Patents Assigned to Stone Chemical Company
  • Compositions for removing lead from metal surfaces
    Patent number: 8618038
    Abstract: The invention provides an aqueous composition that includes a hydroxy-substituted mono-, di-, or tri-carboxylic acid; phosphoric acid; a surfactant; and water. The invention further provides a method for removing lead from the surface of metal, the method includes contacting a metal surface with an aqueous composition that includes a hydroxy-substituted mono-, di-, or tri-carboxylic acid; phosphoric acid; a surfactant; and water; to provide a metal surface with a reduced amount of leachable lead. The leachable lead on the surface of the metal can be reduced to below 1 ppb by using the composition described herein.
    Type: Grant
    Filed: June 23, 2010
    Date of Patent: December 31, 2013
    Assignee: Stone Chemical Company
    Inventors: David Hunt, George Kuhlmann
  • Compositions and methods for removing lead from metal surfaces
    Patent number: 7771542
    Abstract: The invention provides an aqueous composition that includes a hydroxy-substituted mono-, di-, or tri-carboxylic acid; phosphoric acid; a surfactant; and water. The invention further provides a method for removing lead from the surface of metal, the method includes contacting a metal surface with an aqueous composition that includes a hydroxy-substituted mono-, di-, or tri-carboxylic acid; phosphoric acid; a surfactant; and water; to provide a metal surface with a reduced amount of leachable lead. The leachable lead on the surface of the metal can be reduced to below 1 ppb by using the composition described herein.
    Type: Grant
    Filed: May 24, 2007
    Date of Patent: August 10, 2010
    Assignee: Stone Chemical Company
    Inventors: David Hunt, George Kuhlmann