Claims
- 1. Acicular iron oxyhydroxide comprising particles which have an average major axis of 0.01 to 0.5 μm and containing not less than 0.1 wt. % and not more than 30 wt. % of Al and/or Si in the iron oxyhydroxide and that release not less than 0.1 wt. % and not more than 2 wt. % of H2O at 100° C.
- 2. Acicular iron oxyhydroxide of claim 1, wherein the particles have two or more branches, the branching direction of these particles being skewed toward a two-dimensional orientation.
- 3. Acicular iron oxyhydroxide of claim 1, wherein the particles have a specific surface area measured by the BET method within the range of 40 to 150 m2/g and a TAP density of not less than 0.40 g/cm2 and not more than 1.2 g/cm2.
- 4. Acicular iron oxyhydroxide of claim 3, wherein the particles have a compression density of 1.0 to 2.0 g/cm3 and a true specific gravity 3.5 to 4.3 g/cm3.
- 5. Acicular iron oxyhydroxide of claim 1, wherein the particles have a crystalline diameter of 50 to 150 angstrom.
- 6. Acicular iron oxyhydroxide of claim 1, wherein the particles have a pH of 6 to 11.
- 7. Acicular iron oxyhydroxide of claim 1, wherein the particles have a pH of 8 to 10.
- 8. A non-magnetic layer of a coating type magnetic recording medium comprising acicular iron oxyhydroxide of claim 1.
Priority Claims (2)
Number |
Date |
Country |
Kind |
8-89976 |
Mar 1996 |
JP |
|
8-220746 |
Aug 1996 |
JP |
|
Parent Case Info
This application is a Continuation of application Ser. No. 08/952,438 filed Nov. 20, 1997 now U.S. Pat. No. 5,040,043 which is a 371 of PCT/JP97/00927, filed Mar. 21, 1997.
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Number |
Name |
Date |
Kind |
5503911 |
Aoki et al. |
Apr 1996 |
|
5587232 |
Hayashi et al |
Dec 1996 |
|
5686378 |
Katamoto |
Nov 1997 |
|
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582 472 |
Aug 1993 |
EP |
4-167225 |
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Continuations (1)
|
Number |
Date |
Country |
Parent |
08/952438 |
|
US |
Child |
09/501993 |
|
US |