Ink directly determines the tone, color and clarity of the image on the printed matter, so ink plays an important role in printing. With the development of technology, the varieties of ink are increasing. Do you really know them? Next, I will take you to know about various inks in the printing and packaging industry and their future development trends.
A variety of different inks
1. Lithographic Printing Ink
Lithographic printing ink is a kind of viscous ink with certain viscosity, most of which are dry ink with oxidized conjunctiva, which has good water resistance. It can be divided into sheet-fed ink and web ink. The former is mostly quick-drying oxidized conjunctival ink, while the latter is mainly permeable drying. It can also be divided into offset printing bright resin ink, offset printing rotary ink and so on.
2. relief printing ink
Relief printing ink is a kind of viscous ink, and its viscosity varies greatly, which is related to the printing speed of the printing machine. Its drying methods include osmotic drying, oxidized conjunctiva drying, volatile drying and so on, or a combination of several ways. Embossing inks include rotary black ink, book black ink, color relief ink, etc.
3. Gravure printing ink
Gravure printing ink (gravure ink) can be divided into two categories, one is gravure ink and the other is engraving gravure ink. The former is a very dilute fluid with low viscosity, which is completely dried by solvent volatilization. It is a volatile drying ink and can be printed on non-absorbent substrates. The latter has higher viscosity, higher yield value, no greasiness, and basically relies on oxidized conjunctiva for drying.
4.Stencil printing ink
The stencil printing ink requires good fluidity, low viscosity, fast passing through the mesh, rapid infiltration and drying after being transferred to the surface of absorbent substrate, and good adhesion on the surface of non-absorbent substrate. Its drying methods are as follows: volatile drying, oxidative polymerization, osmotic drying, two-component reaction, ultraviolet drying and so on. The ink can be divided into copying printing ink, Screen Printing Ink and so on.
5.Special printing ink
Many special inks need thicker ink to perform well, which can be divided into foaming ink, magnetic ink, fluorescent ink, conductive ink and so on. It needs to have the characteristics of no volatile solvent, no odor, no blocking, fast curing speed, strong water resistance, bright color and so on.
6. Plant ink
Three main components of ink: pigment, binder and additive.
Pigment can provide color for ink; Binder is a kind of wet substance that can disperse pigment evenly, such as oil, water, soybean or other vegetable oil. Additives such as paraffin wax and petroleum fraction are helpful to dilute and improve the performance of ink on printing press.
Petroleum-based inks were widely used more than 50 years ago, because they have the advantages of fast drying speed and high cost efficiency. But the fly in the ointment is that the drying process of this ink will cause damage to the environment. Petroleum-based ink not only uses non-renewable resources, but also produces VOC-- in the drying process-causing environmental pollution and global climate.
7. Conductive silver ink
Not only is the demand for silver ink in traditional applications such as thin film switches and PCB still stable, but a number of new applications are gradually taking shape, which will bring new business income to silver ink manufacturers.
8.Nano ink
9. Epoxy screen printing ink The epoxy silk screen printing ink has uniform and bright ink layer, good pigment dispersibility, uniform fineness, good screening and leveling properties, excellent adhesion to polar substrates after curing, and high hardness, luster, good water resistance, weather resistance and chemical resistance.
(1) before use, add a proper amount of diluent and mix well;
(2) Please use special diluent for different types of inks;
(3) Trial printing is confirmed to meet the requirements before mass production;
(4) Removing grease and impurities from the surface of the printed matter to promote the adhesion effect;
(5) Static electricity on the surface of screen or printed matter will cause pinholes in the ink after printing;
(6) Too high ambient humidity will affect the printing effect;
(7) The products can be stacked and shipped only after coating is done; After the operation is completed, the remaining ink is tightly sealed in the container;
Safety rules: When using and storing ink and diluent, fireworks are strictly prohibited. When using ink and thinner, pay attention to the good ventilation condition of the construction site, and try to avoid direct contact with the skin. If you accidentally splash a lot of water into your mouth, nose, eyes and ears, you should ask a doctor for help directly. If you are allergic, you should apply a layer of skin care cream or wear impermeable gloves before using it.
10. Thermosetting ink Thermosetting ink, also known as plastic melt ink,
Plastic Ink, resin ink, etc., is mainly composed of plasticizer and resin, with additives and pigments. Because it can only be cured by heating, it does not plug the screen during printing, and it can be printed continuously in wet sleeve, which greatly improves the production efficiency.
Thermosetting ink is a new generation of textile printing ink. Because of its many advantages, it has largely replaced the traditional printing materials abroad. In addition to the use of mucilage and water slurry for processing under the specified requirements of the printing house, most printing manufacturers have learned and used thermosetting ink in large quantities to process high-precision products.
New trend of ink At present, more than 95% of plastic flexible packaging is printed by gravure printing. Our common printing ink is generally made of chlorinated polymers. In the process of production and use, aromatic solvents such as toluene are needed to dissolve and adjust the viscosity of the ink. Therefore, in the process of production and printing, a large number of harmful gases will be volatilized, which will destroy the ozone layer of the atmosphere and endanger the health and safety of workers (fire). The safety of food soft packaging products is also very poor, benzene is easy to remain in the dry ink microfilm layer, and xylene is more likely to cause the increase of benzene residue. Benzene residue will pollute the food in the package. At present, although alcohol-soluble ink is environmentally friendly, it will still pollute the environment, and there will be solvent residues. The PE (polyethylene) film made of flexible packaging has poor leakage resistance and strong adsorption, which easily pollutes the PE film in the packaging with the unpleasant smell of ethyl acetate.
According to the regulations of various countries on the use of ink, at the end of last century, countries and regions such as Japan, South Korea and Southeast Asia have eliminated toluene printing ink. In the 1980s, the United States advocated
Water Based Printing Ink, and banned the use of solvent based printing ink.
At present, there are no special regulations on the production and use of plastic ink, but the use of printing ink has relevant requirements in relevant laws and regulations. Nowadays,
Water Based Plastic Ink, as an alternative product of solvent ink, is recognized by more and more color printing and packaging industries because of its non-flammable and green environmental protection characteristics, and is also concerned by ink production enterprises and society in many aspects. It is an inevitable trend that the ink in flexible packaging printing is completely water-based.
To use water based plastic ink for printing, first of all, it does not need to use solvents, only water can be used. How much solvent can be added in the printing industry? For example, if you add 50%-100% solvent to ink, and mistakenly think that the more solvent you add, the better, and the lower the cost. Actually, 50%-100% of the solvent is added during the whole printing process. This is because the volatilization of solvent causes the viscosity of ink to change and is added. The faster the printing speed, the faster the volatility of the diluent to be prepared, and the more times the solvent is added. This is equivalent to increasing the printing cost. Therefore, it is not after 10 kilograms of ink is added to 5 kilograms of solvent that printing begins.
According to the standard of ink industry, high color density and low viscosity are good inks. Diluent is added to the ink only to reduce the viscosity of the ink. Make it suitable for printing, such as excessive addition, the color density of ink will decrease. The weight of the binder is reduced at the same time, so that a good product cannot be printed. Therefore,
Water Based Ink only adds pure water, and it is added at one time (prepress). In the printing process, it won't cause color change because of viscosity change, and it won't be like ink, which is a waste product caused by adding thinner during printing, thus greatly improving the qualified rate of printed products. The cost of solvent is saved, and the appearance of waste products is reduced. This is one of the cost advantages of water based plastic ink.
