Weatherable and abrasion resistant coating systems for polymeric substrates
View Patent ↗Disclosed herein is a primer composition comprising an inorganic UV absorbing agent and a polymer selected from (i) a copolycarbonate, and (ii) a polyurethane obtained by reaction of a polyisocyanate and a copolycarbonate diol. Also disclosed is a coated article comprising a polymeric substrate, a primer layer disposed on at least one surface of said substrate, and an abrasion-resistant layer disposed on said primer layer, where the primer layer is made from the primer composition of the invention.
1. A primer coating composition comprising (1) an inorganic UV absorbing agent selected from the group consisting of CeOx, TiOx, ZnOx, ZrOx, and combinations thereof, wherein x is 1-2; and (2) a polymer selected from (i) a linear copolycarbonate comprising repeating units A and B, and (ii) a polyurethane obtained by reaction of a polyisocyanate and a linear copolycarbonate diol comprising repeating units A and B,
wherein repeating units A and B are represented by the following formulae:
wherein the molar ratio of units (A) to units (B) is in the range of from about 9:1 to about 1:9, and wherein R 1 is a divalent C8 to C12 alicyclic group, R 2 is a divalent group selected from the group consisting of ethylene, propylene, and combinations thereof, n is an integer ranging from 4 to 40;
wherein the UV absorbing agent is present in an amount of from about 33 weight percent to about 80 weight percent based on a total dry weight of the primer composition, wherein the primer composition upon drying and curing forms an optically transparent coating.
2. The primer coating composition of claim 1 , wherein the copolycarbonate of component (2)(i) comprising terminal groups, wherein each terminal group is a member selected from the group consisting of a hydroxyl group, and a substituted silyl group of the formula
wherein R 1 is a monovalent hydrocarbon residue having 1 to 10 carbon atoms, each Y is independently a member selected from the group consisting of a halogen atom, an alkoxy group having 1 to 10 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, and a is a number having a value of from 1 to 3.
3. The primer coating composition of claim 2 wherein substantially all of the terminal groups of the copolycarbonate of component (2)(i) are silyl groups of Formula (1).
4. The primer coating composition of claim 1 wherein substantially all the terminal groups of the copolycarbonate of component (2)(i) are hydroxyl groups.
5. The primer coating composition of claim 1 wherein each occurrence of R 1 is independently
6. The primer coating composition of claim 1 wherein the polyisocyanate is a diisocyanate represented by
OCN—R 4 —NCO,
wherein R 4 is selected from
7. The primer coating composition of claim 1 polyurethane is hydroxyl-terminated or isocyanate-terminated.
8. The primer coating composition of claim 7 wherein the polyurethane is silylated with at least one compound selected from the group consisting of aminosilane and isocyanatosilane.
9. The primer coating composition of claim 8 wherein the aminosilane is of the general formula:
wherein R 6 is hydrogen or an alkyl group of from about 1 to about 10 carbon atoms, R 7 is a divalent alkylene group of from about 1 to about 10 carbon atoms, R 2 and R 3 each independently is an alkyl group of from about 1 to about 6 carbon atoms or an aryl group of from about 6 to about 8 carbon atoms, and b has a value of 0, 1 or 2; and
the isocyanatosilane is of the general formula:
wherein R 8 is a divalent alkylene group of from about 1 to about 10 carbon atoms, R 4 and R 5 each independently is an alkyl group of from about 1 to about 6 carbon atoms or an aryl group of from about 6 to about 8 carbon atoms, and c has a value of 0, 1 or 2.
10. A coated article comprising a polymeric substrate, a primer layer disposed on at least one surface of said substrate, and an abrasion-resistant layer disposed on said primer layer, wherein said primer layer is made from the primer coating composition of claim 1 .
11. The coated article of claim 10 wherein said abrasion-resistant layer is an organic-based topcoat.
12. The coated article of claim 10 wherein said abrasion-resistant layer is a silicone hardcoat.
13. The coated article of claim 10 wherein said abrasion-resistant layer is a hydrogenated silicon oxycarbide layer.
14. The coated article of claim 13 wherein the hydrogenated silicon oxycarbide layer is deposited on the primer layer by a method selected from the group consisting of plasma enhanced chemical vapor deposition, expanding thermal plasma, microwave plasma, inductively coupled plasma, high density plasma chemical vapor deposition, and combinations thereof.
15. The coated article of claim 10 , wherein said substrate is selected from polycarbonates and copolycarbonates, acrylic polymers, polyesters, polyamides, polyimides, acrylonitrile-styrene copolymer, styrene-acrylonitrile-butadiene terpolymer, polyvinyl chloride, polyethylene, and combinations thereof.
16. A method for providing a polymeric substrate coated with a weather and abrasion-resistant coating system, comprising the steps of:
(i) applying the primer coating composition of claim 1 onto a polymeric substrate;
(ii) curing the primer composition to provide a primer layer; and
(iii) disposing an abrasion-resistant layer onto the primer layer thereby making the polymeric substrate coated with a weather and abrasion-resistant coating system.
17. The method of claim 16 wherein the abrasion-resistant layer is an organic-based topcoat.
18. The method of claim 16 wherein the abrasion-resistant layer is a silicone hardcoat.
19. The method of claim 16 wherein the abrasion-resistant layer is a hydrogenated silicon oxycarbide layer.
20. The method of claim 16 wherein said polymeric substrate is selected from polycarbonates and copolycarbonates, acrylic polymers, polyesters, polyamides, polyimides, acrylonitrile-styrene copolymer, styrene-acrylonitrile-butadiene terpolymer, polyvinyl chloride, polyethylene, and combinations thereof.