 | 2002-12-24 | 2003-06-25 | $7700.00 | Window Closed / Lapsed |