# US 9,517,459 B2 · Photocatalytic coating film and method for producing same

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- Number: US 9,517,459 B2
- Document ID: US9517459B2
- Status: Granted
- Kind: B2
- Application number: 14/124,292
- Filed: 2012-06-06
- Published: 2014-04-17
- Granted: 2016-12-13
- Earliest claimed: 2011-06-07
- Assignees: Daicel Corporation
- Applicants: Toru Nakai; Yoshinori Funaki; Toshikazu Nakamura
- Inventors: Toru Nakai; Yoshinori Funaki; Toshikazu Nakamura
- Web page: https://patentgrep.com/patent/US9517459B2

## CPC

- B01J 31/38: of titanium, zirconium or hafnium
- B01J 23/745: Iron
- B01J 35/39: Photocatalytic properties
- B01J 37/0215: {Coating}
- B01J 37/0219: {the coating containing organic compounds}
- G02B 27/0006: {with means to keep optical surfaces clean, e.g. by preventing or removing dirt, stains, contamination, condensation (G02B1/18 takes precedence; cleaning in general B08B)}
- B01J 21/063: {Titanium; Oxides or hydroxides thereof}
- B01J 35/58: Fabrics or filaments
- G02B 1/18: Coatings for keeping optical surfaces clean, e.g. hydrophobic or photo-catalytic films (G02B1/16 takes precedence)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

Provided is a photocatalytic coating film that can develop excellent photocatalytic activity and exhibit superior adhesion to an adherend surface. The photocatalytic coating film is obtained by applying and drying a photocatalytic coating composition containing at least rod-like or needle-like titanium oxide particles and a binder component so that the photocatalytic coating film contains the titanium oxide particles in a content of 0.5 g/m2 or more. The photocatalytic coating film contains the titanium oxide particle in a content per unit volume (1 m2 by 1 μm thick) of less than 3.0 g. The titanium oxide particles preferably have an aspect ratio of 1.5 or more, the aspect ratio specified as the ratio of a long side length to a short side length of particle. The compositional ratio (by weight) of the titanium oxide particles to the binder component in the photocatalytic coating film is preferably from 1:6 to 30:1.

## Claims

### Claim 1

A photocatalytic coating film obtained by applying and drying a photocatalytic coating composition comprising at least rod-shaped or needle-shaped titanium oxide particles and a binder component so that the photocatalytic coating film contains the titanium oxide particles in a content of 0.5 to 3.0 g/m2, the photocatalytic coating film containing the titanium oxide particles in a content of less than 3.0 g per unit volume (1 m2 by 1 μm thick) and having a porous structure, the titanium oxide particles being rutile titanium dioxide particles bearing a transition metal compound, the transition metal compound being selectively supported on, of exposed crystal faces of the titanium oxide particles, (111) face acting as an oxidation site.

### Claim 2 (depends on 1)

The photocatalytic coating film according to claim 1, wherein the titanium oxide particles have an aspect ratio of 1.5 or more, the aspect ratio specified as a ratio of a long side length to a short side length of particle.

### Claim 3 (depends on 1, 2)

The photocatalytic coating film according to one of claims 1 and 2, wherein the photocatalytic coating film has a compositional ratio (by weight) of the titanium oxide particles to the binder component of from 1:6 to 30:1.

### Claim 4 (depends on 1)

The photocatalytic coating film according to claim 1, wherein the transition metal compound is an iron compound.

### Claim 5 (depends on 1)

The photocatalytic coating film according to claim 1, wherein the binder component comprises at least one compound selected from the group consisting of titanium peroxide, silicon compounds, and fluorocarbon resins.

### Claim 6 (depends on 1)

The photocatalytic coating film according to claim 1, wherein the binder component comprises at least titanium peroxide.

### Claim 7 (depends on 1)

A method for producing the photocatalytic coating film of claim 1, the method comprising the steps of:
preparing a photocatalytic coating composition comprising at least rod-shaped or needle-shaped titanium oxide particles and a binder component, the titanium oxide particles being rutile titanium dioxide particles bearing a transition metal compound, the transition metal compound being selectively supported on, of exposed crystal faces of the rutile titanium oxide particles, (111) face acting as an oxidation site; and
applying and drying the photocatalytic coating composition.

### Claim 8 (depends on 7)

The method for producing the photocatalytic coating film, according to claim 7, further comprising the step of supporting a transition metal compound on rod-shaped or needle-shaped rutile titanium dioxide particles under exciting light irradiation to give rod-shaped or needle-shaped rutile titanium dioxide particles bearing the transition metal compound, the transition metal compound being selectively supported on, of exposed crystal faces of the rutile titanium dioxide particles, (111) face acting as an oxidation site.

### Claim 9 (depends on 1)

A photocatalyst-coated article comprising: a substrate; and the photocatalytic coating film of claim 1.

### Claim 10 (depends on 9)

The photocatalyst-coated article according to claim 9, wherein the substrate is made from a plastic material.

### Claim 11 (depends on 1)

The photocatalytic coating film according to claim 1, having a thickness of 1.5 μm or less.