Rockwool Lightly Resin Bonded mattress are made of fine fibers spun from selected rocks melted at high temperature and bonded with a thermosetting resin. The uniform distribution of fibers, the fine diameter of fiber and flexibility are the unique characteristics of Polybond. Rockwool Lightly Resin Bonded mattress. The properties are controlled to form mattress of predetermined density and thickness. The flexibility of mattress enable it to be application curved surfaces & hence are ideal for industrial boiler insulation, hot air duct insulation, tank insulation.