Coating compositions containing ethylenically unsaturated polyurethanes as binders

1. A binder-containing coating composition, curable by free radical polymerization, wherein the binder resins comprise

A) about 10 to 95% by weight of the reaction product of

i) one or more polyisocyanate adducts containing isocyanurate, iminooxadiazine dione, urethane, biuret, allophanate, uretdione and/or carbodiimide groups with

ii) a hydroxyl component containing

ii-a) one or more hydroxyl compounds containing two ethylenically unsaturated groups and corresponding to formula I

CH 2 ═C(R 1 )—C(O)—O—R 2 —CH 2 —O—R 3   (I)

wherein

R 1 is H or CH 3 ,

R 2 is —CH(CH 2 OH)— or —CH 2 CH(OH)—,

R 3 is —C(O)—C(R 1 )═CHR 8 or —CH 2 CH═CHR 8 and

R 8 is H, CH 3 or phenyl, and

ii-b) up to 30 hydroxyl equivalent %, based on the total hydroxyl equivalents of component A-ii), of a hydroxyl compound other than A-ii-a), which has a number average molecular weight of 32 to 400,

wherein the NCO:OH equivalent ratio of component A-i) to component A-ii) is 1.10:1 to 1:1.10,

B) 5 to about 60% by weight of the reaction product of

i) one or more polyisocyanate adducts containing isocyanurate, iminooxadiazine dione, urethane, biuret, allophanate, uretidione and/or carbodiimide groups with

ii) a hydroxyl component containing

ii-a) one or more hydroxy functional lactone ester (meth)acrylates having a number average molecular weight of about 200 to 2000 and corresponding to formula II

CH 2 ═C(R 1 )—C(O)—O—R 4 —[O—C(O)—R 5 ] n —OH  (II)

wherein

n is an integer from 1 to 5,

R 1 is as defined above,

R 4 represents an alkylene group or substituted alkylene group having 2 to 10 carbon atoms, which may be substituted with one or more alkyl groups having 1 to 12 carbon atoms, and

R 5 represents a straight or branched chain alkylene group having 3 to 8 carbon atoms, which may be substituted with one or more alkyl groups having 1 to 12 carbon atoms, and

ii-b) up to 30 hydroxyl equivalent %, based on the total hydroxyl equivalents of component B-ii), of a hydroxyl compound other than B-ii-a), which has a number average molecular weight of 32 to 400,

wherein the NCO:OH equivalent ratio of component B-i) to component B-ii) is 1.10:1 to 1:1.10,

C) 0 to about 85% by weight of the reaction product of

i) one or more polyisocyanate adducts containing isocyanurate, iminooxadiazine dione, urethane, biuret, allophanate, uretdione and/or carbodiimide groups with

ii) a hydroxyl component containing

ii-a) one or more hydroxy functional (meth)acrylates corresponding to formula III

HO—R 4 —O—C(O)—C(R 1 )═CH 2   (III)

wherein R 1 and R 4 are as defined above and

ii-b) up to 30 hydroxyl equivalent %, based on the total hydroxyl equivalents of component C-ii), of a hydroxyl compound other than C-ii-a), which has a number average molecular weight of 32 to 400,

wherein the NCO:OH equivalent ratio of component C-i) to component C-ii) is 1.10:1 to 1:1.10,

wherein the coating composition additionally contains

D) 0 to about 100% by weight of one or more copolymerizable monomers containing 1 to 4 ethylenically unsaturated groups, and

E) 0 to about 150% by weight of one or more inert organic solvents,

wherein i) the %'s by weight of components A), B) and C) total 100%, based on the total weight of components A), B) and C); ii) the %'s by weight of components D) and E) are based on the total weight of components A), B) and C); iii) the %'s by weight of components B) and C) are present in a total amount of at least 5% by weight; and iv) components D) and E) are present in a total amount of at least about 10% by weight.

2. The composition of claim 1 wherein isocyanate components A-i), B-i) and C-i) may be the same or different and comprise a polyisocyanate adduct having a viscosity at 23° C. and at 100% solids of less than 2000 mPa·s.

3. The composition of claim 2 wherein isocyanate components A-i), B-i) and C-i) may be the same or different and comprise a polyisocyanate adduct prepared from 1,6-hexamethylene diisocyanate.

4. The composition of claim 1 wherein in component A), R 3 is —C(O)—C(R 1 )═CH 2 ; in component B), n is 2, R 1 is H, R 4 is C 2 -alkylene, and R 5 is a C 5 -alkylene; and in component C), R 4 is C 2 -C 4 -alkylene, which may be substituted with a methyl group.

