Patents by Inventor Nancy A. Rao

Nancy A. Rao has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5312879
    Abstract: A method for preparing an advanced epoxy cationic resin from an epoxy resin containing oxirane groups by converting at least some of the oxirane groups to cationic groups is improved by using as the epoxy-based resin a blend of (I) an epoxy resin obtained by reacting in the presence of a suitable catalyst (1) a diglycidylether of an aliphatic diol which diol is essentially free of ether oxygen atoms, such as a condensation product of 1,4-butanediol and epichlorohydrin, optionally (2) a diglycidylether of a dihydric phenol, for example a diglycidyl ether of bisphenol A, (3) a dihydric phenol such as bisphenol A, and optionally (4) a capping agent such as p-nonylphenol and (II) a different cationic epoxy resin. Such resin blends can be utilized in cathodic electrodeposition coating systems.
    Type: Grant
    Filed: July 16, 1993
    Date of Patent: May 17, 1994
    Assignee: The Dow Chemical Company
    Inventors: Nancy A. Rao, Richard A. Hickner
  • Patent number: 5260355
    Abstract: A method for preparing an advanced epoxy cationic resin from an epoxy-based resin containing oxirane groups by converting at least some of the oxirane groups to cationic groups is improved by using as the epoxy-based resin a blend of (I) an epoxy-based resin obtained by reacting in the presence of a suitable catalyst (1) a diglycidylether of an aliphatic diol which diol is essentially free of ether oxygen atoms, such as a condensation product of 1,4-butanediol and epichlorohydrin, optionally (2) a diglycidylether of a dihydric phenol, for example a diglycidyl ether of bisphenol A, (3) a dihydric phenol such as bisphenol A, and optionally (4) a capping agent such as p-nonylphenol and (II) a different cationic epoxy-based resin. Such resin blends can be utilized in cathodic electrodeposition coating systems.
    Type: Grant
    Filed: February 22, 1993
    Date of Patent: November 9, 1993
    Assignee: The Dow Chemical Company
    Inventors: Nancy A. Rao, Richard A. Hickner
  • Patent number: 5206274
    Abstract: A method for preparing an advanced epoxy cationic resin from an epoxy-based resin containing oxirane groups by converting at least some of the oxirane groups to cationic groups is improved by using as the epoxy-based resin a blend of (I) an epoxy-based resin obtained by reacting in the presence of a suitable catalyst (1) a diglycidylether of an aliphatic diol which diol is essentially free of ether oxygen atoms, such as a condensation product of 1,4-butanediol and epichlorohydrin, optionally (2) a diglycidylether of a dihydric phenol, for example a diglycidyl ether of bisphenol A, (3) a dihydric phenol such as bisphenol A, and optionally (4) a capping agent such as p-nonylphenol and (II) a different cationic epoxy-based resin. Such resin blends can be utilized in cathodic electrodeposition coating systems.
    Type: Grant
    Filed: June 21, 1991
    Date of Patent: April 27, 1993
    Assignee: The Dow Chemical Company
    Inventors: Nancy A. Rao, Richard A. Hickner
  • Patent number: 5064880
    Abstract: A method for preparing an advanced epoxy cationic resin from an epoxy-based resin containing oxirane groups by converting at least some of the oxirane groups to cationic groups is improved by using as the epoxy-based resin a blend of (I) an epoxy-based resin obtained by reacting in the presence of a suitable catalyst (1) a diglycidylether of an aliphatic diol which diol is essentially free of ether oxygen atoms, such as a condensation product of 1,4-butanediol and epichlorohydrin, optionally (2) a diglycidylether of a dihydric phenol, for example a diglycidyl ether of bisphenol A, (3) a dihydric phenol such as bisphenol A, and optionally (4) a capping agent such as p-nonylphenol and (II) a different cationic epoxy-based resin. Such resin blends can be utilized in cathodic electrodeposition coating systems.
    Type: Grant
    Filed: September 8, 1989
    Date of Patent: November 12, 1991
    Assignee: The Dow Chemical Company
    Inventors: Nancy A. Rao, Richard A. Hickner
  • Patent number: 4980397
    Abstract: A method for preparing an advanced epoxy cationic resin from an opoxy-based resin containing oxirane groups by converting at least some of the oxirane groups to cationic groups, wherein the improvement is using as the epoxy-based resin an advanced epoxy resin obtained by reacting in the presence of a suitable catalyst (1) a diglycidylether of an aliphatic diol which is essentially free of ether oxygen atoms, such as a diglycidyl ether of 1,4-butanediol, (2) a diglycidylether of a dihydric phenol, for example a diglycidyl ether of bisphenol A and (3) a dihydric phenol such as bisphenol A and optionally a capping agent such as p-nonylphenol.Coating compositions suitable for electro-deposition are prepared from the product obtained by the process.
    Type: Grant
    Filed: July 6, 1989
    Date of Patent: December 25, 1990
    Assignee: The Dow Chemical Company
    Inventors: Nancy A. Rao, Richard A. Hickner
  • Patent number: 4977202
    Abstract: A method for preparing an advanced epoxy cationic resin from an epoxy-based resin containing oxirane groups by converting at least some of the oxirane groups to cationic groups, wherein the improvement is using as the epoxy-based resin an advanced epoxy resin obtained by reacting in the presence of a suitable catalyst (1) a diglycidylether of an aliphatic diol which is essentially free of ether oxygen atoms, such as a diglycidyl ether of 1,4-butanediol, (2) a digylcidylether of a dihydric phenol, for example a diglycidyl ether of bisphenol A and (3) a dihydric phenol such as bisphenol A and optionally a capping agent such as p-nonylphenol.Coating compositions suitable for electrodeposition are prepared from the product obtained by the process.
