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Packaging bag printing – advantages and disadvantages of domestic gravure printing inks and directions for improvement

[Plastic packaging bags] Plastic gravure inks are mainly used in food packaging, salt packaging, cosmetic packaging, and pharmaceutical packaging. Food packaging is mainly based on composite inner printing ink, and some candy paper uses surface printing ink; retort packaging uses high temperature cooking ink, and general vacuum packaging uses polyester ink; dairy product packaging should use water-resistant, acid-resistant and temperature-resistant inks; Pharmaceutical packaging and cosmetic packaging are mainly based on polyester inks; some manufacturers of salt packaging use surface printing inks, some manufacturers use composite printing inks, but more manufacturers use polyester inks; There are more and more products using compound printing and special special inks. Composite packaging bags, aluminum foil bags, plastic packaging bags The application of water-based inks is the general trend of gravure printing inks currently used in China, which contain a large amount of organic solvents (about 50%). Solvents such as toluene, ethyl acetate and methyl ethyl ketone have low boiling point, high volatility, and contain aromatic hydrocarbons, which are both toxic and flammable, and are the main sources of environmental pollution. Intaglio inks are generally made of chlorinated polymers. In the ink production process, chlorinated polymers require the use of strong solvents (such as aromatic solvents such as toluene) to dissolve, and toluene is used to adjust the viscosity of the ink during the printing process. The chlorofluorocarbon gas volatilized in the production of chlorinated polymer inks can destroy the ozone layer of the atmosphere. The use of aromatic solvents (toluene) during the printing process poses a hazard to workers’ health and safety (fire hazard). In addition, ink solvent residues in packaging products are a concern. Benzene is very easy to remain in the dried ink film layer (low speed printing requires xylene to adjust the drying speed of the ink, but xylene is more likely to remain), and benzene residues will contaminate the food or supplies in the package. Although gravure alcohol ester ink is the leader in alcohol-soluble ink, although there is no benzene and no ketone, it will still pollute the environment, and there will be solvent residues. The production of plastic gravure ink is being restricted by regulations such as Fire Law, Labor Safety Law, Sanitation Law, etc. Therefore, it will become an inevitable trend to actively develop and apply green gravure ink that meets environmental protection requirements, that is, water-based ink. Water-based gravure ink as an alternative system to solvent-based ink has attracted attention from many departments, and the water-based ink in packaging film printing is also developing vigorously. On the whole, the important reason why water-based gravure ink has not been further popularized is that the printing performance and quality are still not up to the standard of solvent-based gravure ink printing. The main reason is that the surface tension of water is large, which makes the ink difficult to wet; the water does not volatilize, and the printing speed cannot be improved. If you want to obtain the printing speed and printing quality of gravure solvent-based ink, not only the water-based ink itself needs advanced technical improvement , and the gravure equipment and printing plate rollers also need to be improved. For example: change the etched plate roller or electroengraving roller with a printing screen depth of about 38 microns to 42 microns into a laser plate making cylinder with a printing screen depth of about 24 microns to 28 microns. The printing plate roller also needs to use durable Manufactu from corrosive materials. More powerful and efficient ink drying systems, as well as equipment components such as ink squeegees, are also requi to be retrofitted on the press, and these improvements require considerable investment and time. Since water-based gravure inks are not printed on paper, plastic film printing cannot completely replace solvent-based inks. Therefore, the ink industry has been working hard to develop alcohol-soluble inks with less environmental pollution. Alcohol-ester composite plastic gravure inks have the characteristics of low odor, no benzene and ketones. Alcohol-soluble ink can help us solve the problem of toluene-based ink, benzene damage to health and benzene residue affecting the quality of packaged food. The production of such environmentally friendly inks will definitely improve the competitiveness of gravure printing in the field of plastic flexible packaging printing. In countries such as Japan, South Korea and Southeast Asia, toluene-based inks have been eliminated and replaced by alcohol-soluble gravure inks. In Europe, flexographic printing and gravure printing are strongly advocated to use alcohol-soluble inks (benzene-soluble inks are prohibited), and the United States has taken the lead in the development of water-based inks. Alcohol-soluble inks have been gradually applied in the domestic gravure printing industry. It is foreseeable that in the near future, the development trend of inks for flexible packaging in China is: benzene-soluble inks will be replaced by alcohol-soluble inks, and water-soluble inks will have great development. space. At present, the domestic gravure industry is looking forward to: a single solvent (easy to recycle), surface printing, inner printing, compounding, and cooking in one, suitable for all kinds of plastic films, and adaptable to any climate (which can uce the production of enterprises Cost), high-speed, medium-speed, low-speed are suitable, low-cost, gravure ink in the general sense appea in the market. Suggestions for ink manufacturers: foreign printing presses have fast printing speed, standardized production environment, large variety and batch, and specific color, so the requirements for ink are limited to high solid content, low viscosity, bright color, and strong tinting strength. In China, most of them are medium and low-speed printing machines, and the domestic printing machines are uneven, the performance disparity is too large, the product batch is small, the variety is large, the production environment is relatively poor, and the operation is not standardized. Therefore, the requirements for inks are more diverse, and the inks must have strong adaptability, good fluidity, and low prices. In addition, due to the operator’s mentality, using imported ink, if there is a problem with printing, they choose to adjust the printing machine. In turn, if there is a problem with domestic ink printing, it is usually the problem of finding ink and printing plate. [Packaging bag printing] The ink circulation system of domestic gravure printing presses is poor (except for high-speed printing presses of transfer ink supply type), and many medium and small packaging color printing plants do not even use ink circulation systems. Some operators do not understand the inking rules of gravure printing, and have little understanding of the performance of the ink. 40%~50%). Therefore, what is more needed is to popularize the basic knowledge education of plastic flexible packaging production technology, as well as technical services after ink sales. Composite packaging bag, aluminum foil bag, plastic packaging bag

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