US4385155A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing crosslinked poly(vinyl alcohol)
Assignee: WR Grace and Co
•
Filing: 1981-12-02
•
Granted: 1983-05-24
•
Expires: 2001-12-02
Abstract
Abstract Poly(vinyl acetate) latex reacted with an aldehyde at acid pH to prepare crosslinked poly(vinyl alcohol) suitable as water-loss agent in drilling fluids.
Inventors
- 👤 Alan S. Michaels
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:28
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/28; Y; Y10; Y10S; Y10S507/00; Y10S507/903
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
41 words
Method of preparing crosslinked poly(vinyl alcohol) comrpising reacting poly(vinyl acetate) latex with an aldehyde in an aqueous medium at a pH of about 0-4, with the weight ratio of poly(vinyl acetate):aldehyde of about 50-200:1, and removing the resulting crosslinked poly(vinyl alcohol).
Claim 2
Dependent Claim
41 words
Method of preparing crosslinked poly(vinyl alcohol) comrpising reacting poly(vinyl acetate) latex with an aldehyde in an aqueous medium at a pH of about 0-4, with the weight ratio of poly(vinyl acetate):aldehyde of about 50-200:1, and removing the resulting crosslinked poly(vinyl alcohol).
Claim 3
Dependent Claim
23 words
Method according to claim 1 in which the aldehyde is a monomer selected from the group consisting of formaldehyde, paraformaldehyde, glyoxal, or glutaraldehyde.
Claim 4
Dependent Claim
43 words
Method according to claim 2 in which the aldehyde is formaldehyde, the pH is about 1.0-1.5; the latex at least is about 5% by weight of poly(vinyl acetate); the reaction temperature is about 20°-100° C.; and the reaction time is about 0.5-24 hours.
Claim 5
Dependent Claim
64 words
Method according to claim 3 in which about 100 parts by weight of poly(vinyl acetate) latex containing about 55% poly(vinyl acetate) by weight is acidified to pH 1.0 with hydrochloric acid; 1.3 parts by weight of 37% formaldehyde by weight is added; the reaction mixture is heated to about 80° C. for about 5 hours with stirring; and the product is recovered and dried.
Claim 6
Dependent Claim
14 words
Method according to claim 4 in which the aqueous medium contains 16% sodium sulfate.
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) | 1986-05-23 | 1986-11-22 | 1987-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-23 | 1990-11-22 | 1991-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-23 | 1994-11-22 | 1995-05-24 | $7700.00 | Window Closed / Lapsed |