Overcome the difficult problem of plastic film surface treatment

At present, the amount of synthetic organic polymer materials such as plastics, fibers, and synthetic rubbers using petroleum as raw materials is increasing, and is still growing rapidly. However, in actual use, people gradually found that such materials have many surface problems, such as low surface hardness, poor barrier properties, difficult to print, difficult to bond, static electricity, and poor biocompatibility. These surface problems not only seriously affect these products The application performance also greatly limits the further expansion of its application market.

Plastic film is one of the most important uses of plastic, accounting for about 35% of the amount of plastic used. Due to the large relative surface area of ​​the plastic film, its surface problems are more prominent, which are mainly manifested as difficult to print, difficult to bond, difficult to compound, produce droplets, and generate static electricity. The plastic film surface treatment technology currently used in industry in China is the corona method, but this method has great limitations and is not suitable for many bulk uses. Plasma surface modification technology has been included in the national "863" plan, but so far there has been no technical breakthrough, the main reason is that the high vacuum required by the technology makes it difficult to become a bulk industrial product surface modification technology to solve the existing Film products and problems in production, it is of great significance to develop high-performance and functionalized film products and expand the application market of plastic films.

The Laboratory of Surface Engineering of Organic Materials, School of Materials Science and Engineering, Beijing University of Chemical Technology has been developing a hydrophilic / hydrophobic asymmetric plastic film with intermittent small-scale test, mold test and pilot test since 1996. Continuous production of new processes. The plastic film products obtained by the new surface treatment technology still have the original hydrophobicity of the film on one side, and the polarity of the surface can be arbitrarily adjusted according to different needs until it is completely hydrophilic. Of course, you can also process both sides of the film at the same time to obtain a symmetrically modified product.

This technology is suitable for almost all organic plastic films, such as PE, PP, PVC, PET, nylon, etc. The characteristics of graft polymerization make the modified layer and the original base film chemically connected, and the properties are very stable. Among them, the "new technology for the preparation of long-acting fog-free plastic greenhouses", which combines the application basis and application tests, has passed the pilot test organized by the Ministry of Education, and completed the industrial pilot test from the pilot test to industrialization. A semi-continuous production demonstration device and workshop with a processing width of 2 meters were established, and preparations for industrial production were completed. The production device can be used as a separate processing production line for off-line processing of the finished film, or the processing unit can be attached to the original film blowing or film production line to directly obtain high-performance or functional film products, and the investment cost is lower. With this complete set of technology, the surface of one or both sides of the produced plastic film can be freely adjusted until it is completely hydrophilic; it can also introduce functional groups or reactive groups, such as acids, bases, and hydroxyl groups, on one or both sides of the plastic film as needed. , Amino, anhydride, epoxy, etc. This laid the foundation for the development of special plastic films with various novel properties. At present, there are two problems in the actual use of industrial packaging films such as PE, PP, PVC, PET, etc., which are difficult to print and difficult to bond.

Generally, the surface of the film is corona treated before printing, sometimes coated with a special primer, and then used expensive special printing ink, so the cost is high and the printing quality is not good. This technology can introduce strong polar hydrophilic groups to the surface of the film, and because the graft chain is chemically linked to the base film, the new surface has durability and 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 use traditional water-based ink to reduce costs. For food packaging, in addition to the problems of surface printing, inner layer printing, bonding, and heat sealing, the barriers to oxygen, moisture, and fragrance are the most important indicators. PE and PP have excellent barriers to water, but poor barriers to oxygen; PET and nylon have high barriers to oxygen, but poor water; PVDC has good barriers to oxygen and water, but forms a film PVOH (polyvinyl alcohol) is the best oxygen barrier film, but it is difficult to digest and sterilize because it is dissolved in water. Now using the single-sided hydrophilic PE, BOPP or BOPET modified film produced by this technology, it is easy to obtain a PVDC coated composite film, a high-end food packaging film that is both oxygen and water barrier sandwiching PVOH between the two PE films 、 Using adhesive-free mid-range food packaging film composed of processed PE or PP and processed PET, high-end low-cost aluminum-plastic composite film, anti-fogging and anti-condensation fresh-keeping bags and other new composite packaging films.

In addition, paper-plastic composite packaging has become the main body of cement, grain, fertilizer and some industrial products and raw materials. However, such composite packaging bags are difficult to separate and reuse, not only causing new environmental pollution, but also increasing costs. Therefore, there is an urgent need to develop "green paper-plastic composite packaging bags". In 199, Lanzhou Jinan New Technology Co., Ltd. made a breakthrough in this technology, and produced a new composite packaging bag of vinylon water-soluble yarn. This technology uses water-soluble polyvinyl alcohol as a binder to bond paper and vinylon yarn together. The inner layer is recycled paper bag, the outer layer is national standard paper bag paper, the middle is bonded with mesh vinylon water-soluble yarn, and put into water after use. The polyvinyl alcohol and vinylon dissolve, allowing the paper to be recycled. However, this product has the disadvantages of poor water resistance and difficulty in recycling vinylon. Now, using new technology has opened another route, that is, the polyolefin film is hydrophilically modified on one side, and then the film is bonded to the paper with a water-soluble adhesive to obtain a high-strength, water-soluble, and anti-aging paper. Plastic composite packaging materials, soak the paper side with water after use, the paper and polyolefin film will be naturally separated, and can be recycled separately.

At present, there is no such industrialized processing technology at home and abroad, and there is no such series of products on the market. Therefore, this technology has complete independent intellectual property rights. Its promotion and application can not only bring huge economic benefits for enterprises, but also increase environmental awareness. Today, it will have huge social benefits.

PS is Polystyrene that usually clear, hard and brittle. It is low density and one of the most common used plastics which used to be produced several million tonnes per year. Normally, it is transparent, but can be coloured with colourants. It can be used into different packages such as DVD cases, clamshells, lids, blister, disposable cutlery.

PS Blister Packaging Tray

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ShenZhen YaoLong Colour Printing Co., LTD. , https://www.ylprinting.com