Patent EP0278734A2 successfully refreshed from Google Patents.
EP0278734A2
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Boron nitride preceramic polymers
Assignee: Ultrasystems Defense and Space Inc
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Filing: 1988-02-09
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Granted: —
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Expires: 2008-02-09
Abstract
Abstract A preceramic substituted borazine polymer of the formula: wherein R is methyl, ethyl, propyl, or butyl, and x is a positive integer. Also disclosed are methods for making the polymer, methods for converting the polymer into coatings, shaped articles, articles including fibers and filaments formed from the polymer, blends of the foregoing polymer and preceramic triamino-N-tris (trialkylsilyl) borazines, and methods for thermally decomposing the foregoing polymers to form shaped articles of boron nitride.
Inventors
- 👤 Kazimiera J. L. Paciorek
- 👤 Reinhold H. Kratzer
- 👤 David H. Harris
- 👤 Wilfried Krone-Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 18:51
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/583; C01; C01B; C01B21/00; C01B21/06; C01B21/064; C04B35/622; C04B35/62227; C07; C07F; C07F7/00; C07F7/02; C07F7/08; C07F7/10; C08; C08G; C08G79/00; C08G79/08
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
25 words
The polymer 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
25 words
The polymer 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
2 words
The pentamer
Claim 4
Dependent Claim
2 words
The pentamer
Claim 5
Dependent Claim
12 words
The polymer of Claim 1 in the form of fibers or filaments.
Claim 6
Dependent Claim
18 words
A mixture of the polymer of Claim 1 and the polymer in the form of fibers or filaments.
Claim 7
Dependent Claim
11 words
The polymer of Claim 1 in the form of shaped articles.
Claim 8
Dependent Claim
9 words
The polymer in the form of a shaped article.
Claim 9
Dependent Claim
9 words
The polymer in the form of a shaped article.
Claim 10
Dependent Claim
18 words
A mixture of the polymer of Claim 1 and the polymer in the form of a shaped article.
Claim 11
Dependent Claim
23 words
The mixture of the polymer of Claim 4 and the polymer of Claim 7, wherein the polymers are present in approximately equal proportions.
Claim 12
Dependent Claim
92 words
The process of preparing the polymer of Claim 1, comprising the steps of: (a) reacting chloroborazine with a disilazine in a mixture of organic solvents, said mixture having at least one aromatic component and at least one non-polar aliphatic components, in an atmosphere of an inert gas, and at a temperature below 0°C but above the freezing point of said mixture for a period long enough to form a polymer solution; (b) removing precipitate from said polymer solution; and (c) then isolating the polymer by removing said solvents from said polymer solution.
Claim 13
Dependent Claim
22 words
The process of Claim 9, wherein said atmosphere comprises a gas or a mixture of gases selected from nitrogen, helium, and argon.
Claim 14
Dependent Claim
17 words
The process of Claim 10, wherein said gas or said mixture of gases is at ambient pressure.
Claim 15
Dependent Claim
40 words
The process of Claim 9, wherein chloroborazine and hexamethyldisilazine are reacted in a solvent mixture comprising equal parts of benzene and hexane for a period of from about 3 to about 24 hours at temperatures from about -50° to -30°C.
Claim 16
Dependent Claim
55 words
A process for preparing a ceramic material from the borazine polymer of Claim 1, comprising the step of gradually heating said borazine polymer precursor in a system having an atmosphere of ammonia gas at a rate required to bring the temperature of said system to about 1000°C within a period of 4 to 24 hours.
Claim 17
Dependent Claim
23 words
The process of Claim 13, wherein said ammonia atmosphere is at a pressure between about 400 mm Hg and about 760 mm Hg.
Claim 18
Dependent Claim
73 words
A process for preparing boron nitride ceramic from substituted borazine polymer, comprising the steps of: (a) heating said substituted borazine polymer under an atmosphere of a hydrogen halide gas at a temperature of at least 40°C but below the softening temperature of said polymer to raise the softening temperature of said polymer; and (b) then heating said polymer under an ammonia atmosphere at a temperature sufficient to convert said polymer to boron nitride.
Claim 19
Dependent Claim
73 words
A process for preparing boron nitride ceramic from substituted borazine polymer, comprising the steps of: (a) heating said substituted borazine polymer under an atmosphere of a hydrogen halide gas at a temperature of at least 40°C but below the softening temperature of said polymer to raise the softening temperature of said polymer; and (b) then heating said polymer under an ammonia atmosphere at a temperature sufficient to convert said polymer to boron nitride.
Claim 20
Dependent Claim
13 words
The process of Claim 15, wherein said hydrogen halide gas is hydrogen chloride.
Claim 21
Dependent Claim
20 words
The process of Claim 16, wherein said hydrogen halide gas is present at a pressure of approximately 100 mm Hg.
Claim 22
Dependent Claim
21 words
The process of Claim 15, wherein said ammonia gas is present at a pressure of approximately 400 to 760 mm Hg.
Claim 23
Dependent Claim
77 words
A process for coating an object with boron nitride, comprising the steps of: (a) immersing said object in either a solution of substituted borazine polymer in a solvent for said polymer or a melt of said polymer under an atmosphere of a non-reactive gas to polymer coat said object; (b) removing said polymer-coated object from said solution; and (c) heating said polymer-coated object under an atmosphere of ammonia gas to convert said polymer coating to boron nitride.
Claim 24
Dependent Claim
77 words
A process for coating an object with boron nitride, comprising the steps of: (a) immersing said object in either a solution of substituted borazine polymer in a solvent for said polymer or a melt of said polymer under an atmosphere of a non-reactive gas to polymer coat said object; (b) removing said polymer-coated object from said solution; and (c) heating said polymer-coated object under an atmosphere of ammonia gas to convert said polymer coating to boron nitride.
Claim 25
Dependent Claim
22 words
The process of Claim 19, further comprising repeating steps (a) through (c) to coat said object with multiple layers of boron nitride.
Claim 26
Dependent Claim
31 words
The process of Claim 19, wherein said substituted borazine polymer in said immersing step is in the form of a solution and the solvent for said polymer is hexane or heptane.
Claim 27
Dependent Claim
21 words
The process of Claim 19, wherein said ammonia gas in said step (c) is at a pressure of approximately 500 mm.
Claim 28
Dependent Claim
38 words
The process of Claim 19, wherein said process further comprises heating said polymer-coated object in an atmosphere of acid halide gas after removing said object from said solution in step (b) and prior to proceeding to step (c).
Claim 29
Dependent Claim
13 words
The process of Claim 19, wherein the hydrogen halide gas is hydrogen chloride.
Claim 30
Dependent Claim
19 words
The process of Claim 19, wherein the hydrogen halide gas is at a pressure of approximately 100 mm Hg.
Claim 31
Dependent Claim
47 words
The process of Claim 19 or 23, wherein said substituted borazine polymers are condensed B-triamino-N-tris (trialkylsilyl) borazines, singly and doubly bridged, and mixtures thereof 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 32
Dependent Claim
16 words
The process of Claim 19 or 23, wherein said borazine polymer is substituted with silylamino groups.
Claim 33
Dependent Claim
15 words
The process of Claim 26, wherein said borazine polymer is the polymer of Claim 1.
References Cited (Backward Citations)
No citation records indexed.
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