Ink is an indispensable material for the decoration and packaging of printed goods. By printing, the surface of the package becomes beautiful, colorful, and attractive. In recent years, with the rapid development of the printing industry, various plastic and paper packaging and printing have been continuously improved, and the product packaging grades are increasingly demanding. Composite flexible packaging printing is different from general packaging printing, that is, the former is the inner printing, the latter is the printing, the ink used by the two is correspondingly called the printing ink and the surface printing ink, we must analyze the two before printing The difference in inks and the correct use of them have great significance.
Most of China’s inks are composed of 20% to 40% of binders, 5% to 15% of pigments, 40% to 60% of organic solvents and 0% to 5% of additives. The binder is a binder resin, which is a component of the chain of the ink, which bonds the pigment to the material to be printed, acts as an adhesion, and makes the ink glossy.
The pigment determines the type of color. The solvent dissolves the resin, adjusts the viscosity, adjusts the drying speed, and improves the wetting action on the printing material. The additive acts to improve viscosity, weather resistance, ageing resistance, and gloss. The following is a brief analysis of the difference between the printing ink and the printing ink in our factory.
The difference between the materials
The binder of the printing ink is mainly polyamide resin, which has good adhesion and good gloss, but it is not suitable under high temperature conditions, and the fastness of compounding is poor. The binder of non-cooking type printing ink is mainly chlorinated polypropylene, foreign Nitric acid fiber and vinyl chloride–vinyl acetate copolymer resin are also useful. Domestic Jinlong GD-1 and Oriental 200 are all such. The high-temperature cooking of the printing ink amount of the binder is polyurethane, when used, a certain amount of hardener is added, the two liquids are mixed, and the reaction cross-links, such as the Oriental 300 type.
The difference between the solvents used
The solvent used for the surface printing ink is mainly xylene and isopropyl alcohol. In general, the printing ink solvent is mainly toluene and ethyl acetate. The high temperature cooking ink is mainly composed of ethyl ketone and ethyl acetate. The printing ink solvent is suitable for high-speed printing, the solvent has a high volatility, and the solvent residual amount is particularly small.
Wear resistance difference
Since the polyamide resin has good flexibility and has large elasticity, the added auxiliaries have improved wear resistance and are relatively strong against external objects. The printing ink resin chlorinated polypropylene resin is particularly rigid and has poor wear resistance. Because it is printed, the wear resistance requirement is correspondingly lower.
Different differences in accessories
The printing ink and the printing ink are different due to the connection, etc., and the auxiliary additives and additives are also different. The surface printing ink is often added with dehydrated apple and kiwi fruit acid ester to improve adhesion, increase gloss and increase viscosity. The printing ink also incorporates various pigment dispersants, reinforcing agents, defoamers and other additives.
Difference in printing process
The printing process is exactly the same as the general plate making process, but the image on the printing plate is reverse image when the plate is printed, the positive image is printed after printing, the graphic image is positive in the printing plate, and the reverse image is printed after printing. The printing ink of the printing ink is slow, and the printing speed of the printing ink is faster than the printing speed.