Patent US4309245A successfully refreshed from Google Patents.
US4309245A
Expired / Lapsed
US
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Process for manufacturing boron nitride fiber felt using a Fourdrinier machine
Assignee: Stemcor Corp
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Filing: 1980-03-28
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Granted: 1982-01-05
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Expires: 2000-03-28
Abstract
Abstract A process is disclosed for producing a non-woven boron nitride (BN) fiber felt. Boron nitride fibers are blended with a lesser amount of boron oxide fibers and a nondissolving, anhydrous liquid medium to form a homogeneous slurry. The slurry is deposited on the moving screen of a Fourdrinier machine where the liquid content is gradually reduced until sufficient fiber to fiber contact is made to provide internal cohesiveness, to form a felt. The felt may be further treated by heating it in an anhydrous gas atmosphere at a sufficient temperature to soften the boron oxide binder to fuse the BN fibers together, and then converting the interstitial boron oxide into boron nitride. The resulting boron nitride-bonded boron nitride felt may be used as an electric cell separator in a lithium sulfide battery.
Inventors
- 👤 John L. Tworek
- 👤 Gordon R. Rignel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:48
CPC Classifications
D; D21; D21H; D21H5/00; D21H5/12; D21H5/18; D21H13/00; D21H13/36; H; H01; H01M; H01M50/00; H01M50/40; H01M50/489; Y; Y02; Y02E; Y02E60/00; Y02E60/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
171 words
A process for producing boron nitride-bonded boron nitride fiber mats, comprising the steps of: blending boron nitride fibers and boron oxide fibers in a ratio by weight of about 50-99% of boron nitride fibers and about 1-50% of boron oxide fibers, said fibers having a length of from about 0.1 inch to about 1.0 foot, with CCl 2 F--CClF 2 to form a homogeneous slurry; distributing said slurry in an essentially uniformly thick layer upon the moving screen of a Fourdrinier machine; suctioning essentially all of said Freon from said slurry-supporting surface of said screen, yielding a boron nitride and boron oxide fiber felt; heating said felt in an anhydrous gas selected from the group consisting of inert gases, nitrogen, ammonia, air, and mixtures thereof, to a sufficient temperature to fuse said boron oxide fibers to said boron nitride fibers; and heating the fused felt in an anhydrous ammonia atmosphere to a sufficient temperature, and for a sufficient time to convert essentially all boron oxide in the fibers to boron nitride.
Claim 2
Dependent Claim
171 words
A process for producing boron nitride-bonded boron nitride fiber mats, comprising the steps of: blending boron nitride fibers and boron oxide fibers in a ratio by weight of about 50-99% of boron nitride fibers and about 1-50% of boron oxide fibers, said fibers having a length of from about 0.1 inch to about 1.0 foot, with CCl 2 F--CClF 2 to form a homogeneous slurry; distributing said slurry in an essentially uniformly thick layer upon the moving screen of a Fourdrinier machine; suctioning essentially all of said Freon from said slurry-supporting surface of said screen, yielding a boron nitride and boron oxide fiber felt; heating said felt in an anhydrous gas selected from the group consisting of inert gases, nitrogen, ammonia, air, and mixtures thereof, to a sufficient temperature to fuse said boron oxide fibers to said boron nitride fibers; and heating the fused felt in an anhydrous ammonia atmosphere to a sufficient temperature, and for a sufficient time to convert essentially all boron oxide in the fibers to boron nitride.
Claim 3
Dependent Claim
49 words
The process as set forth in claim 1, wherein said sufficient temperature to convert the boron oxide to boron nitride is from about 200° C. to about 900° C., and said sufficient time to convert the boron oxide to boron nitride is from about 2 to about 72 hours.
Claim 4
Dependent Claim
30 words
The process as set forth in claim 1, wherein said sufficient temperature to fuse said boron oxide fibers to said boron nitride fibers is from 460° C. to 1,400° C.
Claim 5
Dependent Claim
26 words
The process as set forth in claim 1, wherein said moving screen is moving at a speed of from about 1.0 to 100 feet per minute.
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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) | 1985-01-04 | 1985-07-06 | 1986-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-04 | 1989-07-06 | 1990-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-04 | 1993-07-06 | 1994-01-05 | $7700.00 | Window Closed / Lapsed |