Printing processing skills of the hottest flexible

2022-08-08
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Printing processing skills of flexible packaging materials

plastic film

common plastic films include: PE, PP, PVC, PS, PV. We should vigorously promote the civil aircraft aluminum material management system and cooperation mechanism a, PC, pet, CA, NY. The printing characteristics of these plastic films are:

1 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 adhesion to printing ink and enhance the firmness of prints, surface activation treatment is carried out before printing

2. Hygroscopicity is mostly affected by the relative humidity of the surrounding air and expands and deforms, resulting in poor overprint

3. Affected by the change of tension, the elongation of the film increases with the increase of tension within the allowable range of strength, which makes it difficult for the accuracy of color printing overprint

4. The surface is smooth, without hairy pores, and the ink layer is not easy to be fixed or fixed firmly. After the first color is printed, it is easy to be stuck by the ink overprinted by the next color, making the pattern and text incomplete and causing defects

5. The surface oil layer exudes. For the film made of additives, the additives are easy to seep out when the full range resolution of printing remains unchanged, and an 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 this kind of film

6. As 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 plastic film must be surface treated before printing

cellophane

cellophane is characterized by high transparency, strong gloss, and extra bright color after printing pictures and texts, which can not be achieved by plastic film; The printing adaptability is good, and there is no need to go through any treatment before printing. The cellophane also has anti-static treatment performance, which is not easy to absorb dust, and avoids printing faults such as text dust. However, the moisture resistance is poor, and the film is easy to deform under the influence of temperature and humidity, which makes it difficult to register pictures and texts during printing

aluminum foil

the characteristics of aluminum foil are:

1 It is light in weight, with metallic luster, good lightproof performance, and high reflection ability to heat and light. Metallic luster and reflection ability can improve the brightness of printing color

2. Good isolation, strong protection, impermeable to gas and water vapor, preventing moisture absorption and gasification of the contents, and not vulnerable to bacteria and insects

3. Good shape stability, not affected by humidity changes. Easy to process, aluminum foil can be printed, colored, embossed, surface coated, glued, painted, etc

4. It cannot bear force, has no sealing property, has pinholes and is easy to wrinkle, so it is generally not used alone. It is usually processed into composite materials with paper and plastic film, which overcomes the shortcomings of no sealing property, and its isolation and other advantages have also been brought into full play

aluminum foil is widely used in food, medicine and other packaging fields. Aluminum foil is compounded with plastic film, which effectively uses the characteristics of high temperature cooking resistance and complete shading to make cooking bags, which can pack cooked food. Multi layer composite film is also used in the packaging of cookies, snacks, beverages and other small foods

vacuum aluminum plating film

compared with aluminum foil, vacuum aluminum plating greatly saves aluminum consumption. The former is only 1/100~1/200 of the latter, but it has metal luster and insulation. Because the thickness of vacuum aluminum coating is relatively thin, only 0.4-0.6 m, it can not be used to replace aluminum foil composite films that need high barrier, such as vacuum packaging and high-temperature cooking bags. The cost of vacuum aluminum plating is lower than that of aluminum foil, and it will be greatly developed in the field of food trademarks. In recent years, vacuum aluminum plating paper is gradually replacing aluminum foil in cigarette, cold meal carton, chewing gum and other packaging

the main function of vacuum aluminized film is to replace aluminum foil composite, so that the soft plastic packaging also has a beautiful silver luster, improve the barrier and shading of the soft packaging film bag, and thus 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 adjustment. Indirect aluminizing process can be adopted for PE film and Pt. In order to provide the fastness of aluminum plating, foreign countries adopt the method of coating the bottom layer on the plated substrate film, while in China, there is generally no bottom coating surface, and only corona treatment is carried out on the surface. There are two methods of vacuum aluminizing the film, which can be reverse printed on the facial mask of the film, that is, inner printing, and then vacuum aluminizing and compounding with the bottom film. You can also reverse print on the facial mask, and then dry compound it with the vacuum aluminized bottom film. The bottom film of the latter must be CPP or IPP with good heat resistance and can be heat sealed

when vacuum aluminizing on the printed facial mask, although it is internal printing, it is not necessary to use internal printing ink, just an ink with excellent heat resistance. If the printed matter darkens and loses its luster after vacuum aluminizing, it is because of the poor heat resistance of the ink. Vacuum aluminizing on the printing surface, because the adhesive resin in the ink is a good undercoat, the fastness of aluminizing is better, especially when printing full-scale field, the fastness of aluminizing layer is better

composite film

there are many kinds of composite films. The common ones are the combination of cellophane and plastic film, plastic film and plastic film, aluminum foil and plastic film, aluminum foil, glass, paper and plastic film, various papers and their prints and various plastic films, etc. there are as many as 30~40 kinds, and the number of composite layers is generally 25. The basic structure of various composite films is to use non thermoplastic or high melting point films such as Pt, BOPP, NY, pet as the outer layer and PP, PE as the inner layer for comprehensive application. The commonly used composite film structure is also used for many purposes. When choosing composite film, we should also consider the printing performance in order to obtain exquisite trademark patterns

composite films are widely used in the outer packaging of food, such as fast food, quick-frozen food, puffed food, etc. in shopping malls. These are made of composite films. The composite films can not only maintain the excellent characteristics of single-layer films, but also their own shortcomings. After compounding, they have new characteristics to meet the different requirements of commodities for films. For example, food packaging requires that the films have excellent properties such as moisture-proof, gas proof, light proof, oil resistance, high temperature resistance, good heat sealing, but also have good printability and decorative art effect, Performance and requirements are difficult to achieve with a single film. Take the most widely used PE film for example, although it has excellent transparency, moisture resistance, heat resistance and chemical stability, its oil resistance and oxygen resistance are limited, and its printability is poor. 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 has excellent transparency, no static electricity, not easy to pollute, easy to bond, but poor toughness, water resistance and moisture resistance. Aluminum foil has the luster and thermal conductivity of flashing metal light to which special strips have been set, and has good resistance to moisture, steam, light and grease, but it has the disadvantages of easy cracking, lack of softness, and no thermal adhesion

the thin desert of each layer is compounded together. At the same time, it has excellent properties such as moisture-proof, gas proof, light proof, heat-resistant, oil resistant, and good heat sealing performance, making it an 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, which has good insulation performance and is conducive to the long-term storage of food; BOPP film is used for the outer layer, which has excellent dimensional stability. Gravure printing is used on the back, and adhesive is used to compound with aluminum foil to ensure the firmness and smoothness of printing color. The inner layer adopts PE film, which takes advantage of its advantages of heat resistance, softness and easy sealing. After the combination of the three, it can withstand 120 ℃ high-temperature sterilization treatment, and microorganisms will not be immersed, which plays a role in preserving freshness and taste

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