US4599437A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Continuous process for varying molecular weight of organopolysiloxanes
Assignee: Wacker Chemie AG
•
Filing: 1985-08-19
•
Granted: 1986-07-08
•
Expires: 2005-08-19
Abstract
Abstract In a process for varying the molecular weight of linear or cyclic organopolysiloxanes in the presence of a catalyst which is solid in the reaction mixture at the reaction temperature, the improvement comprising that the catalyst which is solid in the reaction mixture at least at the respective reaction temperature and the organopolysiloxane whose molecular weight is to be changed are continuously and simultaneously passed through a heated cylindrical reactor whose contents is mechanically moved, the reactor having a length to inside diameter ratio of 1:1 to 20:1 and its interior pressure being held at 50 to 500 hPa (abs.) and the catalyst is removed from the mixture after leaving the reactor.
Inventors
- 👤 Manfred Riederer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:05
CPC Classifications
C; C07; C07F; C07F7/00; C07F7/02; C07F7/21; C07F7/08; C07F7/0834; C07F7/0838; C07F7/0872; C07F7/0874; C08; C08G; C08G77/00; C08G77/04; C08G77/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
112 words
In a process for varying the molecular weight of linear or cyclic organopolysiloxanes in the presence of a catalyst which is solid in the reaction mixture at the reaction temperature, the improvement comprising that the catalyst which is solid in the reaction mixture at least at the respective reaction temperature and the organopolysiloxane whose molecular weight is to be changed are continuously and simultaneously passed through a heated cylindrical reactor whose contents is mechanically moved, the reactor having a length to inside diameter ratio of 1:1 to 20:1 and its interior pressure being held at 50 to 500 hPa (abs.) and the catalyst is removed from the mixture after leaving the reactor.
Claim 2
Dependent Claim
112 words
In a process for varying the molecular weight of linear or cyclic organopolysiloxanes in the presence of a catalyst which is solid in the reaction mixture at the reaction temperature, the improvement comprising that the catalyst which is solid in the reaction mixture at least at the respective reaction temperature and the organopolysiloxane whose molecular weight is to be changed are continuously and simultaneously passed through a heated cylindrical reactor whose contents is mechanically moved, the reactor having a length to inside diameter ratio of 1:1 to 20:1 and its interior pressure being held at 50 to 500 hPa (abs.) and the catalyst is removed from the mixture after leaving the reactor.
Claim 3
Dependent Claim
22 words
The process of claim 1 wherein the catalyst solid in the reaction mixture at the reaction temperature is an acid-activated bleaching earth.
Claim 4
Dependent Claim
20 words
The process of claim 1 wherein the catalyst solid in the reaction mixture at the reaction temperature is acid-activated montmorillonite.
Claim 5
Dependent Claim
17 words
The process of claim 1 wherein the particle size of the catalyst is at most 180 mm.
Claim 6
Dependent Claim
24 words
The process of claim 1 wherein the amount of catalyst is 0.1 to 30% by weight based on the total weight of organosilicon compound.
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) | 1989-07-07 | 1990-01-06 | 1990-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-07 | 1994-01-06 | 1994-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-07 | 1998-01-06 | 1998-07-08 | $7700.00 | Window Closed / Lapsed |