US4115340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Inversion of water-in-oil emulsions of polyacrylamide in hard water
Assignee: Wyeth Holdings LLC
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Filing: 1977-05-11
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Granted: 1978-09-19
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Expires: 1997-05-11
Abstract
Abstract Anionic water-in-oil emulsions of polyacrylamide are readily inverted in hard water for dissolution of the polymer therein by effecting inversion at a dilution such that insufficient hardness is present to cause emulsion breaking.
Inventors
- 👤 Richard Earl Ellwanger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:31
CPC Classifications
C; C08; C08F; C08F20/00; C08F20/02; C08F20/52; C08F20/54; C08F20/56
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
76 words
A process for inverting an anionic water-in-oil emulsion containing from about 5 to 75 weight percent of a polyacrylamide in hard water as the continuous phase of the inverted emulsion, which process comprises diluting said emulsion with a quantity of hard water which is insufficient to break said emulsion but sufficient to effect inversion to an oil-in-water emulsion, agitating the diluted emulsion to effect inversion, and thereafter diluting the oil-in-water emulsion formed with additional hard water.
Claim 2
Dependent Claim
76 words
A process for inverting an anionic water-in-oil emulsion containing from about 5 to 75 weight percent of a polyacrylamide in hard water as the continuous phase of the inverted emulsion, which process comprises diluting said emulsion with a quantity of hard water which is insufficient to break said emulsion but sufficient to effect inversion to an oil-in-water emulsion, agitating the diluted emulsion to effect inversion, and thereafter diluting the oil-in-water emulsion formed with additional hard water.
Claim 3
Dependent Claim
19 words
The process of claim 1 wherein said anionic water-in-oil emulsion contains 25 weight percent of polymer prior to dilution.
Claim 4
Dependent Claim
17 words
The process of claim 1 wherein said polyacrylamide contains 100 mole percent of repeating units of acrylamide.
Claim 5
Dependent Claim
15 words
The process of claim 1 wherein said hard water contains 400 ppm Ca +2 .
Claim 6
Dependent Claim
15 words
The process of claim 1 wherein said hard water contains 800 ppm Ca +2 .
Claim 7
Dependent Claim
19 words
The process of claim 2 wherein said water-in-oil emulsion is diluted to 2 weight percent of polymer for inversion.
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) | 1981-09-18 | 1982-03-20 | 1982-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-18 | 1986-03-20 | 1986-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-18 | 1990-03-20 | 1990-09-19 | $7700.00 | Window Closed / Lapsed |