Patents by Inventor Yeong Choi

Yeong Choi 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: 5824766
    Abstract: A polyamideamic acid resin prepolymer represented by formula A having isophorone diamine as one of monomers, ##STR1## in which k, l, m and n are integer of 1 or more, respectively, and ##EQU1## --R-- is at least one group selected from the group consisting of ##STR2## --R'-- is a cis- and trans-conformational mixture of ##STR3## high heat resistant polyamideimide foam produced therefrom, and processes for producing them are disclosed.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: October 20, 1998
    Assignee: Korea Research Institute of Chemical Technology
    Inventors: Kil-Yeong Choi, Mi-Hie Yi, Moon-Young Jin, Young-Taik Hong
  • Patent number: 5693744
    Abstract: An amorphous polyamide represented by the formula(2) ##STR1## in which each R is at least one alkylene radical having 1 to 10 carbon atoms, R' is an electron acceptor group represented by the formula(3), ##STR2## wherein Y is --C.tbd.N, --NO.sub.2, --SO.sub.2 --R(R.dbd.C.sub.n H.sub.2n+1, n=1 to 20 alkyl derivatives), ##STR3## R" is at least one aliphatic or aromatic divalent group having 2 to 20 carbon atoms, and n is an integer of more than 3, having second order nonlinear optical property, and a method for preparing the polymer by the polycondensation of dicarboxylic acid derivative, having second order nonlinear optical property in its side chain, with diamine are disclosed.
    Type: Grant
    Filed: June 21, 1995
    Date of Patent: December 2, 1997
    Assignee: Korea Research Institute of Chemical Technology
    Inventors: Kil Yeong Choi, Moon Young Jin, Young Wun Kim
  • Patent number: 5532334
    Abstract: A process for preparing polyamideimide resins having high molecular weights as described wherein major problems of prior art processes such as low heat resistance and low melt flowability are improved. Polyamideimide resins having an intrinsic viscosity of 0.4 to 1.50 dl/g as measured on a solution of dimethylacetamide as a solvent at a concentration of 0.5 g/dl at 30.degree. C., are prepared by reacting an aromatic tricarboxylic acid anhydride with an aromatic diamine in N-methyl pyrrolidone solvent in the presence of a first catalyst selected from a group consisting of thionyl chloride, p-toluenesulphonly chloride, sulfuryl chloride, cyanuric chloride and phosphorus trichloride at a temperature of 50.degree. C. to 130.degree. C. over a period of 1 to 5 hours and further reacting the resultant reaction mixture in the presence of a second catalyst which is a compound of the formula (RO).sub.
    Type: Grant
    Filed: November 14, 1994
    Date of Patent: July 2, 1996
    Assignee: Korea Research Institute of Chemical Technology
    Inventors: Kil-Yeong Choi, Dong-Hack Suh, Mi-Hie Yi, Young-Taik Hong, Jong-Chan Won
  • Patent number: 5521276
    Abstract: Polyamideimide resins having the formula (I) ##STR1## in which repeating units are bound in a head to tail or head to head manner,R is at least two divalent groups selected from the group consisting of ##STR2## (cis-, trans- conformational mixture) wherein one divalent group is ##STR3## group in a PAI molecule, produced by introducing isophorone diamine into the conventional aromatic polyamideimide resins.
    Type: Grant
    Filed: June 22, 1994
    Date of Patent: May 28, 1996
    Assignee: Korea Research Institute of Chemical Technology
    Inventors: Kil-Yeong Choi, Mi-Hie Yi, Jae-Heung Lee, Moon-Young Jin, Young-Taik Hong
  • Patent number: 5489616
    Abstract: This invention relates to a process of manufacturing phosphoric acid-type chelate resins as uranyl ion adsorbents having enhanced chelation and re-utilizing ability by introducing plenty of phosphoric acid groups both on main- and side-chain of the copolymer skeleton. The resin is prepared by both the radical suspension copolymerization of vinyl monomers such as styrene, divinylbenzene, and bis-(2-chloroethyl) vinylphosphonate and the additional introduction of phosphono group onto the copolymer.
    Type: Grant
    Filed: April 7, 1993
    Date of Patent: February 6, 1996
    Assignee: Korea Research Institute of Chemical Technology
    Inventors: In Hwan Park, Kil-Yeong Choi, Jin-Chul Jung, Jae-Oh Joo
  • Patent number: 5457163
    Abstract: This invention relates to a process of manufacturing phosphoric acid-type chelate resins as uranyl ion adsorbents having enhanced chelation and re-utilizing ability by introducing plenty of phosphoric acid groups both on main- and side-chain of the copolymer skeleton. The resin is prepared by both the radical suspension copolymerization of vinyl monomers such as styrene, divinylbenzene, and bis-(2-chloroethyl) vinylphosphonate and the additional introduction of phosphono group onto the copolymer.
    Type: Grant
    Filed: November 30, 1993
    Date of Patent: October 10, 1995
    Assignee: Korea Research Institute Of Chemical Technology
    Inventors: In Hwan Park, Kil-Yeong Choi, Jin-Chul Jung, Jae-Oh Joo
  • Patent number: 5243010
    Abstract: This invention relates to the aromatic polyamide resin of the following general formula(I) having pendant silyl groups characterized in that the said polyamide resin has excellent solubility for the films to be easily prepared by solvent casting as well as useful as coating materials, can be used at higher temperature than the reported polyamides because of the excellent heat stability, and also has excellent adhesive strength in the blend with glass fiber.
    Type: Grant
    Filed: March 13, 1992
    Date of Patent: September 7, 1993
    Assignee: Korea Research Institute of Chemical Technology
    Inventors: Kil-Yeong Choi, Mi Hie Yi
  • Patent number: 5241037
    Abstract: Nadimide-terminated polyarylate prepolymers having the formula (I) ##STR1## wherein n is an integer not less than 1, and cured polyarylate resins produced by thermal curing the prepolymers, and processes for producing them are disclosed.The cured polyarylate resins according to the present invention have excellent chemical resistance and high-temperature resistance as well as good mechanical properties and processability.
    Type: Grant
    Filed: July 6, 1992
    Date of Patent: August 31, 1993
    Assignee: Korea Research Institute of Chemical Technology
    Inventors: Kil-Yeong Choi, Mi-Hie Yi, Sam-Kwon Choi
  • Patent number: 5212277
    Abstract: The present invention relates to new polyetherimideimides having imideimide group with the following structural formula(I) and inherent viscosity of 0.27.about.0.71 dl/g, which can be made by effecting reaction between an aromatic bis(ether anhydride) and an organic diamine or an aromatic bis(nitro imideimide) and a metal salt of diol.
    Type: Grant
    Filed: January 10, 1991
    Date of Patent: May 18, 1993
    Assignees: Korea Research Institute of Chemical Technology, Cheil Industries, Inc.
    Inventors: Kwang-Sup Lee, Kil-Yeong Choi, Jong C. Won, Byoung K. Park, In-Tae Lee