# US 2014/0194274 A1 · Method for manufacturing titania coated alumina fiber aggregate

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- Number: US 2014/0194274 A1
- Document ID: US20140194274A1
- Status: Published application
- Kind: A1
- Application number: 14/033,943
- Filed: 2013-09-23
- Published: 2014-07-10
- Earliest claimed: 2005-06-30
- Assignees: K2R Co., Ltd.
- Applicants: K2R Co., Ltd.
- Inventors: Kenichiro TANAKA; Licca TANAKA; Tsutomu HARADA
- Web page: https://patentgrep.com/patent/US20140194274A1

## CPC

- B01J 21/063: {Titanium; Oxides or hydroxides thereof}
- B01D 53/88: Handling or mounting catalysts
- B01J 21/04: Alumina
- B01J 35/39: Photocatalytic properties
- B01J 35/58: Fabrics or filaments
- B01J 37/0226: {Oxidation of the substrate, e.g. anodisation}
- B01J 37/08: Heat treatment {(B01J37/0009, B01J37/0018 take precedence)}
- C04B 30/02: containing fibrous materials
- C04B 35/10: based on aluminium oxide
- C04B 35/46: based on titanium oxides or titanates (containing also zirconium or hafnium oxides, zirconates or hafnates C04B35/49)
- C04B 41/009: {characterised by the material treated}
- C04B 41/5041: {Titanium oxide or titanates}
- C23C 8/10: Oxidising
- C23C 8/80: After-treatment
- C23C 28/04: only coatings of inorganic non-metallic material
- C23C 28/042: {including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides}
- B01D 2255/802: Photocatalytic
- B01D 2257/404: Nitrogen oxides other than dinitrogen oxide
- B82Y 40/00: Manufacture or treatment of nanostructures
- C02F 1/32: with ultraviolet light
- C02F 1/725: {by catalytic oxidation}
- C02F 2305/023: Reactive oxygen species, singlet oxygen, OH radical
- C02F 2305/10: Photocatalysts
- C04B 2111/00827: {Photocatalysts}
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)

## Abstract

Provided is a method for manufacturing a titania coated alumina fiber aggregate which includes the steps of: forming an aluminum fiber aggregate where aluminum fibers are aggregated with density per unit volume of 0.5 g/cm3 to 3 g/cm3; forming an alumina fiber aggregate where an oxide film having a film thickness of 50 nm or more is formed on alumina fibers; and forming a titania coated alumina fiber aggregate where a titania thin film is formed on alumina fibers.

## Claims

### Claim 1

A method for manufacturing a titania coated alumina fiber aggregate comprising the steps of:
forming an aluminum fiber aggregate where a plurality of aluminum fibers made of aluminum and having a fiber length of 5 mm to 20 cm are stored and are pressed in a predetermined mold frame in a state where the aluminum fibers are entangled thus forming an aluminum fiber aggregate having a desired shape where the aluminum fibers are aggregated with density per unit volume of 0.5 g/cm3 to 3 g/cm3;
forming an alumina fiber aggregate where the aluminum fiber aggregate is heated up to a temperature approximately half of a melting point of the aluminum while maintaining a temperature gradient of approximately 5° C. or less per minute and, thereafter, the alumina fiber aggregate is maintained at a temperature of approximately half of the melting point for 30 minutes to 3 hours so as to form an oxide film having a film thickness of 5 nm or more on the aluminum fibers and, thereafter, the aluminum fiber aggregate is heated up to a temperature close to a melting point thereof and, thereafter, the aluminum fiber aggregate is maintained around the temperature close to the melting point for 30 minutes to 12 hours thus forming the alumina fiber aggregate with the oxide film having a film thickness of 50 nm or more; and
forming a titania coated alumina fiber aggregate where the alumina fiber aggregate is immersed in a sol liquid containing a titania compound, and is pulled up from the sol liquid, and the sol liquid adhered to surfaces of the alumina fibers which constitute the alumina fiber aggregate is dried and, thereafter, the alumina fibers are baked thus forming a titania thin film on the alumina fibers whereby the titania coated alumina fiber aggregate is manufactured.

### Claim 2 (depends on 1)

A method for manufacturing a titania coated alumina fiber aggregate according to claim 1, wherein, before drying the sol liquid, a gas is sprayed to the alumina fiber aggregate which is pulled up from the sol liquid thus allowing the gas to be sprayed to contact points between the alumina fibers constituting the alumina fiber aggregate.

### Claim 3 (depends on 1)

A method for manufacturing a titania coated alumina fiber aggregate according to claim 1, wherein ultrasonic vibrations are applied to the alumina fiber aggregate for a predetermined time during a period within which the alumina fiber aggregate is immersed in the sol liquid and, thereafter, the alumina fiber aggregate is held in a stationary state while being immersed.

### Claim 4 (depends on 3)

A method for manufacturing a titania coated alumina fiber aggregate according to claim 3, wherein the ultrasonic vibrations are applied for 30 seconds to 30 minutes.

### Claim 5 (depends on 3)

A method for manufacturing a titania coated alumina fiber aggregate according to claim 3, wherein the alumina fiber aggregate is held in a stationary state for 1 minute to 24 hours.

### Claim 6 (depends on 1)

A method for manufacturing a titania coated alumina fiber aggregate according to claim 1, wherein the sol liquid contains 15 to 25 weight % of titanium diisopropoxybis(acetylacetonate), 5 to 10 weight % of isopropyl alcohol, 55 to 75 weight % of ethanol and 5 to 10 weight % of water.

### Claim 7 (depends on 6)

A method for manufacturing a titania coated alumina fiber aggregate according to claim 6, wherein the immersion of the alumina fiber aggregate in the sol liquid is performed in a hermetically-sealed vessel having a volume larger than a volume of the stored sol liquid using the sol liquid at a temperature of 35° C. to 60° C., and the alumina fiber aggregate is immersed while allowing alcohol contained in the sol liquid to volatilize thus increasing a pressure of a gas phase in the hermetically-sealed vessel.

### Claim 8 (depends on 7)

A method for manufacturing a titania coated alumina fiber aggregate according to claim 7, wherein a mixing ratio of titanium diisopropoxybis(acetylacetonate), ethanol and water in the sol liquid is set to 3.5:9:1.

### Claim 9 (depends on 1)

A method for manufacturing a titania coated alumina fiber aggregate according to claim 1, wherein the baking of the alumina fiber aggregate is performed by heating the alumina fiber aggregate up to 450° C. while maintaining a temperature elevation gradient of 2 to 15° C./min, and the alumina fiber aggregate is held at 450° C. for a predetermined time.