The material selection method of the composite packaging bag is as follows: 1, Surface material. Most of the non-heat-sealing materials are used, and materials with good heat resistance and small thermal deformation should be considered, such asbopa,bopet,bopp, paper, etc. 2inner material. That is, a heat-sealable material, with a lower heat distortion temperature than the surface material30It is suitable for heat sealing at ℃. If the thermal deformation temperature difference between the surface layer material and the heat sealing layer material is too small, it will bring difficulties to the temperature control of bag making, because the temperature is low and the sealing fastness is poor, which cannot meet the requirements. The sealing fastness will increase the temperature. Since the thermal deformation temperature difference between the inner and outer layers is too small, it is easy to burn the surface material. For the same heat-sealing material, its heat-sealing strength will increase as the thickness of the heat-sealing material increases. Therefore, the inner material of the back sealing bag and the stand-up bag should be30μmThe thickness above is suitable, if the inner layer material is too thin, it will affect the sealing of the finished bag. 3,zipper. A zipper seal with a lower heat-sealing temperature should be selected, generally at a lower heat-sealing temperature than that of the inner layer material.5~10℃ is better.The above is the selection method of composite packaging bag materials.