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US 4,230,781 AGranted
Method for making etch-resistant stencil with dichromate-sensitized alkali-caseinate coating
AssigneeRCA Corporation
InventorsJoseph J. Piascinski, Ernest E. Doerschuk, III
Life of this patent
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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.
Claims10
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.
2 more elements
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.
7 more elements
Dependencies are inferred from the claim text.