Solution for use in the prevention of smear in the manufacture of printed circuit boards
OwnerJeffrey W. Fredericksoninventor
Life of this patent
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Abstract
A solution and a method of using it for preventing smear in the manufacture of printed circuit boards includes monoethanolamine combined with a fatty acid for neutralizing the active amine except in the presence of relatively high heat, and a surface tension reducing agent. The solution is applied to the printed circuit board as holes are being drilled. The friction of the drill bit on the printed circuit board generates heat which activates the amine allowing it to attack the inner glass epoxy walls of the printed circuit board and prevent smear.
Claims4
A composition for preventing smear in the drilling a printed circuit board having a fiberglass/epoxy substrate, said composition consisting essentially of the following components in the following amounts:
- (a) 4-20 vol% fatty acids;
- (b) 4-20 vol% of an amine selected from monoethanolamine, diethylamine, and mixtures thereof;
- (c) 1-7 vol% of a surfactant;
- (d) 0.1-0.2 vol% n-amyl alcohol;
- and
- (d) balance water.
Dependencies are inferred from the claim text.