In the process of printing composite packaging bags, the printing composite process is often used. Surface corona treatment of tea packaging bags, aluminum foil bags, plastic packaging bags and plastic films: Before printing and lamination, the surface of the substrates PE, PP, aluminum foil, etc. must be corona treated to improve the printing lamination firmness and achieve the desired effect. , to ensure that the critical surface tension during printing and compounding is greater than 38 mN/m; for the composite film used for cooking, the thickness of the inner substrate should be greater than 70 μ to ensure sufficient heat sealing strength. Composite packaging bag process: composite film can improve various characteristics of a single film, and can improve the protection of the contents, including moisture resistance, oil resistance, barrier properties, shading properties and air tightness. food bags, food packaging bags, vacuum packaging bags