Rca Inc.

Abraham Goldman

Robert L Quinn

Philip Michael Heyman

Pabitra Datta

In a method of manufacturing, the steps of: providing a workpiece comprising a main body and a machine-readable marking on a portion of the body, depositing on the marking and the surrounding surface an overcoating of a liquid polymeric composition that is curable by exposure to ultraviolet radiation, and then irradiating the liquid overcoating with ultraviolet radiation so that the overcoating cures to a solid nontacky, light-transmitting protective coating. The workpiece, with the cured protective coating thereon, may be subjected to processing steps wherein extraneous matter may adhere to the coating, and then be cleaned leaving the cured coating intact.

Method for making a protective coating on a machine-readable marking

Method for making a protective coating on a machine-readable marking and

The method comprises producing on the surface to be etched a stencil of a light-hardened PVA. The stencil is produced by light hardening selected portions of a film or coating consisting essentially of dichromate-sensitized PVA containing about 5 to 30 weight percent with respect to the weight of PVA solids of N-methylol acrylamide. After light hardening, the nonhardened portions of the film are removed, thereby producing the stencil. The stencil is baked to improve its etch resistance, the surface is etched through the stencil, and then the stencil is removed from the surface.

Etching method using a PVA stencil containing N-methylol acrylamide

The method comprises producing on the surface to be etched a stencil of a light-hardened PVA. The stencil is produced by light hardening selected portions of a film or coating consisting essentially of dichromate-sensitized PVA. The PVA is about 85% to 97% hydrolyzed and has a molecular weight of 75,000 to 100,000. After light hardening, the nonhardened portions of the film are removed, thereby producing the stencil. The stencil is baked to improve its etch resistance, the surface is etched through the stencil, and then the stencil is removed from the surface.

Etching method using a hardened PVA stencil

The etch resistance of a casein-based photoresist pattern to low specific gravity ferric chloride-based etchant solutions is increased by treating the photoresist pattern with a methylene blue solution, containing at least 0.1 weight percent methylene blue, prior to exposure to the etchant solution.

Improving etch-resistance of casein-based photoresist pattern

The addition of N-methylol acrylamide as an accelerator to casein-based aqueous photoresist compositions reduces the baking temperature required to render the developed resist etch resistant.

Aqueous photoresist of casein and N-methylol acrylamide

Aqueous photoresist comprising casein and methylol acrylamide

The method comprises applying to a surface to be etched a coating of a liquid composition comprising an acid-precipitated casein, alkali dichromate photosensitizer, sodium borate and water. The layer is dried, photoexposed, developed and baked to produce an etch-resistant stencil.

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Kendall Park, NJ, United States of America

Abraham Goldman