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US 4,597,890 AGranted
Solvent blend for removing flux residues
AssigneeThe Dow Chemical Company
InventorsSusan M. Dallessandro, Wesley L. Archer, Stephen P. Krupp
Life of this patent
Estimating the term…
Abstract
Stable methylchloroform solvent compositions in combination with from about 3 to about 5 volume percent of 2-butanol and from about 1 to about 3 volume percent of 3-methyl-1-butyn-3-ol have been shown to be superior solvents for removing flux from circuit boards. Such compositions have no flash point and maintain excellent distribution of the components in the vapor and liquid sections of the defluxing apparatus.
Claims3
A methylchloroform defluxing solvent composition have no flash point as measured by Cleveland Open Cup method consisting of:
- (a) 93 to 96% by volume of methylchloroform containing by volume (1) 0.69-0.80% butylene oxide, (2) 0.35-0.45% nitromethane and (3) 3.0-3.4% diethylene ether as stabilizers based on the methylchloroform and
- (b) 4 to 7% by volume of a mixture of 2-butanol and 3-methyl-1-butyn-3-ol wherein the alcohols are present in amounts of 3 to 5% and 1 to 2%, respectively, based on the total volume of the defluxing composition.
Dependencies are inferred from the claim text.