How to realize the environmental protection of fil

2022-08-17
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How to realize the environmental protection of thin film gravure printing ink

gravure printing uses more VOC as solvent in the ink, which causes more air pollution and great damage to the human body, especially the nervous system. VOC will also have photochemical reaction with nitrogen oxides in the air, producing ozone and smoke. Therefore, it is imperative to develop gravure printing ink with environmental protection requirements. How to achieve environmental protection of film gravure printing ink? The so-called compliance with environmental requirements is to change the composition of ink and use environmentally friendly materials to prepare new ink

I. benzene free solvent ink and water-based ink

the fundamental difference between water-based ink and solvent based ink is that the solvent used in water-based ink is water rather than organic solvent, which significantly reduces VOC emissions, prevents air pollution, does not affect human health, is not easy to burn, has stable inkiness, bright colors, does not corrode plates, is simple to operate, cheap, has good post press adhesion, strong water resistance, and dries quickly, Therefore, it is especially suitable for food, beverage, medicine and other packaging printing materials. It is a world recognized environmental friendly printing material, and it is also the only ink approved by the American food and drug association among all printing inks at present. At present, 40% of plastic printing in the United States uses water-based ink, and other economically developed countries (such as Japan, Germany, France, etc.) use more and more water-based ink in plastic film printing. Britain has legislated to prohibit the printing of one c8800 collection card with solvent based ink; Food film. According to relevant information, in the United States, the proportion of volatile components of water-based inks that meet the VOC regulations is less than 25% and the moisture is more than 75%; Less water in the use of ink, non-volatile ingredients in more than 60% of these two standards. Water based inks are usually used for printing paper products, including paper plastic composite products. Its characteristic is that it can meet the ink absorption of paper printing and make the printing full. What is more difficult is that its solvent is water and ethanol, which is an environmental friendly green ink

at present, many companies still use intaglio printing inks, which are generally made of chlorinated polymers. In the process of ink production, chlorinated polymers need to be dissolved in strong solvents (such as aromatic solvents such as toluene), and toluene is needed to adjust the viscosity of ink in the printing process. Now, chlorinated polymer ink system is considered not suitable for environmental protection requirements. This is because the chlorofluorocarbons it volatilizes in production will destroy the ozone layer. In the process of ink production and printing, the use of aromatic solvents (toluene) will harm the health and safety of workers. In addition, solvent residue in packaging inks is another important issue that needs attention. As toluene is a slow drying solvent, it is very easy to remain in the dry ink film, which will corrode the food in the package and produce harmful odor

the production of plastic gravure printing ink is being restricted by laws and regulations such as fire protection law, labor safety law and health law. Therefore, it will become an inevitable trend to actively develop and apply green gravure printing ink and water-based ink that meet the requirements of environmental protection

second, water-based gravure printing of film packaging materials

although water-based gravure printing ink as an alternative system of toluene ink has attracted a lot of attention, the oil ink based printing in packaging film printing has not yet reached the real practical stage. On the whole, the important reason why water-based gravure inks have not been further popularized is that the printing performance and quality still cannot meet the standard of solvent based gravure inks. This is mainly due to the high surface tension of water, which makes the ink difficult to wet. If we want to obtain the printing speed and printing quality of gravure solvent ink, not only the water-based ink itself needs advanced technology, but also the gravure equipment and printing plate roller need to be improved. For example, the groove depth is about 38 ~ 42 μ M corrosion or engraving plate roller is changed to groove depth of about 24 ~ 28 μ M laser plate making roller also needs more effective and powerful drying equipment and components such as printing roller, ink pump and scraper that must be made of corrosion-resistant materials. These improvements require considerable investment

III. intaglio alcohol soluble composite plastic ink

because water-based intaglio ink can not fully replace toluene ink, the ink industry has been working hard to develop alcohol soluble ink that can be accepted by the environment. Alcohol soluble inks can effectively solve the health damage caused by toluene inks and the impact of solvent residues on the quality of packaged food. In Europe and the United States, this development has become a trend. In Asia, such as Singapore, South Korea and other countries, toluene inks are being eliminated and will be replaced by alcohol soluble intaglio inks. Alcohol soluble inks have been widely used in the domestic gravure printing industry. It can be predicted that in the near future, alcohol soluble inks will occupy the main share of the ink market for high-end food and drug flexible packaging in China

gravure alcohol soluble composite plastic ink has the characteristics of low odor and no benzene. The use of this kind of environmental friendly ink will improve the competitiveness of gravure in the field of packaging and printing

IV. the development trend of traditional ink to environmental friendly ink in the Asia Pacific region

environmental friendly ink is an important field worthy of attention. In many countries in the Asia Pacific region, environmental protection regulations will be more and more stringent, and some printers are difficult to adapt to this change in the current severe economic situation, while ink manufacturers are working hard to meet the requirements of these new standards

the Asia Pacific ink industry has seen a trend from traditional solvent based inks to environmentally friendly inks such as water-based flexographic inks, soybean oil inks, UV inks, etc. The development and production capacity of environmental friendly ink has become one of the key factors for ink manufacturers to win in the Asia Pacific region in the future

at present, the demand for intaglio printing ink based on toluene packaging is still growing. Toluene Free nitrocellulose based printing ink also has a certain market share in some large multinational packaging companies, but it is not very large. UV curable inks are becoming increasingly popular in Southeast Asia, but so far a large number of such inks still rely on imports. Eventually, these strict environmental regulations will be implemented. When the environmental protection regulations come into effect, ink manufacturers must consider environmental protection issues when replacing oils with suitable viscosity, whether they are produced in this country or imported indirectly. At present, China has no strict or indirect regulations on ink, but just like China's coating industry, environmental regulations on ink will be introduced sooner or later. VOC free ink and water-based ink have been tested in the minds of every ink manufacturer or in the laboratory, so that they can be quickly put on the market when environmental protection regulations are issued

author/Wang experimental principle: Su Xia under the specified sample conditions

source: Guangdong packaging 2005/6

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