Patent US4707556A successfully refreshed from Google Patents.
US4707556A
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Boron nitride polymeric precursors
Assignee: Ultrasystems Defense and Space Inc
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Filing: 1987-02-13
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Granted: 1987-11-17
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Expires: 2007-02-13
Abstract
Abstract Silyl containing cyclic borazines are prepared by reacting chloroborazine with disilazanes.
Inventors
- 👤 Kazimiera J. L. Paciorek
- 👤 Reinhold H. Kratzer
- 👤 David H. Harris
- 👤 Wilfried Krone-Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:27
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/06; C01B21/064; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/583; C04B35/622; C04B35/62227; C07; C07F; C07F7/00; C07F7/02; C07F7/08; C07F7/10; C08; C08G; C08G79/00; C08G79/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
26 words
The polymer ##STR3## where R is methyl, ethyl propyl, or butyl of the general formula C n H 2n+1 and where x is a positive integer.
Claim 2
Dependent Claim
26 words
The polymer ##STR3## where R is methyl, ethyl propyl, or butyl of the general formula C n H 2n+1 and where x is a positive integer.
Claim 3
Dependent Claim
3 words
The pentamer ##STR4##
Claim 4
Dependent Claim
3 words
The pentamer ##STR4##
Claim 5
Dependent Claim
53 words
The process of preparing the polymer of claim 1 which comprises the steps of (1) reacting chloroborazine with a disilazane in a suitable solvent at temperatures -78° to 0° C., (2) slow warm up to room temperature, (3) separation of the precipitated by-product by filtration, (4) isolation of the polymer by solvent removal.
Claim 6
Dependent Claim
34 words
A process in accordance with claim 3 wherein chloroborazine and hexamethyldisilazane are reacted in a benzene/hexane mixture as a solvent for a period from about 3 to 24 hr at -50° to -30° C.
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) | 1990-11-16 | 1991-05-18 | 1991-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-16 | 1995-05-18 | 1995-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-16 | 1999-05-18 | 1999-11-17 | $7700.00 | Window Closed / Lapsed |