What are the requirements for printing with water-based ink?
The main cause of foam problem in water based ink is that water is used as diluent, and a certain amount of emulsifier must be used in emulsion polymerization to decrease the surface tension of emulsion system
1) the pigment used to deepen the color, the amount should generally be controlled in 0 ~ 30%, more than 30% will make the ink in the connection content is too low, leading to its adhesion and wear resistance decline.2) pH stabilizer is used to adjust and control the pH value of water-based ink, and make it stable at 8 ~ 9.5, to ensure the printing status of water-based ink. At the same time, it can also adjust the viscosity of water-based ink, and dilute the ink.3) slow drying agent used to reduce the drying degree of ink, slow drying agent can inhibit and slow down the drying speed of water-based ink, prevent ink from drying on the printing plate, reduce the printing defects such as block and paste printing. The amount of slow drying agent should generally be controlled in the total ink of 0 ~ 10%, if the amount is too much, the ink is not dry thoroughly, printed matter will stick dirty or produce peculiar smell.4) water based ink dilution agent is mainly used to reduce the depth of color, dosage is unlimited. But adding a large amount of diluting agent may result in a slight increase in viscosity of ink and water. At the same time, a small amount of diluents can be added to adjust the viscosity.5) diluted profits are mainly used to reduce the viscosity of ink, the amount should be controlled within 3%, it will not reduce the color depth of ink, and can keep the pH value of ink unchanged. The thinner should be added slowly while stirring, so as to prevent the viscosity from being too low. If more diluents are added or water is diluted with a high hardness tap water, bubbles should be added.
There is not much difference in printing equipment.Effect of water-based ink printability by printing conditions, surface properties, substrate temperature and humidity and storage time of objective conditions, so when in use, need to get the best printing effect of ink do fine adjustment with some additives. The auxiliaries commonly used in water-based ink are pigment, pH value stabilizer, slow drying agent, defoaming agent, diluting agent and so on. In printing, we should be familiar with the characteristics and usage of auxiliaries.
