Patents by Inventor John T. Hsieh

John T. Hsieh 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).

  • Mixed chromium catalyst,and alkene and alkyl aluminum hydride-modified ziegler catalyst for multimodal HDPE
    Patent number: 5408015
    Abstract: Multimodal high-density ethylene polymers or copolymers (HDPE) of broad molecular weight distribution suitable for blow-molding and films are prepared with a chromium oxide catalyst mixed with a MgO-supported Ziegler catalyst, modified with an alkene and with alkyl aluminum hydride, and with an MgO additive.
    Type: Grant
    Filed: October 1, 1990
    Date of Patent: April 18, 1995
    Assignee: Mobil Oil Corporation
    Inventors: John T. Hsieh, Ann L. Pruden
  • High efficiency catalyst for high bulk density polyethylene
    Patent number: 4167493
    Abstract: A unique high efficiency catalyst for the polymerization of ethylene has been developed based on the use of methanol treated magnesium oxide as support, an equimolar mixture of titanium tetrachloride and tetrabutyltitanate as titanium source impregnated on the support, and an organoaluminum compound as reducing agent. The polyethylene produced by this catalyst has narrow molecular weight distribution, high bulk density, high melt index, and minimum catalyst residue due to the high polymer to catalyst ratio.
    Type: Grant
    Filed: October 12, 1978
    Date of Patent: September 11, 1979
    Assignee: Arco Polymers, Inc.
    Inventor: John T. Hsieh