Aqueous, two-component polyurea coating compositions
AssigneeBayer Aktiengesellschaft
InventorSanjay Luthra
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Abstract
The present invention is directed to an aqueous coating composition having a solids content of 20 to 96% by weight and containing a) a polyisocyanate component which is dispersible in water and has an average NCO functionality of 2 to 6 and b) a polyaspartate corresponding to the formula ##STR1## and c) water, which is present in an amount of at least 4% by weight, based on the solids content of components a) and b), wherein components a) and b) are present in an amount sufficient to provide an equivalent ratio of isocyanate groups to amino groups of at least 0.9:1.
Claims20
An aqueous coating composition having a solids content of 20 to 96% by weight and comprising
- a) a polyisocyanate which is dispersible in water and has an average NCO functionality of 2 to 6 and
- b) a polyaspartate corresponding to the formula ##STR5## wherein X represents an organic group which has a valency of n and is inert towards isocyanate groups at a temperature of 100.degree. C. or less,
- R.sub.1 and R.sub.2 may be the same or different and represent organic groups which are inert towards isocyanate groups at a temperature of 100.degree. C. or less, or R.sub.1 and R.sub.2 together with the .beta.-carbon atom form a cycloaliphatic or heterocyclic ring,
- R.sub.3 and R.sub.4 may be identical or different and represent hydrogen or organic groups which are inert towards isocyanate groups at a temperature of 100.degree. C. or less and
- n has a value of 2 to 6, and
- c) water, which is present in an amount of at least 4% by weight, based on the solids content of components a) and b),
- wherein components a) and b) are present in an amount sufficient to provide an equivalent ratio of isocyanate groups to amino groups of at least 0.9:1.
An aqueous coating composition having a solids content of 20 to 96% by weight and comprising
- a) a polyisocyanate which is dispersible in water and has an average NCO functionality of 2 to 6 and
- b) a polyaspartate corresponding to the formula ##STR6## wherein X represents an organic group which has a valency of n and is inert towards isocyanate groups at a temperature of 100.degree. C. or less,
- R.sub.1 and R.sub.2 may be the same or different and represent organic groups which are inert towards isocyanate groups at a temperature of 100.degree. C. or less, or R.sub.1 and R 2 together with the .beta.-carbon atom form a cycloaliphatic or heterocyclic ring,
- R.sub.3 and R.sub.4 may be identical or different and represent hydrogen or organic groups which are inert towards isocyanate groups at a temperature of 100.degree. C. or less and
- n has a value of 2 to 6, and
- c) water, which is present in an amount of at least 4% by weight, based on the solids content of components a) and b),
- wherein components a) and b) are present in an amount sufficient to provide an equivalent ratio of isocyanate groups to amino groups of at least 1.7:1.
Dependencies are inferred from the claim text.