Analysis on the development trend of the most popu

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Analysis on the development trend of green teaching materials recently, the green printing of teaching materials proposed by the state as the primary measure to promote the development of green printing has its special significance. Teaching materials are mostly used by primary and secondary school students. As their learning tools, teaching materials can be said to be something they must contact every day. At present, due to the uneven overall level of the industry and people's weak awareness of safety and environmental protection, there are a lot of problems in textbook printing

problem 1: ink fragrance and ink

the toxic chemical elements contained in the ink diffuse in the air, making the ink give off a taste, that is, what people call ink fragrance. The ink used for textbook printing often contains volatile organic solvents such as ethanol, isopropanol, butanol, propanol, butanone, ethyl acetate, toluene, xylene, etc. these organic solvents volatilize continuously during the printing process, emitting toxic and irritating benzene substances. Although most of the solvents will be removed after the ink is dried, there will still be some residues. When students read books printed with this kind of ink for a long time, the inhaled gas will affect the central nervous system of the brain and pose a threat to their health

what's more, the ink used for book printing has fine pigment particles and strong adsorption capacity. It contains heavy metal elements such as lead, chromium, cadmium and mercury, all of which are toxic. Their emissions will not only cause damage to the natural environment, but also lead to chronic poisoning of human body, or enter brain tissue through blood, causing brain damage. According to research, the absorption of lead by developing adolescents is several times higher than that of adults, and lead poisoning has a great impact on the intelligence of adolescents. Therefore, inkjet, when the ink containing these heavy metals is in close contact with the human body, especially students and children, the consequences are unimaginable

problem 2: packaging

EVA hot melt adhesive and solvent based coating process used in post press binding of general teaching materials also contain some volatile organic solvents. The smell of these solvents is usually carcinogenic, which endangers the health of students and the environment

in addition, in the production process of teaching paper, a large number of additives, brighteners, fluorescent agents, etc. are generally added, which greatly improves the whiteness of the paper. Reading for a long time will cause visual fatigue, especially for primary and secondary school students. Reading will make their eyesight decline rapidly, and the waste water discharged after adding additives will also have a great impact on the environment. In order to put an end to pollution and ensure the health and safety of students, green textbooks came into being

policy support for green textbooks

in order to speed up the promotion process of green printing, yanxiaohong, deputy director general of the General Administration of publishing, convened relevant publishing and printing units to deploy the pilot printing work of using environmental protection materials for primary and secondary school textbooks this autumn, and instructed that the printing and distribution Management Department of the general administration should be specifically responsible for this work, with the full cooperation of the green printing promotion management office of the China Printing Technology Association

in the pilot work of green printing of primary and secondary school textbooks, there are seven publishing units, namely, Beijing Normal University Press, people's education press, people's Art Press, people's music press, Education Science Press, Shanghai Education Press and Shanghai Foreign Language Education Press, Beijing MEITONG Printing Co., Ltd., people's education press printing plant, Beijing Jingshi Printing Co., Ltd., Sichuan Xinhua printing plant Sichuan Xinhua Color Printing Co., Ltd., Sichuan Jinzhu Printing Co., Ltd., Sichuan Lianxiang Printing Co., Ltd., Chengdu high tech Zone Longjiang color printing factory, Shandong Linyi Xinhua Printing logistics group, Shanghai Zhonghua Printing Co., Ltd., Shanghai printing factory silk printing branch of the Commercial Press, as well as Tianjin Dongyang Ink Co., Ltd., HANGHUA ink Chemical Co., Ltd., Wuxi Wanli adhesive materials Co., Ltd Henkel (China) Investment Co., Ltd. and other relevant production units of environmental protection raw and auxiliary materials participated in the pilot work

in September, 2010, after the General Administration of publication and the Ministry of environmental protection of the people's Republic of China (hereinafter referred to as the Ministry of environmental protection) signed the strategic cooperation agreement on the implementation of green printing, the two departments respectively entrusted the China Printing Technology Association and the environmental development center to undertake the implementation and promotion of green printing. In the announcement on the implementation of green printing, it is pointed out that from 2012 to 2013, a green printing framework will be built in the whole printing industry. Relevant green printing standards have been formulated and issued successively, and green printing has been gradually promoted in the fields of bills, tickets, food and drug packaging, etc; Establish green printing demonstration enterprises and issue relevant supporting policies for green printing; We will basically achieve full coverage of green printing of primary and secondary school textbooks, and accelerate government procurement for green printing. It is understood that since the Ministry of environmental protection issued and implemented the first national environmental protection standard for the printing industry "technical requirements for environmental labeling products" on March 2, 2011, the first green printing certification has been officially launched. By the end of March 2011, 319 enterprises from all provinces (autonomous regions and municipalities) have reported to participate in the green printing certification, of which more than 60 enterprises have submitted certification materials, and more than 20 enterprises have accepted on-site certification inspection

this time, the green printing takes the printing of green primary and secondary school textbooks as the starting point. Caohongsui, deputy director of the printing and distribution management department of the General Administration of publication, said that the promotion of green printing will gradually expand to the printing of government purchased products, food, medicine and other packaging printing fields, starting from primary and secondary school textbooks. This year, the General Administration of publishing conducted a pilot project in seven publishing houses. 100 teaching materials were printed with environmentally friendly ink and glue, totaling more than 15 million copies, involving more than 20 provinces, cities and autonomous regions. The green printing of primary and secondary school textbooks should be realized within three years, and the green printing of all publications should be completed within five years

materials of green textbooks

the green of green textbooks is mainly reflected in the materials used. In terms of ink, offset printing ink with environmental label certification is adopted; In the post press cover coating materials, more environmentally friendly pre coating, water-based coating or UV glazing are used; In terms of adhesives, hot melt adhesives with higher safety are used; In terms of paper, some publishing houses have also selected natural color paper produced by crop straw for printing

