Synthesis and properties of nylon 6/66/510 used as hot melt adhesives for metal plate with low-surface-energy coating

In this work, nylon 6/66 and nylon 6/66/510 containing 5 ∼ 20 mol % nylon-510 were synthesized to be used as hot melt adhesive for metal plate with low-surface-energy coating. The effects of mole fraction of nylon-510 (Xm) on the thermal and mechanical properties of nylon 6/66/510 were systematically studied. The results demonstrated that: (1) the melting point of the copolyamide decreases and the glass transition temperature decreases when the Xm value increases; (2) the tensile strength of nylon 6/66/510 remains almost unchanged and is almost equal to that of nylon 6/66; (3) the elongation at break of nylon 6/66/510 is significantly higher than that of nylon 6/66. The crystal structure of the copolyamide was also investigated by wide-angle X-ray diffraction (WAXD). The hot-melt adhesives (HMAs) were prepared from nylon 6/66/510, and the adhesive experiments of HMAs to aluminum sheet with low-surface-energy coating were carried out. The results showed that the peeling strength of HMAs based on nylon 6/66/510 reaches a maximum value when Xm = 15 mol %.