When infiltration of liquid adhesive is not well be sticky surface, air bubbles left in the gap formed in the weak area. For example, impurities dissolved in molten adhesive insoluble in cured adhesive, glue to form another phase after solidification, glued with adhesives as a whole have a weak boundary layer (WBL). WBL in addition to technological factors, interactions in molten polymer into a network or forming process, adhesives and surface adsorption Thermodynamics of boundary layer structure in uneven. WBL inhomogeneity of the boundary layer will appear. Stress relaxation and crack the WBL's development will be different, which greatly affects the overall performance of materials and products.