Discussing the Application of Plasma Technology in Carton and Case Gluing Processes

Particle energy in low-temperature plasma typically ranges from several to a dozen electronvolts, which is greater than the binding energy of polymer materials (also several to a dozen electronvolts), allowing for the breaking of chemical bonds in organic macromolecules and the formation of new ones; however, it is significantly lower than that of high-energy radioactive rays, affecting only the material surface without impacting the matrix's properties. In low-temperature plasma that is not in thermodynamic equilibrium, electrons possess higher energy, capable of breaking the chemical bonds of surface molecules, enhancing the reactivity of particles in chemical reactions (greater than in thermal plasma), while neutral particles have temperatures close to room temperature. These advantages provide suitable conditions for the surface modification of thermosensitive high molecular polymer materials. Through low-temperature plasma surface treatment, various physical and chemical changes occur on the material surface, resulting in etching and roughening, the formation of dense cross-linked layers, or the introduction of oxygen-containing polar groups, improving hydrophilicity, adhesion, dyeability, biocompatibility, and electrical properties. Processing the material surface under appropriate conditions leads to significant changes in the surface morphology, introducing multiple oxygen-containing groups, transforming the surface from non-polar and non-adhesive to polar, adhesive, and hydrophilic, which is beneficial for bonding, coating, and printing.
Currently, various film production commonly employs corona treatment to address surface affinity issues. However, since corona treatment can only be conducted between adjacent parallel electrodes with limited distance, it is not suitable for surface polarization of three-dimensional objects. Using flame treatment has its drawbacks, as all polymers are flammable and have low melting points. When organic materials are exposed to high-temperature flames, they can deform, discolor, become rough, burn, and emit toxic gases due to the high-temperature treatment. Moreover, the process is difficult to control.