US4377677A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing polycarbosilanes
Assignee: Ube Corp
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Filing: 1981-11-05
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Granted: 1983-03-22
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Expires: 2001-11-05
Abstract
Abstract A method of preparing polycarbosilanes having high molecular weight and also having the major structural unit of silicon-carbon linkage. The method comprises heating a polysilane at 50°-600° C. in atmosphere of an inert gas and distilling out a low molecular weight polycarbosilane fraction having the number mean molecular weight of 300-600, followed by polymerizing the fraction by heating it at 250°-500° C. in atmosphere of an inert gas. The polycarbosilane obtained by the method of the present invention is useful for the precursor of preparing silicon carbide fibres and shaped articles.
Inventors
- 👤 Tadashi Iwai
- 👤 Takashi Kawahito
- 👤 Masahiro Tokuse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:40
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565; C04B35/571; C08; C08G; C08G77/00; C08G77/60
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
87 words
A process of preparing polycarbosilanes having high molecular weight and having the repetitive silicon-carbon-silicon linkage as the major structural unit, which comprises heating a polysilane having the repetitive silicon-silicon linkage as the major structural unit at 50°-600° C. in an atmosphere of an inert gas and distilling out a low molecular weight polycarbosilane fraction having the number mean molecular weight of 300-600, and then polymerizing said distilled fraction by heating it at 250°-500° C. in atmosphere of an inert gas to form said high molecular weight polycarbosilane.
Claim 2
Dependent Claim
87 words
A process of preparing polycarbosilanes having high molecular weight and having the repetitive silicon-carbon-silicon linkage as the major structural unit, which comprises heating a polysilane having the repetitive silicon-silicon linkage as the major structural unit at 50°-600° C. in an atmosphere of an inert gas and distilling out a low molecular weight polycarbosilane fraction having the number mean molecular weight of 300-600, and then polymerizing said distilled fraction by heating it at 250°-500° C. in atmosphere of an inert gas to form said high molecular weight polycarbosilane.
Claim 3
Dependent Claim
38 words
The process of claim 1, wherein said polysilanes comprise the following structural unit: ##STR5## wherein R is a lower alkyl group, a phenyl group or a hydrogen atom and n is an integer which is at least 3.
Claim 4
Dependent Claim
60 words
The process of claim 2, wherein said fraction containing said low molecular weight polycarbosilane comprises polysilane having the following structural unit (I) and polycarbosilane having the following structural unit (II): ##STR6## wherein R is a lower alkyl group, a phenyl group or a hydrogen atom and wherein the ratio of said polysilane to said polycarbosilane being from 1:1 to 6:1.
Claim 5
Dependent Claim
13 words
The method of claim 2, wherein said R groups are substantially methyl groups.
Claim 6
Dependent Claim
24 words
The process of claim 3 or 4, wherein said heating and distillation is at a temperature between 150°-500° C. and at around normal pressure.
Claim 7
Dependent Claim
24 words
The process of claim 5, wherein said polymerization is carried out at a temperature of between about 300°-500° C. and at around normal pressure.
Claim 8
Dependent Claim
26 words
The process of claim 3 or 4, wherein said polymerization is carried out at a temperature of between about 300°-500° C. and at around normal pressure.
Claim 9
Dependent Claim
28 words
The process of claim 7, wherein said high molecular weight polycarbosilane has a number mean molecular weight of between 1000-2,500 and wherein said R groups are methyl groups.
Claim 10
Dependent Claim
30 words
The process of claim 3 or 4, wherein said high molecular weight polycarbosilane has a number mean molecular weight of between 1000-2,500 and wherein said R groups are methyl groups.
Claim 11
Dependent Claim
28 words
The process of claim 6, wherein said high molecular weight polycarbosilane has a number mean molecular weight of between 1,573-1,900 and wherein said R groups are methyl groups.
References Cited (Backward Citations)
US4310482A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-21 | 1986-09-20 | 1987-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-21 | 1990-09-20 | 1991-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-21 | 1994-09-20 | 1995-03-22 | $7700.00 | Window Closed / Lapsed |