Ink, printing colorants. It consists of pigments, binders and additives. For books, packaging, decoration, architectural decoration and other printing. Ink is the embodiment of information, the most direct carrier of graphic information.
Ink is one of the important consumables in the printing process, and it is also one of the major components of printing costs for printing companies. The good or bad ink performance directly determines the printing company's printing efficiency is high and low. At present, China's major printing inks can be divided into four categories: solvent-based inks (traditional inks), UV inks, water-based inks, water-based UV inks, of which the latter three are environmentally friendly inks. Most people know little about ink. Although water-based inks and UV inks are often heard in the ear, why these specific inks are environmentally-friendly inks do not know what their superiority is. Now the author compares the knowledge of printing inks with Yip's ink and Zhongyi's ink.
Basic parameters
The main components of the ink include: pigments, binders, auxiliaries. The pigment determines the hue and color intensity of the ink and reflects the reproducibility of the ink. The binder is one of the main components of the ink and acts as a medium for the dispersion of colorants and auxiliary materials. It is prepared by dissolving a small amount of natural resins, synthetic resins, cellulose, rubber derivatives, etc. in a dry oil or solvent. With a certain degree of fluidity, the ink forms a uniform thin layer after printing and forms a film layer with a certain strength after drying, and has a protective effect on the pigment, making it difficult to fall off. The nature of the binder directly determines the flowability, viscosity, and drying of the ink, so the basic parameters of the ink are determined by the binder. Auxiliaries mainly play a role in regulating the drying properties and viscosity of the ink.
Solvent-based inks and water-based inks and other environmentally friendly inks, the main difference is in the connection material. Traditional inks are mainly composed of stupid, oil and other organic solvents. Usually, such organic solvents are toxic and cause harm to people and the environment. The solvent of water-based ink is mainly composed of non-toxic solvents such as ethanol and water, which are not harmful to the human body and the environment. The water-based ink has good fluidity, strong color reproduction, good adhesion, strong water resistance, and rapid drying. The world-accepted environmentally-friendly printing materials are also the only inks approved by the US Food and Drug Association in all printing inks.
Viscosity: When the liquid is flowing, it will be deformed and the frictional resistance generated when the two layers of inks move relative to each other. Viscosity is an important property of the ink that determines the stability of the ink transfer on the press. Nowadays, printing inks are mostly pseudoplastic fluids. The characteristic of this fluid is that when the fluid itself deforms, it will produce a shear rate, and when the shear rate increases, the year will decrease. When it reaches a certain value, the viscosity of the fluid will Staying the same, the viscosity at this time becomes the yield value of the fluid. To ensure that the ink in the printing press, the stable transmission viscosity must reach a certain degree, to ensure that the ink will not leak in the ink fountain, when the ink roller reaches a certain speed, the ink will stabilize the flow out.
Dryness: It is the ability of the ink to transfer from the ink roller to the substrate to the ink completely adhered to the substrate. It depends on the connection material. Printing drying methods can be roughly divided into: volatile drying, oxidative conjunctiva drying, osmotic drying, and UV light drying. Volatile drying is the use of the volatility of the connecting material itself to dry the way, most of the fast volatile binders are toxic; oxidative conjunctiva drying is the way the binder material itself undergoes a chemical reaction and drying; penetration drying is through the connection materials and printing The “anchoring effect†of the material and the method of drying with a secondary binding force; the UV drying chamber is dried by UV light irradiation. The quality of drying directly determines the quality of printed matter. Drying too fast If the ink is too late to spread, it will dry up, which will cause the printing outlets to spread insufficiently and the quality of the printing will be reduced. When the drying is too slow, when the paper is collected, it will cause dirt. Therefore, the dryness of the ink must be controlled within a certain range, and the ink drying performance must be paid attention to when purchasing.