US4235959A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic matt layers or surfaces
Assignee: Individual
•
Filing: 1979-02-02
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Granted: 1980-11-25
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Expires: 1999-02-02
Abstract
Abstract Hydrophilic coating compositions are made comprising a protective colloid and dispersed therein a matting agent. The matting agent is obtained by mixing in aqueous medium area, formaldehyde and an aqueous colloidal dispersion of silica. The mixture is buffered to keep the pH at 3.2 or lower. Urea and formaldehyde are polycondensed while vigorously stirring until particles comprising urea-formaldehyde resin and silica are formed of average particle size of 1-8 μm. The rate of stirring is reduced and the pH is raised to 5 or higher to prevent afterpolycondensation and agglomeration of the polymer particles. A hydrophilic colloid is then dissolved in the reaction mixture. Photographic light-sensitive silver halide material incorporating a layer formed from the hydrophilic coating composition.
Inventors
- 👤 Victor J. M. Thijs, deceased
- 👤 administrator Paul E. Huyghebaert
- 👤 Nikolaas C. De Jaeger
- 👤 Bernard H. Tavernier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:01
CPC Classifications
C; C08; C08L; C08L61/00; C08L61/20; C08L61/22; C08L61/24; C08G; C08G12/00; C08G12/02; C08G12/04; C08G12/10; C08G12/12; G; G03; G03C; G03C1/00; G03C1/76; G03C1/95; Y; Y10; Y10S; Y10S430/00; Y10S430/151; Y10S430/162
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
120 words
A photographic light-sensitive silver halide material incorporating a layer formed from a coating composition comprising gelatin and dispersed therein a matting agent, said coating composition having been prepared by mixing in aqueous medium urea, formaldehyde, and an aqueous colloidal dispersion of silica particles, said mixture being buffered to keep the pH of the mixture at 3.2 or lower, polycondensing the urea and formaldehyde while vigorously stirring the mixture until particles comprising urea-formaldehyde resin and silica are formed having an average particle size between 1 and 8 μm, reducing the rate of stirring and raising the pH of the mixture to 5 or higher to prevent afterpolycondensation and agglomeration of the polymer particles and dissolving a gelatin in the reaction mixture.
Claim 2
Dependent Claim
120 words
A photographic light-sensitive silver halide material incorporating a layer formed from a coating composition comprising gelatin and dispersed therein a matting agent, said coating composition having been prepared by mixing in aqueous medium urea, formaldehyde, and an aqueous colloidal dispersion of silica particles, said mixture being buffered to keep the pH of the mixture at 3.2 or lower, polycondensing the urea and formaldehyde while vigorously stirring the mixture until particles comprising urea-formaldehyde resin and silica are formed having an average particle size between 1 and 8 μm, reducing the rate of stirring and raising the pH of the mixture to 5 or higher to prevent afterpolycondensation and agglomeration of the polymer particles and dissolving a gelatin in the reaction mixture.
Claim 3
Dependent Claim
42 words
A photographic light-sensitive material according to claim 1, wherein the said layer is a protective layer over a light-sensitive layer and contains from 2 to 3 g of the matting agent per 30 g of the gelatin present in the coating composition.
Claim 4
Dependent Claim
49 words
A photographic light-sensitive material according to claim 1, wherein the said layer is a subbing layer comprising particles of an average diameter of 2 to 4 μm in such an amount that in the dried layer from 0.1 to 10 mg of the matting particles are present per sq.m.
Claim 5
Dependent Claim
21 words
The photographic light-sensitive material according to claim 1, wherein the silica particles have an average diameter between 10 and 100 nm.
Claim 6
Dependent Claim
24 words
The photographic light-sensitive material according to claim 1, wherein the said mixture is buffered with a mixture of citric acid and disodium hydrogen phosphate.
Claim 7
Dependent Claim
20 words
The photographic light-sensitive material according to claim 1, wherein the said polycondensation reaction occurs at a temperature below 50° C.
Claim 8
Dependent Claim
28 words
The photographic light-sensitive material according to claim 1, wherein the polycondensation of urea and formaldehyde occurs in the presence of a salt of ammonium to produce spherical particles.
Claim 9
Dependent Claim
18 words
The photographic light-sensitive material according to claim 7, wherein the ammonium salt is ammonium chloride or ammonium sulphate.
References Cited (Backward Citations)
US1929290A
Cited
US2819165A
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US3253926A
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US3539378A
Cited
US3627563A
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US3915709A
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US3920456A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-11-25 | 1984-05-26 | 1984-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-25 | 1988-05-26 | 1988-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-25 | 1992-05-26 | 1992-11-25 | $7700.00 | Window Closed / Lapsed |