Search Patents
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Patent number: 5308547Abstract: Novel compositions useful as fluid gelling agents, especially for use in subterranean applications such as drilling fluids, are prepared by reacting an aqueous dispersion of a clay, such as bentonite, with an aqueous gel of a monodispersed mixed metal layered hydroxide of the formula Li.sub.m D.sub.d T(OH).sub.(m+2d+3+na) A.sub.a.sup.n, where D is a divalent metal, such as Mg, T is a trivalent metal, such as Al, and A represents other monovalent or polyvalent anions, the formula being described in detail in the disclosure.Type: GrantFiled: November 15, 1991Date of Patent: May 3, 1994Assignee: The Dow Chemical CompanyInventors: John L. Burba, III, Audrey L. Barnes
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Patent number: 5196143Abstract: Novel compositions useful as fluid gelling agents, especially for use in subterranean applications such as drilling fluids, are prepared by reacting an aqueous dispersion of a clay, such as bentonite, with an aqueous gel of a monodispersed mixed metal layered hydroxide of the formula Li.sub.m D.sub.d T(OH).sub.(m+2d+3+na) A.sup.n.sub.a.H.sub.2 O, where x is zero or more representing excess water of hydration, where D is a divalent metal, such as Mg, T is a trivalent metal, such as Al, and A represents other monovalent or polyvalent anions, the formula being described in detail in the disclosure.Type: GrantFiled: May 10, 1991Date of Patent: March 23, 1993Assignee: The Dow Chemical CompanyInventors: John L. Burba, III, Audrey L. Barnes
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Patent number: 5658859Abstract: The present invention relates to a pseudoplastic fluid composition including water, a mixed metal layered hydroxide dispersed in the water to impart preselected rheological properties to the fluid and a fluid loss additive composition including one or more of a carboxymethyl substituted vegetable starch, a carboxymethylated cellulosic compound or mixtures thereof in an amount effective to inhibit loss of fluid and with the degree of substitution being selected so that the carboxymethyl substituted compound is soluble in the fluid at the concentration of use without materially adversely affecting the rheological properties of the fluid and so that the fluid is resistant to fermentation. The improved composition includes a crosslinked carboxymethylated vegetable starch which has a degree of substitution in the broad range from about 0.3 to about 0.8 and in a narrower range of about 0.4 to about 0.Type: GrantFiled: January 30, 1996Date of Patent: August 19, 1997Assignee: Dowell Schlumberger IncorporatedInventors: John L. Burba, III, Lindsay J. Fraser
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Patent number: 5084209Abstract: Crystalline layered mixed metal hydroxides (LMMHs) which are substantially free of unbound water and which conform substantially to the general formulaLi.sub.m D.sub.d T(OH).sub.(3+m+d),wherem represents an amount of Li of from 0 to 3,D represents a divalent metal cation, and d represents an amount of D of from 0 to 8.0,T represents a trivalent metal cation, and (3+m+d) represents an amount which substantially satisfies the valence requirements of Li, D and T, andwhere m+d does not equal zero,are prepared, in an organic reaction medium which is essentially free of unbound water, by mixing predetermined metal organo compounds in predetermined ratios and reacting the metal organo compounds with at least one reagent which supplies OH.sup.- ions to replace the beginning anions in the mixture of metal compounds.A preferred LMMH is one which conforms substantially to the generic formula Mg.sub.d Al(OH).sub.(3+d), where d represents the amount of Mg per each unit of Al.Type: GrantFiled: November 6, 1990Date of Patent: January 28, 1992Assignee: The Dow Chemical CompanyInventors: John L. Burba, III, Steve A. Sims, Thomas M. Knobel
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Patent number: 5418271Abstract: Coating formulations which behave as elastic solids having reversible stress-induced fluidity are prepared by creating a fluid having distributed therein effective amounts of ionic charge sites and countercharge sites. For instance, elastic solids having reversible stress-induced fluidity are prepared by combining liquid formulations with a dispersion of a small, but effective, amount of at least one crystalline mixed metal hydroxide conforming substantially to the formulaLi.sub.m D.sub.d T(OH).sub.(m+2d+3+n.multidot.a) (A.sup.n).sub.a .multidot.xH.sub.2 Owhere m is zero to one, D is a divalent metal, d is from zero to 4, T is a trivalent metal, A represents at least one anion or negative-valence radical of valence n and a is the amount of A, where n is 1 or more, (m+2d+3+n.multidot.a) is equal to or greater than 3, (m+d) is greater than zero, and xH.sub.2 O represents excess waters of hydration, if any.Type: GrantFiled: October 11, 1991Date of Patent: May 23, 1995Assignee: The Dow Chemical CompanyInventors: John L. Burba, III, Peter A. Doty, Christopher P. Christenson, Susan K. Falcone, Andrea H. Hazlitt, Thomas M. Knobel, Wilfred C. Meyer, Arthur E. Read, Jr., Edgar F. Hoy, Avis L. McCrary, Ha Q. Pham, Stanley F. Simpson, Steve A. Sims, Betty J. Smith
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Patent number: 5232627Abstract: Adducts of clay, especially of the smectite variety, most especially bentonite, are prepared with an effective amount of at least one activated mixed metal oxide or oxy-hydroxide (AHMMO) formed by dehydrating hydrotalcite or a mixture comprising magnesium oxide and aluminum oxide, or a crystalline mixed metal hydroxide conforming substantially to the formulaLi.sub.m D.sub.d T(OH).sub.(m+2d+3+n.a) (A.sup.n).sub.a. xH.sub.2 Owhere m is zero to one, D is a divalent metal, d is from zero to 4, T is a trivalent metal, A represents at least one anion or negative-valence radical of valence n, where n is 1 or more, (m+2d+3+n.a) is equal to or greater than 3, (m+d) is greater than zero, and xH.sub.2 O represents excess waters of hydration. These adducts are useful, e.g., in drilling muds and in viscosity modification of a wide variety of fluids.Type: GrantFiled: April 16, 1991Date of Patent: August 3, 1993Assignee: The Dow Chemical CompanyInventors: John L. Burba, III, Arthur E. Read, Jr., Edgar F. Hoy
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Patent number: 5721198Abstract: Elastic solids having reversible stress-induced fluidity are prepared, e.g., by combining liquid formulations with a crystalline mixed metal hydroxide conforming substantially to the formulaLi.sub.m D.sub.d T(OH).sub.(m+2d+3+n.multidot.a) (A.sup.n).sub.a .multidot.xH.sub.2 Owhere m is amount of Li, d is amount of divalent metal D, T is a trivalent metal, A represents at least one anion or negative-valence radical of valence n and a is the amount of A, and xH.sub.2 O represents excess waters of hydration, if any. These make useful coatings.The instantly reversible fluidization of these unique elastic solids may be expressed as:.sigma.=k.sub..alpha. .epsilon. when .epsilon.<F, for the solid phase; and.sigma.=f(d.epsilon.'/dt) when .epsilon.'>F, (this equation represents a generalized form for the usual theological equations); for a cycle of .epsilon., -xF <.epsilon.<xF, and when .epsilon.' equals 0 the liquid phase changes back to the solid phase, andwhere the symbol .sigma. represents stress; k.Type: GrantFiled: August 18, 1995Date of Patent: February 24, 1998Assignee: The Dow Chemical CompanyInventors: John L. Burba, III, Christopher P. Christenson