US4047965A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Non-frangible alumina-silica fibers
Assignee: 3M Co
•
Filing: 1976-05-04
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Granted: 1977-09-13
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Expires: 1996-05-04
Abstract
Abstract Transparent, smooth, fracture resistant, discreet, refractory oxide fibers of homogeneous chemical composition comprising 96 to 100 weight percent of a mixture or chemical combination of 67 to 77 parts by weight alumina and 23 to 33 parts by weight silica, said fibers having a predominant polycrystalline phase of mullite, transitional alumina, or a mixture of both, said refractory fibers being made by fiberizing a viscous liquid of oxide precursors comprising a silica sol and a water dispersible alumina sol or water soluble or dispersible organic aluminum salt, and drying, collecting, and calcining the resulting green fibers.
Inventors
- 👤 Karl A. Karst
- 👤 Harold G. Sowman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:19
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/62227; C04B35/62231; C04B35/6224; C04B35/62245; C04B35/626; C04B35/62605; C04B35/62645; C04B35/62675; C04B2235/00; C04B2235/02; C04B2235/30; C04B2235/32; C04B2235/3201; C04B2235/3203; C04B2235/3205; C04B2235/3206; C04B2235/3208; C04B2235/3213; C04B2235/3215; C04B2235/3224; C04B2235/3225; C04B2235/3227; C04B2235/3231; C04B2235/3232; C04B2235/3239; C04B2235/3241; C04B2235/3244; C04B2235/3262; C04B2235/327; C04B2235/3272; C04B2235/3275; C04B2235/3279; C04B2235/3281; C04B2235/3284; C04B2235/3293; C04B2235/3294; C04B2235/44; C04B2235/443; C04B2235/447; C04B2235/448; C04B2235/449; C04B2235/50; C04B2235/52; C04B2235/5208; C04B2235/526; C04B2235/5264; C04B2235/54; C04B2235/5409; C04B2235/60; C04B2235/602; C04B2235/6025; C04B2235/70; C04B2235/72; C04B2235/721; C04B2235/80; C04B2235/96; C04B2235/9646; C04B2235/9653; C04B2235/9661
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
62 words
Transparent, smooth, fracture resistant, discrete, refractory oxide fibers uniformly round in cross section and of homogenous chemical composition comprising 96 to 100 weight percent of a mixture or chemical combination of 67 to 77 parts by weight alumina and 23 to 33 parts by weight silica, and fibers having a predominant polycrystalline phase of mullite, transitional alumina, or a mixture of both.
Claim 2
Dependent Claim
62 words
Transparent, smooth, fracture resistant, discrete, refractory oxide fibers uniformly round in cross section and of homogenous chemical composition comprising 96 to 100 weight percent of a mixture or chemical combination of 67 to 77 parts by weight alumina and 23 to 33 parts by weight silica, and fibers having a predominant polycrystalline phase of mullite, transitional alumina, or a mixture of both.
Claim 3
Dependent Claim
11 words
Fibers according to claim 1, wherein said polycrystalline phase is mullite.
Claim 4
Dependent Claim
30 words
Fibers according to claim 1, wherein said polycrystalline phase is mullite, the crystallites of which have an average size greater than 500 Angstroms, as determined by x-ray powder diffraction analysis.
Claim 5
Dependent Claim
35 words
Fibers according to claim 1, wherein said polycrystalline phase is transitional alumina and is in admixture with silica, said admixture being transformable at 1200 to 1400° C to a polycrystalline phase which is predominantly mullite.
Claim 6
Dependent Claim
90 words
Fibers according to claim 1, further comprising up to 4 total weight percent additive inorganic oxides selected from the group consisting of glass formers, intermediate glass formers, and non-glass formers, each said glass former being present in an amount up to 2 weight percent, each said intermediate glass former and non-glass former being present in an amount less than 1 weight percent or present in the amount of 1 to 2 weight percent provided an amount of 0.5 to 2 total weight percent of said glass formers is also present.
Claim 7
Dependent Claim
44 words
Fibers according to claim 1, further comprising up to 2 weight percent each of boria or phosphorus pentoxide, or both, the balance being a mixture or chemical combination of 70 to 75 parts by weight alumina and 25 to 30 parts by weight silica.
Claim 8
Dependent Claim
51 words
Fibers according to claim 1, further comprising from 0.5 up to 1 weight percent of boria of phosphorus pentoxide, or both, the balance being 99 to 99.5 weight percent of a mixture or chemical combination of 70 to 75 parts by weight alumina and 25 to 30 parts by weight silica.
Claim 9
Dependent Claim
47 words
Fibers according to claim 1, wherein said alumina and silica are present as 3Al 2 O 3 .2SiO 2 in the amount of 99 weight percent, said fibers further comprising 0.5 weight percent B 2 O 3 , and 0.5 weight percent P 2 O 5 .
Claim 10
Dependent Claim
13 words
Fibers according to claim 1 having a friability index of at least 0.2.
