US4230781A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making etch-resistant stencil with dichromate-sensitized alkali-caseinate coating
Assignee: RCA Licensing Corp
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Filing: 1976-02-19
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Granted: 1980-10-28
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Expires: 1996-02-19
Abstract
Abstract Method comprises applying to a surface to be etched a coating of a liquid composition having a pH of about 5.8 to 7.0 and comprising an alkali caseinate, an alkali dichromate photosensitizer, sodium borate and water. The layer is dried, photoexposed, developed and baked to produce an etch-resistant stencil.
Inventors
- 👤 Joseph J. Piascinski
- 👤 Ernest E. Doerschuk, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:13
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/20; G03F7/00; G03F7/004; G03F7/04; H; H05; H05K; H05K3/00; H05K3/0073; H05K3/0076
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
99 words
A method for producing an etch-resistant stencil upon a surface comprising applying to said surface a coating of a liquid composition having a pH of about 5.8 to 7.0 and comprising (i) an alkali caseinate, (ii) an alkali dichromate photosensitizer for said caseinate (iii) hydrated sodium borate, the weight of said hydrated sodium borate comprising 0.10 to 0.35 of the weight of said alkali caseinate, and (iv) water, drying said coating, photoexposing said coating to a light image, developing said exposed coating to produce said stencil, and then baking said stencil in air to render said pattern etch resistant.
Claim 2
Independent Claim
99 words
A method for producing an etch-resistant stencil upon a surface comprising applying to said surface a coating of a liquid composition having a pH of about 5.8 to 7.0 and comprising (i) an alkali caseinate, (ii) an alkali dichromate photosensitizer for said caseinate (iii) hydrated sodium borate, the weight of said hydrated sodium borate comprising 0.10 to 0.35 of the weight of said alkali caseinate, and (iv) water, drying said coating, photoexposing said coating to a light image, developing said exposed coating to produce said stencil, and then baking said stencil in air to render said pattern etch resistant.
Claim 3
Dependent Claim
24 words
The method defined in claim 1 wherein the weight of said sodium borate comprises 0.18 to 0.30 of the weight of said alkali caseinate.
Claim 4
Dependent Claim
19 words
The method defined in claim 1 wherein said composition has a pH in the range of 6.5 to 6.9.
Claim 5
Dependent Claim
19 words
The method defined in claim 1 wherein said dry coating before baking is about 40 to 100 microinches thick.
Claim 6
Dependent Claim
20 words
The method defined in claim 1 wherein said alkali caseinate is sodium caseinate and said alkali dichromate is ammonium dichromate.
Claim 7
Dependent Claim
143 words
In a method for producing an apertured mask for a cathode-ray tube, the steps comprising (a) applying to each major surface of a metal sheet a coating of a liquid, water-based coating composition having a pH of about 5.8 to 7.0 and consisting essentially of (i) alkali caseinate, (ii) an alkali dichromate photosensitizer for said caseinate, (iii) hydrated sodium borate, the weight of said hydrated sodium borate comprising 0.10 to 0.35 of the weight of said alkali caseinate, and (iv) water, (b) drying said coatings, (c) exposing said dry coatings to light images, (d) developing said exposed coatings to produce stencils on each of said major surfaces, (e) baking said stencils in air to render said stencils etch resistant, (f) and then applying an etchant for said metal sheet to both of said major surfaces until said sheet is etched a desired amount.
Claim 8
Dependent Claim
143 words
In a method for producing an apertured mask for a cathode-ray tube, the steps comprising (a) applying to each major surface of a metal sheet a coating of a liquid, water-based coating composition having a pH of about 5.8 to 7.0 and consisting essentially of (i) alkali caseinate, (ii) an alkali dichromate photosensitizer for said caseinate, (iii) hydrated sodium borate, the weight of said hydrated sodium borate comprising 0.10 to 0.35 of the weight of said alkali caseinate, and (iv) water, (b) drying said coatings, (c) exposing said dry coatings to light images, (d) developing said exposed coatings to produce stencils on each of said major surfaces, (e) baking said stencils in air to render said stencils etch resistant, (f) and then applying an etchant for said metal sheet to both of said major surfaces until said sheet is etched a desired amount.
Claim 9
Dependent Claim
21 words
The method defined in claim 6 wherein the specific gravity of said coating composition is in the range 1.028 to 1.036.
Claim 10
Dependent Claim
17 words
The method defined in claim 6 wherein said pH is in the range of 6.5 to 6.9.
Claim 11
Dependent Claim
19 words
The method defined in claim 8 wherein said pattern is baked in air at about 260° to 325° C.
Claim 12
Dependent Claim
19 words
The method defined in claim 8 wherein said sheet is of cold-rolled steel and said etchant includes ferric chloride.
References Cited (Backward Citations)
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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) | 1983-10-28 | 1984-04-28 | 1984-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-28 | 1988-04-28 | 1988-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-28 | 1992-04-28 | 1992-10-28 | $7700.00 | Window Closed / Lapsed |