Cleaning process

An industrial cleaning process in which a contaminant of soldering flux or wax is removed from a substrate contaminated therewith, comprising:

• (A) contacting the substrate with a cleaning composition consisting essentially of a substantially water-insoluble monobasic acid ester present in an amount in excess of 50 wt. % of the composition and having the formula
• RCOOR.sub.1
• wherein R is an alkyl group having about 8 to about 16 carbon atoms and R.sub.1 is an alkyl group having 1 to about 4 carbon atoms;
• (B) maintaining the cleaning composition in contact with the substrate for a period of time at least sufficient to solubilize the contaminant;
• (C) removing a mixture of the cleaning composition and solubilized contaminant from the substrate by contact with water to provide a substrate having a contamination rating of no greater than about 14 micrograms NaCl equivalent/square inch (MIL-P-28809A);
• and
• (D) separating the water from said mixture, the separated water being substantially free of water-soluble organic material and having a chemical oxygen demand of no greater than about 1,000 ppm.

A method for removing wax from a metallic or plastic surface contaminated therewith comprising:

• (A) contacting the surface having thereon wax with a cleaning composition consisting essentially of a substantially water-insoluble monobasic acid ester present in an amount in excess of 50 wt. % of the composition and having the formula
• RCOOR.sub.1
• wherein R is an alkyl group having about 8 to about 16 carbon atoms and R.sub.1 is an alkyl group having 1 to about 4 carbon atoms;
• (B) maintaining the cleaning composition in contact with the surface for a period of time at least sufficient to solubilize the wax;
• and
• (C) removing cleaning composition and solubilized wax from the surface.

A method for removing residue which includes soldering flux from a metallic or plastic surface contaminated therewith comprising:

• (A) contacting the surface with a cleaning composition consisting essentially of:
• (1) a substantially water-insoluble monobasic acid ester present in an amount in excess of 50 wt. % of the composition and having the formula
• RCOOR.sub.1
• wherein R is an alkyl group having about 8 to about 16 carbon atoms and R.sub.1 is an alkyl group having 1 to about 4 carbon atoms;
• and (2) another cleaning agent selected from the group consisting of dibasic esters, petroleum hydrocarbons, ketones, ethers and alcohols in an amount less than 50 wt. % of the composition;
• (B) maintaining the cleaning composition in contact with the surface for a period of time at least sufficient to solubilize the residue;
• and
• (C) removing cleaning composition and solubilized residue from the surface.