Hydrophobic perlite is a glassy granular products. It is a certain size of perlite after the appropriate temperature preheating, high temperature calcined expansion and the special hydrophobic treatment. It is neutral, non-flammable, tasteless, acid and alkali and with good chemical stability. Compared with ordinary hydrophobic products, it has good durability. Hydrophobic perlite is particularly suitable in LNG / LPG transport ships, large cryogenic liquid storage tanks and other ultra-low temperature insulation.