LOCTITE 401 LOCTITE® 401 is a fast-fixturing instant adhesive (industrial grade) designed for the assembly of a wide range of materials where uniform stress distribution and high tensile and/or shear strength are required. Using primer LOCTITE® SF 770, the assembly of difficult-to-bond (PP, PE, PTFE) materials is possible. In addition, it is suited for bonding porous materials such as wood, paper, leather and fabric.