Patents by Inventor Hee Ju Yoo

Hee Ju Yoo 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: 20090017710
    Abstract: A polypropylene homopolymer melt blown resin comprising a melt flow rate of about 300 to about 2500 g/10 min. at 230° C., a polydispersion index of about 1.3 to about 2.9, and a melting point of at least 160° C.
    Type: Application
    Filed: February 2, 2007
    Publication date: January 15, 2009
    Applicant: Basell Polyolefine GmbH
    Inventors: Daniele Bugada, Hee Ju Yoo
  • Patent number: 5858293
    Abstract: A spunbonded material having improved tensile strength is made by (1) continuously extruding a propylene homopolymer or random propylene/ethylene copolymer having a melt flow rate of about 3 to about 30 g/10 min at a temperature above 500.degree. F. through a spinneret to form discrete filaments, (2) drawing the filaments to molecularly orient the polymer filaments, and (3) depositing the filaments in a substantially random manner onto a carrier belt to form a web. The propylene polymer contains an additives package that includes an organic phosphite, a hindered phenol compound, calcium stearate, and, optionally, a hydrotalcite compound.
    Type: Grant
    Filed: September 30, 1997
    Date of Patent: January 12, 1999
    Assignee: Montell North America Inc.
    Inventor: Hee Ju Yoo
  • Patent number: 5820981
    Abstract: A propylene homopolymer having a stick-point of 30 cm or less during melt spinning, an oligomer content of less than 1500 ppm without postpolymerization treatment to remove oligomers, and a melt flow rate greater than 300 dg/min is prepared by radiation visbreaking in a multistage fluidized bed reactor. The polymer is subjected to irradiation in the substantial absence of oxygen, followed by a multistage treatment in the presence of a controlled amount of oxygen. The radiation visbreaking process can also be applied to other propylene polymer materials. The propylene polymer materials produced by this radiation visbreaking process can be used, for example, for extrusion coating, film production, and injection molding.
    Type: Grant
    Filed: April 2, 1996
    Date of Patent: October 13, 1998
    Assignee: Montell North America Inc.
    Inventors: Stephen D. Williams, Hee Ju Yoo, Miriam R. Drickman
  • Patent number: 5804304
    Abstract: A propylene homopolymer having a stick-point of 30 cm or less during melt spinning, an oligomer content of less than 1500 ppm without postpolymerization treatment to remove oligomers, and a melt flow rate greater than 300 dg/min is prepared by radiation visbreaking in a multistage fluidized bed reactor. The polymer is subjected to irradiation in the substantial absence of oxygen, followed by a multistage treatment in the presence of a controlled amount of oxygen. The radiation visbreaking process can also be applied to other propylene polymer materials. The propylene polymer materials produced by this radiation visbreaking process can be used, for example, for extrusion coating, film production, and injection molding.
    Type: Grant
    Filed: August 8, 1997
    Date of Patent: September 8, 1998
    Assignee: Montell North America Inc.
    Inventors: Stephen D. Williams, Hee Ju Yoo