Insulating glass is made of two or more than two pieces of glass between which a space with certain width is partitioned by aluminum frame filled with highly efficient molecular absorbent. The edge of insulating glass is sealed by high strength sealing sealants. To ensure the performance of IGU, double sealing must be used. Butyl should be used for the first sealing, polysulfide rubber or silicon structural sealants should be chosen accoding to glazing manner.