Patents by Inventor Alfred Froehlich

Alfred Froehlich 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).

  • Photographic material containing sulphonic acid group containing disazo dyestuffs
    Patent number: 4118232
    Abstract: The invention is directed essentially to photographic material containing, on a carrier, a layer with azo dyestuffs of the formula ##STR1## wherein A, B, X and Y are certain substituents, in a second main aspect azo dyestuffs of the formula ##STR2## wherein B' represents certain substituents and in a third main aspect azo deystuffs of the formulaA.sub.1 --N.dbd.N--B.sub.1 --NH--CO--X.sub.1 --Y--Z.sub.1 --OC--HN--B.sub.1 --N.dbd.N--A.sub.1wherein A.sub.1, B.sub.1, X.sub.1, Z.sub.1 and Y are certain substituents.The photographic materials provide advantages stemming from the use of the dyestuffs of the invention which are distinguished by particularly high fastness to light coupled with excellent bleachability, good resistance to diffusion and advantageous color strength.
    Type: Grant
    Filed: March 15, 1977
    Date of Patent: October 3, 1978
    Assignee: Ciba-Geigy AG
    Inventors: Bernhard Piller, John Lenoir, Alfred Froehlich, Thomas Stauner, Paul Tschopp
  • Sulfonic-acid-group containing disazo dyestuffs
    Patent number: 4051123
    Abstract: In a first main aspect azo dyestuffs of the formula ##STR1## wherein A, B, X and Y are certain substituents, in a second main aspect azo dyestuffs of the formula ##STR2## wherein B' represents certain substituents and in a third main aspect azo dyestuffs of the formulaA.sub.1 --N.dbd.N--B.sub.1 --NH--CO--X.sub.1 --Y--Z.sub.1 --OC--HN--B.sub.1 --N.dbd.N--A.sub.1wherein A.sub.1, B.sub.1, X.sub.1, Z.sub.1 and Y are certain substituents as well as the use of said azo dyestuffs in photographic material are disclosed.
    Type: Grant
    Filed: August 21, 1975
    Date of Patent: September 27, 1977
    Assignee: Ciba-Geigy AG
    Inventors: Bernhard Piller, John Lenoir, Alfred Froehlich, Thomas Stauner, Paul Tschopp