Prevention of water staining of aluminum

Claim 1

A method in the manufacture, transportation or storage of aluminous metal sheet, wherein water staining of such sheet is prevented by applying to the surface of the sheet, in neat form, a continuous film of at least 0.5 milligram per square foot of a protective composition having a hydroxyl value greater than 15 and consisting essentially of a product derived from: (a) an aliphatic or cycloaliphatic polybasic acid containing from 18 to 72 carbon atoms and 2 to 4 carboxyl groups, and (b) a polyol partial ester derived from a C 12 -C 22 aliphatic monocarboxylic acid and a polyol selected from the group consisting of aliphatic polyols and ether polyols obtained by the condensation of two or more aliphatic polyol molecules or by ethoxylation of an aliphatic polyol, said polyols containing from 3 to 30 carbon atoms and 3 to 22 hydroxyl groups, with not more than 70% of the available hydroxyl groups esterified, the weight ratio of (a) to (b) ranging from 20:1 to 1:4.

Claim 2

A method in the manufacture, transportation or storage of aluminous metal sheet, wherein water staining of such sheet is prevented by applying to the surface of the sheet, in neat form, a continuous film of at least 0.5 milligram per square foot of a protective composition having a hydroxyl value greater than 15 and consisting essentially of a product derived from: (a) an aliphatic or cycloaliphatic polybasic acid containing from 18 to 72 carbon atoms and 2 to 4 carboxyl groups, and (b) a polyol partial ester derived from a C 12 -C 22 aliphatic monocarboxylic acid and a polyol selected from the group consisting of aliphatic polyols and ether polyols obtained by the condensation of two or more aliphatic polyol molecules or by ethoxylation of an aliphatic polyol, said polyols containing from 3 to 30 carbon atoms and 3 to 22 hydroxyl groups, with not more than 70% of the available hydroxyl groups esterified, the weight ratio of (a) to (b) ranging from 20:1 to 1:4.

Claim 8

A method in the manufacture, transportation or storage of aluminous metal sheet, wherein water staining of such sheet is prevented by applying to the surface of the sheet a solution consisting essentially of an inert aliphatic or aromatic hydrocarbon diluent having a 100° F. viscosity of 20 to 100 SUS and at least 0.1 weight percent of a protective composition having a hydroxyl value greater than 15 and derived from: (a) an aliphatic or cycloaliphatic polybasic acid containing from 18 to 72 carbon atoms and 2 to 4 carboxyl groups, and (b) a polyol partial ester derived from a C 12 -C 22 aliphatic monocarboxylic acid and a polyol selected from the group consisting of aliphatic polyols and ether polyols obtained by the condensation of two or more aliphatic polyol molecules or by ethoxylation, said polyols containing from 3 to 30 carbon atoms and 3 to 22 hydroxyl groups, with not more than 70% of the available hydroxyl groups esterified, the weight ratio of (a) to (b) ranging from 20:0 to 1:4, and subsequently evaporating substantially all of said diluent, such that said protective composition is present on the sheet as a continuous film containing at least 0.5 milligram of said protective composition per square foot.

Claim 9

A method in the manufacture, transportation or storage of aluminous metal sheet, wherein water staining of such sheet is prevented by applying to the surface of the sheet a solution consisting essentially of an inert aliphatic or aromatic hydrocarbon diluent having a 100° F. viscosity of 20 to 100 SUS and at least 0.1 weight percent of a protective composition having a hydroxyl value greater than 15 and derived from: (a) an aliphatic or cycloaliphatic polybasic acid containing from 18 to 72 carbon atoms and 2 to 4 carboxyl groups, and (b) a polyol partial ester derived from a C 12 -C 22 aliphatic monocarboxylic acid and a polyol selected from the group consisting of aliphatic polyols and ether polyols obtained by the condensation of two or more aliphatic polyol molecules or by ethoxylation, said polyols containing from 3 to 30 carbon atoms and 3 to 22 hydroxyl groups, with not more than 70% of the available hydroxyl groups esterified, the weight ratio of (a) to (b) ranging from 20:0 to 1:4, and subsequently evaporating substantially all of said diluent, such that said protective composition is present on the sheet as a continuous film containing at least 0.5 milligram of said protective composition per square foot.