Method of inhibiting cavitation-erosion corrosion of aluminum surfaces using carboxylic acid based compositions comprising polymerizable-acid graft polymers
AssigneePrestone Products Corporation
InventorsAleksei V. Gershun, Peter M. Woyciesjes
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Abstract
This invention relates to a method of inhibiting the cavitation-erosion corrosion of aluminum surfaces. The method comprises the step of contacting the aluminum surface with a formulation comprising a corrosion inhibitor composition comprising one or more carboxylic acids, or salts or isomers thereof, and a polymerizable-acid graft polymer which comprises an unsaturated grafting acid and an alkylene oxide polymer, or copolymers thereof. This method has been demonstrated to be a surprisingly effective means to inhibit cavitation-erosion corrosion of aluminum surfaces found in the cooling systems of internal combustion engines.
Claims27
A method for inhibiting the cavitation-erosion corrosion of aluminum surfaces comprising the step of contacting said surfaces with a formulation comprising a corrosion inhibitor composition, said corrosion inhibitor composition comprises (a) one or more carboxylic acids, or salts thereof, and (b) a polymerizable-acid graft polymer comprising from about 1.0% to about 60% by weight of an unsaturated grafting acid and an alkylene oxide polymer, said polymerizable-acid graft polymer having the following formula:
- R"--[(OC.sub.n H.sub.2n).sub.z OR'].sub.a
- wherein
- each R' is independently selected from the group consisting of a hydrogen atom, hydrogen radicals and acyl radicals free of aliphatic unsaturation;
- R" is selected from the group consisting of a hydrogen atom, hydrogen radicals, amine-containing radicals and acyl radicals, provided that all the R' and R" groups are not, at the same time, a hydrogen atom;
- each "n" has, independently, a value of from 2 to 4;
- each "z" has, independently, a value of from 4 to about 3500;
- "a" has a value of from 1 to 4
- and said formulation further comprising an alkali metal hydroxide in an amount sufficient to adjust the pH of the formulation to from 6.0 to 9.0.
A method for inhibiting the cavitation-erosion corrosion of aluminum surfaces comprising the step of contacting said surfaces with an antifreeze coolant formulation comprising:
- (a) a liquid alcohol which function is as a freezing point depressant;
- (b) from about 0.1% to about 5.5% by weight of a corrosion inhibitor composition comprising (i) one or more carboxylic acids, or salts thereof, and (ii) a polymerizable-acid graft polymer comprising from about 1.0% to about 60% by weight of an unsaturated grafting acid and an alkylene oxide polymer, said polymerizable-acid graft polymer having the following formula:
- R"--[(OC.sub.n H.sub.2n).sub.z OR'].sub.a
- wherein
- each R' is independently selected from the group consisting of a hydrogen atom, hydrogen radicals, and acyl radicals free of aliphatic unsaturation;
- R" is selected from the group consisting of a hydrogen atom, hydrogen radicals, amine-containing radicals and acyl radicals, provided that all the R' and R" groups are not, at the same time, a hydrogen atom;
- each "n" has, independently, a value of from 2 to 4;
- each "z" has, independently, a value of from 4 to about 3500;
- "a" has a value of from 1 to 4;
- (c) an alkali metal hydroxide in an amount sufficient to adjust the pH of the formulation to from 6.0 to 9.0, and
- (d) from about 10% to about 9.0% by weight water.
A method for inhibiting the cavitation-erosion corrosion of aluminum surfaces comprising the step of contacting said surfaces with an antifreeze coolant formulation comprising:
- (a) from about 80% to about 99% by weight of a liquid alcohol which functions as a freezing point depressant;
- (b) from about 2.0% to about 5.0 by weight of a mixture of 2-ethylhexanoic acid, or salts thereof, and neo-decanoic acid, or salts thereof,
- (c) from about 0.01% to about 20 of a polymerizable-acid graft polymer comprising (i) acrylic acid and (ii) an alkylene oxide polymer comprising a copolymer of EO and PO polymers;
- (d) from about 10% to about 90% by weight water;
- and said formulation further comprising an alkali metal hydroxide in an amount sufficient to adjust the pH of th formulation to from 6.0 to 9.0.
Dependencies are inferred from the claim text.