Study Of Low-temperature Plasma Treatment For Improving Print Adaptability Of Plastic Films

In recent years, plastics have been widely used in printing and packaging field, because they have many advantages comparing to other materials. While plastics' low surface energy cause many problems in printing process, such as hard to be printed, adhered and compounded. Presently, Corona is usually used to treat plastic films surface before printing in domestic enterprises, but this method has a lot of deficiencies. So it is important to find out a more efficient treatment method to improve the print adaptability of plastics.Low-temperature Plasma (LTP) physics and application have huge influence on the development of high-tech economy and the reconstruction of traditional industry. One important applied field of LTP is surface treatment. LTP with positive ions and negative ions is produced through the high frequency discharge that can lead to inert gases activation. Those positive ions are accelerated by electric field to bombard the plastic films' surface. This method can destroy chemical bond and increase the surface energy.The paper introduces LTP method to printing and packaging field, attempts to use LTP technology to improve the surface energy, coarse degree and the oil ink adhesive force of plastic films. So the print adaptability is improved. The paper begin with the study of LTP technology mechanism and the sample-PE film's print adaptability, which is the theory basic of the research. Then, the experiments are done at different time, different pressure and different plasmas(Ar,O₂,N₂,Ar/O₂).The results of the experiments are measured and analyzed via AFM, the tests of oil ink adhesive force, the critical surface tension test liquid, contact angle and XPS. The best treatment condition based on existing study equipment is found out by means of comparing a mass of experimental data and analysis results. Finally, some conclusions are educed according to the whole study, which are expected to be the theory and experimental basics of further study in plastic films' surface treatment.