Organosilyl functionalized particles and the production thereof
Particles of metal and non-metal oxides may be readily functionalized with organosilyl groups, even in the absence of catalysts, when methylene-spaced alkoxysilanes are used for functionalizing. When an excess of alkoxy groups relative to metal-OH groups are present, the resulting functionalized particles exhibit high reactivity, particularly upon exposure to moisture. Functionalization is particularly useful with particles of organopolysiloxane resins.
1. Organosilyl-functionalized particles of the formula I,
PR(O (u+t)/2 )[O u/2 (R 2 O) v−u R 1 3−v SiCR 3 2 —A] s (O 1/2 R 4 ) t (I)
where
PR is a particle radical comprising oxygen atoms and silicon atoms, selected from the group consisting of colloidal silica, organopolysiloxane resins, and mixtures thereof,
A is a radical selected from the group consisting of R 5 O—, R 5 2 N—, (R 5 O) 2 OP—, R 5 2 NC(O)NR 5 —, R 6 OC(O)NR 5 —, and OCN—,
R 1 and R 3 are each hydrogen or an optionally halogen-substituted hydrocarbon radical having 1-18 carbon atoms,
R 2 is an alkyl radical having 1-6 carbon atoms or an ω-oxaalkyl-alkyl radical having in total 2-10 carbon atoms,
R 4 is hydrogen or an optionally substituted monovalent hydrocarbon radical having 1-18 carbon atoms,
R 5 is hydrogen or an optionally halogen-, OR 2 —, NR 2 2 — or epoxy-functional hydrocarbon radical having 1-18 carbon atoms,
R 6 is an optionally halogen, OR 2 —, NR 2 2 — or epoxy-functional hydrocarbon radical having 1-18 carbon atoms,
s has a value >0,
t has a value of greater than or equal to 0,
u has values 1, 2 or 3,
v has values 1, 2 or 3,
wherein the organosilyl-functionalized particles have an average diameter of from about 1 nm to 1000 nm, and are prepared by functionalizing particles PR with an organosilyl-functionalizing agent dissolved in organic solvent, the functionalizing agent comprising at least one organosilicon compound of the formula (II)
(R 2 O) v R 1 3−v Si—CR 3 2 —A (II).
2. The organosilyl-functionalized particles of claim 1 , which are organopolysiloxane resins of the formula III,
(R 7 3 SiO 1/2 ) k (R 7 2 SiO 2/2 ) l (R 7 SiO 3/2 ) m (SiO 4/2 ) n [O u/2 (R 2 O) v−u R 1 3−v SiCR 3 2 —A] s (O 1/2 R 4 ) t (III)
where
R 7 is hydrogen or an optionally halogen-substituted hydrocarbon radical having 1-18 carbon atoms,
k has a value greater than or equal to 0,
l has a value greater than or equal to 0,
m has a value greater than or equal to 0,
n has a value greater than or equal to 0,
the sum of k+l+m+n produces a value of 1, and
R 1 , R 2 , R 3 , R 4 , u, v, s, and t are as defined for the formula I.
3. The organosilyl-functionalized particles of claim 1 , wherein R 5 is a C 1 to C 6 alkyl radical or a phenyl radical.
4. The organosilyl-functionalized particles of claim 1 , wherein R 6 is a C 1 to C 6 alkyl radical or a phenyl radical.
5. The organosilyl-functionalized particles of claim 1 , wherein R 1 is a methyl or ethyl group.
6. The organosilyl-functionalized particles of claim 1 , wherein R 3 is a C 1 to C 6 alkyl radical or a phenyl radical.
7. A process for preparing the organosilyl-functionalized particles of claim 1 , wherein colloidal silica or organopolysiloxane resin particles are reacted with a functionalizing compound consisting essentially of at least one silane of the formula II,
(R 2 O) v R 1 3−v Si—CR 3 2 —A (II)
where A, R 1 , R 2 , R 3 , and v are as defined for the formula I, wherein v is 1 or 2.
8. The organosilyl-functionalized particles of claim 1 , which have an average particle size of from 10 nm to 1000 nm.
9. The organosilyl-functionalized particles of claim 1 , which have an average particle size of from 1 nm to 100 nm.
10. The organosilyl-functionalized particles of claim 1 , which have an average particle size of from 10 nm to 100 nm.
11. The organosilyl-functionalized particles of claim 8 which consist of organosilyl-functionalized organopolysiloxane resin particles.
12. The organosilyl-functionalized particles of claim 9 which consist of organosilyl-functionalized organopolysiloxane resin particles.
13. The organosilyl-functionalized particles of claim 10 which consist of organosilyl-functionalized organopolysiloxane resin particles.
14. The organosilyl-functionalized particles of claim 1 which consist of organosilyl-functionalized colloidal silica particles.
15. The organosilyl-functionalized particles of claim 10 which consist of organosilyl-functionalized colloidal silica particles.
16. The organosilyl-functionalized particles of claim 1 , wherein v in formula (II) is 1.
17. The organosilyl-functionalized particles of claim 1 , wherein v is 1 and u is 1.
18. The organosilyl-functionalized particles of claim 1 , wherein v is 2 or 3 and u is smaller than v.