Water-based ink
In the past, traditional solvent based inks were used in the printing industry. Due to the pollution and damage of organic solvents, especially in the application of printing and packaging materials, such as food, medicine, cosmetics, cigarettes, liquor and children toys, The toxic effects of residual organic solvents on human body have attracted great attention from all over the world, and relevant laws and regulations have been worked out to strictly limit the use of solvent based inks.
Preparation of the main group of water-based ink is a pigment, binder, water and additives (including additives, wetting agent, defoaming agent, thickening agent, catalyst drying agent and diluent, fungicides, increase pH regulator, anti slip agent liniment etc.). It is necessary to mix ingredients, mix and mix and make up the process of rolling and grinding on three rolling mill or sand grinding.
The common base material is polymer water solution and polymer emulsion. The available polymer solutions are aqueous solutions of starch, modified starch, dextrin, cellulose, polyvinyl alcohol and other materials. Water soluble polymers have the disadvantages of low molecular weight, large viscosity, small solid content, poor water resistance of coating, unsatisfactory mechanical properties and durability.
At present, most of the high grade water-based ink is used as polymer emulsion. Such as pure acrylic emulsion, styrene acrylic emulsion, ethylene propylene emulsion, carboxylated styrene butadiene latex, polyurethane emulsion, EVA emulsion, epoxy resin microemulsion, alkyd resin microemulsion and so on. The most used of them is pure acrylic emulsion. Because of its excellent coating adhesion, high gloss, light color, high transparency, good weatherability and other excellent properties. It has been widely used in the preparation of high quality water-based inks. Polyurethane emulsion is also used for the preparation of water-based inks for printing polypropylene, polyester, polyvinyl chloride and other plastic films. The coating has high gloss and toughness, and can obtain high quality printing effect.