At present, the amount of synthetic organic macromolecular materials, such as plastics, fibers and synthetic rubber, is increasing rapidly. But in the practical use, people gradually found that this kind of material surface of many problems, such as low surface hardness, barrier property is poor, difficult to printing, adhesive, static electricity, and poor biological intermiscibility, these problems not only severely affected the surface performance, the use of these products are market to further expand greatly limits its application.

Plastic film is one of the most important USES of plastic, accounting for about 35% of the plastic consumption. Due to the relatively large surface area of plastic film, its surface problem is more prominent, mainly difficult to print, difficult to bond, difficult to compound, produce fog droplets, static electricity and so on. At present, the surface treatment technology of plastic film used in industry in China is corona method. Plasma surface modification has been included in the national "863", but so far no technical breakthrough, the main reason is that the technical requirements of high vacuum degree makes it hard to become a major industrial products of the surface modification technology to solve the problems existing in the existing film products and production, the development of high performance and functional film products, expanding the application of plastic film market is of great significance.

Since 1996, the organic material surface engineering laboratory of school of materials, Beijing university of chemical technology has developed a new technology for continuous production of hydrophilic/hydrophobic asymmetric plastic film, which is characterized by surface optical grafting. One side of the plastic film products obtained by the new surface treatment technology still has the original hydrophobicity of the film, while the other side can be arbitrarily adjusted according to different needs of the surface polarity until it reaches complete hydrophilic. Of course, the two sides of the film can be treated at the same time to get symmetrical modified products.

This technology is suitable for almost all organic plastic film, such as PE, PP, PVC, PET, nylon and so on. The properties of graft polymerization make the modified layer bond with the original film, and the properties are very stable. Long-term development of the "no droplets plastic greenhouses preparation of new technology", combined with the application basis and application test, after the pilot appraisal by the ministry of education, and completed the transition from pilot to industrialized industrial pilot, set up a processing width is 2 meters of semi-continuous production demonstration plant and workshop, finished for industrialized production. The production device can be used as a separate processing line to process the finished film, or the processing unit can be attached to the original blown film or pulled film production line and directly obtain high performance or functional film products, with lower investment cost. With this technology, the surface of one or both sides of the plastic film can be adjusted freely until it is completely hydrophilic. Functional groups or reactive groups, such as acids, bases, hydroxyl groups, amino groups, anhydrides and epoxies, can also be introduced to one or both sides of the plastic film as required. This has laid a foundation for the development of various novel properties of special plastic film. At present, PE, PP, PVC, PET and other industrial packaging film in the actual use of two problems, difficult to print and difficult to stick.

The surface of the film is usually treated with corona before printing, sometimes with a special primer, and then the use of expensive special printing inks, so the cost is high, and the printing quality is not good. This technology can introduce strong polar hydrophilic groups into the surface of the film, and because the graft chain and the matrix film are linked by chemical bonds, the new surface has durability, which can fundamentally change the existing plastic film printing technology. Not only can solve the problem of organic solvent pollution of plastic film printing, but also can use traditional water-based ink to reduce costs. And to food packaging character, besides must consider and solve the problem such as printing of surface or inside layer, stick, heat sealing, the cut off sex to oxygen, moisture and fragrance is the mainest index. PE and PP have good resistance to water, but poor resistance to oxygen. PET and nylon have higher isolation to oxygen, but less to water. PVDC has good barrier to oxygen and water, but poor film-forming property and single film-forming strength, high cost; PVOH(polyvinyl alcohol) is the best insulating film, but because it dissolves in water, it is difficult to steam and disinfect. Now use produced by the technology of single hydrophilic PE, BOPP, or modified BOPET film, it's easy to get PVDC coated composite membrane, PVOH sandwiched by two PE membrane oxygen insulation and waterproof of high-grade food packaging film, with PE or PP and PET no adhesive composed of middle-grade food packaging film, high-grade low-cost aluminum-plastic composite membrane, prevent atomization and prevent condensation bags, new composite packaging film, etc.