5. The composition of claim 2 wherein in component A), R 3 is —C(O)—C(R 1 )═CH 2 ; in component B), n is 2, R 1 is H, R 4 is C 2 -alkylene, and R 5 is a C 5 -alkylene; and in component C), R 4 is C 2 -C 4 -alkylene, which may be substituted with a methyl group.

6. The composition of claim 3 wherein in component A), R 3 is —C(O)—C(R 1 )═CH 2 ; in component B), n is 2, R 1 is H, R 4 is C 2 -alkylene, and R 5 is a C 5 -alkylene; and in component C), R 4 is C 2 -C 4 -alkylene, which may be substituted with a methyl group.

7. A process for preparing a coated substrate comprising coating a substrate with a binder-containing coating composition and curing said coating composition by free radical polymerization, wherein the binder resins comprise

A) about 10 to 95% by weight of the reaction product of

i) one or more polyisocyanate adducts containing isocyanurate, iminooxadiazine dione, urethane, biuret, allophanate, uretdione and/or carbodiimide groups with

ii) a hydroxyl component containing

ii-a) one or more hydroxyl compounds containing two ethylenically unsaturated groups and corresponding to formula I

CH 2 ═C(R 1 )—C(O)—O—R 2 —CH 2 —O—R 3   (I)

wherein

R 1 is H or CH 3 ,

R 2 is —CH(CH 2 OH)— or —CH 2 CH(OH)— and

R 3 is —C(O)—C(R 1 )═CHR 8 or —CH 2 CH═CHR 8 and

R 8 is H, CH 3 or phenyl, and

ii-b) up to 30 hydroxyl equivalent %, based on the total hydroxyl equivalents of component A-ii), of a hydroxyl compound other than A-ii-a), which has a number average molecular weight of 32 to 400,

wherein the NCO:OH equivalent ratio of component A-i) to component A-ii) is 1.10:1 to 1:1.10,

B) 5 to about 60% by weight of the reaction product of

i) one or more polyisocyanate adducts containing isocyanurate, iminooxadiazine dione, urethane, biuret, allophanate, uretdione and/or carbodiimide groups with

ii) a hydroxyl component containing

ii-a) one or more hydroxy functional lactone ester (meth)acrylates having a number average molecular weight of about 200 to 2000 and corresponding to formula II

CH 2 ═C(R 1 )—C(O)—O—R 4 —[O—C(O)—R 5 ] n —OH  (II)

wherein

n is an integer from 1 to 5,

R 1 is as defined above,

R 4 represents an alkylene group or substituted alkylene group having 2 to 10 carbon atoms, which may be substituted with one or more alkyl groups having 1 to 12 carbon atoms, and

R 5 represents a straight or branched chain alkylene group having 3 to 8 carbon atoms, which may be substituted with one or more alkyl groups having 1 to 12 carbon atoms, and

ii-b) up to 30 hydroxyl equivalent %, based on the total hydroxyl equivalents of component B-ii), of a hydroxyl compound other than B-ii-a), which has a number average molecular weight of 32 to 400,

wherein the NCO:OH equivalent ratio of component B-i) to component B-ii) is 1.10:1 to 1:1.10,

C) 0 to about 85% by weight of the reaction product of

i) one or more polyisocyanate adducts containing isocyanurate, iminooxadiazine dione, urethane, biuret, allophanate, uretdione and/or carbodiimide groups with

ii) a hydroxyl component containing

ii-a) one or more hydroxy functional (meth)acrylates corresponding to formula III

HO—R 4 —O—C(O)—C(R 1 )═CH 2   (III)

wherein R 1 and R 4 are as defined above and

ii-b) up to 30 hydroxyl equivalent %, based on the total hydroxyl equivalents of component C-ii), of a hydroxyl compound other than C-ii-a), which has a number average molecular weight of 32 to 400,

wherein the NCO:OH equivalent ratio of component C-i) to component C-ii) is 1.10:1 to 1:1.10,

wherein the coating composition additionally contains

D) 0 to about 100% by weight of one or more copolymerizable monomers containing 1 to 4 ethylenically unsaturated groups, and

E) 0 to about 150% by weight of one or more inert organic solvents,

wherein i) the %'s by weight of components A), B) and C) total 100%, based on the total weight of components A), B) and C); ii) the %'s by weight of components D) and E) are based on the total weight of components A), B) and C); iii) the %'s by weight of components B) and C) are present in a total amount of at least 5% by weight; and iv) components D) and E) are present in a total amount of at least about 10% by weight.

8. The process of claim 7 wherein said curing step comprises exposing the coating composition to UV radiation.

9. The process of claim 8 wherein said radiation has a wavelength of at least 320 nm.

10. The process of claim 8 wherein said radiation has a wavelength of about 320 to 450 nm.