Curable composition containing surface-modified particles
Coating compositions exhibiting improved reproducibility and improved scratch resistance contain an ethylenically unsaturated binder and filler particles functionalized with an ethylenically unsaturated group-containing monoalkoxy silane.
1 - 8 . (canceled)
9 . A curable composition comprising a binder bearing at least one ethylenically unsaturated group and functionalized particles which possess at least one ethylenically unsaturated group on their surface and contain radicals of the formula I,
—SiR 2 2 —(CR 3 2 ) n -A-D-C (I),
where the functionalized particles are prepared by reacting
(a) particles of metal oxides, metal-silicon mixed oxides, silicon dioxide, colloidal silicon dioxide, organopolysiloxane resins or combinations 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 B of the general formula II,
(R 1 O)R 2 2 Si—(CR 3 2 ) n -A-D-C (II),
their hydrolysis condensation products or mixtures thereof,
(c) and optionally with water, where
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 —(CR 3 2 ) n -A-D-C 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 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 whose carbon chain is optionally interrupted by nonadjacent oxygen, sulfur or NR 4 groups,
C is an ethylenically unsaturated group,
n is greater than or equal to 1, and
Me is a metal atom.
10 . The composition of claim 9 , wherein the particles are selected from pyrogenic silica, colloidal silica, and silicone resins.
11 . The composition of claim 9 , wherein the hydrocarbon radical R 1 is a methyl, ethyl or phenyl radical.
12 . The composition of claim 9 , 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 .
13 . The composition of claim 9 , wherein the ethylenically unsaturated groups in the binder are capable of free-radical, cationic or anionic polymerization.
14 . The composition of claim 9 , wherein the ethylenically unsaturated groups in the binder can be polymerized by actinic radiation or thermal treatment.
15 . The composition of claim 9 , wherein the ethylenically unsaturated groups in the binder comprise vinyl groups, methacrylate groups, acrylate groups, acrylamide groups, or mixtures thereof.
16 . A process for providing a scratch resistant coating on a substrate, comprising coating said substrate with a composition of claim 9 , and curing the composition.