With the improvement of living standards, people put forward higher requirements for food packaging. As a printing material, ink must abide by the principle of no transfer when it is used in food packaging. Conventional ink is not allowed to be used in food packaging. The printer must ensure that all solvents in the ink are volatilized after printing, and the ink is required to be cured thoroughly and meet the corresponding standards of the application industry.
In the current food plastic packaging printing, benzene soluble chlorinated polypropylene ink is the most widely used. This kind of ink manufacturing and use technology are mature, mainly used in BOPP (biaxially oriented polypropylene) materials, and gravure printing. Although this kind of ink has good printability, good post press processing performance, and fast drying, due to (1) the relatively high toxicity of toluene, the residual solvent value of printed matter is high; (2) the thermal stability of chlorinated polypropylene is poor, chlorine is easy to release in the production and storage process to form hydrogen chloride, which makes the ink strong acid, and seriously corrodes the printing plate roller production; (3) benzene Soluble ink can destroy the ozone layer, in the use process will also cause harm to the health and safety of workers, and residues in the packaging products, under certain conditions, will cause a certain degree of pollution to the food in the packaging. This kind of ink is tending to be eliminated, in Europe and some developed countries have formulated the prohibition or control of the use of this ink.
It is because of the benzene soluble ink problems, environmental friendly ink came into being. The use of environmental friendly ink, not only does not cause environmental pollution, but also does not cause harm to the operator, but also does not cause damage to the food inside.
The environmental friendly inks that have been put on the market include:
1. Water based ink
Water based ink is the most commonly used ink for flexographic packaging printing at home and abroad. It is mainly composed of water-soluble resin, organic pigment, solvent and related auxiliaries by compound grinding. Water soluble resin is a binder for water-based ink. Water soluble acrylic modified resin is often used as a binder in China. Its heat resistance, weatherability, chemical resistance, pollution resistance and gloss have obvious advantages. Both direct dispersion and synthetic polymer emulsion show excellent performance. Water based ink does not contain volatile organic solvents, which can not only reduce printing residues. In addition, it can prevent fire due to electrostatic contact with flammable solvents. Water based ink is not only a new "green" printing ink, but also the best product to replace benzene soluble ink.
2. UV curing ink
UV curable ink refers to the ink which is cured by crosslinking reaction of the binder in the ink under the irradiation of a certain wavelength of UV light. Before the binder dissolves, the macromolecular prepolymer forms the ink film firmly. UV curable ink is mainly used for flexible printing on soft substrate. It is composed of prepolymer, reactive diluent, pigment, additive and photoinitiator / composite. Among them, the selection of reactive diluents has an impact on the migration reaction in the ink formula; the additives can adjust the ink performance (printability, ink migration, substrate wetting, friction coefficient, wear resistance, pigment dispersion and stability) and the odor of printed matter; it is required that the spectrum range of the pigment to UV absorption is as small as possible, and the ideal pigment should have dispersion It has the advantages of good leveling, strong coloring power, small UV absorption under light irradiation and no harm to polymerization. When printing with UV curing ink, attention should be paid to the inhibition of polymerization reaction, surface tension and wetting effect, the correlation between ink viscosity and humidity, and the expansion of printing plate; because the adhesion of ink to plastic is not good, flame treatment or corona discharge treatment should be done to the plastic to improve the adhesion of plastic surface.
3. Electron beam curing ink (EB ink)
Electron beam curing ink is a kind of ink that can quickly change from liquid to solid under the irradiation of high energy electron beam, also known as EB ink. The electron beam energy is high, it has a strong penetration to pigment and filler and other solid components, and the ink absorption will not be hindered by pigment or filler, and the drying inside the ink film will not be affected.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service.
The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries.
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