With the flourishing development of industries in various countries and the general improvement of people’s living standards, the increasingly polluted environment of the Earth and the atmosphere on which human beings live is threatening the quality of human life and even the survival of human beings. The printing industry occupies an important position in the national economy. Brilliant and colorful prints have brought about civilization while also causing environmental pollution. Ink is the largest source of pollution in the printing industry. The annual output of inks in the world has exceeded 3 million tons, solvent-based inks account for 30-40%, and the amount of organic solvents used by inks worldwide is more than 1 million tons per year. Organic volatile substances produced by inks ( VOC emissions have reached hundreds of thousands of tons. These organic volatiles can form a more serious greenhouse gas effect than carbon dioxide, and in the sun will form oxides and photochemical smog, seriously polluting the atmosphere and affecting people's health. It is of important long-term significance to reduce and eliminate the pollution of printing to the environment and turn printing into a green one. Guangdong Province's “Environment for Volatile Organic Compounds in Packaging and Printing Industry†jointly formulated by the Guangdong Provincial Department of Environmental Protection and the Guangdong Provincial Bureau of Quality and Technical Supervision will be implemented on November 1, 2010. It is imminent to reduce organic volatiles (VOC) emissions from the printing industry.
At present, the organic volatile matter (VOC) generated by the ink causes atmospheric pollution, and gravure printing is the most serious. It is a difficult problem for the printing industry in the world to completely solve the problem of organic matter (VOC) emissions from gravure printing. Although all countries in the world are developing and using water-based gravure printing inks, water-based gravure printing inks can reduce organic volatiles (VOC) emissions to a certain extent, but the effect of water-based gravure ink printing products, printing levels, clarity, ink layer Thick, uniform ink, saturation, bright color, are not as good as solvent-based inks, because the printing of water-based inks needs to be dried under high temperature conditions. It is difficult to print plastic flexible packaging products in foods, cosmetic products, and medicines.
The UV gravure printing machine under the N2 protection condition is at the world's leading level and can realize the goal of zero discharge of organic volatile matter (VOC) by gravure printing. At the same time, it also solved the application of UV ink on the gravure printing machine. Through UV ink printing, the printing quality of gravure printing has been greatly improved. Gravure printing is a very effective printing method. Gravure printing is rich in layers, clear, thick ink layer, uniform ink, high saturation, bright and bright color, and can reproduce the original effect. However, due to the traditional gravure printing technology, the ink has a low solid content and a large amount of solvent volatilization, so that the printed dots are not full, and the dot reduction effect is not as good as the offset printing; at the same time, the concentration of the ink changes due to the volatilization of the solvent, and the consistency of the print color is affected. . With UV printing, these problems have been completely solved, and the effect of dot reduction is higher than that of offset printing.
In view of the international and domestic technological status, Zhongshan Youwei Printing Equipment Co., Ltd. has invested a lot of manpower and financial resources to develop in 2006. At present, UV gravure printing machines have been successfully developed without solvent N2 protection, and a number of national invention patents have also been obtained. Through the printing of this equipment, the zero discharge of gravure printing organic solvents (VOC) has been completely achieved; the VOC residues detected by the test products printed by the cigarette packet process are less than the YC/T207-2006 volatility of cigarette strips and box wrappers. Determination of Organic Compounds: 2% of the National Standard for Headspace Gas Chromatography. The following is a test report of the toxic and hazardous residues in printed matter entrusted by Shenzhen Jinjia Group Co., Ltd. with the three samples using this technology:
The technical features of UV gravure printing presses with N2 protection are:
1, Solve the application of UV ink in gravure printing machine;
2. Due to UV drying characteristics under N2 protection conditions, UV inks do not dry under oxidizing atmosphere when they are dried. UV inks need not be considered when they are produced: When photoinitiators absorb UV energy after drying, radicals or ions and oxidizing atmospheres are generated. The reaction consumes photoinitiators, and the oxidative atmosphere reacts with hydrogen bonds to produce hydroxyl groups and unsaturated hydrocarbons to produce small molecular organic volatile substances; the difficulty of UV ink production technology is reduced, and the material cost of the UV ink is also reduced. UV inks The cost has been greatly reduced compared to the cost of traditional UV ink production in the past;
3, due to UV drying under N2 protection conditions, the photoinitiator absorbs ultraviolet light energy after drying to generate free radicals or ions will not be oxidized, and the ultraviolet light energy is fully utilized during drying; therefore, UV drying under N2 protection conditions consumes The energy is about 15% of the conventional UV curing energy under the same conditions;
4, due to the above reasons, the overall cost of UV gravure printing under N2 protection conditions is comparable to solvent-based ink gravure printing;
5, UV ink is environmentally friendly ink, no organic solvents. UV drying under N2 protection conditions, because there is no oxidizing atmosphere, will not produce the small molecule organic volatile substances due to reaction of oxidizing atmosphere with hydrogen bonds and hydroxyl groups and unsaturated hydrocarbons, so it is more environmentally friendly. If the N2 protection control is under ideal conditions, the target of zero (or micro) residual VOC can be achieved when the printed matter is printed;
6, less loss of printing products: due to the use of UV drying, paper drying path than the traditional high-speed gravure printing machine rotation is short, so each time the boot per color group to reduce the waste of paper about 10 meters, this waste per color group can be Save tens of thousands.
7, high efficiency: paper drying path is reduced and there is no temperature when the prints are dry, the printing system does not require high printing system, can achieve higher speed printing.
8. Wide applicability: After UV drying, various printing processes can be realized in the printing machine, such as offset printing, flexo printing, screen printing, ice printing, foaming, and indentation. Can be achieved.
9. The quality of the printed product is good: After the test, we found that the printed matter printed by the project is not only better than the quality of the traditional gravure printing machine in the printing field, but also has a higher quality than the traditional offset printing machine. Printing machine