Patents by Inventor Dieter Frietag

Dieter Frietag 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).

  • Branched, high-molecular weight thermoplastic polycarbonates
    Patent number: 4185009
    Abstract: The invention relates to a process for the preparation of branched, thermoplastic, high-molecular weight and soluble polycarbonates having improved properties, by incorporation of 3,3-bis-(4-hydroxyaryl)-oxindoles as a branching agent. The invention further relates to the polycarbonates obtained in accordance with this process.
    Type: Grant
    Filed: October 26, 1977
    Date of Patent: January 22, 1980
    Assignee: Bayer Aktiengesellschaft
    Inventors: Karsten-Josef Idel, Dieter Frietag, Werner Nouvertne
  • 1,1,3,4,6-Pentamethyl-3-(3,5-dimethyl-4-hydroxyphenyl)-indan-5-ol polycarbonates
    Patent number: 4129612
    Abstract: The present invention is concerned with aromatic thermoplastic polycarbonates which contain at least about 0.5 mole % of structural units derived from 1,1,3,4,6-pentamethyl-3-(3,5 dimethyl-4-hydroxyphenyl)-indan-5-ol. The polymers disclosed herein may be homopolymers of these units or copolymers with other aromatic dihydroxy compounds and/or tri or higher functional branching agents. These homopolymers or copolymers may be used per se or they may be blended with other thermoplastic resins, particularly other aromatic polycarbonates. In addition, these polymers may be used to prepare coatings which may be cross-linked by heat treatment or radiation or they may be used as the base for graft polymerization.
    Type: Grant
    Filed: March 28, 1977
    Date of Patent: December 12, 1978
    Assignee: Bayer Aktiengesellschaft
    Inventors: Volker Serini, Gerhard Friedhofen, Dieter Frietag, Jurgen Heuser