Process for reversible thickening of a liquid
AssigneeThe Dow Chemical Company
InventorsGene D. Rose, Arthur S. Teot, Peter A. Doty
Life of this patent
Estimating the term…
Abstract
Industrial liquids containing viscoelastic surfactant compositions can be reversibly thickened and broken. For example, a thickened industrial liquid can exhibit good solids carrying capacity, and after the viscosity of the liquid is broken, using techniques such as change in pH, addition of a hydrocarbon, change in temperature, etc., the solids can be easily removed therefrom. Viscosity can be again provided to the industrial liquid without the necessity of adding substantial amounts of additional thickener.
Claims38
A method for reversibly altering the viscosity of an aqueous liquid, the method comprising the steps of contacting the aqueous liquid with an amount of a viscoelastic surfactant comprising a surfactant ion having a hydrophobic moiety chemically bonded to an ionic, hydrophilic moiety and a counterion having a moiety capable of associating with the surfactant ion sufficient to increase the viscosity of the aqueous liquid and breaking the viscosity of the aqueous liquid containing the viscoelectric surfactant by contacting the liquid with an effective amount of a miscible or immiscible hydrocarbon or substituted hydrocarbon such that the viscosity of the liquid can subsequently be substantially restored.
A method for using a thickened aqueous liquid for carrying solids, the method comprising the steps of thickening the aqueous liquid with an amount of a viscoelastic surfactant comprising a surfactant ion having a hydrophobic moiety chemically bonded to an ionic, hydrophilic moiety and a counterion having a moiety capable of associating with the surfactant ion sufficient to provide the aqueous liquid with an improved solids carrying capacity over an unthickened liquid, suspending solids in the thickened liquid, and subsequently breaking the viscosity of the aqueous liquid without the need for increased shear so the solids can more effectively be removed from the liquid than from the thickened liquid.
A method for reversibly altering the viscosity of an aqueous liquid, the method comprising the steps of contacting the aqueous liquid with an amount of a nonionic viscoelastic surfactant comprising a surfactant molecule having a hydrophobic moiety chemically bonded to a nonionic, hydrophilic moiety sufficient to increase the viscosity of the aqueous liquid and breaking the viscosity of the aqueous liquid containing the viscoelastic surfactant by contacting the liquid with an effective amount of a miscible or immiscible hydrocarbon or substituted hydrocarbon, whereby the viscosity of the liquid can subsequently be substantially restored.
A method for reversibly altering the viscosity of an aqueous liquid, the method comprsiing the steps of contacting the aqueous liquid with a viscoelastic surfactant represented by the formula:
- R.sub.1 (Y.sup..sym.)X.sup..crclbar.
- wherein R.sub.1 is a hydrophobic moiety, Y.sup..sym. is a cationic solubilizing moiety chemically bonded to R.sub.1 and X.sup..crclbar. is a counterion associated with Y.sup..sym., the viscoelastic surfactant being employed in an amount sufficient to increase the viscosity of the aqueous liquid, and breaking the viscosity of the aqueous liquid containing the viscoelastic surfactant by contacting the liquid containing the viscoelastic surfactant in a fashion such that the liquid does not need to be subjected to increased shear to reduce the viscosity and the viscosity of the liquid can subsequently be substantially restored.
A method for reversibly altering the viscosity of an aqueous liquid, the method comprising the steps of contacting the aqueous liquid with an amount of a fluoroaliphaitic viscoelastic surfactant compound represented by the formula R.sub.f Z.sup.1 wherein R.sub.f is a saturated or unsaturated fluoroaliphatic moiety and Z.sup.1 is an ionic moiety or potentially ionic moiety sufficient to increase the viscosity of the aqueous liquid and breaking the viscosity of the aqueous liquid containing the viscoelastic surfactant in a fashion such that the liquid does not need to be subjected to increased shear to reduce the viscosity and the viscosity of the liquid can subsequently be substantially restored.
Dependencies are inferred from the claim text.