Patents by Inventor Klaus Elfert

Klaus Elfert 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).

  • Semipermeable membranes
    Patent number: 4383923
    Abstract: Semipermeable composite membranes consisting of a microporous substrate and a semipermeable layer built of polymer material containing urazole structures.
    Type: Grant
    Filed: June 29, 1981
    Date of Patent: May 17, 1983
    Assignee: Bayer Aktiengesellschaft
    Inventor: Klaus Elfert
  • Semipermeable membranes of aromatic disulfimide containing polyamides
    Patent number: 4269967
    Abstract: The invention relates to membranes which consist of aromatic polyamides containing disulphimide groups and have relative viscosities .eta..sub.rel of .gtoreq.1.4 as measured on a 0.5% N-methylpyrrolidone solution at 20.degree. C., and which may be used for ultrafiltration and inverse osmosis. The membranes of these polyamides according to the invention have a high permeability to water, for example, a throughflow of 1000-5000 1/m.sup.2 d under a pressure of 20 bars, and a high retention capacity for dissolved substances.
    Type: Grant
    Filed: May 30, 1979
    Date of Patent: May 26, 1981
    Assignee: Bayer Aktiengesellschaft
    Inventors: Klaus Elfert, Gerhard D. Wolf, Hans J. Rosenkranz
  • Process of using a semi-permeable membrane of acrylonitrile copolymers
    Patent number: 4252652
    Abstract: A disulphimide group-containing acrylonitrile copolymer semi-permeable membrane which comprises:(A) from 99 to 50% by weight of acrylonitrile units;(B) from 1 to 50% by weight of units of an acrylonitrile-copolymerizable ethylenically unsaturated monomer containing one or two disulphimide groups; and(C) from 0 to 30% by weight of units of one or more other acrylonitrile-copolymerizable olefinically unsaturated monomer, the sum of the percentages amounts to 100.The semi-permeable membranes may be used in reverse osmosis and ultrafiltration.
    Type: Grant
    Filed: September 12, 1979
    Date of Patent: February 24, 1981
    Assignee: Bayer Aktiengesellschaft
    Inventors: Klaus Elfert, Hans J. Rosenkranz, Gerhard D. Wolf, Francis Bentz
  • Semipermeable membranes of heterocyclic copolyamides
    Patent number: 4221903
    Abstract: The invention relates to semipermeable membranes with a water absorption capacity of from 4.5 to 11% by weight, preferably from 4.5 to 8% by weight, as measured on approximately 40.mu. thick symmetrical films at room temperature and at 65% relative air humidity, a throughflow of 130 to 200 l/m.sup.2 d for a desalination level of 94.6 to 99.5% and consisting of an aromatic heterocycle-containing copolyamide with a relative viscosity of .gtoreq.1.4, as measured on a 0.5% N-methyl pyrrolidone solution at a temperature of 20.degree. C.
    Type: Grant
    Filed: July 24, 1978
    Date of Patent: September 9, 1980
    Assignee: Bayer Aktiengesellschaft
    Inventors: Klaus Elfert, Gerhard D. Wolf, Francis Bentz, Hans E. Kunzel
  • Semipermeable membranes of copolyamides
    Patent number: 4217227
    Abstract: The invention relates to semipermeable membranes with a water absorption capacity of from 4.5 to 10% by weight preferably from 4.5 to 8% by weight as measured on approximately 40.mu. thick symmetrical films at room temperature and 65% relative air humidity, with a throughflow of at least 80 1/m.sup.2 d for a desalination level of at least 85% and consisting of a fully aromatic copolyamide with a relative viscosity of .gtoreq.1,4, as measured on a 0.5% N-methyl pyrrolidone solution at a temperature of 20.degree. C.
    Type: Grant
    Filed: June 29, 1978
    Date of Patent: August 12, 1980
    Assignee: Bayer Aktiengesellschaft
    Inventors: Klaus Elfert, Gerhard D. Wolf, Francis Bentz, Hans E. Kunzel
  • Separation of aromatic hydrocarbons from mixtures, using polyurethane membranes
    Patent number: 4115465
    Abstract: A process for separating an aromatic hydrocarbon of the general formula ##STR1## wherein R represents an alkyl group having 1 to 3 carbon atoms andn is 0, 1, 2, or 3 (and wherein the groups R, when n is 2 or 3 can be the same or different),From a mixture comprising said compound and one or more aliphatic hydrocarbon, cycloaliphatic hydrocarbon, alcohol, ether, ketone or a carboxylic acid ester which comprises contacting said mixture with a polyurethane membrane.
    Type: Grant
    Filed: May 26, 1977
    Date of Patent: September 19, 1978
    Assignee: Bayer Aktiengesellschaft
    Inventors: Klaus Elfert, Hans Jurgen Rosenkranz, Hans Rudolf
  • Semipermeable membranes of sulphonated polybenz-1,3-oxazin-2,4-diones
    Patent number: 4069215
    Abstract: Semipermeable membranes of sulphonated polybenz-1,3-oxazin-2,4-diones for separating or enriching organic sulphonates by the method of inverse osmosis or ultrafiltration.
    Type: Grant
    Filed: August 10, 1976
    Date of Patent: January 17, 1978
    Assignee: Bayer Aktiengesellschaft
    Inventors: Klaus Elfert, Jurgen Hinz, Rudolf Binsack
  • Sulphonated polybenz-1,3-oxazin-2,4-diones
    Patent number: 4059580
    Abstract: Novel, sulphonated polybenz-1,3-oxazin-2,4-diones are produced by reacting polybenzoxazin diones with chlorosulphonic acid in a molar ratio of from 1:1 to 1:10.
    Type: Grant
    Filed: August 10, 1976
    Date of Patent: November 22, 1977
    Assignee: Bayer Aktiengesellschaft
    Inventors: Klaus Elfert, Jurgen Hinz, Rudolf Binsack