In order to enhance the drilling sealing effect and improve the gas drainage efficiency of coal mines, this paper combines material composite mechanism, microcapsule technology, and expansion mechanism to produce efficient drilling sealing materials. Aluminum powder is the main driving force for the expansion of the sealing material and the expansion effect reached a maximum at an addition amount of 0.15%. The use of microcapsule technology to treat the expansive agent can delay the time during which the expansive agent works, so that it expands after the material is at a suitable strength, reduces the loss of expansion energy caused by premature expansion, and achieves coordinated development of expansion-strength. Polymer has good flexibility and cohesiveness. It can fully adapt to the change of particles between cement and mortar drying process. It exists in the cement stone space in a continuous network structure. (c) 2019 Elsevier B.V. All rights reserved.