The commonly used plastic films of plastic film are PE, PP, PVC, PS, PVA, PC, pet, CA, NY. The printing characteristics of these plastic films are as follows: 1) the plastic film is a non-polar polymer compound, and its adhesion to printing ink is very poor. In order to make the surface of plastic film have good ink adhesion ability and enhance the firmness of printed matter, the surface activation treatment is carried out before printing ② Hygroscopicity is mostly affected by the relative humidity of the surrounding air, which results in poor overprint; ③ due to the change of tension, the elongation of film increases with the increase of tension in the range of allowable strength, which brings difficulties to the accuracy of color printing overprint ④ The surface is smooth and there are no pores. The ink layer is not easy to be fixed or not fixed firmly. After the first color printing, it is easy to be stuck off by the next color overprint ink, which makes the pattern and text incomplete, resulting in defects; ⑤ the surface oil layer exudes. In the printing process, the additive part of the film is easy to seep, and a layer of oily layer, ink layer, coating or other adhesive is formed on the surface of the film, which is not easy to bond firmly on the surface of the film; ⑥ Because the plastic film is a non-polar material, there are no pores, and the ink is not easy to dry. These characteristics are not conducive to printing, so the surface treatment of plastic film must be carried out before printing. The characteristics of cellophane and cellophane are: high transparency, strong gloss, bright color after printing, which is not achieved by plastic film; good printability, without any treatment before printing, cellophane also has anti-static treatment performance, is not easy to absorb dust, and avoids printing failure such as image and text sticky dust. However, due to poor moisture resistance, the film is easy to deform due to the influence of temperature and humidity, which makes it difficult to register pictures and texts during printing. The characteristics of aluminum foil are: 1) light weight, metallic luster, good light repellency, high reflection ability to heat and light, metal luster and reflection ability can improve the brightness of printing color; 2) good isolation, strong protection, gas and water vapor permeability, prevent moisture absorption and gasification of the contents, and are not easy to be damaged by bacteria and insects; ③ The shape is stable and not affected by humidity change. It is easy to process and can be used for printing, color difference, embossing, surface coating, gluing and painting of aluminum foil; ④ it can not bear force, has no sealing property, has pinholes and is easy to wrinkle, so it is not used alone in general. It is usually processed with paper and plastic film to make composite material, which overcomes the defect of non sealing, and its advantages such as isolation are fully developed. Aluminum foil is widely used in food, medicine and other packaging fields. Aluminum foil is compounded with plastic film, which effectively utilizes the characteristics of high-temperature cooking and complete shading to make cooking bags, which can package cooked food. Multilayer composite film is also used for packaging biscuits, snacks, drinks and other snacks. The main function of vacuum aluminizing film is to replace aluminum foil composite, so that the soft plastic packaging also has silver white beautiful luster, improve the barrier and shading of flexible packaging film bag, so as to reduce the cost. The substrate film of vacuum aluminum plating is polypropylene film with high melting point, including CPP, IPP and BOPP. PET film, NY film and paper can also be directly vacuum aluminized after pretreatment or humidity control. PE film and Pt can adopt indirect aluminizing process. In order to provide the fastness of aluminum plating, the method of coating the bottom layer on the substrate film is adopted in foreign countries, while there is no bottom coating surface in China, only corona treatment is carried out on the surface. There are two ways of vacuum aluminizing of thin films, which can be reversed printed on the mask of the film, that is, inner seal, then vacuum aluminized and then combined with the bottom film. It can also be reversed printed on the mask, and then dry composite with the vacuum aluminized bottom film. The bottom film of the latter must be CPP or IPP with good heat resistance and heat sealing.It should be pointed out that when vacuum aluminizing is applied to the printed mask, though it is printed inside, it does not need to use internal ink, only the ink with good heat resistance can be used. If the vacuum aluminizing after the printing dark, lose its luster, this is because of the poor heat resistance of the ink. When vacuum aluminizing is carried out on the printing surface, because the adhesive resin in the ink is a good primer, the fastness of aluminum plating is better, especially when printing full-scale field. Compared with aluminum foil, vacuum aluminizing can greatly save the amount of aluminum. The former is only 1 / 100-1 / 200 of the latter, but it has the luster and insulation of metal. As the thickness of vacuum aluminizing layer is relatively thin, only 0.4-0.6? M, it can not be used to replace the aluminum foil composite film with high barrier property, such as vacuum packaging and high temperature cooking bag. The cost of vacuum aluminum plating is lower than that of aluminum foil, and it will be greatly developed in the fields of food trademark. In recent years, vacuum aluminized paper is gradually replacing aluminum foil in packaging of cigarettes, cold meal boxes, chewing gum, etc. Composite film is widely used in food packaging, such as fast food, frozen food, puffed food and so on. These films are made of composite films. The composite films not only maintain the excellent characteristics of single-layer films, but also have their own shortcomings. After compounding, they have new characteristics to meet the different requirements of commodities for films. For example, food packaging requires that films have excellent properties such as moisture-proof, gas-proof, light-proof, oil-resistant, high-temperature resistant, heat-sealing good, and also have good printability and decorative art effect The properties and requirements are difficult to be achieved by a single film. Take the most widely used PE film, although it has excellent transparency, moisture resistance, heat resistance, chemical stability, but its oil resistance, oxygen resistance is limited, poor printability. Pet and PA films have high tensile strength and fatigue strength, but the former has poor moisture resistance, while the latter has poor heat sealing and chemical resistance. PE (glass property) has excellent transparency, no static electricity, no pollution, easy adhesion, but poor toughness, water resistance and moisture resistance. Aluminum foil has flashing metallic luster and thermal conductivity, and has good resistance to moisture, steam, light and grease. However, it is easy to crack, lack of flexibility and no thermal adhesion. Each layer of thin desert compound together, at the same time with moisture, gas, light, heat, oil resistance, good heat sealing and other excellent properties, become a relatively ideal packaging material. For example: the current high-grade rp-h cooking bag is a three-layer composite film based on plastic film. Its middle is aluminum foil with good insulation, which is conducive to the long-term storage of food; BOPP film is used for the outer layer, which has excellent dimensional stability. The back gravure printing is carried out, and the bonding agent is combined with aluminum foil to ensure the firmness and smoothness of printing color. The inner layer is made of PE film, which has the advantages of heat resistance, softness and easy sealing. After the combination of the three, it can withstand 120 ℃ high temperature sterilization treatment, and the microorganism will not be immersed in it, so it can keep fresh and taste. There are many kinds of composite films. The common ones are glass paper and plastic film, plastic film and plastic film, aluminum foil and plastic film, aluminum foil, glass, paper and plastic film, various paper and printed matter and plastic film, etc. there are as many as 30-40 kinds, and the number of composite layers is generally 2-5. The basic structure of all kinds of composite films is that non thermoplastic or high melting point films such as Pt, BOPP, NY, pet are used as outer layer and PP and PE as inner layer for comprehensive application. Common composite film structure composition, there are many uses, in the choice of composite film, but also to consider the printing performance, in order to obtain exquisite trademark patterns.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service.
The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries.
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