Claim 11
Dependent Claim
16 words
Fibers according to claim 1 having a surface area of less than 1 m 2 /g.
Claim 12
Dependent Claim
8 words
Fibers according to claim 1 which are continuous.
Claim 13
Dependent Claim
9 words
Yarn comprising fibers of claim 1 which are continuous.
Claim 14
Dependent Claim
23 words
Fibers according to claim 1 which are nonporous, free of shot, free of alpha alumina, and containing less than 0.1 weight percent carbon.
Claim 15
Dependent Claim
12 words
Fibers according to claim 1 with uniform diameters up to 25 micrometers.
Claim 16
Dependent Claim
17 words
Fibers according to claim 1 which are straight, and having uniform diameters of 7 to 15 micrometers.
Claim 17
Dependent Claim
131 words
Transparent, smooth, discrete, continuous, refractory, ceramic oxide fibers of homogeneous chemical composition comprising 99 to 99.5 weight percent of a mixture or chemical combination of 70 to 75 parts by weight alumina and 25 to 30 parts by weight silica, 0.5 to 1 weight percent of boria or phosphorus pentoxide, or both, and less than 0.1 weight percent carbon, said fibers being free of alpha alumina and having a polycrystalline phase of predominantly transitional alumina in admixture with silica which admixture is transformable upon firing said fibers at 1200° to 1400° C to mullite crystallites, said fibers having a friability index of at least 0.5 and a surface area less than 1 m 2 /g, said fibers being straight and uniformly round with a uniform diameter of 7 to 15 micrometers.
Claim 18
Dependent Claim
131 words
Transparent, smooth, discrete, continuous, refractory, ceramic oxide fibers of homogeneous chemical composition comprising 99 to 99.5 weight percent of a mixture or chemical combination of 70 to 75 parts by weight alumina and 25 to 30 parts by weight silica, 0.5 to 1 weight percent of boria or phosphorus pentoxide, or both, and less than 0.1 weight percent carbon, said fibers being free of alpha alumina and having a polycrystalline phase of predominantly transitional alumina in admixture with silica which admixture is transformable upon firing said fibers at 1200° to 1400° C to mullite crystallites, said fibers having a friability index of at least 0.5 and a surface area less than 1 m 2 /g, said fibers being straight and uniformly round with a uniform diameter of 7 to 15 micrometers.
Claim 19
Dependent Claim
7 words
Yarn comprising the fibers of claim 16.
Claim 20
Dependent Claim
8 words
Woven fabric comprising the fibers of claim 16.
Claim 21
Dependent Claim
15 words
A composite comprising a plastic, elastomeric, metallic, or ceramic matrix and fibers of claim 1.
Claim 22
Dependent Claim
68 words
A method for forming the refractory fibers of claim 1, which comprises fiberizing a viscous liquid of oxide precursors comprising a silica sol and a water dispersible alumina sol of water soluble or dispersible organic aluminum salt, said liquid having equivalent alumina and silica contents within or along the boundary lines A-B-C-D of FIG. 1 of the accompanying drawing, and drying, collecting, and calcining the resulting green fibers.
Claim 23
Dependent Claim
99 words
A method for forming the yarn of claim 17, which comprises continuously extruding through a plurality of stationary orifices a viscous aqueous dispersion comprising colloidal silica and a water soluble organic aluminum salt calcinable to alumina, said dispersion having equivalent alumina and silica contents within or along the boundary lines A-B-C-D of FIG. 1 of the accompanying drawing, continuously drawing in air the resulting continuous green fibers, continuously collecting said green fibers together as a strand, and continuously firing said strand in air in a relaxed, loose, unrestrained configuration to calcine it and convert it into said refractory yarn.
Claim 24
Dependent Claim
79 words
Transparent, smooth, fracture resistant, discrete, refractory oxide fibers uniformly round in cross-section and of homogeneous chemical composition comprising 96 to 100 weight percent of a mixture or chemical combination of 67 to 77 parts by weight alumina and 23 to 33 parts by weight silica, said fibers having a predominant polycrystalline phase of mullite, transitional alumina, or a mixture of both, a friability index of at least 0.2 and a surface area of less than 1 m 2 /g.
Claim 25
Dependent Claim
79 words
Transparent, smooth, fracture resistant, discrete, refractory oxide fibers uniformly round in cross-section and of homogeneous chemical composition comprising 96 to 100 weight percent of a mixture or chemical combination of 67 to 77 parts by weight alumina and 23 to 33 parts by weight silica, said fibers having a predominant polycrystalline phase of mullite, transitional alumina, or a mixture of both, a friability index of at least 0.2 and a surface area of less than 1 m 2 /g.
Claim 26
Dependent Claim
22 words
Fibers according to claim 1 wherein said homogeneous chemical composition consists essentially of said mixture or chemical combination of alumina and silica.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-12 | 1981-03-14 | 1981-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-12 | 1985-03-14 | 1985-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-12 | 1989-03-14 | 1989-09-13 | $7700.00 | Window Closed / Lapsed |