Patents by Inventor Walter Iff

Walter Iff 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: 4997917
    Abstract: The invention relates to a process for the preparation of asymmetrical 1:2 chromium complex dyes of not less than 90% purity and containing at least one water-solubilizing group, which process comprises reacting a mixture of two metallizable azo dyes that contain different diazo components and different coupling components, or a mixture of a metallizable azo dye and a metallizable azomethine dye, in the molar ratio of 0.85:1.0 to 1.2:1.0, with the proviso that only one of said two mixture components contains at least one water-solubilizing group, with a chromium donor, under pressure and at a temperature above 100.degree. C. and in the pH range from 0 to 2, and subsequently carrying out further reaction in a weakly acid, neutral or weakly alkaline pH range, utilizing a single vessel for all steps.The dyes obtained by the process of the invention are particularly suitable for dyeing wool or polyamide materials.
    Type: Grant
    Filed: March 4, 1985
    Date of Patent: March 5, 1991
    Assignee: Ciba-Geigy Corporation
    Inventors: Walter Iff, Daniel Parisot, Hans Schaller
  • Patent number: 4933437
    Abstract: The invention relates to a process for the preparation of asymmetrical 1:2 chromium complex azo dyes of not less than 90% purity and containing at least one water-solubilizing group, which process comprises reacting a mixture of two metallizable azo dyes that contain identical diazo components or identical coupling components, in the molar ratio of 0.85:1.0 to 1.2:1.0, with the proviso that only one of said two azo dyes contains at least one water-solubilizing group, with a chromium donor, under pressure and at a temperature above 100.degree. C. and in the pH range from 0 to 2, and subsequently carrying out further reaction in a weakly acid, neutral or weakly alkaline pH range, utilizing a single vessel for all stepsThe dyes obtained by the process of the invention are particularly suitable for dyeing wool or polyamide materials.
    Type: Grant
    Filed: March 23, 1987
    Date of Patent: June 12, 1990
    Assignee: Ciba-Geigy Corporation
    Inventors: Walter Iff, Daniel Parisot, Hans Schaller