US3853932A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing silanol end-stopped polymers of low molecular weight
Assignee: General Electric Co
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Filing: 1973-12-28
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Granted: 1974-12-10
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Expires: 1993-12-28
Abstract
Abstract A process for producing low molecular weight silanol end-stopped diorganopolysiloxane polymers comprising contacting a cyclic diorganotrisiloxane with an acid-activated hydroaluminum silicate clay which is preferably a sulfuric acid-activated montomorillonite clay in the presence of water and a polar organic solvent and separating the desired product. The cyclictrisiloxane, water and a polar solvent are preferably present in a uniform homogeneous phase at the time the acidactivated hydroaluminum silicate clay catalyst is introduced into the system for producing the silanol end-stopped diorganopolysiloxane polymers containing an average of three to 10 diorganosiloxy units.
Inventors
- 👤 J Razzano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:08
CPC Classifications
C; C07; C07F; C07F7/00; C07F7/02; C07F7/08; C07F7/0834; C07F7/0838; C07F7/0872; C07F7/0874; C08; C08G; C08G77/00; C08G77/04; C08G77/14; C08G77/16
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
20 words
A PROCESS FOR PRODUCING LOW MOLECULAR WEIGHT SILANOL END-STOPPED DIORGANOPOLYSILOXANE POLYMERS COMPRISING (A) CONTACTING A CYCLIC TRIMER OF THE FORMULA,
Claim 2
Dependent Claim
20 words
A PROCESS FOR PRODUCING LOW MOLECULAR WEIGHT SILANOL END-STOPPED DIORGANOPOLYSILOXANE POLYMERS COMPRISING (A) CONTACTING A CYCLIC TRIMER OF THE FORMULA,
Claim 3
Dependent Claim
21 words
The process of claim 1 in which the cyclic trimer, water and polar solvent are present in a uniform homogeneous phase.
Claim 4
Dependent Claim
20 words
The process of claim 1 wherein the polar solvent is selected from the class consisting of acetone, dioxane, and tetrahydrofuran.
Claim 5
Dependent Claim
52 words
The process of claim 1 wherein in step (a) there is present 0.1 to 10 parts of acid-activated hydroaluminum silicate clay per 100 parts of the trimer, 0.5 to 10 parts of the polar solvent per part of the trimer and 0.05 to 1 parts of water per part of the trimer.
Claim 6
Dependent Claim
29 words
The process of claim 1 wherein step (a) is carried out at a temperature in the range of 50*-80* C for a time period of 2 to 12 hours.
Claim 7
Dependent Claim
17 words
The process of claim 1 wherein the acidactivated hydroaluminum silicate is a sulfuric acid treated montomortillonate clay.
Claim 8
Dependent Claim
102 words
The process of claim 1 further comprising adding in step (b) 0.1 to 5 parts of MgO per part of the acid treated hydroaluminum silicate clay, stripping the polar solvent at a temperature in the range of 20*-60* C, and at a pressure of 100-200 mm of Hg pressure, filtering out the MgO and acid-activated hydroaluminum silicate clay and stripping off the low boiling siloxanes and water at a temperature in the range of 100*-140*C at a pressure of 10-100 mm of Hg so as to obtain the desired silanolstopped diorganopolysiloxane having an average of anywhere from three to 10 diorganosiloxy units.
Claim 9
Dependent Claim
82 words
The process of claim 1 further comprising in step (b) filtering out the acid-activated hydroaluminum silicate clay, stripping off the acetone at a temperature in the range of 20*-60* C at a pressure of 100-200 mm of Hg, stripping out the low boiling siloxanes and water at a temperature in the range of 100*-140* C at a pressure of 10-100 mm of Hg so as to obtain the desired silanolstopped diorganopolysiloxane having an average of anywhere from three to 10 diorganosiloxy units.
Claim 10
Dependent Claim
19 words
The process of claim 1 wherein R is selected from the class consisting of methyl, ethyl, vinyl and phenyl.
Claim 11
Dependent Claim
20 words
The process of claim 1 wherein R is selected from the class consisting of CH3-, CH3CH2-, CF3CH2CH2- and mixtures thereof.
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) | 1977-12-09 | 1978-06-10 | 1978-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-09 | 1982-06-10 | 1982-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-09 | 1986-06-10 | 1986-12-10 | $7700.00 | Window Closed / Lapsed |