Low foaming alkaline cleaner comprising a surfactant mixture of an EO-PO-EO block copolymer and a PO-ZO-PO block copolymer

Claim 1

A cleaning solution for cleaning and etching a metal surface with an alkali treatment including an alkali metal hydroxide and an alkali metal salt of gluconic acid, the improvement comprising including in said cleaning solution the combination of a low foaming ethylene oxide - propylene oxide block copolymer surfactant of the structure (RO)--(R'O) n --(RO) and a defoaming reverse ethylene oxide - propylene oxide block copolymer surfactant of the structure (R'O)--(RO) n --(R'O) as the sole foam agents where R is ethylene and R' is propylene; wherein the ratio of ethylene oxide - propylene oxide block copolymer to reverse ethylene oxide - propylene oxide block copolymer is from about 1 to 3 to about 3 to 1; and wherein the concentration of ethylene oxide - propylene oxide block copolymer surfactant and reverse ethylene oxide - propylene oxide block copolymer surfactant in the cleaning solution ranges from about 0.005 to about 0.18 volume percent.

Claim 3

A method of cleaning and etching a metal surface with an alkaline cleaning solution comprising an alkali metal hydroxide and an alkali metal salt of gluconic acid, the improvement comprising including in said solution the combination of a low foaming ethylene oxide - propylene oxide block copolymer surfactant of the structure (RO)--)R'O) n --(RO) and a defoaming reverse ethylene oxide - propylene oxide block copolymer surfactant of the structure (R'O)--(RO) n --(R'O) as the sole foam agents where R is ethylene and R' is propylene; wherein the ratio of ethylene oxide - propylene oxide block copolymer to reverse ethylene oxide - propylene oxide block copolymer is from about 1 to 3 to about 3 to 1; and wherein the concentration of ethylene oxide - propylene oxide block copolymer surfactant and reverse ethylene oxide - propylene oxide block copolymer surfactant in the cleaning solution ranges from about 0.005 to about 0.18 volume percent.

Claim 4

A method of cleaning and etching a metal surface with an alkaline cleaning solution comprising an alkali metal hydroxide and an alkali metal salt of gluconic acid, the improvement comprising including in said solution the combination of a low foaming ethylene oxide - propylene oxide block copolymer surfactant of the structure (RO)--)R'O) n --(RO) and a defoaming reverse ethylene oxide - propylene oxide block copolymer surfactant of the structure (R'O)--(RO) n --(R'O) as the sole foam agents where R is ethylene and R' is propylene; wherein the ratio of ethylene oxide - propylene oxide block copolymer to reverse ethylene oxide - propylene oxide block copolymer is from about 1 to 3 to about 3 to 1; and wherein the concentration of ethylene oxide - propylene oxide block copolymer surfactant and reverse ethylene oxide - propylene oxide block copolymer surfactant in the cleaning solution ranges from about 0.005 to about 0.18 volume percent.