US5039771A
Expired / Lapsed
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Method for the preparation of a ladder-type organopolysiloxane
Assignee: Shin-Etsu Chemical Co Ltd
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Filing: 1989-01-16
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Granted: 1991-08-13
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Expires: 2009-01-16
Abstract
Abstract An oligomeric cage-like poly(silsesquioxane) of the general formula ##STR1## in which R is a monovalent hydrocarbon group and m is 4 to 12, can be polymerized by being admixed with a catalyst, e.g. alkali hydroxide or fluoride, and irradiated with microwaves. Different from conventional method of thermal polymerization, the polymerization reaction proceeds very uniformly at a high velocity to give a polymer of a high average molecular weight and narrow molecular weight distribution.
Inventors
- 👤 Takashi Morimoto
- 👤 Hiroshi Yoshioka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:54
CPC Classifications
C; C08; C08G; C08G77/00; C08G77/04; C08G77/06; C08G77/08; C08G77/14; C08G77/16
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
118 words
A method for the preparation of an organopolysiloxane having a ladder-like molecular structure represented by the general formula ##STR5## in which R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms and the subscript n is a positive integer, which comprises the steps of: (a) dispersing an alkali metal hydroxide or alkali metal fluoride as a catalyst in an oligomeric organopolysiloxane having a cage molecular structure represented by the general formula ##STR6## in which R has the same meaning as defined above and the subscript m is a positive integer in the range from 4 to 12, to form a mixture; and (b) irradiating the mixture with electromagnetic waves of a microwave frequency.
Claim 2
Independent Claim
118 words
A method for the preparation of an organopolysiloxane having a ladder-like molecular structure represented by the general formula ##STR5## in which R is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms and the subscript n is a positive integer, which comprises the steps of: (a) dispersing an alkali metal hydroxide or alkali metal fluoride as a catalyst in an oligomeric organopolysiloxane having a cage molecular structure represented by the general formula ##STR6## in which R has the same meaning as defined above and the subscript m is a positive integer in the range from 4 to 12, to form a mixture; and (b) irradiating the mixture with electromagnetic waves of a microwave frequency.
Claim 3
Dependent Claim
32 words
The method for the preparation of an organopolysiloxane having a ladder-like molecular structure as claimed in claim 1 wherein the mixture irradiated with the electromagnetic waves further comprises diphenyl ether or biphenyl.
Claim 4
Dependent Claim
45 words
The method for the preparation of an organopolysiloxane having a ladder-like molecular structure as claimed in claim 2 wherein the amount of the diphenyl ether or biphenyl is in the range from 0.5 to 20% by weight based on the amount of the oligomeric organopolysiloxane.
Claim 5
Dependent Claim
32 words
The method for the preparation of an organopolysiloxane having a ladder-like molecular structure as claimed in claim 1 wherein the catalytic compound is an alkali metal hydroxide or an alkali metal fluoride.
Claim 6
Dependent Claim
43 words
The method for the preparation of an organopolysiloxane having a ladder-like molecular structure as claimed in claim 1 wherein the amount of the catalytic compound is in the range from 0.01 to 5% by weight based on the amount of the oligomeric organopolysiloxane.
Claim 7
Dependent Claim
32 words
The method for the preparation of an organopolysiloxane having a ladder-like molecular structure as claimed in claim 1 wherein the microwaves frequency is in the range from 1000 MHz to 1000 GHz.
Claim 8
Dependent Claim
36 words
The method for the preparation of an organopolysiloxane having a ladder-like molecular structure as claimed in claim 1 wherein the intensity of the irradiation with electromagnetic waves is in the range from 3 to 1000 watts·hour/g.
Claim 9
Dependent Claim
28 words
The method for the preparation of an organopolysiloxane having a ladder-like molecular structure as claimed in claim 1 wherein the group denoted by R is a phenyl group.
References Cited (Backward Citations)
US3294738A
Cited
US3294737A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-08-12 | 1995-02-11 | 1995-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-12 | 1999-02-11 | 1999-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-12 | 2003-02-11 | 2003-08-13 | $7700.00 | Window Closed / Lapsed |