Tin/tin-lead stripping solutions
Stripping solution for tin or tin alloys
Composition and method for stripping films from printed circuit boards Patent #: 4713144
ApplicationNo. 451054 filed on 12/15/1989
US Classes:134/3, Including acidic agent134/41, Metal base work, acid treating252/79.4With organic material
ExaminersPrimary: Pal, Asok
Assistant: Ojan, Ourmazd S.
Attorney, Agent or Firm
International ClassesC23G 001/02
AbstractA composition for removing a layer of tin, lead or tin/lead alloy from a copper substrate such as a printed circuit board comprises an aqueous solution of nitric acid and ferric acid and also contains anthranilic acid to inhibit the degree of attack on the copper substrate. A surfactant, such as a mixture of cocoamine and an ethoxylated fatty alcohol or a mixture of a phosphate ester and an ethylene oxide/propylene oxide copolymer, may also be present to improve the brightness of the remaining copper.