E.i. Dupont De Nemours and Company

An-Gong Yeh

James Lewis Hohman, Jr

Timothy Allan Bell

Tyau-Jeen Lin

Thomas William Harding

Michael Patrick Chouinard

Sandra L Witman

Laurence J Levase

Paul Francis Herman

Wronald Scott Best

Harry J Spinelli

Robert P Held

Jose Esteban Valentini

Dhiren V Patel

Michael J Eiseman

Yia-Ching Ray

Robert Paul Held

James L Hohman

Harry Joseph Spinelli

This invention pertains to aqueous inkjet inks containing self-dispersing pigments and effective amounts of one or more multivalent cations, said inks having increased optical density when printed.

Inkjet inks with increased optical density

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 &#x3bc;moles/M. Pigments from this process and ink jet inks containing the self-dispersing pigments, are also provided.

Self-dispersing pigment and process of making and use of same

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. The stabilized particles of the present invention are also well suited for use in ink jet inks, pigmented waterborne and solvent borne coating compositions, and pigmented powder coating compositions.

Method of producing stabilized organic pigment particles and device therefor

This invention relates to an improved apparatus for treating the surface of particles by plasma-activated gas species to modify the particle surfaces.

Treatment of deagglomerated particles with plasma-activated species

A method for optimizing the processing of continuous media mills is disclosed. It has been found that using a differential pressure device to measure the pressure drop across the mill allows the on line determination of the state of media fluidization in the mill. Operation within an optimum mill base flow rate range is needed to have good fluidization of the media so that grinding can be efficient. Using differential pressure measurement allows a precise determination of the mill base flow rate range which provides full fluidization of the media and mill base flow rate control within that range.

On line control method to determine media fluidization in a media mill

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Broomall, PA, United States of America

An-Gong Yeh