Patents by Inventor Sandra L. Witman

Sandra L. Witman 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).

  • Self-dispersing pigment and process of making and use of same
    Patent number: 6852156
    Abstract: A process is provided in which a pigment is oxidated with ozone in an aqueous environment in which the mixture of ozone, water and pigment is subjected to a dispersive mixing operation; and/or the pH of the mixture is maintained in a range of 6-8, whereby the pigment is self-dispersing and preferably has an acid value of less than 3 ?moles/M2. Pigments from this process and ink jet inks containing the self-dispersing pigments, are also provided.
    Type: Grant
    Filed: May 23, 2001
    Date of Patent: February 8, 2005
    Assignee: E.I. du Pont de Nemours and Company
    Inventors: An-Gong Yeh, Michael J. Eiseman, Robert Paul Held, James L. Hohman, Dhiren V. Patel, Yia-Ching Ray, Harry Joseph Spinelli, Sandra L. Witman
  • Device for producing stabilized organic pigment particles
    Publication number: 20040149169
    Abstract: A method of producing self dispersible organic pigment particles stabilized by the method. The method includes modifying organic pigment particles and then contacting the surface modified particles with an aqueous vapor entrained in a carrier gas to produce the stabilized organic pigment particles. Typically the pigment particles are modified by exposing their surfaces to ozone or a plasma-activated process gas. The surface stabilizing method prevents the violent exothermic reaction, which occurs when surface modified pigment particles are exposed to ambient air. The method is accomplished in a device, which includes a reactor, means for introducing in the reactor aqueous vapor entrained in a carrier gas and an agitator assembly for deagglomerating during surface modification the pigment particles placed in the reactor.
    Type: Application
    Filed: January 22, 2004
    Publication date: August 5, 2004
    Inventors: An-Gong Yeh, Sandra L. Witman, James L. Hohman
  • Method of producing stabilized organic pigment particles and device therefor
    Patent number: 6709507
    Abstract: A method of producing self dispersible organic pigment particles stabilized by the method. The method includes modifying organic pigment particles and then contacting the surface modified particles with an aqueous vapor entrained in a carrier gas to produce the stabilized organic pigment particles. Typically the pigment particles are modified by exposing their surfaces to ozone or a plasma-activated process gas. The surface stabilizing method prevents the violent exothermic reaction, which occurs when surface modified pigment particles are exposed to ambient air. The method is accomplished in a device, which includes a reactor, means for introducing in the reactor aqueous vapor entrained in a carrier gas and an agitator assembly for deagglomerating during surface modification the pigment particles placed in the reactor.
    Type: Grant
    Filed: August 23, 2002
    Date of Patent: March 23, 2004
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: An-Gong Yeh, Sandra L. Witman, James L. Hohman
  • Method of producing stabilized organic pigment particles and device therefor
    Publication number: 20030077446
    Abstract: A method of producing self dispersible organic pigment particles stabilized by the method. The method includes modifying organic pigment particles and then contacting the surface modified particles with an aqueous vapor entrained in a carrier gas to produce the stabilized organic pigment particles. Typically the pigment particles are modified by exposing their surfaces to ozone or a plasma-activated process gas. The surface stabilizing method prevents the violent exothermic reaction, which occurs when surface modified pigment particles are exposed to ambient air. The method is accomplished in a device, which includes a reactor, means for introducing in the reactor aqueous vapor entrained in a carrier gas and an agitator assembly for deagglomerating during surface modification the pigment particles placed in the reactor.
    Type: Application
    Filed: August 23, 2002
    Publication date: April 24, 2003
    Inventors: An-Gong Yeh, Sandra L. Witman, James L. Hohman
  • Self-dispersing pigment and process of making and use of same
    Publication number: 20020014184
    Abstract: A process is provided in which a pigment is oxidated with ozone in an aqueous environment in which the mixture of ozone, water and pigment is subjected to a dispersive mixing operation; and/or the pH of the mixture is maintained in a range of 6-8, whereby the pigment is self-dispersing and preferably has an acid value of less than 3 &mgr;moles/M2. Pigments from this process and ink jet inks containing the self-dispersing pigments, are also provided.
    Type: Application
    Filed: May 23, 2001
    Publication date: February 7, 2002
    Inventors: An-Gong Yeh, Michael J. Eiseman, Robert Paul Held, James L. Hohman, Dhiren V. Patel, Yia-Ching Ray, Harry Joseph Spinelli, Sandra L. Witman