TWO-COMPONENT, POLYASPARTIC COATING COMPOSITIONS

1 . A polyurea coating composition comprising the reaction product of:

an isocyanate-functional component (A) comprising:

a) an aliphatic isocyanate functional material; and

b) a cycloaliphatic isocyanate functional material; and

an isocyanate-reactive component (B) comprising at least one polyaspartic acid ester component.

2 . The polyurea coating composition of claim 1 , wherein the aliphatic isocyanate functional material comprises a reaction product of hexamethylene diisocyanate and a hydroxy-functional ether compound.

3 . The polyurea coating composition of claim 1 , wherein the aliphatic isocyanate functional material comprises an allophanate reaction product of hexamethylene diisocyanate and a hydroxy-functional ether compound.

4 . The polyurea coating composition of claim 1 , wherein the aliphatic isocyanate functional material comprises an allophanate reaction product of hexamethylene diisocyanate and a hydroxy-functional polyether.

5 . The polyurea coating composition of claim 1 , wherein the aliphatic isocyanate functional material comprises an allophanate reaction product of hexamethylene diisocyanate and a hydroxy-functional polyether prepared using DMC catalysis.

6 . The polyurea coating composition of claim 1 , wherein the aliphatic isocyanate functional material comprises an allophanate reaction product of hexamethylene diisocyanate and a hydroxy-functional ether compound, the aliphatic isocyanate functional material having an isocyanate functionality of at least 4, a glass transition temperature less than −40° C., and a % NCO less than 10%.

7 . The polyurea coating composition of claim 1 , wherein the cycloaliphatic isocyanate functional material comprises a reaction product of isophorone diisocyanate and a mono-functional alcohol.

8 . The polyurea coating composition of claim 1 , wherein the cycloaliphatic isocyanate functional material comprises an allophanate-modified isocyanurate trimer reaction product of isophorone diisocyanate and a mono-functional alcohol.

9 . The polyurea coating composition of claim 1 , wherein the cycloaliphatic isocyanate functional material comprises an allophanate-modified isocyanurate trimer reaction product of isophorone diisocyanate and a mono-functional alcohol selected from the group consisting of methanol, ethanol, n-propanol, isopropanol, butanol isomers, pentanol isomers, hexanol isomers, heptanol isomers, octanol isomers, nonanol isomers, decanol isomers, 2-ethylhexanol, trimethyl hexanol, cyclohexanol, fatty alcohols having 11 to 20 carbon atoms, vinyl alcohol, allyl alcohol, and combinations of any thereof.

10 . The polyurea coating composition of claim 1 , wherein the cycloaliphatic isocyanate functional material comprises a reaction product of isophorone diisocyanate and a mono-functional alcohol, the cycloaliphatic isocyanate functional material having an isocyanate functionality of at least 2.3, and a glass transition temperature between 25° C. and 65° C.

11 . The polyurea coating composition of claim 1 , wherein the weight ratio of the cycloaliphatic isocyanate functional material to the aliphatic isocyanate functional material is from about 95:5 to about 50:50.

12 . The polyurea coating composition of claim 1 , wherein the polyaspartic acid ester corresponds to the formula:

wherein

X represents an organic group which has a valency of n and is inert towards isocyanate groups at a temperature of 100° C. or less, preferably the group obtained, more preferably the hydrocarbon group obtained, by removing the amino groups from an aliphatic, araliphatic or cycloaliphatic polyamine, more preferably a diamine, and

R 1 and R 2 may be the same or different and represent organic groups which are inert towards isocyanate groups at a temperature of 100° C. or less, preferably an alkyl group containing 1 to 9 carbons and more preferably methyl, ethyl or butyl groups, or R 1 and R 2 together with the β-carbon atom form a cycloaliphatic or heterocyclic ring,

R 3 and R 4 may be identical or different and represent hydrogen or organic groups which are inert towards isocyanate groups at a temperature of 100° C. or less and

n has a value of at least 2, preferably 2 to 6, more preferably 2 to 4 and most preferably 2.