1. Ink

ink is one of the largest pollution sources in the printing industry. Traditional offset printing inks usually use petroleum solvents, which contain toxic and harmful chemicals such as heavy metals, organic volatiles and aromatics. The five publishing houses that conducted the green printing experiment of teaching materials in Beijing used offset printing inks with environmental label certification, all of which were aromatic free soybean inks, provided by Tianjin Toyo Ink Co., Ltd. and HANGHUA ink Chemistry Co., Ltd. These ink suppliers are all involved in the compilation of national environmental protection standards related to offset printing ink, gravure printing ink and flexo printing ink

environmental friendly inks use less mineral oil and more vegetable oil, which not only reduces the use of petroleum solvents, reduces environmental pollution, but also reduces the health hazards to operators and consumers. Gongzhangshui, chief engineer of HANGHUA ink Chemical Co., Ltd., said

the environment-friendly ink used in the experimental teaching materials takes renewable soybean oil as the carrier, partially replacing the petroleum solvent which is increasingly exhausted, because the petroleum solvent will remain in the pages, while the vegetable oil is safe. Zhou Mei, the technical consultant of Tianjin Toyo Ink Co., Ltd., said that taking the environmentally friendly offset sheet fed ink as an example, the content of vegetable oil in the certified product must reach more than 20%. Compared with the general offset printing ink, about 100 kg of petroleum solvent per ton of product is reduced. If the green printing of teaching materials is promoted nationwide, the use of petroleum solvents can be greatly reduced. At the same time, due to the increase of vegetable oil content, the VOC (volatile organic compounds) content of the ink is reduced, and the VOC emission during the printing drying process will be reduced by about 10%

in addition, the environmentally friendly soybean ink also uses aromatic free solvents. Gongzhangshui said: generally, the aromatic hydrocarbon content in the solvent used for inks is 10% ~ 20%. Environmentally friendly inks use aromatic free solvents, that is, the aromatic hydrocarbon content in the solvent is less than 1%. Compared with the original solvent, the aromatic free solvent has less odor and less irritation to skin. Therefore, it is a solvent with less risk to human health, shrinkage and porosity, and the impact of cooling rate on tissues. Moreover, due to the good biodegradability of the solvent, the environmental pollution to the earth is reduced, and it is a solvent friendly to the earth's environment

2. After printing cover coating process

experts demonstrated that in order to achieve green printing, the key point in the printing process is to solve the ink pollution problem, while in the post printing process, the core is to solve the pollution problem caused by the film covering process. In the pilot project of this green textbook, it is learned that each publishing house and printing plant has used three more environmentally friendly coating or glazing processes, namely, pre coating, water-based coating or UV glazing

lamination is to attach a film on the surface of printed packages. Its function is to make printed materials more beautiful, firm and durable. It is often used on the cover of primary and secondary school textbooks. Zhong Jinyu, chairman of Beijing kangdexin composite materials Co., Ltd., told Yu in the field of 3C lithium-ion batteries that for many years, China has been using solvent based instant coating technology to complete film coating, but it uses solvents containing benzene, which is easy to cause operators to suffer from leukemia, blood cancer, infertility and other serious diseases. The workshop is also prone to sudden fire due to static electricity generated by film materials, and it is difficult to recycle the coated paper and film materials. According to statistics, solvent based coating still accounts for about 68% of the film covering market of printing and packaging in China

at present, there are two more environmentally friendly coating technologies in the market, namely, water-based instant coating technology and pre coating technology, of which the pre coating technology is the most environmentally friendly. Pre coating is a kind of pollution-free and high viscosity printing and packaging material that combines hot-melt adhesive or low-temperature resin with film substrate through special equipment. The utility model has the advantages of no pollutants, high-speed production, more exquisite printing and low drying energy consumption

according to Zhong Yu, 60%~70% of primary and secondary school textbooks in China have used precoating technology, and primary and secondary school textbooks in Beijing have used precoating film to comprehensively replace solvent based instant coating film five years ago, making primary and secondary school textbooks take the lead in the field of publication printing. However, in the whole domestic film covering market, this environmental protection process has only 10% market share. In the United States, solvent based coating has been completely eliminated since 1996. At present, 95% use precoating technology, 3% use water-based coating, and 2% use UV glazing process. The pre coating technology in Europe also has a 65% utilization rate, and the remaining 35% is water-based adhesive film and UV glazing. It can be seen that the overall promotion of post press environmental protection film covering process in China has lagged behind that in the United States for 15 years

Zhong Yu said: promoting the comprehensive replacement of pre coating is the key measure to realize green printing. This time, the General Administration of publication signed a strategic cooperation agreement with the Ministry of education and the Ministry of environmental protection, which will accelerate the promotion of pre coating, and the era of comprehensive replacement of pre coating is coming. He predicted that China will be able to complete the comprehensive replacement of post press pre coating technology in the next three to five years

in addition to the pre coating process, some printing houses also use water-based coating in the cover of teaching materials, or change the coating to UV glazing. The water-based coating contains less harmful solvents and is easy to recover. After changing the post press cover technology from laminating to glazing, the wear resistance of teaching materials can be basically met. And, because there is a UV curing factor in the glazing oil, it can be cured after a few seconds of ultraviolet irradiation

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