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Epoxy Ink For Marking Transistor Caps

IP.com Disclosure Number: IPCOM000098126D
Original Publication Date: 1960-Feb-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Radovsky, DA: AUTHOR

Abstract

The smooth metal cap on transistors presents a difficult which to print identifying numerals. A need is created for a type of marking ink which is resistant to rubbing and solvents. The need is for an ink that withstands flux removal methods when the transistors are mounted on printed wiring boards. Flux removal methods usually entail the use of a chlorinated solvent together with ultrasonics or the use of alcohol with or without ultrasonics. Although an ink is supposed to resist such solvents, it should also be removable by another solvent such as acetone if remarking is required.

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Epoxy Ink For Marking Transistor Caps

The smooth metal cap on transistors presents a difficult which to print identifying numerals. A need is created for a type of marking ink which is resistant to rubbing and solvents. The need is for an ink that withstands flux removal methods when the transistors are mounted on printed wiring boards. Flux removal methods usually entail the use of a chlorinated solvent together with ultrasonics or the use of alcohol with or without ultrasonics. Although an ink is supposed to resist such solvents, it should also be removable by another solvent such as acetone if remarking is required.

Ordinary metal marking inks are not suited for the treatment accorded the transistor caps on printed circuit boards while they are being cleaned. Such ordinary inks are only partially resistant to the chlorinated solvent and are not at all resistant to alcohol.

A metal marking ink prepared with Epoxy resin withstands any of the flux removal techniques already mentioned. The particular Epoxy resin ink noted here is suitable by virtue of superior adhesion to the metal, chemical and solvent resistance after curing. While ordinary inks contain ingredients that dry but do not cure, the present Epoxy ink contains thermosetting resins and actually cures at a low temperature.

One form of the Epoxy marking ink may be made according to the following formulation: 48.0 Parts by weight Epoxy Resin (Solids)

1.8 Parts by weight Urea Formaldehyde Resin (Solids

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