Colloid systems and wetting agents; subcombinations thereof; pro – Continuous liquid or supercritical phase: colloid systems;... – Aqueous continuous liquid phase and discontinuous phase...
Reexamination Certificate
2001-07-06
2004-12-14
Metzmaier, Daniel S. (Department: 1712)
Colloid systems and wetting agents; subcombinations thereof; pro
Continuous liquid or supercritical phase: colloid systems;...
Aqueous continuous liquid phase and discontinuous phase...
C516S067000, C516S071000, C516S077000, C252S077000, C507S922000, C507S924000, C510S480000, C510S490000, C510S502000, C510S503000
Reexamination Certificate
active
06831108
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to viscoelastic fluids which contain a surfactant and to methods of suspending particles using such viscoelastic fluids.
BACKGROUND OF THE INVENTION
It is known to thicken the aqueous phase of a suspension of solid particles or emulsified droplets. The addition of thickeners increases the viscosity of the aqueous phase and thereby retards settling of the particles or droplets. Such retardation is useful to maintain the particles or droplets in suspension during the storage, use, and/or transport of the suspension
Polymeric thickeners, e.g. starches, which thicken by entanglement of the polymeric chains, have been used to viscosify the aqueous phase of suspensions. Such thickeners can degrade under the influence of mechanical shear or chemical scission (e.g. by oxidation or hydrolysis) of the polymeric chains which results in a loss of viscosity and, thus, suspension stability.
Cationic surfactants have been found which form rod-like micelles under certain conditions. The presence of the rod-like micelles imparts to the fluid viscoelastic properties. However, cationic surfactants tend to have high toxicity and very low biodegradability.
SUMMARY OF THE INVENTION
The present invention provides a viscoelastic fluid useful as a thickener for the suspension of particles. The viscoelastic fluids consist of an amphoteric/zwitterionic surfactant and an organic acid/salt and/or inorganic salts.
Thus, this invention specifically relates to a viscoelastic fluid comprising:
(1) an aqueous medium;
(2) an amount of a surfactant selected from the group consisting of amphoteric surfactants, zwitterionic surfactants, and mixtures thereof, effective to render said aqueous medium viscoelastic; and
(3) a member selected from the group consisting of organic acids, organic acid salts, inorganic salts, and combinations of one or more organic acids or organic acid salts with one or more inorganic salts.
In yet another embodiment of the present invention, the invention relates to a viscoelastic fluid consisting essentially of:
(1) an aqueous medium;
(2) an amount of a surfactant comprising an amine oxide surfactant; and
(3) an anionic surfactant containing a hydrophobe having at least 14 carbon atoms.
The term “viscoelastic” refers to those viscous fluids having elastic properties, i.e., the liquid at least partially returns to its original form when an applied stress is released. The thickened aqueous viscoelastic fluids are useful as water-based hydraulic fluids in lubricant and hydraulic fracturing fluids to increase permeability in oil production.
The present invention also relates to a method for distributing suspended solid particles such as excavation by-products in a fluid comprised of the viscoelastic fluid of this invention, wherein the solid particles remain suspended for an extended period of time to a side, by transporting the fluid to a site while the solid particles remain suspended in the fluid and depositing the fluid to such site.
This invention also relates to a method for fracturing a subterranean formation comprising pumping the inventive viscoelastic fluid through a wellbore and into a subterranean formation at a pressure sufficient to fracture the formation.
This invention also relates to a detergent formulation comprising a detersive surfactant in admixture with a viscoelastic fluid of this invention.
This invention also relates to the use of the viscoelastic fluid as a drift control agent for agricultural formulations. In this regard, this invention relates to an aqueous formulation of an agricultural chemical and an amount of the viscoelastic fluid of this invention sufficient to increase the average droplet size of a spray of said formulation.
REFERENCES:
patent: RE28945 (1976-08-01), Miscovich et al.
patent: 4615825 (1986-10-01), Teot et al.
patent: 4735731 (1988-04-01), Rose et al.
patent: 4806256 (1989-02-01), Rose et al.
patent: 5055219 (1991-10-01), Smith
patent: 5076359 (1991-12-01), Yeh
patent: 5202112 (1993-04-01), Prencipe et al.
patent: 5258137 (1993-11-01), Bonekamp et al.
patent: 5439317 (1995-08-01), Bishop et al.
patent: 5470383 (1995-11-01), Schermann et al.
patent: 5536437 (1996-07-01), Motyka
patent: 5551516 (1996-09-01), Norman et al.
patent: 5556628 (1996-09-01), Derian et al.
patent: 5575921 (1996-11-01), Askin et al.
patent: 5591377 (1997-01-01), Nickel et al.
patent: 5607678 (1997-03-01), Moore et al.
patent: 5624891 (1997-04-01), Smialowicz et al.
patent: 5639722 (1997-06-01), Kong et al.
patent: 5728665 (1998-03-01), Choy et al.
patent: 6258859 (2001-07-01), Dahayanake et al.
patent: 6482866 (2002-11-01), Dahayanake et al.
patent: 1298697 (1992-04-01), None
patent: 0 681 832 (1995-03-01), None
Flow Birefringence and Rheological Measurements on Viscoelastic Detergent Solutions, H. Hoffmann, M. Lobel and U. Reilage, Lehrstuhl fur Physikalisohe Chemie der Universitat Bayreuth Universilatsstrape 30, D-8580 Bayreuth, B.R.D., pp. 237-260, date unknown.
Phase Structure and Rheological Properties of a Mixed Zwitterionic/Anionic Surfactant System, Dorothy Saul, Gordon J. T. Tiddy, Barbara A. Wheeler, Phillip A. Wheeler, and Edwin Willis, Unilever Research Port Sunlight Laboratory, Port Sunlight, Wirral, Cheshire L62 4XN, Jul. 5th, 1973, pp. 163-170.
Influence of Ionic Surfactants and the Viscoelastic Properties of Zwitterionic Surfactant Solutions, H. Hoffman, A. Rauscher, M. Gradzielski, and S.F. Schulz, Lehrstuhl fur Physikalische Chemie, Universitat Bayreuth, Universitutstrasse 30, W-8580 Bayreuth, Germany, May 18, 1992, pp. 2140-2146.
Dahanayake Manilal S.
Derian Paul Joel
Dino David
Li Ruoxin
Niu Joseph H. Y.
Metzmaier Daniel S.
Ohlandt Greeley Ruggiero & Perle LLP
Rhodia Inc.
LandOfFree
Viscoelastic surfactant fluids and related methods of use does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Viscoelastic surfactant fluids and related methods of use, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Viscoelastic surfactant fluids and related methods of use will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3304895