US4228270A
Expired / Lapsed
US
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Polyborodiphenylsiloxanes
Assignee: Asahi Kasei Corp
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Filing: 1978-12-13
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Granted: 1980-10-14
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Expires: 1998-12-13
Abstract
Abstract A polyborodiphenylsiloxane having main repeating units of the formula, ##STR1## wherein X is a hydrogen atom or ##STR2## and a weight-average molecular weight of about 800 to about 5,000, and a method of preparing the same, which comprises polycondensing a borodiphenylsiloxanol of the formula, ##STR3## wherein n is zero or one, at a temperature of from about 140° C. to about 400° C. in the absence of a solvent.
Inventors
- 👤 Hiroshi Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:40
CPC Classifications
C; C08; C08L; C08L85/00; C08L85/04; C07; C07F; C07F7/00; C07F7/02; C07F7/08; C07F7/0834; C07F7/0836; C07F7/0838; C07F7/0872; C07F7/0874; C07F7/0876; C08G; C08G77/00; C08G77/48; C08G77/56; C08G79/00; C08G79/08
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
29 words
A polyborodiphenylsiloxane having main repeating units of the formula, ##STR10## wherein X is a hydrogen atom or ##STR11## and a weight-average molecular weight of about 800 to about 5,000.
Claim 2
Dependent Claim
29 words
A polyborodiphenylsiloxane having main repeating units of the formula, ##STR10## wherein X is a hydrogen atom or ##STR11## and a weight-average molecular weight of about 800 to about 5,000.
Claim 3
Dependent Claim
17 words
The polyborodiphenylsiloxane of claim 1, wherein the weight-average molecular weight ranges from about 800 to about 2,000.
Claim 4
Dependent Claim
42 words
A method of preparing the polyborodiphenylsiloxane of claim 1, which comprises polycondensing a borodiphenylsiloxanol of the formula, ##STR12## wherein n is zero or one, at a temperature of from about 140° C. to about 400° C. in the absence of a solvent.
Claim 5
Dependent Claim
45 words
The method of claim 3, wherein the polycondensation is carried out at a temperature of from about 140° C. to about 250° C. for about one hour and further at a temperature of from about 250° C. to about 400° C. for about one hour.
Claim 6
Dependent Claim
16 words
The method of claim 3, wherein the polycondensation is carried out in an inert gas atmosphere.
Claim 7
Dependent Claim
14 words
The method of claim 3, wherein the polycondensation is carried out under reduced pressure.
Claim 8
Dependent Claim
87 words
The method of preparing the polyborodiphenylsiloxane of claim 1 which comprises reacting boric acid with diphenylsilanediol in a mole ratio of the boric acid to the diphenylsiloxanediol of from about 1/3 to about 2/3 at a temperature of from about 80° C. to about 140° C. in the absence of a solvent to form a borodiphenylsiloxanol of the formula, ##STR13## wherein n is zero or one, and polycondensing the borodiphenylsiloxanol at a temperature of about 140° C. to about 400° C. in the absence of a solvent.
References Cited (Backward Citations)
US2517945A
Cited
US3161613A
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FR1547330A
Cited
US3519671A
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US3519670A
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US4152509A
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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) | 1983-10-14 | 1984-04-14 | 1984-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-14 | 1988-04-14 | 1988-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-14 | 1992-04-14 | 1992-10-14 | $7700.00 | Window Closed / Lapsed |