Researchers recreate Korean traditional coating agent

“He ordered to paint the palace again, four million dos (a traditional Korean unit equivalent to 18 liters) of Myeongyoo (traditional coating agent) were used.”

It was recorded in the 13th volume of King Taejo of the Annals of the Joseon Dynasty. Myeongyoo was applied to Dancheong, the traditional multicolored paintwork, of the palace where King Taejo lived. It was a boiled mixture of perilla oil, litharge, talc and potassium.

Myeongyoo, a coating agent applied to wooden buildings or Dancheong, is a kind of an adhesive made up of dried oil extracted from unroasted perilla seeds. Moister prevents woods from being rot. However, Myeongyoo masters disappeared and it could be found only in literature. Six hundred years later, scientists have recreated the traditional coating agent.

A group of researchers dedicated for developing Korean traditional cultural technologies whose average age of 59.8 years old, the eldest in the Korean Institute of Science and Technology, have successfully restored Myeongyoo based on historical documents.

The researchers have found that potassium, litharge, and talc serve as catalysts and boiling and mixing of Myeongyoo provides oxygen to the mixture. Focused on this, they successfully reproduced the traditional coating agent without catalysts by injecting 99.9-percent pure oxygen and boiling the mixture at 80 to 120 Celsius degrees. While restoring a traditional method, they upgraded it by adding modern scientific technologies in a more environmentally-friendly manner. They said that the new Myeongyoo without using catalysts are clearer than the traditional one.

The researchers also successfully reinterpreted the traditional brassware. It is good for food storage because copper removes bacteria. However, melting copper and tin creates many bubbles. It breaks easily in the molding process and holes created from bubbles needs a process of making the surface smooth with sandpaper.

In the traditional method, straws are used to remove gas in the mixture. The researchers replaced them with a degassing agent. As the material gets harder, it does not break easily in the molding process. The improved process leaves only 100 milligrams of small bubbles per kilogram but their goal is to create traditional brassware with no bubble at all. “If modern technology is combined with traditional materials, we can reproduce our culture and contribute to creating an upgraded and better version,” said Han Ho-gyu, the leader of the researchers.

yskwon@donga.com