What ink is used to print coffee packaging bags
What ink is used to print coffee packaging bags & Custom Coffee Bags & Pouches is well printed.
At present, in the printing of coffee plastic packaging, the most widely used is the benzene-soluble chlorinated polypropylene ink series. The production and application technology of this series of inks are very mature, mainly used for back printing on BOPP (biaxially oriented polypropylene) by gravure printing, with excellent printing adaptability, good processing performance and fast drying speed. faster. But there are still many deficiencies in this printing method.
1. The ink contains toluene, and the printed product has a high residual solvent value;
2. The thermal stability of chlorinated polypropylene is poor, and it is easy to release chlorine and form hydrogen chloride (commonly known as hydrochloric acid) in the air, which makes the ink show strong acidity and has a corrosive effect on the printing plate roller;
3. Benzene-soluble ink can also release substances that destroy the ozone layer. During the process of production and use, it will also cause harm to the health of production workers. At the same time, harmful substances are likely to remain in the finished product, thereby polluting the food in the packaging bag ;
Because of this, benzene-soluble chlorinated polypropylene inks have been gradually eliminated, and laws and regulations to prohibit or control the use of benzene-soluble chlorinated polypropylene inks have also been issued in Europe and other developed countries.
In order to avoid and solve various problems of benzene-soluble ink, environmental protection ink came into being and began to be widely used in various countries. Why is it named as environmentally friendly ink? That's because this series of inks will not pollute the environment during production and use, and will not cause physical harm to users, nor will it contaminate the food in the coffee packaging bag. At present, there are generally three types of environmentally friendly inks widely used in China:
1. Water-based ink
Water-based ink (Water-based ink), referred to as Yanhuang ink, flexographic water-based ink, also known as liquid ink, is mainly made of water-soluble resin, organic pigments, solvents and related additives through compound grinding. Water-based ink is currently the ink used in most flexographic packaging printing at home and abroad. Water-soluble resin is the linking material of water-based ink. Water-soluble acrylic modified resin is often used as the linking material in China. It has significant advantages in heat resistance, weather resistance, chemical resistance, pollution resistance and gloss. Regardless of direct dispersion Both dissolved and synthetic polymer emulsions have excellent performance. Water-based inks do not contain volatile organic solvents, which can not only reduce the residual toxicity of printed products, but also prevent fires caused by static electricity and flammable solvents.
Water-based ink is not only a new type of "green" printing ink, but also the best product to replace benzene-soluble ink. Water-based ink is especially suitable for packaging and printing products that require strict hygiene conditions such as tobacco, alcohol, coffee, beverages, medicines, and children's toys.
2. Ultraviolet (UV) curing ink
The curing process of UV curing ink is a photochemical reaction process, that is, under the action of ultraviolet energy, the prepolymer is cured into a film in a very short time. In addition to causing the surface of the ink to cure, the ultraviolet rays can penetrate into the liquid ultraviolet rays Cures the ink and stimulates further curing of the deep ink film. In traditional inks, the ink based on oil is solidified under oxidation, while the ink based on solvent or water is mainly solidified by the evaporation of water or solvent, and part of the ink can penetrate into the paper. Therefore, compared with traditional inks, the polymerization and drying of UV-curable inks is more thorough, without any evaporation or solvent-based pollutants, and the ink film is 100% cured. UV-curable inks are mainly used for flexible printing on soft substrates, which consist of prepolymers, reactive diluents, pigments, additives, and photoinitiators/synthesis. Among them, the choice of reactive diluent has an impact on the migration reaction in the ink formulation; the performance of additives on the ink (printability, ink migration, substrate wetting, friction coefficient, abrasion resistance, pigment dispersion and stability) properties) and the smell of printed matter to be adjusted; the spectral range of the pigment’s absorption of ultraviolet light is required to be as small as possible. The ideal pigment should have good dispersion, good leveling, strong tinting power, and small ultraviolet absorption under light irradiation. Response to non-hazardous features. When printing with UV-curable inks, attention should be paid to the inhibition of polymerization, surface tension and wetting, the correlation between ink viscosity and humidity, and the expansion of printing plates; Plastics are flame treated or corona treated to improve adhesion to the plastic surface.
3. Electron beam curing ink (EB ink)
Electron beam curing ink refers to the ink that can quickly change from liquid to solid under the irradiation of high-energy electron beams, also known as EB ink. Electron beam curing ink is mainly composed of pigments, linking materials, auxiliary agents, coloring materials and so on. The energy of the electron beam is high, and it has strong penetrating power to solid components such as pigments and fillers. The absorption of ink will not be hindered by pigments or fillers, and the drying inside the ink film will not be affected.
In the drying of the ink film layer after printing with ordinary ink, the linking material in the ink is generally absorbed and volatilized by the substrate, while the solid matter remains on the surface of the substrate to form a thin ink layer. Electron beam curing is a process of using electron beams as irradiation energy, performing radiation chemical reactions with active liquid chemical formulas, and rapidly drying and curing at room temperature.
Since electron beam is a type of radiation, electron beam radiation can also be classified as radiation curing. Radiation curing is a new technology developed on the basis of existing science and technology. It mainly uses a scanning electron accelerator. In radiation curing, the electron beam of the electron accelerator scans the surface of the substrate to achieve curing processing. The basic meaning is to use ultraviolet light or electron beams as energy sources to trigger a chemically active liquid formula to achieve a fast-response curing process on the surface of the substrate. The biggest advantage of UV curing and electron beam curing technology from traditional technologies (such as thermal curing) is that radiation curing uses high-efficiency ultraviolet light or electron beams as the initiation means to quickly achieve coating curing. Among them, electron beam radiation is composed of a batch of accelerated electron streams. Under the action of high-energy electron beams, free radicals or ion radicals are generated, and free radicals or ion radicals are cross-linked with other substances to form a network polymer. Compared with ultraviolet light, the particle energy is much higher than ultraviolet light, which can ionize the air, and electron beam curing generally does not require a photoinitiator, can directly initiate chemical reactions, and has greater penetrating power to substances than ultraviolet light.
With the improvement of the country's requirements for the printing industry, the emphasis on environmental protection awareness and the continuous development of environmental protection printing technology, consumers have higher and higher requirements for coffee packaging, which also puts forward higher requirements for the use of ink materials in printing. requirements. Therefore, environmentally friendly inks will surely become one of the mainstream printing materials in the future coffee packaging industry.
