Rocket case insulation (ROCASIN) developed In ISRO is a rubber compound based on the copolymer of acrylonitrile and polybutadiene known as NBR as per ASTM code. It is specially formulated to serve as a rocket motor case insulation having compatibility to propellant grain system. This has high strength and strain capability and excellent thermal erosion resistance properties as would be desirable in any rocket motor insulation compound. Due to its low coefficient of gas diffusion, ROCASIN finds application as impermeable liners for FRP vessels holding nitrogen at high pressures. Other than sheet form, it finds use as moulded elastomeric flight components like igniter head end insulation, igniter nozzle liners, convergent liners, insulation boot, thermal boot, head end domes etc.