Patents by Inventor Cheuk C. Yau

Cheuk C. Yau 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).

  • Patent number: 5608031
    Abstract: This invention relates to a polyester resin prepared by adding one or more dicarboxylic acid components to one or more glycol components containing 1,4-cyclohexanedimethanol equalling 100 mole %,the polyester resin having been prepared in the presence of a catalyst/stabilizer system consisting essentially of antimony compounds and phosphorous compounds and compounds selected from the group consisting essentially of zinc compounds, gallium compounds, and silicon compounds.
    Type: Grant
    Filed: November 30, 1995
    Date of Patent: March 4, 1997
    Assignee: Eastman Chemical Company
    Inventors: Cheuk C. Yau, Leslie S. Moody
  • Patent number: 5498749
    Abstract: Provided is a method useful for separating and removing impurities such as cyclohexane dimethanol (CHDM) and other additives from their mixture with dimethylterehthalate (DMT), formed during a depolymerization process such as methanolysis of poly(ethyene terephthalate) (PET), poly(cyclohexyldimethylene terephthalate) (PCT), or copolyers of PET and PCT. The separation and removal of CHDM is accomplished via either melt or solution crystallization of the DMT following excess methanol removal (via distillation) of the methanolysis reactor products.
    Type: Grant
    Filed: October 22, 1993
    Date of Patent: March 12, 1996
    Assignee: Eastman Chemical Company
    Inventors: William H. Heise, Daniel P. Folk, Cheuk C. Yau, Chester W. Sink
  • Patent number: 5393871
    Abstract: Disclosed is an improvement in a process for producing linear polyesters wherein a precursor polyester is first formed and subsequently the precursor polyester is formed into particles and further polymerized in the solid state, wherein the improvement comprises contacting the particles while at a temperature of about 140.degree. to about 2.degree. C. below the melting point of the polyester with the vapor of water or an organic compound having at least one OH group.
    Type: Grant
    Filed: January 4, 1993
    Date of Patent: February 28, 1995
    Assignee: Eastman Chemical Company
    Inventors: Cheuk C. Yau, Clinton Cherry
  • Patent number: 5393863
    Abstract: Disclosed is an improvement in a process for producing branched polyesters wherein a precursor polyester is first formed and subsequently the precursor polyester is formed into particles and further polymerized in the solid state, wherein the improvement comprises contacting the particles while at a temperature of about 140.degree. to about 2.degree. C. below the melting point of the polyester with the vapor of water or an organic compound having at least one OH group.
    Type: Grant
    Filed: January 4, 1993
    Date of Patent: February 28, 1995
    Assignee: Eastman ChemicalI Company
    Inventors: Cheuk C. Yau, Clinton Cherry
  • Patent number: 5385773
    Abstract: Disclosed is a process for producing copolyesters having repeat units from a dicarboxylic acid component comprising at least 90 mol % terephthalic acid and a glycol component comprising about 10-95 mol % 1,4-cyclo-hexanedimethanol and from about 90-5 mol % ethylene glycol comprising reacting the dicarboxylic acid component and the glycol component at temperatures sufficient to effect esterification or transesterification and polycondensing the reaction product in the presence of a catalyst and inhibitor system consisting essentially of Mn, Zn, Ti, Ge and P, all parts by weight based on the weight of the copolyester.
    Type: Grant
    Filed: April 27, 1993
    Date of Patent: January 31, 1995
    Assignee: Eastman Chemical Company
    Inventors: Cheuk C. Yau, Clinton Cherry
  • Patent number: 5340907
    Abstract: Disclosed is a process for producing copolyesters having repeat units from a dicarboxylic acid component comprising at least 90 mol % terephthalic acid and a glycol component comprising about 10-95 mol % 1,4-cyclohexanedimethanol and from about 90-5 mol % ethylene glycol comprising reacting the dicarboxylic acid component and the glycol component at temperatures sufficient to effect esterification or transesterification and polycondensing the reaction product in the presence of a catalyst and inhibitor system consisting essentially of Mn, Zn, Ti, Ge and P, all parts by weight based on the weight of the copolyester.
    Type: Grant
    Filed: June 28, 1993
    Date of Patent: August 23, 1994
    Assignee: Eastman Chemical Company
    Inventors: Cheuk C. Yau, Clinton Cherry
  • Patent number: 5145742
    Abstract: Disclosed is a configuration for a polymer pellet having improved reactivity for solid-state polymerization and less tendency to stick during processing with heat. The pellets have a reduced path length for volatiles to travel to the exterior of the pellet, and reduced contact area in a packed condition.
    Type: Grant
    Filed: August 3, 1990
    Date of Patent: September 8, 1992
    Assignee: Eastman Kodak Company
    Inventor: Cheuk C. Yau