    Type: Grant
    Filed: July 6, 1989
    Date of Patent: December 11, 1990
    Assignee: The Dow Chemical Company
    Inventors: Nancy A. Rao, Richard A. Hickner
  • Patent number: 4946569
    Abstract: A method for preparing an advanced epoxy cationic resin from an epoxy-based resin containing oxirane groups by converting at least some of the oxirane groups to cationic groups, wherein the improvement is using as the epoxy-based resin a blend of (I) an epoxy-based resin obtained by reacting in the presence of a suitable catalyst (1) a diglycidylether of a polyetherpolyol, such as a condensation product of dipropylene glycol and epichlorohydrin having an epoxy equivalent weight of 185, optionally (2) a diglycidylether of a dihydric phenol, for example a diglycidyl ether of bisphenol A, (3) a dihydric phenol such as bisphenol A, and optionally (4) a capping agent such as p-nonylphenol and (II) a different cationic epoxy-based resin. Such resin blends can be utilized in cathodic electrodeposition coating systems. Use of the diglycidylether of a polyetherpolyol provides coating compositions with lower viscosity and produces deposition coatings of higher film build than compositions without this component.
    Type: Grant
    Filed: January 17, 1989
    Date of Patent: August 7, 1990
    Assignee: The Dow Chemical Company
    Inventors: John M. McIntyre, Nancy A. Rao, Richard A. Hickner
  • Patent number: 4883572
    Abstract: A method for preparing an advanced epoxy cationic resin from an epoxy-based resin containing oxirane groups by converting at least some of the oxirane groups to cationic groups is improved by using as the epoxy-based resin a blend of (I) an epoxy-based resin obtained by reacting in the presence of a suitable catalyst (1) a diglycidylether of an aliphatic diol which diol is essentially free of ether oxygen atoms, such as a condensation product of 1,4-butanediol and epichlorohydrin, optionally (2) a diglycidylether of a diphenol, or example a diglycidyl ether of disphenol A, (3) a diphenol such as bisphenol A, and optionally (4) a capping agent such as p-nonylphenol and (II) a different cationic opoxy-based resin. Such resin blends can be utilized in cathodic electrodeposition coating systems.
    Type: Grant
    Filed: July 2, 1987
    Date of Patent: November 28, 1989
    Assignee: The Dow Chemical Company
    Inventors: Nancy A. Rao, Richard A. Hickner
  • Patent number: 4872961
    Abstract: Cathodic electrodepositable coating compositions comprising an aqueous dispersion of (1) at least one cationic epoxy-based resin, (2) at least one blocked isocyanate crosslinker, and (3) a solvent system containing one or more organic solvents are improved by (a) employing a blocked isocyanate crosslinker which deblocks at a temperature of less than about 160.degree. C., and (b) employing as the solvent system, one which is substantially free of any organic solvent which will react with isocyanate groups at the temperature employed to cure said coating.
    Type: Grant
    Filed: August 28, 1987
    Date of Patent: October 10, 1989
    Assignee: The Dow Chemical Company
    Inventors: John M. McIntyre, Kenneth W. Anderson, Nancy A. Rao, Richard A. Hickner
  • Patent number: 4868230
    Abstract: A method for preparing an advanced epoxy cationic resin from an epoxy-based resin containing oxirane groups by converting at least some of the oxirane groups to cationic groups, wherein the improvement is using as the epoxy-based resin an advanced epoxy resin obtained by reacting in the presence of a suitable catalyst (1) a diglycidylether of an aliphatic diol which is essentially free of ether oxygen atoms, such as a diglycidyl ether of 1,4-butanediol, (2) a diglycidylether of a dihydric phenol, for example a diglycidyl ether of bisphenol A and (3) a dihydric phenol such as bisphenol A and optionally a capping agent such as p-nonylphenol.Coating compositions suitable for electrodeposition are prepared from the product obtained by the process.
    Type: Grant
    Filed: July 2, 1987
    Date of Patent: September 19, 1989
    Assignee: The Dow Chemical Company
    Inventors: Nancy A. Rao, Richard A. Hickner
  • Patent number: 4829104
    Abstract: A method for preparing an advanced epoxy cationic resin from an epoxy-based resin containing oxirane groups by converting at least some of the oxirane groups to cationic groups, wherein the improvement is using as the epoxy-based resin a blend of (I) an epoxy-based resin obtained by reacting in the presence of a suitable catalyst (1) a diglycidylether of a polyetherpolyol, such as a condensation product of dipropylene glycol and epichlorohydrin having an epoxy equivalent weight of 185, optionally (2) a diglycidylether of a dihydric phenol, for example a diglycidyl ether of bisphenol A, (3) a dihydric phenol such as bisphenol A, and optionally (4) a capping agent such as p-nonylphenol and (II) a different cationic epoxy-based resin. Such resin blends can be utilized in cathodic electrodeposition coating systems. Use of the diglycidylether of a polyetherpolyol provides coating compositions with lower viscosity and produces deposition coatings of higher film build than compositions without this component.
    Type: Grant
    Filed: July 18, 1986
    Date of Patent: May 9, 1989
    Assignee: The Dow Chemical Company
    Inventors: John M. McIntyre, Richard A. Hickner, Nancy A. Rao