Patents by Inventor Woo Sok Han

Woo Sok Han 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).

  • Pyridone-based yellow monoazo dye for use in thermal transfer and ink compositions comprising same
    Patent number: 5929218
    Abstract: The present invention relates to pyridone-based yellow monoazo dyes used in thermal transfer having following formula(I) which have good stability and hue. ##STR1## wherein, R.sub.1 is hydrogen atom; unsubstituted or substituted alkyl group of from 1 to 8 carbon atoms with alkoxy or aryl; or unsubstituted or sustituted aryl group with alkoxy or halogen.And,X is hydrogen atom; alkyl group of from 1 to 4 carbon atoms; alkoxy group; or halogen;R.sub.2 is selected from the following groups; ##STR2## wherein, R.sub.3 and R.sub.4 are independently selected from groups consisting hydrogen, substituted or unsubstituted alkyl group of from 1 to 4 carbon atoms, halogen, alkyl carboxylate, and carbonyl group;R.sub.3 -R.sub.4 is noncyclization with R.sub.3 and R.sub.4 and selected respectively from the above substituents(R.sub.3 and R.sub.
    Type: Grant
    Filed: May 8, 1996
    Date of Patent: July 27, 1999
    Assignee: Hansol Paper Co., Ltd.
    Inventors: Ki Taek Lee, Young Seup Son, Woo Sok Han, Beom Jun Joo, Soon Yeol Eom