Curable silsesquioxane polymers, compositions, articles, and methods
A curable silsesquioxane polymer, a composition including such polymer, an article having a layer disposed thereon that includes the curable polymer and/or the cured polymer, and a method of forming a cured coating, wherein the curable silsesquioxane polymer includes a three-dimensional branched network having the formula: wherein the oxygen atom at the * is bonded to another Si atom within the three-dimensional branched network; R is an organic group comprising an ethylenically unsaturated group; and R2 is an organic group that is not an ethylenically unsaturated group; R 3 is a non-hydrolyzable group; and n or n+m is an integer of greater than 3.
1. A curable composition comprising a photoinitiator and a curable silsesquioxane polymer comprising a three-dimensional branched network having the formula:
wherein:
the oxygen atom at the * is bonded to another Si atom within the three-dimensional branched network;
R is an organic group comprising an ethylenically unsaturated group selected from vinyl and alkenyl;
R2 is an organic group that is not an ethylenically unsaturated group;
R 3 is a non-hydrolyzable group; and
n or n+m is an integer of greater than 3; wherein the curable silsesquioxane polymer comprises a hydrosilylation catalyst, and optionally a polyhydrosiloxane crosslinker.
2. The curable composition of claim 1 wherein R 3 is independently selected from alkyl, aryl, aralkyl, alkaryl, optionally comprising substituents.
3. The curable composition of claim 1 wherein the polymer further comprises OH groups present in an amount of no greater than 5 wt-% of the silsesquioxane polymer.
4. The curable composition of claim 1 wherein the silsesquioxane polymer is free of OH groups.
5. The curable composition of claim 1 wherein n is an integer of no greater than 200.
6. The curable composition of claim 1 wherein R has the formula Y—Z, wherein Y is the depicted covalent bond or a group selected from alkylene, arylene, alkarylene, and araalkylene; and Z is an ethylenically unsaturated group selected from a vinyl group and an alkenyl group.
7. The curable composition of claim 1 wherein R2 has the formula Y—X, wherein Y is the depicted covalent bond or a group selected from alkylene, arylene, alkarylene, and aralkylene; and X is hydrogen, alkyl, aryl, alkaryl, aralkyl; or a reactive group that is not an ethylenically unsaturated group.
8. The curable composition of claim 6 wherein Y is a (C1-C20)alkylene group, a (C6-C12)arylene group, a (C6-C12)alk(C1-C20)arylene group, or a (C6-C12)ar(C1-C20)alkylene group.
9. The curable composition of claim 1 which has peel force from glass of at least 1 N/dm.
10. The curable composition of claim 1 further comprising nanoparticles, organic solvent, or a mixture thereof.
11. An article comprising a substrate and the curable composition of claim 1 in a layer disposed on at least a portion of at least one surface of the substrate.
12. An article comprising a substrate and a cured coating layer prepared by UV curing the composition of claim 1 disposed on at least a portion of at least one surface of the substrate.
13. An article comprising a substrate and a cured coating layer prepared by thermal curing the composition of claim 1 disposed on at least a portion of at least one surface of the substrate.
14. The curable silsesquioxane polymer of claim 1 wherein the curable polymer has a weight loss of less than 90% at 200° C.
15. The curable composition of claim 1 further comprising at least one monomer, oligomer, or polymer comprising ethylenically unsaturated groups.
16. The curable composition of claim 15 wherein the ethylenically unsaturated groups of the monomer, oligomer, or polymer are (meth)acrylate, vinyl, or a combination thereof.
17. The curable composition of claim 15 wherein the monomer, oligomer, or polymer is a siloxane containing monomer, oligomer or polymer.
18. The curable composition of claim 15 wherein the siloxane containing polymer comprises vinyl or (meth)acrylate groups.
19. The curable composition of claim 1 wherein and n and m are selected such that the copolymer comprises at least 25 mol % of repeat units comprising R.