Alcohol-free printing using alcohol substitutes is easier to achieve water-ink balance. Printing with a specific thickness of ink film that has not been diluted with alcohol can produce higher quality prints with fine dots and less emulsification.
Alcohol substitutes differ from IPA (isopropyl alcohol) in several key properties, including their viscosity, surface tension, pH, and fountain solution conductivity. Alcohol-free products cannot be applied to different printing machines at will, which requires close communication with printing operators to seek the best fountain solution formula from suppliers.
Adding IPA to the fountain solution will greatly increase its viscosity, but many alcohol substitutes have little or no effect on viscosity. Due to the reduced viscosity of alcohol substitutes, less fountain solution is measured by squeezing or using a measuring roller on a continuous contact dampening roller, which must increase the dampening roller speed, leading many printing operators to erroneously conclude that More water must be used when printing with alcohol substitute fountain solution. In fact, the solution to increase the viscosity to a certain extent is to cool the fountain solution.
The ability to quickly wet the printing plate and form a thin water film are the two key requirements of offset printing on the fountain solution, which is mainly determined by the surface tension of the fountain solution. It is generally believed that fountain solution with low surface tension can be better used in high-speed printing, but there are reports in Europe that are contrary to this. It is understood that current alcohol substitutes can achieve the low surface tension of IPA used by printing operators.
The surface tension of pure water is 72 × 10-3 N / m. In the fountain solution, the alcohol concentration is 10% ～ 25%. Reduce the surface tension to reach (35 ～ 45) × 10-3 N / m. Can make the fountain solution form a continuous film quickly, covering the entire printing plate. The alcohol-free fountain solution uses surfactants and solvents to reduce surface tension.
Eye Shadow,Eyeshadow Palette,Cosmetic Eyeshadow,Colorful Eyeshadow Palette
Guangzhou Yafei Makeup Toiletry Co.,Ltd , https://www.yfmakeupbrush.com