Patents by Inventor Hartmut Luker

Hartmut Luker 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).

  • Pipe of polyethylene having improved mechanical properties
    Patent number: 5908679
    Abstract: The invention relates to a high strength pipe of ethylene polymer having a bimodal molecular weight distribution. Such pipe has a stress cracking resistance of .gtoreq.1400 h, a fracture toughness of .gtoreq.7 mJ/mm.sup.2 and a modulus of creep in flexure, measured according to DIN 54852-Z4, of .gtoreq.1100 N/mm.sup.2. The pipe according to the invention is produced from an ethylene polymer in which the ratio of weight of the low molecular weight fraction to the weight of the higher molecular weight fraction is in the range from 0.5 to 2.0 and which has a melt flow index MFI.sub.5/190.degree. C. of .ltoreq.0.35 g/10 min. It is particularly suitable for the transportation of gases and water.
    Type: Grant
    Filed: October 6, 1997
    Date of Patent: June 1, 1999
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Joachim Berthold, Ludwig Bohm, Werner Breuers, Johannes Friedrich Enderle, Manfred Fleissner, Rainer Lecht, Hartmut Luker, Ulrich Schulte, Heiner Bromstrup
  • Process for the preparation of a 1-olefin polymer
    Patent number: 5202398
    Abstract: If the transition metal component used in an olefin polymerization catalyst is the product of the reaction between a siloxane-substituted metallocene of titanium, zirconium or hafnium and a hydroxyl group-containing support material, for example silicon dioxide, these metallocene catalysts can be employed in existing polymerization plants which are designed for the suspension process.
    Type: Grant
    Filed: December 13, 1989
    Date of Patent: April 13, 1993
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Martin Antberg, Hartmut Luker, Ludwig Bohm
  • Process for the preparation of an ethylene/propylene copolymer
    Patent number: 5086134
    Abstract: The invention relates to a process for the preparation of a predominantly crystalline ethylene/propylene copolymer having less than 15 mol % of propylene units, which can be carried out in liquid propylene as the suspending agent, if metallocene catalyst components of the formulae I, II or III are employed and the partial pressures of ethylene and propylene have a specific ratio. ##STR1## By means of this process, it is possible to increase the possible uses of polymerization plants which work with liquid propylene.
    Type: Grant
    Filed: October 19, 1989
    Date of Patent: February 4, 1992
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Martin Antberg, Walter Spaleck, Jurgen Rohrmann, Hartmut Luker, Andreas Winter
  • Polyethylene wax, and a process for the preparation thereof
    Patent number: 5023388
    Abstract: Polyethylene waxes having a very narrow molecular weight distribution, high isotacticity, a narrow grain size distribution and a high bulk density are obtained by means of a catalyst comprising a metallocene and an aluminoxane, in the presence of small amounts of hydrogen during the polymerization.
    Type: Grant
    Filed: December 19, 1988
    Date of Patent: June 11, 1991
    Assignee: Hoechst Aktiengesellschaft
    Inventor: Hartmut Luker
  • Process for the preparation of polyolefins
    Patent number: 4769510
    Abstract: In the polymerization of propylene and other higher 1-olefins, polymers which have a high degree of isotacticity and a narrow distribution of molecular weight are obtained in the presence of a catalyst system composed of a zirconium compound which is stereo-rigid and chiral and a linear or cyclic aluminoxane. In addition, the catalyst system is exceptionally active.
    Type: Grant
    Filed: November 25, 1985
    Date of Patent: September 6, 1988
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Walter Kaminsky, Klaus Kulper, Maria Buschermohle, Hartmut Luker