বিউগ’লবিউটানেল
বিউটাইল ৰবৰ (Assamese)
1. Butyl rubber, sometimes just called "butyl", is a synthetic rubber, a copolymer of isobutylene with isoprene. The abbreviation IIR stands for isobutylene isoprene rubber. Polyisobutylene, also known as... from wikipedia.org