Section 07 PLASTICS AND ARTICLES THEREOF; RUBBER AND ARTICLES THEREOF 40 Rubber and articles thereof 40 02 Synthetic rubber and factice derived from oils, in primary forms or in plates, s 40 02 31 40 02 31 00 Commodity Code Description 40 02 31 00 00 -- Isobutene-isoprene (butyl) rubber (IIR)