Patents by Inventor Leo Zhaoqing Liu

Leo Zhaoqing Liu 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).

  • Publication number: 20040072699
    Abstract: A method of depolymerizing galactomannan-type polysaccharide polymers and xanthan, preferably galactomannans, to a pre-selected lower molecular weight by irradiation with high energy electron beams. The preferred galactomannans for treatment according to this method are guar gum, guar splits and hydroxypropyl guar. In a preferred embodiment the guar gum is depolymerized preferably to a molecular weight of about 150,000 Daltons to about 200,000 Daltons. The depolymerized guar has a polydispersity of less than about 3.0 and is useful in oil well fracturing to enhance oil production.
    Type: Application
    Filed: June 24, 2003
    Publication date: April 15, 2004
    Inventors: Leo Zhaoqing Liu, Christian Priou
  • Publication number: 20040010106
    Abstract: Monomer compounds comprising several cationic groups are provided. The invention also relates to a process for making these monomer compounds. The process is highly selective and prevents unwanted reactions leading to undesired structures. The invention relates also to polymers, including copolymers, comprising units deriving from said monomer compounds. The monomer compounds comprise several cationic groups, e.g.
    Type: Application
    Filed: June 3, 2003
    Publication date: January 15, 2004
    Inventor: Leo Zhaoqing Liu
  • Publication number: 20030204014
    Abstract: A polymer produced by polymerizing via water-in-oil emulsion polymerization one or more water soluble monomers with one or more polyalkoxylated monomers wherein said one or more polyalkoxylated monomers contains at least 25 alkylene oxide units and wherein said product demonstrates thermothickening properties, its method of manufacture and use thereof is disclosed.
    Type: Application
    Filed: April 9, 2003
    Publication date: October 30, 2003
    Inventors: Dominic Wai-Kwing Yeung, Leo Zhaoqing Liu, Bruno Rc Langlois, Dominique Charmot, Pascale Corpart
  • Patent number: 6376631
    Abstract: The present invention relates to processes for making polymers from at least one tertiary amino-containing monomer and at least one vinyl-functional monomer, while controlling residual monomers and avoiding production of Michael addition adducts. The process employs one or more of the following steps to avoid such adducts, maintaining at least one tertiary amino-containing monomer and at least one vinyl-functional monomer separate until the polymerization reaction, maintaining the at least one tertiary amino-containing monomer and at least one vinyl-functional monomer free of water until the polymerization reaction, and employing high temperatures for the polymerization reaction. The polymers are useful in personal care products, fabric detergent, hand dishwashing detergent, oil well treating chemicals, fire-fighting foam, agricultural chemicals, flocculants, coagulants, and household cleaners.
    Type: Grant
    Filed: September 27, 2000
    Date of Patent: April 23, 2002
    Assignee: Rhodia, Inc.
    Inventors: Dominic Wai Kwing Yeung, Leo Zhaoqing Liu, Richard E. Rice