US3891607A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of thermoreversible coacervates
Assignee: Bayer AG
•
Filing: 1973-08-21
•
Granted: 1975-06-24
•
Expires: 1993-08-21
Abstract
Abstract A thermoreversible coacervate obtained by copolymerising acrylic acid and acrylamide in aqueous solution and by adjusting the pHvalue of said solution to below 3.3 and the temperature to below the coacervate transition temperature.
Inventors
- 👤 Rainer Kuhn
- 👤 Nikolaus Schon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:15
CPC Classifications
C; C08; C08F; C08F220/00; C08F220/02; C08F220/04; C08F220/06; C08F20/00; C08F20/02; C08F20/52; C08F20/54; C08F20/56
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
88 words
A PROCESS FOR THE PRODUCTION OF A THERMOREVERSIBLE COACERVATE WHICH COMPRISES COPOLYMERIZING FROM 30 TO 50 MOL PERCENT OF ACRYLIC ACID AND FROM 70 TO 30 MOL PERCENT OF ACRYLAMIDE IN AQUEOUS SOLUTION IN THE PRESENCE OF A FREE-RADICAL CATALYST AND IN THE ABSENCE OF A WATER-SOLUBLE INORGANIC SALT AT A TEMPERATURE BETWEEN TO COACERVATE TRANSITION TEMPERATURE AND 100*C., LOWERING THE PH-VALUE OF THE SOLUTION EITHER PRIOR TO, DURING OR AFTER POLYMERIZATION TO BELOW 3.3 AND ADJUSTING THE TEMPERATURE OF THE SOLUTION TO BELOW THE COACERVATE TRANSITION TEMPERATURE.
Claim 2
Dependent Claim
88 words
A PROCESS FOR THE PRODUCTION OF A THERMOREVERSIBLE COACERVATE WHICH COMPRISES COPOLYMERIZING FROM 30 TO 50 MOL PERCENT OF ACRYLIC ACID AND FROM 70 TO 30 MOL PERCENT OF ACRYLAMIDE IN AQUEOUS SOLUTION IN THE PRESENCE OF A FREE-RADICAL CATALYST AND IN THE ABSENCE OF A WATER-SOLUBLE INORGANIC SALT AT A TEMPERATURE BETWEEN TO COACERVATE TRANSITION TEMPERATURE AND 100*C., LOWERING THE PH-VALUE OF THE SOLUTION EITHER PRIOR TO, DURING OR AFTER POLYMERIZATION TO BELOW 3.3 AND ADJUSTING THE TEMPERATURE OF THE SOLUTION TO BELOW THE COACERVATE TRANSITION TEMPERATURE.
Claim 3
Dependent Claim
17 words
The process of claim 1 wherein the molar ratio of acrylic acid to acrylamide is about 1:1.
Claim 4
Dependent Claim
33 words
The process of claim 1 wherein the total concentration of acrylic acid and acrylamide in said aqueous solution is from 3 to 30 percent by weight, based on the weight of the water.
Claim 5
Dependent Claim
33 words
The process of claim 1 wherein the total concentration of acrylic acid and acrylamide in said aqueous solution is from 5 to 15 percent by weight, based on the weight of the water.
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) | 1978-06-23 | 1978-12-23 | 1979-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-23 | 1982-12-23 | 1983-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-23 | 1986-12-23 | 1987-06-24 | $7700.00 | Window Closed / Lapsed |