The problem of solvent residue has always been a difficult problem for ink enterprises. In the hygienic requirements of BOPP / PE composite packaging, the residual amount of benzene solvent must be less than 3mg / m2. With the continuous improvement of people's requirements on food hygiene, how to reduce the solvent residue in food packaging printing has become the focus of ink enterprises.
According to our understanding, we can reduce the residual solvent in food packaging printing from the following aspects:
1. Among eva-40w, MP-45 and cl-pp, cl-pp always brings the highest residual solvent, while ev-40w brings the least residual solvent. Therefore, under the condition of ensuring the composite strength, the content of cl-pp can be appropriately reduced and the content of eva-4ow can be enhanced;
2. Suitable cl-pp was selected. If the formula cost is acceptable, pp803mws produced by Japanese paper can be selected, which can be reduced to 50% under the same dosage;
3. When eva-40w, MP-45 and cl-pp are dissolved, a part of ethyl ester and residual solvent reducing agent are added, which can effectively reduce the residual amount of toluene solvent in ink film;
4. Check whether the solvent used for ink and printing is pure. If there is a small amount of high boiling point solvent, the residual solvent may be too high, and even lead to serious odor of printed matter;
5. Adjustment during printing and compounding:
① When preparing dilution solvent, toluene solvent should be used as little as possible, and the mixed solvent of toluene: acetic acid: butanone = 2:5:3 can be selected;
② In the process of printing, the exhaust air in the drying channel of the printing machine should be increased, and the temperature of the drying channel should be appropriately increased. If conditions permit, the drying channel can be opened for several times after the white ink is printed
③ In the process of printing, the viscosity of the ink can be appropriately reduced.
The above information is edited and arranged by Dongguan Beite packaging material Co., Ltd., which specializes in composite packaging www.dgbpk.com