# US 7,407,606 B2 · Electroconductive powder and method for production thereof

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- Number: US 7,407,606 B2
- Document ID: US7407606B2
- Status: Granted
- Kind: B2
- Application number: 10/565,244
- Filed: 2004-07-22
- Published: 2006-09-21
- Granted: 2008-08-05
- Earliest claimed: 2003-07-23
- Assignees: Ishihara Sangyo Kaisha, Ltd.
- Inventors: Katsuichi Chiba; Yuichi Yasuda
- Web page: https://patentgrep.com/patent/US7407606B2

## CPC

- H01B 1/08: oxides
- C01G 23/00: Compounds of titanium {(preparation of Ti-compounds from ores or scraps C22B34/12)}
- C09C 1/3661: {Coating}
- C01P 2006/40: Electric properties
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C09C: TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES (treatment of materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone C04B14/00, C04B18/00, C04B20/00); PREPARATION OF CARBON BLACK {; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS}
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

A method for producing a titanium dioxide powder having a well electroconductive layer containing substantially no antimony, which comprises providing a titanium dioxide powder containing specific amounts or less of alkali metals, such as sodium and potassium, alkaline earth metals, such as magnesium and calcium, and metals having a valence of four or less, such as aluminum, zinc and iron, preparing an aqueous suspension of the titanium dioxide powder, adding an acidic aqueous solution containing a tin compound and a phosphorus compound and an alkaline solution to the above aqueous suspension so that the aqueous suspension has a pH in the range of 2 to 6 or 8 to 12, and firing the resulting product at a temperature of 600 to 925° C.

## Claims

### Claim 1

A method for producing an electroconductive powder which comprises adding an aqueous acidic solution in which a tin compound and a phosphorus compound are dissolved and an aqueous alkaline solution to an aqueous suspension of titanium dioxide in which the content of a metallic element having a valence of 4 or less contained in the titanium dioxide as an impurity is 0.02 or less as (B) obtained by the following formula (2)
(B)=(M′1)×(4−n′1)×(M′2)×(4−n′2)+(M′3)×(4−n′3)+(M′4)×(4−n′4)+ . . . +(M′Y)×(4−n′Y) Formula (2):
(in the above formula, M′1, M′2, M′3, M′4, . . . , M′Y represent an atomic ratio of each metallic element having a valence of 4 or less, the atomic ratio being to Ti of titanium dioxide, n′1, n′2, n′3, n′4, . . . , n′Y represent a valence number of each metallic element having the atomic ratio of M′1, M′2, M′3, M′4, . . . , M′Y, Y in M′Y and n′Y represents the number of the metallic element contained in the titanium dioxide and can have a natural number of 1 or more,
with maintaining pH of the aqueous suspension in the range of 2-6 or 8-12, then fractionating the resulting product, and firing the product in an air or in an atmosphere of low oxygen concentration at a temperature of 600-925° C. to form an electroconductive layer containing tin oxide and phosphorus on the surface of the titanium dioxide.

### Claim 2 (depends on 1)

A method according to claim 1, wherein the pH is 8-12.

### Claim 3 (depends on 1)

A method according to claim 1, wherein the firing is carried out in the atmosphere of low oxygen concentration.

### Claim 4 (depends on 1)

An electroconductive powder obtained by the method of claim 1 wherein the electroconductive powder obtained has an electroconductive layer containing tin oxide and phosphorus, but containing no antimony on the surface of titanium dioxide, and the content of a metallic element having a valence of 4 or less which is contained as an impurity in the electroconductive powder is 0.1 or less as (A) obtained by the following formula (1):
(A)=(M1)×(4−n1)+(M2)×(4−n2)+(M3)×(4-n3)+(M4)×(4−n4)+ . . . +(MX)×(4−nX) Formula (1):
(in the above formula, M1, M2, M3, M4, . . . , MX represent an atomic ratio of each metallic element having a valence of 4 or less to Sn of the tin oxide in the electroconductive powder, n1, n2, n3, n4, . . . , nX represent a valence number of each metallic element having the atomic ratio of M1, M2, M3, M4, . . . , MX, X in MX and nX represents the number of the metallic element contained in the electroconductive powder and can have a natural number of 1 or more.

### Claim 5 (depends on 1)

An electroconductive powder obtained by the method of claim 1 wherein the pH of the aqueous suspension is maintained in the range of 8-12 and the electroconductive powder obtained has an electroconductive layer containing tin oxide and phosphorus, but containing no antimony on the surface of titanium dioxide, and the content of a metallic element having a valence of 4 or less which is contained as an impurity in the electroconductive powder is 0.1 or less as (A) obtained by the following formula (1):
(A)=(M1)×(4−n1)+(M2)×(4−n2)+(M3)×(4-n3)+(M4)×(4−n4)+ . . . +(MX)×(4−nX) Formula (1):
(in the above formula, M1, M2, M3, M4, . . . , MX represent an atomic ratio of each metallic element having a valence of 4 or less to Sn of the tin oxide in the electroconductive powder, n1, n2, n3, n4, . . . , nX represent a valence number of each metallic element having the atomic ratio of M1, M2, M3, M4, . . . , MX, X in MX and nX represents the number of the metallic element contained in the electroconductive powder and can have a natural number of 1 or more; and
a specific surface area of the electroconductive layer is 70 m2/g or smaller.

### Claim 6 (depends on 4, 5)

An electroconductive powder obtained by the method of claim 4 or 5, wherein the amount of the tin oxide forming the electroconductive layer is in the range of 0.015-0.3 g as SnO2 per 1 m2 of the surface area of titanium dioxide.

### Claim 7 (depends on 4, 5)

An electroconductive powder obtained by the method of claim 4 or 5, wherein the amount of the phosphorus contained in the electroconductive layer with respect to tin oxide is a proportion of 0.10-0.50 in terms of the atomic ratio P/Sn.