Patents by Inventor Walter Loffelmann

Walter Loffelmann 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: 5879554
    Abstract: A synthetic membrane consisting of a mixture of polysulfone and sulfonated polysulfone and not more than 20 wt. % of other polymers, characterized in that the mixture contains 0.5 to 8 wt. % sulfonated polysulfone, possibly as the salt of sulfonic acid, and a method for manufacturing this synthetic membrane, characterized in that one or more solvents are added to a mixture composed of 0.5 to 8 wt. % sulfonated polysulfone, possibly as the salt of sulfonic acid, polysulfone and not more than 20 wt. % of other polymers, the mixture is dissolved to form a polymer solution, the latter is shaped, and precipitated to form a membrane in a precipitating bath by means of one or more precipitating agents.
    Type: Grant
    Filed: April 7, 1995
    Date of Patent: March 9, 1999
    Assignee: Akzo Nobel N.V.
    Inventors: Walter Loffelmann, Jurgen Passlack, Harald Schmitt, Heinz-Dieter Sluma, Michael Schmitt
  • Patent number: 5290448
    Abstract: An asymmetric semipermeable membrane for dialysis and/or ultrafiltration is composed of a copolymer of acrylonitrile and acrylic ester and an ionic or ionizable monomer in the form of a hollow fiber. The copolymer is composed of 90.50 to 95.00 wt. % acrylonitrile, 4.99 to 8.60 wt. % acrylic ester, and 0.01 to 0.90 wt. % of the ionic or ionizable monomer. Also provided is a process for its manufacture.
    Type: Grant
    Filed: December 9, 1992
    Date of Patent: March 1, 1994
    Assignee: Akzo NV
    Inventors: Heinz-Dieter Sluma, Jurgen Passlack, Harald Schmitt, Walter Loffelmann, Karl Henke
  • Patent number: 4436839
    Abstract: A method for production of polycarbonate-polyether-blockcopolymers is provided. One or more solutions comprising bisphenol A and polyalkyleneglycol and a phosgene solution are added to a cooled initial reaction medium in a cooled reaction chamber in such a way that the phosgene contacts substantially the reaction partners from the one or more cooled solutions after they have spread in the reaction medium. Preferably the phosgene solution and the one or more solutions are added through tubes ending above the liquid level of the reaction medium such that the solutions added contact only within the stirred reaction mixture the reaction partner. The phosgene is employed in an excess of less than about 10 weight percent of the stochiometrically required weight amount relative to bisphenol A and polyalkyleneglycol. The polymer is useful in the production of membranes for dialysis, ultrafiltration and reverse osmosis.
    Type: Grant
    Filed: August 11, 1980
    Date of Patent: March 13, 1984
    Assignee: Akzo NV
    Inventors: Joachim Behnke, Walter Loffelmann