US4122041A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Siliceous fibers and method of preparing them
Assignee: EIDP Inc
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Filing: 1977-07-01
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Granted: 1978-10-24
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Expires: 1997-07-01
Abstract
Abstract Siliceous fibers characterized by being strong, water-insoluble, and porous, and having a five to seven-sided polygonal cross section are prepared by directionally freezing a quiescent body of aqueous polysilicic acid by subjecting it to a temperature of -5° to -200° C.
Inventors
- 👤 Walter Mahler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:05
CPC Classifications
B; B01; B01J; B01J35/00; B01J35/50; B01J35/58; B01J20/00; B01J20/02; B01J20/10; B01J20/103; B01J21/00; B01J21/06; B01J21/08; Y; Y10; Y10S; Y10S264/00; Y10S264/19
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
61 words
A porous, water-insoluble siliceous fiber characterized by having a cross-sectional diameter of 0.001 to 0.5 mm, and a cross-sectional shape in the form of a five to seven-sided polygon in which at least one side is concave, and an essential chemical composition corresponding to the formula (SiO.sub.2).sub.3.(H.sub.2 O).sub.x in which x is a fractional or whole number from 0 to 6.
Claim 2
Dependent Claim
61 words
A porous, water-insoluble siliceous fiber characterized by having a cross-sectional diameter of 0.001 to 0.5 mm, and a cross-sectional shape in the form of a five to seven-sided polygon in which at least one side is concave, and an essential chemical composition corresponding to the formula (SiO.sub.2).sub.3.(H.sub.2 O).sub.x in which x is a fractional or whole number from 0 to 6.
Claim 3
Dependent Claim
42 words
The siliceous fiber of claim 1 which is further characterized by having a surface area of at least 10 m 2 /g, a tensile strength of at least 5,000 lb/in 2 , and a density of 1.8 to 2.2 g/cc by flotation.
Claim 4
Dependent Claim
22 words
The siliceous fiber of claim 1 which is further characterized by having a surface area of at least 500 m 2 /g.
Claim 5
Dependent Claim
44 words
The siliceous fiber of claim 3 which is further characterized by having a pore volume of at least 0.2 cc/g, an average pore diameter of 10-100 A, and a chemical composition in which x is a fractional or whole number from 0.5 to 6.
Claim 6
Dependent Claim
19 words
The siliceous fiber of claim 4 characterized by having a surface area of 550 to 1200 m 2 /g.
Claim 7
Dependent Claim
37 words
The siliceous fiber of claim 5 characterized by having a cross-sectional diameter of 0.01 to 0.2 mm, a tensile strength of at least 5,000 lb/in 2 , and a density of 1.8 to 2.2 g/cc by flotation.
Claim 8
Dependent Claim
37 words
The siliceous fiber of claim 6 characterized by having a surface area of 550 to 1200 m 2 /g, a pore volume of 0.2 to 0.75 cc/g, and an average pore diameter of 10 to 100 A.
Claim 9
Independent Claim
144 words
A method of making porous, water-insoluble siliceous fibers which comprises directionally freezing a quiescent body of aqueous polysilicic acid which (1) has an SiO 2 content of 0.5 to 20% by weight, (2) has a pH of 1 to 7, and (3) has polymerized to the point where fibers formed from it by directional freezing are water-insoluble, but has not cross-linked to the extent that it contains substantially less than 1 mole of H 2 O for every three moles of SiO 2 , by subjecting it to a temperature of -5° to -200° C. whereby a solid-liquid interface advances through the body of polysilicic acid at a rate such that ice grows in a cellular substructure and siliceous fibers form parallel to the direction of advance of the interface; allowing the frozen mass to thaw; and isolating the resulting porous, water-insoluble siliceous fibers.
Claim 10
Independent Claim
144 words
A method of making porous, water-insoluble siliceous fibers which comprises directionally freezing a quiescent body of aqueous polysilicic acid which (1) has an SiO 2 content of 0.5 to 20% by weight, (2) has a pH of 1 to 7, and (3) has polymerized to the point where fibers formed from it by directional freezing are water-insoluble, but has not cross-linked to the extent that it contains substantially less than 1 mole of H 2 O for every three moles of SiO 2 , by subjecting it to a temperature of -5° to -200° C. whereby a solid-liquid interface advances through the body of polysilicic acid at a rate such that ice grows in a cellular substructure and siliceous fibers form parallel to the direction of advance of the interface; allowing the frozen mass to thaw; and isolating the resulting porous, water-insoluble siliceous fibers.
Claim 11
Dependent Claim
41 words
The method of claim 8 in which the body of polysilicic acid is subjected to a temperature of -10° to -100° C., and the solid-liquid interface advances through the body of polysilicic acid at the rate of at least 0.2 cm/hr.
Claim 12
Dependent Claim
48 words
The method of claim 9 in which the aqueous polysilicic acid has an SiO 2 content of 4 to 15% by weight, and a pH of 3 to 6, and the solid-liquid interface advances through the body of polysilicic acid at the rate of at least 2 cm/hr.
Claim 13
Dependent Claim
18 words
The method of claim 10 in which the aqueous polysilicic acid has a pH of 4.5 to 6.
Claim 14
Dependent Claim
19 words
The method of claim 11 in which the body of polysilicic acid is in the form of a gel.
Claim 15
Dependent Claim
11 words
A sheet composed of siliceous fibers in accordance with claim 1.
Claim 16
Dependent Claim
10 words
The sheet of claim 13 in the form of felt.
Claim 17
Dependent Claim
10 words
The sheet of claim 13 in the form of paper.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-23 | 1982-04-24 | 1982-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-23 | 1986-04-24 | 1986-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-23 | 1990-04-24 | 1990-10-24 | $7700.00 | Window Closed / Lapsed |