US4752339A
Expired / Lapsed
US
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Thixotropic aqueous solutions containing a divinylsulfone-crosslinked polygalactomannan gum
Assignee: Stein Hall and Co Inc
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Filing: 1983-10-31
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Granted: 1988-06-21
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Expires: 2003-10-31
Abstract
Abstract This invention provides a process for preparing a viscoelastic aqueous solution which contains divinylsulfone-crosslinked polygalactomannan gum that is formed in situ. An invention thixotropic aqueous medium is characterized by excellent heat/shear stability and high tolerance to the presence of inorganic salts. A unique property of an invention thixotropic aqueous medium is a time-dependent gradual restoration of high viscosity after cessation of high shear deformation.
Inventors
- 👤 Rachel S. Kohn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 05:25
CPC Classifications
C; C08; C08B; C08B37/00; C08B37/006; C08B37/0087; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/06; C09K8/08; E; E21; E21B; E21B21/00; E21B21/003
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
121 words
A process for producing a thixotropic aqueous solution containing water-soluble divinylsulfone-crosslinked polygalactomannan gum which comprises dissolving in an aqueous medium constituents comprising (1) polygalactomannan gum, (2) between about 0.1-10 weight percent of divinylsulfone, based on the weight of polygalactomannan gum, and (3) a water-soluble basic reagent; wherein the product thixotropic solution at a 1.0 weight percent content level of the polygalactomannan gum exhibits a viscosity of 10,000-120,000 centipoises at a shear rate of 0.3 reciprocal seconds, a viscosity of 300-10,000 centipoises at a shear rate of 5 reciprocal seconds, and a viscosity of 50-300 centipoises at a shear rate of 500 reciprocal seconds, and wherein the solution has the ability to recover the low-shear high-viscosity state over an elapsed time period.
Claim 2
Dependent Claim
121 words
A process for producing a thixotropic aqueous solution containing water-soluble divinylsulfone-crosslinked polygalactomannan gum which comprises dissolving in an aqueous medium constituents comprising (1) polygalactomannan gum, (2) between about 0.1-10 weight percent of divinylsulfone, based on the weight of polygalactomannan gum, and (3) a water-soluble basic reagent; wherein the product thixotropic solution at a 1.0 weight percent content level of the polygalactomannan gum exhibits a viscosity of 10,000-120,000 centipoises at a shear rate of 0.3 reciprocal seconds, a viscosity of 300-10,000 centipoises at a shear rate of 5 reciprocal seconds, and a viscosity of 50-300 centipoises at a shear rate of 500 reciprocal seconds, and wherein the solution has the ability to recover the low-shear high-viscosity state over an elapsed time period.
Claim 3
Dependent Claim
21 words
A process in accordance with claim 1 wherein the polygalactomannan gum is guar gum or an ether derivative of guar gum.
Claim 4
Dependent Claim
23 words
A process in accordance with claim 1 wherein the polygalactomannan gum is locust bean gum or an ether derivative of locust bean gum.
Claim 5
Dependent Claim
15 words
A process in accordance with claim 1 wherein the basic reagent is an inorganic salt.
Claim 6
Dependent Claim
16 words
A process in accordance with claim 1 wherein the basic reagent is an alkali metal salt.
Claim 7
Dependent Claim
15 words
A process in accordance with claim 1 wherein the basic reagent is alkali metal hydroxide.
Claim 8
Dependent Claim
15 words
A process in accordance with claim 1 wherein the basic reagent is alkali metal carbonate.
Claim 9
Dependent Claim
24 words
A process in accordance with claim 1 wherein divinylsulfone crosslinking of polygalactomannan gum occurs in the aqueous solution at a pH above about 7.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-06-21 | 1991-12-21 | 1992-06-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-21 | 1995-12-21 | 1996-06-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-21 | 1999-12-21 | 2000-06-21 | $7700.00 | Window Closed / Lapsed |