Alumina fiber aggregate and its production method

• US 6,746,979 B2
• Filed: 03/20/2003
• Issued: 06/08/2004
• Est. Priority Date: 07/23/2001
• Status: Expired due to Term

• Current Assignee: Maftec Company Limited
• Original Assignee: Mitsubishi Chemical Functional Products, Inc. (Mitsubishi Chemical Group Corp.)
• Inventors: Sasaki, Toshiaki, Shoji, Mamoru, Ikeda, Norio
• Primary Examiner(s): EDWARDS, NEWTON O
• Application Number:
  US10/392,941
• Publication Number:
  US 20030219590A1
• Time in Patent Office: 446 Days
• Field of Search: 428/364, 501/95.1
• US Class Current: 501/95.1
• CPC Class Codes: C04B 2235/3218 Aluminium (oxy)hydroxides, e.g. boehmite, gibbsite, alumina sol
• CPC Class Codes: C04B 2235/3418 Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
• CPC Class Codes: C04B 2235/444 Halide containing anions, e.g. bromide, iodate, chlorite
• CPC Class Codes: C04B 2235/5264 characterised by the diameter of the fibers
• CPC Class Codes: C04B 35/62236 Fibres based on aluminium oxide
• CPC Class Codes: C04B 35/62245 rich in aluminium oxide
• CPC Class Codes: C04B 35/63416 Polyvinylalcohols [PVA]; Polyvinylacetates
• CPC Class Codes: D01F 9/08 of inorganic material working or processing of metal wire B21F; from softened glass, minerals or slags C03B37/00
• CPC Class Codes: D04H 1/4209 Inorganic fibres
• CPC Class Codes: D04H 1/46 by needling or like operations to cause entanglement of fibres D04H1/45 takes precedence; needling machines D04H18/00
• CPC Class Codes: D04H 1/498 entanglement of layered webs
• CPC Class Codes: D04H 1/72 the fibres being randomly arranged
• CPC Class Codes: E04B 1/7662 comprising fiber blankets or batts
• CPC Class Codes: Y10T 428/249921 Web or sheet containing structurally defined element or component
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber

Abstract

An alumina fiber aggregate comprising alumina short fibers whose average diameter is 4.0 to 10.0 μm and smallest diameter is not less than 3.0 μm, and a method of producing an alumina fiber aggregate which comprises spinning a spinning solution containing basic aluminum chloride, a silicon compound, an organic polymer and water by the blowing method, and calcining the obtained aggregate of alumina short fiber precursor, the spinning solution being one in which the aluminum/silicon ratio is 99/1 to 65/35 calculated as Al₂O₃/SiO₂ ratio by weight, the concentration of basic aluminum chloride is 180 to 200 g/L and the concentration of the organic polymer is 20 to 40 g/L. The alumina short fibers in the alumina fiber aggregate are enlarged in diameter to suppress scattering of the fibers.

Claims

1. An alumina fiber aggregate comprising alumina short fibers whose average diameter is 4.0 to 10.0 μ

m and smallest diameter is not less than 3.0 μ

m.

2. An alumina fiber aggregate according to claim 1 comprising alumina short fibers whose smallest diameter is not less than 4.0 μ

m.

3. An alumina fiber aggregate according to claim 1 comprising alumina short fibers whose smallest diameter is not less than 5.0 μ

m.

4. An alumina fiber aggregate according to claim 1 comprising alumina short fibers whose average diameter is 5.0 to 8.0 μ

m.

5. An alumina fiber aggregate according to claim 1 comprising alumina short fibers whose average diameter is 6.0 to 8.0 μ

m.

6. An alumina fiber aggregate according to claim 1, wherein the composition of the alumina short fibers is Al₂O₃:

SiO₂=99;

1 to 65;

35 by weight.

7. A method of producing an alumina fiber aggregate as defined in claim 1, which comprises spinning a spinning solution containing basic aluminum chloride, a silicon compound, an organic polymer and water by the blowing method, and calcining the obtained alumina short fiber precursor aggregate, said spinning solution being one in which the aluminum/silicon ratio is 99/1 to 65/35 calculated as Al₂O₃/SiO₂ ratio by weight, the concentration of basic aluminum chloride is 180 to 200 g/L and the concentration of the organic polymer is 20 to 40 g/L.