Patents by Inventor Friedrich J. Engelhardt

Friedrich J. Engelhardt 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).

  • Water soluble copolymers containing vinyl imidazole as drilling fluid additives
    Patent number: 4471097
    Abstract: Auxiliary agents for chemical flooding of petroleum deposits and auxiliary agents used in well drilling fluids are water-soluble copolymers containing a statistical distribution of(a) 5 to 95% by weight of structural units of formula I ##STR1## (b) 0 to 30% by weight of structural units of formula II ##STR2## (c) 0 to 80% by weight of structural units of formula III ##STR3## (d) 5 to 60% by weight of structural units of formula IV ##STR4## wherein R.sup.1 and R.sup.2 are the same or different and represent hydrogen, methyl, or ethyl or together are trimethylene to cyclic pentamethylene;R.sup.3 represents hydrogen or methyl;R.sup.4 represent a imidazolyl-(1) or imidazolyl-(2) moiety;Y is a single covalent bond or the formula --CO--NH--C(CH.sub.3).sub.2 --CH.sub.2 --; andX.sup.+ is a cation.
    Type: Grant
    Filed: January 11, 1982
    Date of Patent: September 11, 1984
    Inventors: Klaus Uhl, James K. Bannerman, Friedrich J. Engelhardt, Arvind Patel