Patent US4042772A successfully refreshed from Google Patents.
US4042772A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Urea as an additive to improve the viscosity and activity of acrylamide-acrylamide acrylic acid polymers prepared from poor quality acrylamide
Assignee: ChampionX LLC
•
Filing: 1976-11-08
•
Granted: 1977-08-16
•
Expires: 1996-11-08
Abstract
Abstract Poor quality acrylamide can be used to produce good quality water-soluble polymers by conducting the polymerization in the presence of urea.
Inventors
- 👤 Edward G. Ballweber
- 👤 Wood E. Hunter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:19
CPC Classifications
C; C08; C08F; C08F20/00; C08F20/02; C08F20/52; C08F20/54; C08F20/56
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
48 words
A method for making good quality acrylamide and acrylamide acrylic acid polymers which contain at least 50% by weight of acrylamide from contaminated acrylamide which comprises polymerizing acrylamide to form a water-soluble acrylamide polymer in the presence of at least 20% by weight based on acrylamide of urea.
Claim 2
Independent Claim
48 words
A method for making good quality acrylamide and acrylamide acrylic acid polymers which contain at least 50% by weight of acrylamide from contaminated acrylamide which comprises polymerizing acrylamide to form a water-soluble acrylamide polymer in the presence of at least 20% by weight based on acrylamide of urea.
Claim 3
Dependent Claim
25 words
The method of claim 1 where the polymerization is a water-in-oil polymerization and the amount of the urea varies between 25 - 75% by weight.
Claim 4
Dependent Claim
14 words
The method of claim 2 where the polymer is an acrylamide acrylic acid copolymer.
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) | 1980-08-15 | 1981-02-14 | 1981-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-15 | 1985-02-14 | 1985-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-15 | 1989-02-14 | 1989-08-16 | $7700.00 | Window Closed / Lapsed |