https://techcrunch.com/2019/06/30/japan-will-restrict-the-export-of-some-materials-used-in-smartphones-and-chips-to-south-korea/

Japan’s trade ministry said today that it will restrict the export of some tech materials to South Korea, including polyimides used in flexible displays made by companies like Samsung Electronics. The new rules come as the two countries argue over compensation for South Koreans forced to work in Japanese factories during World War II.

The list of restricted supplies, expected to go into effect on July 4, includes polyimides used in smartphone and flexible organic LED displays, and etching gas and resist used to make semiconductors. That means Japanese suppliers who wish to sell those materials to South Korean tech companies such as Samsung, LG and SK Hynix will need to submit each contract for approval.