Patents by Inventor David Keirs

David Keirs 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).

  • Publication number: 20020000177
    Abstract: The present invention provides a process for the production of pigmentary copper phthalocyanine in the beta crystalline phase comprising:
    Type: Application
    Filed: April 19, 1999
    Publication date: January 3, 2002
    Inventors: RICHARD ERNEST MATHERS, DAVID KEIRS, KENNETH GRANT DYKES, THOMAS HEALY
  • Patent number: 6306938
    Abstract: The present invention provides a process for the production of pigmentary copper phthalocyanine in the beta crystalline phase comprising: a) dry or aqueous milling of crude copper phthalocyanine in combination with a natural or chemically modified resin and, optionally, a grinding auxiliary followed by; b) isolation of the milled mass followed by; c) conditioning treatment of the milled mass.
    Type: Grant
    Filed: April 19, 1999
    Date of Patent: October 23, 2001
    Assignee: Ciba Specialty Chemicals Corp.
    Inventors: Richard Ernest Mathers, David Keirs, Kenneth Grant Dykes, Thomas Healy
  • Patent number: 5279654
    Abstract: A pigment composition comprising (A) a pigmentary phthalocyanine, (B) a phthalocyanine derivative of formula ##STR1## where Pc is a residue of a metal-free or metal phthalocyanine, X is --CH.sub.2 -- or --SO.sub.2 --, R.sup.1 and R.sup.2 are independently hydrogen, C.sub.1 -C.sub.20 alkyl optionally substituted by hydroxyl, C.sub.1 to C.sub.4 alkoxy, amino, C.sub.1 to C.sub.10 alkylamino or di(C.sub.1 to C.sub.10 alkyl)amino, C.sub.5 to C.sub.10 cycloalkyl, or phenyl optionally substituted by C.sub.1 to C.sub.4 alkyl, C.sub.1 to C.sub.4 alkoxy or halogen, or R.sup.1 and R.sub.2 together with the indicated nitrogen atom denote a five-, six- or seven-membered heterocyclic ring, or R.sup.1 and R.sup.2 together denote a group of formula ##STR2## R.sup.3 is an o-phenylene group optionally substituted by C.sub.1 to C.sub.4 alkyl, C.sub.1 to C.sub.
    Type: Grant
    Filed: July 20, 1992
    Date of Patent: January 18, 1994
    Assignee: Ciba-Geigy Corporation
    Inventors: David Keirs, Robert Langley, Ian A. Lambie