Dispersion of titanium particles comprising a binder based on polyorgansiloxane

• US 6,403,689 B1
• Filed: 01/19/2000
• Issued: 06/11/2002
• Est. Priority Date: 07/22/1997
• Status: Expired due to Term

• Current Assignee: Bluestar Silicones France SAS
• Original Assignee: Rhodia Chimie (Solvac SA)
• Inventors: Cardinaud, Denis, Lehaut, Corinne
• Primary Examiner(s): Moore, Margaret G.
• Application Number:
  US09/463,201
• Time in Patent Office: 874 Days
• Field of Search: 106/287.16, 106/287.1, 427/387, 524/431, 428/447, 252/600
• US Class Current: 524/431
• CPC Class Codes: C08K 3/22 of metals
• CPC Class Codes: C08L 2666/54 Inorganic substances
• CPC Class Codes: C08L 83/04 Polysiloxanes
• CPC Class Codes: C09D 183/04 Polysiloxanes
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

The invention concerns a dispersion of photocatalytic titanium dioxide particles, wherein the liquid phase comprises at least a cross-linking catalyst and at least a polyorganosiloxane either of formula (I) M_αD_βQ_δ(O_1/2Rⁱ)_ε, or of formula (II): MαDβTγ(O1/2Rⁱ)ε. The invention also concerns the use of this dispersion for treating substrates.

Claims

1. A dispersion in a liquid phase of particles of photocatalytic titanium dioxide, said liquid phase comprising at least one polyorganosiloxane of mean formula (I):

2. A dispersion according to claim 1, wherein α

≦

0.010.

3. A dispersion according to claim 1, wherein Rⁱ is an ethyl or methyl group.

4. A dispersion according to claim 1, wherein the liquid phase comprises a crosslinking catalyst.

5. A dispersion according to claim 4, wherein the crosslinking catalyst is an organic titanium compound or an organic tin compound.

6. A dispersion according to claim 5, wherein the crosslinking catalyst is an alkyl titanate or a dialkyltin dicarboxylate.

7. A dispersion according to claim 1, wherein the liquid phase further comprises an organic solvent which is a solvent for said polyorganosiloxane.

8. A dispersion according to claim 7, wherein the solvent is octamethylcyclotetrasiloxane, white spirit, a C₁-C₈ alcohol, an aliphatic hydrocarbon, or an aromatic hydrocarbon.

9. A dispersion according to claim 1, wherein the particles are titanium dioxide particles having a size of at most 100 nm.

10. A dispersion according to claim 1, wherein the proportions of the particles to the polyorganosiloxane are such that the particles represent at least 5% by weight of the weight of the particles and the polyorganosiloxane.

11. A dispersion according to claim 1, comprising at least 5% by weight of crosslinking catalyst with respect to the weight of the polyorganosiloxane and the catalyst.

12. A process for the preparation of a dispersion as defined in claim 1, comprising the step of mixing the titanium dioxide particles and the polyorganosiloxane.

13. A process for treating a surface of a substrate comprising the step of coating said surface with a dispersion as defined in claim 1.

14. A process according to claim 13, wherein said substrate is an alkaline substrate.

15. A process according to claim 13, wherein said substrate is concrete.