13 . The polyurea coating composition of claim 1 , wherein

X represents the hydrocarbon group obtained by removing the amino groups from an aliphatic, araliphatic or cycloaliphatic diamine,

R 1 and R 2 may be the same or different and represent methyl, ethyl or butyl groups,

R 3 and R 4 represent hydrogen, and

n has a value of 2.

14 . The polyurea coating composition of claim 1 , consisting essentially of the reaction product of:

an isocyanate-functional component (A) comprising:

a) an aliphatic isocyanate functional material; and

b) a cycloaliphatic isocyanate functional material; and

an isocyanate-reactive component (B) comprising at least one polyaspartic acid ester component.

15 . The polyurea coating composition of claim 1 , consisting of the reaction product of:

an isocyanate-functional component (A) comprising:

a) an aliphatic isocyanate functional material; and

b) a cycloaliphatic isocyanate functional material; and

an isocyanate-reactive component (B) comprising at least one polyaspartic acid ester component.

16 . The polyurea coating composition of claim 1 , wherein the equivalent ratio of NCO groups of the isocyanate (A) and the isocyanate reactive-groups of the isocyanate-reactive group component (B) is from about 20:1 to 1:20.

17 . The polyurea coating composition of claim 1 , wherein the equivalent ratio of NCO groups of the isocyanate (A) and the isocyanate reactive-groups of the isocyanate-reactive group component (B) is from about 10:1 to 1:10.

18 . The polyurea coating composition of claim 1 , wherein the equivalent ratio of NCO groups of the isocyanate (A) and the isocyanate reactive-groups of the isocyanate-reactive group component (B) is from about 5:1 to 1:5.

19 . The polyurea coating composition of claim 1 , wherein the equivalent ratio of NCO groups of the isocyanate (A) and the isocyanate reactive-groups of the isocyanate-reactive group component (B) is from about 3:1 to 1:3.

20 . The polyurea coating composition of claim 1 , wherein the equivalent ratio of NCO groups of the isocyanate (A) and the isocyanate reactive-groups of the isocyanate-reactive group component (B) is from about 2:1 to 1:2.

21 . The polyurea coating composition of claim 1 , wherein the equivalent ratio of NCO groups of the isocyanate (A) and the isocyanate reactive-groups of the isocyanate-reactive group component (B) is from about 1.5:1 to 1:1.5.

22 . The polyurea coating composition of claim 1 , wherein the equivalent ratio of NCO groups of the isocyanate (A) and the isocyanate reactive-groups of the isocyanate-reactive group component (B) is from about 1.2:1 to 1:1.2.

23 . The polyurea coating composition of claim 1 , wherein the equivalent ratio of NCO groups of the isocyanate (A) and the isocyanate reactive-groups of the isocyanate-reactive group component (B) is from about 1.1:1 to 1:1.1.

24 . The polyurea coating composition of claim 1 , wherein the equivalent ratio of NCO groups of the isocyanate (A) and the isocyanate reactive-groups of the isocyanate-reactive group component (B) is 1:1.

25 . The polyurea coating composition of claim 1 , wherein the isocyanate reactive-groups of the isocyanate-reactive group component (B) are —OH and —NH groups.

26 . The polyurea coating composition of claim 1 , wherein the isocyanate reactive-groups of the isocyanate-reactive group component (B) are exclusively —NH groups.

27 . The polyurea coating composition of claim 22 , wherein the polyaspartic acid ester is the only —NH functional compound.

28 . A method of coating a metal substrate comprising applying the polyurea coating composition of claim 1 directly to the metal substrate and curing the polyurea coating composition.

29 . The method of claim 24 , wherein the metal substrate is new or weathered galvanized steel.

30 . The method of claim 24 , wherein the metal substrate is treated or untreated steel.

31 . The method of claim 24 , wherein the metal substrate is aluminum.

32 . The method of claim 24 , wherein the metal substrate is a metal alloy.

33 . A substrate coated with the polyurea coating composition of claim 1 .