Surface active blocked isocyanates and coating compositions thereof
View Patent ↗Disclosed herein is a surface active adhesion promoting agent and a coating composition comprising the surface active adhesion promoting agent. The adhesion promoting agent is a blocked isocyanate functional siloxane containing material. Addition of small amount of the adhesion promoting agent to a coating composition, especially clearcoat compositions, helps to provide adhesion to a variety of materials that may be subsequently applied to the coating composition.
1. A surface active adhesion promoting agent comprising at least a blocked isocyanate and a siloxane portion having at least two or more silicon atoms and a number average molecular weight in the range of from 500 to 4500, wherein said surface active adhesion promoting agent is of the formula;
A-Si(X) 3-q R q
wherein q is 0, 1 or 2;
A is G-C(O)NH—R 1 and is attached to the silicon atom through R 1 ;
G is the residue of an isocyanate blocking agent;
each X is independently chosen from the group consisting of OR 2 , OY, OSi(X′) 2 A or a hydrolysable group; wherein at least one of X is OY or OSi(X′) 2 A;
Y is Si(Z) 3-w (R 3 ) w or Si(X′) 2 A;
each X′ is independently chosen from the group consisting of OR 2 , OY or a hydrolysable group;
each Z is independently chosen from the group consisting of OR 4 , OSi(X′) 2 A, OY, hydrolysable group or a silsesquioxane;
R 1 is a divalent organic radical consisting of an alkyl group having from 3 to 4 carbon atoms;
each R, R 2 , R 3 or R 4 is independently chosen from the group consisting of C1 to C8 aliphatic group, C3 to C20 cycloaliphatic, alkylcycloaliphatic, cycloaliphaticalkyl group, C6 to C20 aryl group or a fluorine containing or perfluoro derivative thereof;
w is 0, 1 or 2; and
wherein A-Si(X) 3-q R q has a molecular weight in the range of from 500 to 4500.
2. The surface active adhesion promoting agent of claim 1 wherein each of R, R 2 , R 3 or R 4 is CH 3 .
3. The surface active adhesion promoting agent of claim 1 wherein the blocking agent is a pyrazole.
4. A coating composition comprising a surface active adhesion promoting agent wherein said surface active adhesion promoting agent comprises at least a blocked isocyanate and a siloxane portion having at least two or more silicon atoms and a number average molecular weight in the range of from 500 to 4500, wherein the surface active adhesion promoting agent is of the formula;
A-Si(X) 3-q R q
wherein q is 0, 1 or 2;
A is G-C(O)NH—R 1 and is attached to the silicon atom through R 1 ;
G is the residue of an isocyanate blocking agent, wherein the blocking agent is chosen from the group selected from imidazole, 2-methyl imidazole, 4-methyl imidazole, pyrrole, pyrrolidine, morpholine, pyridine, piperidine, alkyl malonate, acetoacetic ester and cyanoacetic ester and a combination thereof;
each X is independently chosen from the group consisting of OR 2 , OY, OSi(X′) 2 A or a hydrolysable group; wherein at least one of X is OY or OSi(X′) 2 A;
Y is Si(Z) 3-w (R 3 ) w or Si(X′) 2 A;
each X′ is independently chosen from the group consisting of OR 2 , OY or a hydrolysable group;
each Z is independently chosen from the group consisting of OR 4 , OSi(X′) 2 A, OY, hydrolysable group or a silsesquioxane;
R 1 is a divalent organic radical consisting of an alkyl group having from 3 to 4 carbon atoms;
each R, R 2 , R 3 or R 4 is independently chosen from the group consisting of C1 to C8 aliphatic group, C3 to C20 cycloaliphatic, alkylcycloaliphatic, cycloaliphaticalkyl group, C6 to C20 aryl group or a fluorine containing or perfluoro derivative thereof;
w is 0, 1 or 2; and
wherein A-Si(X) 3-q R q has a molecular weight in the range of from 500 to 4500.
5. The coating composition of claim 4 , wherein said coating composition is substantially free from boron.
6. The coating composition of claim 4 wherein each of R, R 2 , R 3 or R 4 is CH 3 .
7. The coating composition of claim 4 wherein the isocyanate blocking agent is dimethylpyrazole.
8. The coating composition of claim 4 , wherein the surface active adhesion promoting agent is present in an amount of 0.5 to 7 percent by weight based on the total weight of the binder components of said coating composition.
9. The coating composition of claim 4 wherein said coating composition is substantially free from boron.