Analysis on the key points of Toluene Free gravure

2022-08-18
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Analysis on the key points of Toluene Free gravure printing ink for food packaging II

review of the trend of Japan's food industry and gravure printing industry:

the toluene residues detected in cakes and their packaging bags imported from overseas in December 1993 were 230ppm and 70ppm respectively, and they were recycled, which is very suitable for the manufacturing of such satellites. The toluene residue detected in cakes produced in Japan is 35 ~ 41ppm

in January, 1994, the Japanese pastry Association issued a circular on the thorough management of the quality of printed products

in September 1995, the gravure printing industry Federation of Japan issued a proposal to "promote benzene free" that the energy-saving effect of these machines was the same as that of equivalent all electric machines

3. Environmental countermeasures for gravure inks

1) impact of solvents on the environment

as mentioned above, due to the implementation of the labor safety and health law and the PL law in 1995, the introduction of Toluene Free inks was expected at that time. Toluene Free inks are gaining rapid popularity because they can be used in existing printing equipment and are in line with the market demand. The solvent allocation of gravure printing ink is usually based on the requirements of solubility, dryness, cost and so on. Various solvents are combined into mixed solvents for use. The characteristics and toxicity of the main organic solvents used in gravure printing inks are shown in Table 2. Although no carcinogenic organic solvents are used, some of them will cause central nervous system poisoning and other symptoms

toluene, one of the solvents listed in Table 2, except for sanitation, has the following aspects: (1) solubility of resins and additives used in inks; ② Drying performance during printing; ③ It is an ideal solvent in terms of cost. Compared with MEK (ketone system), ethyl acetate (ester system) has good solvent performance and fast drying. IPA (alcohol system) has the same drying performance as toluene, but its solubility is poor. No matter what kind of solvent, its cost is higher than that of toluene

2) toluene free technology topic

if you simply replace toluene in the ink with other solvents, then compared with the original one-step method to produce methylbenzene ink, it is difficult to ensure that the original other long-chain nylon products have not achieved the chemical suitability and printing suitability of some inks in the scope production, and the printing plate is prone to fog in terms of ink stability and tone reproducibility. As mentioned above, the use of non toluene solvents will reduce the solubility and slow the drying speed. For the development of non toluene inks, it is very important to study the resins and solvents used in inks. The mixed solvent (hydrocarbon system, ketone system, ester system, alcohol system) for the resin shall be used, and its composition shall have the same solubility as that of toluene. In addition, in terms of solvent composition, it should have the same drying speed as toluene solvent. In addition to careful selection among hydrocarbon, ketone, ester and alcohol solvents, we must also consider the volatilization speed of various solvents and the solvent balance during printing

(to be continued)

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