METHOD OF FORMING HYDROPHILIC INORGANIC COATING FILM AND INORGANIC COATING COMPOSITION

• US 20010008696A1
• Filed: 12/08/1999
• Published: 07/19/2001
• Est. Priority Date: 04/10/1998
• Status: Active Grant

• Current Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Asahi Matsushita Electric Works Ltd. (Panasonic Holdings Corporation)
• Inventors: TAKAHAMA, KOICHI, INOUE, MINORU, IKENAGA, JUNKO, NAKAMOTO, SHOICHI
• Granted Patent: US 6,303,229 B2
• Time in Patent Office: Days
• US Class Current: 428/446
• CPC Class Codes: C09D 183/02 Polysilicates
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

The present invention provides a process for forming a hydrophilic inorganic coated film on a surface of a base material, the process comprising the steps of: (1) preparing an inorganic coating composition which contains, as a major component, a silicone resin obtained by hydrolyzing and condensation-polymerizing only the tetra-functional alkoxysilane represented by the formula: Si(OR)₄ [wherein R represents an alkyl group having carbon atoms up to and including 7 or an aryl group], and has a total solid content of not more than 5% by weight; (2) applying the inorganic coating composition to a surface of the base material to form a coated layer; and (3) drying and curing the coated layer to form a cured coated film having a thickness of 0.01 to 0.5 μm. The hydrophilic inorganic coated film formed by the process of the present invention is highly hydrophilic just after the film is formed, even in the case that it is not irradiated with ultraviolet rays.

Claims

1. A process for forming a hydrophilic inorganic coated film on a surface of a base material, the process comprising the steps of:

(1) preparing an inorganic coating composition which contains, as a major component, a silicone resin obtained by hydrolyzing and condensation-polymerizing only the tetra-functional alkoxysilane represented by formula (I);

Si(or)₄ 

 

(I)

 

[wherein R represents an alkyl group having carbon atoms up to and including 7 or an aryl group], and has a total solid content of not more than 5% by weight;

(2) applying the inorganic coating composition to a surface of the base material to form a coated layer; and

(3) drying and curing the coated layer to form a cured coated film having a thickness of 0.01 to 0.5 μ

m.

2. The process according to

claim 1

, wherein the silicone resin is present in an amount of 50 to 100% by weight in a solid of the inorganic coating composition.

3. The process according to

claim 1

, wherein the R is at least one type selected from the group consisting of a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group and a phenyl group.

4. The process according to

claim 1

, wherein the inorganic coating composition further comprises a photo-semiconductor material as a solid.

5. The process according to

claim 4

, wherein the photo-semiconductor material is present in an amount of 5 to 80 parts by weight for 100 parts by weight of the silicone resin in a solid of the inorganic coating composition.

6. The process according to

claim 4

, wherein the photo-semiconductor material is titanium oxide.

7. The process according to

claim 1

, wherein the base material has a primer coated film on the surface thereof.

8. The process according to

claim 7

, wherein the primer coated film is formed from a silicone type material in the form of an aqueous emulsion.

9. The process according to

claim 1

, wherein the base material is selected from the group consisting of metal, glass, enamel, ceramic, cement, concrete, lumber, wood, plastic and inorganic fiber reinforced plastic.

10. The process according to

claim 1

, wherein the coating is performed by a method selected from the group consisting of the flow coating method, the spray coating method, the roll coating method, the brush coating method, the spin coating method, the dip coating method, the continuous-flow coating method, the curtain coating method, the knife coating method and the bar coating method.

11. An inorganic coating composition which contains, as a major component, a silicone resin and is used to form a hydrophilic inorganic coated film by applying itself to a surface of a base material, followed by drying and curing, wherein the silicone resin is obtained by hydrolyzing and condensation-polymerizing only the tetra-functional alkoxysilane represented by formula (I):

Si(OR)₄ 

 

(I)

[wherein R represents an alkyl group having carbon atoms up to and including 7 or an aryl group];

the total solid content of the inorganic coating composition is not more than 5% by weight; and

the film thickness of the hydrophilic inorganic coated film is 0.01 to 0.5 μ

m.