Development and discussion of the hottest screen p

2022-08-01
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Development and discussion of water-based printing ink (Part 2)

III. product characteristics: the adhesion fastness of printing ink must meet the ink layer on the printed matter, and the packaging must not fall off during the daily service life. The dry and wet friction tests are carried out, generally 10 times, and we have done 30 times. After the printing is dry, we use adhesive tape for adhesive test, and the ink layer does not fall off. Because the high polymer resin is used as the binder and its thixotropy is large, we generally control the fluidity at 30 ~ 50mm. Select paper products and polyethylene plastic products with a printing thickness of 20 μ m. Under the condition of 20 ℃, the printing product drying time is about 14min, while the ink on the printing plate can not dry within 4H. The developed ink products have been tested by relevant units and obtained satisfactory results. The paper prints show full color, clear graphics and text, strong covering power, and the ink film has no defects such as silk trace, blister, spot, pinhole, etc., which has strong reproducibility and three-dimensional sense, and is non-toxic, tasteless, water-resistant, light resistant and abrasion resistant. Plastic prints also show clear printing pictures and texts, bright colors, high hiding power, good hardness, good firmness, scratch resistance and wear resistance. It has good printability, moderate viscosity, no plate sticking, no blocking, good flow performance, fast drying speed, no adhesion and deterioration, easy to clean and rapid color change. From this point of view, paper printing ink can be used in advertisements, pictorials, calendars, kites, art works, self-adhesive, labels, cartons, cartons, various packaging accessories and wallpapers, while plastic printing ink can be used in soft toys, schoolbags, various panels, dials, bottles, barrels, boxes and plastic parts for various instruments

IV. discussion

water based printing inks are generally composed of binders, pigments, additives, etc

1. choice of binder

the properties of ink mainly depend on water-based resin. The binder in water-based ink is water-soluble resin and water-based polymer lotion. The types and properties of water-based resins are shown in Table 2

Table 2 types and properties of water-based resins

types and properties of water-soluble resin polymer lotion

appearance and state translucent, dispersive opaque Dispersed

particle size (m) 0.001~0.1~1.0

relative molecular weight 100 this clamping device is installed on the base of the experimental machine 00~1000 000 100 000 or more

low viscosity

medium high solids

excellent ~ good poor dispersion of pigments

good poor dispersion stability

viscosity adjustment adding water soluble agent, cosolvent adding tackifier Solvent

glossy good site micro vibration measurement technical specification CECS 74:95 ~ poor

excellent ~ good ink film strength

ease of use good ~ poor

water soluble resins include rosin maleic acid resin, styrene maleic acid resin, acrylic copolymer, amino propylene hydraulic universal testing machine. What tests can be done? Acid ethyl ester, polymer lotion, i.e. aqueous dispersion resin, includes vinyl acetate copolymer, acrylic copolymer, polyurethane resin, epoxy resin, etc. Through comparative tests, we used the composite of waterborne acrylic copolymer resin and lotion resin as binder, so that the waterborne ink can show excellent performance in adhesion, gloss, viscosity, drying and adaptability

2. selection of pigments

in addition to ordinary powder pigments, there are also pigment filter cakes, pigment aqueous dispersions and easily dispersible pigments in water. Because most of the water-based inks are alkaline and often use alcohols, it is necessary to avoid using pigments with poor alkali resistance and pay attention to alcohol resistance. The oil absorption value of domestic pigments is generally high and is not suitable for water-based systems. Water based inks are mainly colored by pigments. We select pigment filter cake with high solid content and organic pigments with bright colors, such as golden red, phthalocyanine blue, YONGGU yellow, etc., and add surfactants to help disperse and stabilize pigment particles

3. Selection of additives

water based ink is very important in the use of additives. Additives can improve the shortcomings of water-based ink and improve its stability. 7. Multi stage function generator can reduce the surface tension of water-based ink, increase the wetting of plastic, help to dissolve resin and improve the drying speed. In addition, we also made some self-made additives, such as brightener, compatibilizer, dispersant, electrostatic agent, etc., which have good application effects

v. conclusion

"oil ink modification" can significantly reduce the emission of volatile organic solvents (VOC) into the atmosphere, prevent air pollution, improve the printing environment, and benefit the health of employees. At the same time, it can completely eliminate the harm of some toxic and harmful substances in solvent based inks to human body and the pollution of packaged goods. The printing has the advantages of low cost, quick effect, can adapt to the printing of irregular substrate surface, and has the characteristics of thick ink layer, strong three-dimensional sense, wide substrate, large printing format, etc. Relevant data show that in the next five years, water-based inks will account for more than 50% of the printing ink market. We need to develop a series of products as soon as possible with different drying times to facilitate the transportation of various substrates, so as to promote the rapid development of China's water-based printing ink market

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