Patents by Inventor Walther Cohnen

Walther Cohnen 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).

  • Process for troublefree coating of hydrophobic materials with polyurethanes
    Patent number: 4948634
    Abstract: The present invention relates to a process for troublefree, i.e. flaw-free and uniform, coating of a support which can accept a large amount of electrostatic charge, such as, for example, polycarbonate foils, with a solution of fully reacted polyurethane in organic solvents, more precisely after prior coating of the polycarbonate foil with an organic solution of the sodium salt of polystyrenesulphonic acid.
    Type: Grant
    Filed: May 23, 1989
    Date of Patent: August 14, 1990
    Assignee: Miles Inc.
    Inventors: Walther Cohnen, Alexander Riebel, Karl W. Schranz
  • Multilayered color photographic material having an alkali soluble interlayer
    Patent number: 4940653
    Abstract: In a process for the preparation of a multilayered photographic material in which the layers are applied in at least two stages and the material is dried and wound up in between the stages, sticking of the semi-finished preparations does not occur if the uppermost layer applied in the first stage contains polymer particles soluble in alkali and having an average particle diameter from 0.2 to 5.0 .mu.m.
    Type: Grant
    Filed: September 22, 1989
    Date of Patent: July 10, 1990
    Assignee: Agfa-Gevaert Aktiengesellschaft
    Inventors: Prem Lalvani, Diethart Lademann, Hans Buschmann, Heinz Reif, Walther Cohnen