In the packaging and printing industry, a variety of inks are often used.Hygienic requirements for printing ink
The requirements of ink for food packaging printing are obviously different from those for commercial printing. Food packaging printing ink is required to have non-toxic, heat resistance, cold resistance, oil resistance, solvent resistance, radiation resistance and so on.Hygienic requirements for printing ink
The safety of ink for food packaging printing mainly depends on the adhesion of toner on printing materials and the firmness of ink layer.Hygienic requirements for printing ink
The gloss of toner suitable for electrostatic digital printing is generally not high, because the diameter of toner particles is relatively large, resulting in different gloss in the dark and bright areas of the image. Ink gloss mainly depends on the surface pore structure and smoothness of the substrate, gloss, ink micro unevenness and ink layer thickness.Hygienic requirements for printing ink
If the flexibility of toner is not enough, the toner will fall off during the folding process of food packaging. Gelboflex test method can be used to determine whether the stiffness of toner is excessive.Hygienic requirements for printing ink
The water, oil and solvent resistance of ink refers to the stability of ink film under the erosion of water, oil, solvent and other substances. Among them, solvent resistance is very important for electrostatic digital printing. Printing with poor solvent resistance will not be able to complete the subsequent processes such as glazing and coating.Hygienic requirements for printing ink
In the field of food packaging and printing, packaged food is usually treated in hot water or steam at 120 ℃ for 30 minutes for disinfection and sterilization. But the usual printing toner can not meet such requirements.Hygienic requirements for printing ink
In addition, in carton and cigarette package printing, the wear resistance control of ink layer is particularly important. It is stipulated in the national standard that the wear resistance of ink layer of packaging printing shall not be less than 70% (d0 / D) × 100%, where d represents the average density of the ink layer before friction, and do represents the average density of the ink layer after friction).Hygienic requirements for printing ink
3、 How far is environmentally friendly printing from us
This paper analyzes the close relationship between printing and health from the perspective of safety. Tell readers that many materials are involved in the process of printing and packaging, such as printing materials, ink, fountain solution, ink cleaning agent, polishing coating, binder and so on. Hygienic requirements for printing ink
These materials contain volatile substances and heavy metals, and their safety problems will be directly related to the health of workers. The printed packaging printed with these printing materials will also bring hidden dangers to the health of consumers.Hygienic requirements for printing ink
The relatively safe inks in offset printing are energy curing inks, such as UV ink and EB (electron beam) ink. The main reason why they are safer than ordinary offset printing inks is that they do not contain volatile substances (VOC), but we should still pay attention to them in the process of use, that is, direct skin contact and import are prohibited.Hygienic requirements for printing ink
Compared with oily varnish, water-based varnish, Non volatile (VOC) substances are widely used in flexographic printing. Flexographic printing is a globally recognized environmentally friendly printing method. The main reason is that it can use safe water-based ink for printing.Hygienic requirements for printing ink
In the United States, flexographic printing accounts for more than 75% in the field of packaging printing, but less than 10% in China. The reason is that domestic legislative supervision is not enough, publicity measures are not effective, and the attention of people in the industry is not in place.Hygienic requirements for printing ink