Imports In 2012, North Korea imported $13.8k in Isobutene-isoprene (butyl) rubber (IIR), becoming the 0th largest importer of Isobutene-isoprene (butyl) rubber (IIR) in the world. At the same year, Isobutene-isoprene (butyl) rubber (IIR) was the 0th most imported product in North Korea. North Korea imports Isobutene-isoprene (butyl) rubber (IIR) primarily from: N/A.