Measurement of water - based gravure inks

[guangzhou printing company] on the basis of maintaining the same printing quality as solvent ink, a good water-based gravure printing ink must reach zero VOC emission; Must have good printing suitability; Capable of printing on the surface of various substrate materials; It is also hoped that the cost of this plate printing ink is relatively low.

The use of water-based gravure inks can cause problems such as changing the engraving of gravure rollers, changing the operation of the press, the maintenance of the press, and the replacement of the dryer. Similarly, substrate materials will also strongly affect the ink printing effect, especially for low surface tension substrate such as plastic film materials and coated paper surface printing. For non-coated paper, ink may even lead to paper deformation and crimp, these problems for solvent gravure printing ink is not present.

Importance of PH value in water gravure printing ink:

Compare water-based gravure printing ink and solvent base, from the gravure printing ink scraping blade hole scrape off the excess ink, in the process of using solvent ink printing intaglio printing process as far as possible to reduce evaporation of the solvent, after completion of the stamping process, the ink is transferred to the substrates materials, then slowly ink film formation, in the process of ink solvents must be completed before the ink film adhesion volatilization process, quickly achieve the ink membrane drying. In water-based inks, organic solvents are replaced by a percentage of water, cosolutes, and volatile amines that are necessary to neutralize acidic resins. Due to the slow water volatilization, there is no ink in the printing plate ink hole volatilization drying problem, but there is a problem of drying after printing, so the ink for the selection of amines, the adjustment of PH value is as important as the ink viscosity control. Because the premature release of amine solvents prior to the completion of the embossing process can lead to a decrease in PH, the resin dries in the ink holes in the gravure roller. In addition, water and cosolvent systems are unable to re-dissolve the resin, unlike solvent - based inks. So any possibility of PH going down, redissolving is not possible. In gravure printing, the PH value should be controlled very carefully, because the decrease of the PH value of the ink causes the ink hole to be slowly blocked until it is completely blocked, which is a very serious problem and will cause the printing operation to be unable to continue.

The importance of surface tension in water-based gravure printing inks:

At the same time ink surface tension is an inevitable factor, which is completely different from solvent - based ink. Compared with solvent - based ink, ink surface tension is much higher; And too much surface tension will lead to ink can not wetting substrate material surface and gravure printing roller ink hole, which will cause printing ink film uneven; Due to the ink surface tension, ink film will form a contraction of the substrate surface, resulting in an obvious network of ink film, will also lead to ink can not be evenly transferred from the ink hole to the substrate surface.

However, surface tension can be reduced by carefully selecting the appropriate surfactant or a small amount of alcohol. Despite the enormous labor involved in developing lithographic ink, completely reducing VOC emissions in gravure printing remains a difficult challenge when it comes to maintaining the quality of printing ink (as is the case with solvent inks).