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Chemical Etching of Magnetic Iron Oxide Polymer Blends

IP.com Disclosure Number: IPCOM000092216D
Original Publication Date: 1968-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Rogers, HA: AUTHOR

Abstract

Iron oxide-polymer coatings are removed from polyester substrates in selected areas using a photoresist coating and an alkaline treatment.

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Chemical Etching of Magnetic Iron Oxide Polymer Blends

Iron oxide-polymer coatings are removed from polyester substrates in selected areas using a photoresist coating and an alkaline treatment.

Magnetic iron oxide coatings which contain as binding agents polymeric materials such as polyvinyl chloride, butadiene-styrene, polyurethane, epoxy, etc. homogenized with iron oxide such as Fe(2)O(3) or Fe(3)O(4) are coated onto and firmly adhered to a polyester substrate such as polyethylene glycol terephthalate using moderate heats and very high pressure. The following steps are followed for the chemical etching to remove selected portions of the magnetic iron oxide-binding agent coating.

The coating is cleaned using trichloroethylene. A conventional photoresist material is applied to the surface of the magnetic iron oxide coating and the photoresist is prebaked at 250 degrees F for 15 minutes. The photoresist is exposed under ultraviolet light to a masking negative and then developed in an ordinary degreasing fluid such as trichloroethylene. The area of the coating which is unprotected by the resist is etched by immersing the coated substrate for two minutes in 5 N aqueous sodium hydroxide at a temperature from about 170 degrees to 180 degrees F. A whitish appearance in the areas etched appears on the back side of the polyester film after the two minute immersion in the sodium hydroxide solution. No dissolution of the iron oxide coating is apparent. The coated substrate...