Water-repellent glass and process for preparing same

• US 6,210,750 B1
• Filed: 12/31/1998
• Issued: 04/03/2001
• Est. Priority Date: 06/26/1997
• Status: Expired due to Term

• Current Assignee: Samsung Corning Precision Materials Company Limited (Corning Incorporated)
• Original Assignee: Samsung Corning Company Limited (Corning Incorporated)
• Inventors: Hong, Byung-Sun, Cho, Yun-Ju, Han, Joo-Hun
• Primary Examiner(s): Le, H. Thi
• Application Number:
  US09/224,667
• Time in Patent Office: 824 Days
• Field of Search: 428/403, 428/441, 428/331, 428/428, 428/429, 427/189, 427/190, 427/202, 427/203, 427/204, 427/301, 427/419.2
• US Class Current: 427/190
• CPC Class Codes: C03C 17/42 at least one coating of an organic material and at least one non-metal coating
• CPC Class Codes: C03C 2217/45 Inorganic continuous phases
• CPC Class Codes: C03C 2217/478 Silica
• CPC Class Codes: C03C 2217/76 Hydrophobic and oleophobic coatings
• CPC Class Codes: C08G 77/08 characterised by the catalysts used
• CPC Class Codes: C08L 2666/54 Inorganic substances
• CPC Class Codes: C09D 183/02 Polysilicates
• CPC Class Codes: C09D 183/04 Polysiloxanes
• CPC Class Codes: Y10T 428/259 Silicic material
• CPC Class Codes: Y10T 428/31612 As silicone, silane or siloxane

Abstract

A water-repellent glass comprising a uniform and optically transparent silica film with excellent durability and hardness is prepared by a process which comprises: (a) preparing a colloidal silica suspension by hydrolyzing and polycondensing an alkoxysilane in an organic solvent under a basic condition in the presence of water, and then treating the colloidal silica suspension under an acidic condition, to obtain a silica dispersion containing cross-linked spherical silica particles and linear polysiloxane, (b) combining the silica dispersion with a mixed solvent composed of acetic acid and an alcohol to obtain a coating composition, (c) applying the coating composition on the surface of a glass substrate to form a silica layer therefrom, (d) heat treating the silica layer to provide a silica film on the glass substrate, and (e) applying a water-repellent agent on the silica film to provide the water-repellent glass.

Claims

1. A process for the preparation of a water-repellent glass which comprises:

(a) preparing a colloidal silica suspension by hydrolyzing and polycondensing an alkoxysilane in an organic solvent under a basic condition in the presence of water, and then treating the colloidal silica suspension under an acidic condition, to obtain a silica dispersion containing cross-linked spherical silica particles and linear polysiloxane,

(b) combining the silica dispersion with a mixed solvent composed of acetic acid and an alcohol to obtain a coating composition,

(c) applying the coating composition on the surface of a glass substrate to form a silica layer therefrom,

(d) heat treating the silica layer to provide a silica film on the glass substrate, and

(e) applying a water-repellent agent on the silica film to provide the water-repellent glass plate.

2. The process of claim 1 wherein the alcohol is selected from the group consisting of methanol, ethanol, propanol, butanol and a mixture thereof.

3. The process of claim 1 wherein acetic acid and an alcohol are mixed in a weight ratio of 1:

9 to 9;

1.

4. The process of claim 1 wherein the mixed solvent is mixed with the silica dispersion obtained in Step(a) in a weight ratio of 1:

9 to 9;

1.

5. The process of claim 1 wherein the basic condition lies in a pH range of 9 to 13, and the acidic condition in a pH range of 1 to 4.

6. The process of claim 1 wherein the silica coating composition is applied on the substrate surface by a spray coating method.

7. The process of claim 1 wherein the silica layer is heat treated at a temperature ranging from 100 to 300°

C.

8. The process of claim 7 wherein the silica layer is heat treated at a temperature ranging from 100°

to 120°

C.

9. A water-repellent glass comprising a glass substrate, a silica film and water-repellent film in order, prepared by a process according to any one of claims 1 to 8.

10. The water-repellent glass of claim 9 wherein the silica film has a thickness ranging from 400 to 900 Å

.