| 摘要 |
<p>An aqueous alkaline cleaning solution for removing lubricants or other soiling contaminants from tin without visibly etching it has a pH of about 11 to 13, imparted by an effective amount of an alkaline component and also contains, serving as inhibitor, from 0.02 g/l to 0.06 g/l of one or more quinones and/or polyhydroxybenzenes, these being either unsubstituted or substituted with halo, alkyl, alkoxy, carboxyl, nitro and/or cyano substituents. To prevent precipitation of the calcium and/or magnesium ions which cause water-hardness the solutions desirably contain at least about 0.1 g/l of a polyelectrolyte. The cleaning process using these solutions is operated at from about 100 DEG F to about 130 DEG F (approx. 38 DEG C to 54 DEG C). A solid cleaning composition or an aqueous concentrate can be dissolved in water to form the desired solution.</p> |
