Patents Assigned to Hewing GmbH & Co.
  • Patent number: 4582656
    Abstract: A method of producing molded articles from polyolefin molding compositions crosslinked by irradiation, to which molding composition is added, prior to irradiation, by mixing and/or copolymerizing, from 0.3 to 20 percent by weight of vinylacetate, optionally in a form as pre-copolymerized with a polyolefin. The occurence of undesirable accumulations and discharges of electrical charge concentrations and/or the undesirable foaming of the polyolefin molded articles will thus be suppressed.
    Type: Grant
    Filed: August 6, 1982
    Date of Patent: April 15, 1986
    Assignee: Hewing GmbH & Co.
    Inventor: Manfred Hoffmann
  • Patent number: 4536266
    Abstract: Method for the fluorination of a surface layer of articles molded from plastic, vulcanized rubber or other such macromolecular substances by the exposure of at least a part of the article's surface to a fluorine-yielding liquid in a controllable reaction, the liquid consisting of a solvent or solvent mixture containing dissolved elemental fluorine. Suitable solvents are especially halogen hydrocarbons in accordance with DIN 8962, which are liquid within a temperature range from -30.degree. C. to +10.degree. C., but also water and solvents having perfluoroalkyl groups. The liquid, in which a fluorine concentration between 0.5.times.10.sup.-3 and 1.times.10.sup.-2 mol/l is established by the introduction of fluorine diluted with inert gas, is used to treat the articles for about 20 seconds to 30 minutes; the fluorine can be activated if desired. The liquid can additionally contain sulfur dioxide, oxygen, carbon monoxide, chlorine, bromine, or mixtures thereof.
    Type: Grant
    Filed: December 7, 1983
    Date of Patent: August 20, 1985
    Assignee: Hewing GmbH & Co.
    Inventors: Claus Bliefert, Hans-Michael Boldhaus, Manfred Hoffmann