Curable Composition Containing Surface-Modified Particles
Coating compositions having reproducible properties and high scratch resistance contain an ethylenically unsaturated binder and particles functionalized with an alkoxysilane, the silicon atom of which is spaced from an electron withdrawing group by a methylene group.
1 - 10 . (canceled)
11 . A curable composition comprising a binder bearing at least one ethylenically unsaturated group, and functionalized particles which possess at least one ethylenically unsaturated group and contain radicals of the formula I,
≡Si—CR 3 2 -A-D-C (I),
where the particles are prepared by reacting
(a) particles of a metal oxide, metal-silicon mixed oxide, silicon dioxide, colloidal silicon dioxide, organopolysiloxane resin or combination thereof, the particles possessing functionality selected from Me-OH, Si—OH, Me-O-Me, Me-O—Si—, Si—O—Si, Me-OR 1 and Si—OR 1 , and having an average diameter of less than 1000 nm,
(b) with organosilanes of the general formula II,
(R 1 O) 3-n (R 2 ) n Si—CR 3 2 -A-D-C (II),
their hydrolysis or condensation products, or mixtures thereof, and
where
(c) and optionally water,
R 1 is hydrogen or a hydrocarbon radical having 1 to 6 carbon atoms, whose carbon chain is optionally interrupted by nonadjacent oxygen, sulfur or NR 4 groups,
R 2 is a hydrocarbon radical having 1 to 12 carbon atoms, whose carbon chain is optionally interrupted by nonadjacent oxygen, sulfur or NR 4 groups,
R 3 is hydrogen or a hydrocarbon radical having 1 to 12 carbon atoms, whose carbon chain is optionally interrupted by nonadjacent oxygen, sulfur or NR 4 groups,
R 4 is hydrogen or a hydrocarbon radical having 1 to 12 carbon atoms,
A is oxygen, sulfur, ═NR 4 or ═N-(D-C),
D is a carbonyl group, or an alkylene, cycloalkylene or arylene radical having 1 to 12 carbon atoms, the carbon chain optionally interrupted by nonadjacent oxygen, sulfur or NR 4 groups,
C is an ethylenically unsaturated group,
Me is a metal atom, and
n is 0, 1 or 2.
12 . The composition of claim 11 , wherein the particles are selected from pyrogenic silica, colloidal silica, and silicone resins.
13 . The composition of claim 11 , wherein the hydrocarbon radical R 1 is a methyl, ethyl or phenyl radical.
14 . The composition of claim 11 , wherein at least one group (-A-D-C) is a radical OC(O)C(CH 3 )═CR 3 2 , OC(O)CH═CR 3 2 , NHC(O)C(CH 3 )═CR 3 2 , or NHC(O)CH═CR 3 2 .
15 . The composition of claim 11 , wherein the ethylenically unsaturated groups in the binder are capable of free-radical, cationic or anionic polymerization.
16 . The composition of claim 11 , wherein the ethylenically unsaturated groups in the binder are polymerizable by actinic radiation or thermal treatment.
17 . The composition of claim 11 , wherein the ethylenically unsaturated groups in the binder are selected from vinyl groups, methacrylate groups, acrylate groups, acrylamide groups, and mixtures thereof.
18 . The process for coating a substrate, comprising applying to a surface of said substrate a composition of claim 11 , and curing said composition.