Why resin is the key to packaging ink performance?
Jun 25, 2021Sino Sunman supply all types of resins for making printing inks. Our various resins are used as connection material in printing ink. It can be seen from here that ink resin as the carrier of pigment in ink, is the core material. The quality of these resins will directly affect the performance of the printing ink because the connection material to a large extent determines the important qualities of printing ink. Thus, there is a word that the high quality of printing ink comes from high-quality connection material.
To be specific, the properties of printing ink controlled by resin are:
Fastness
The adhesion of ink to printed material mainly includes chemical bond force, intermolecular force, interface electrostatic force and mechanical force. These forces are derived from the resin used in printing and the substrate material. For different materials, it is crucial to use different resins. Generally speaking, for PE, PP and other non-polar substrates, even by corona surface treatment, its surface tension can only reach 38 Dyne or so. Instead, it should use non-polar resin structure such as Chlorinated Polypropylene resin connection materials; For PET, PA and other surface polarity substrate, Polyurethane resin connection material is better.
Tinting ability
The inorganic pigment is the basic material to provide color for ink, but as the ink adhesion on the surface, there is always some deviation from the original color. The reason lies in printing ink. The pigment particles do not exist alone but are scattered in the connecting medium. On the micro-level, the best wetting dispersion state of a pigment particle is completely wrapped in the resin binder evenly and attached to the substrate surface. The display of color is realized by reflection: the light incident on the coated pigment surface goes through the resin connecting material film layer and is then transmitted to the consumer’s eyes. The transparency of the resin and the size of the color number directly affect the expression of different colors.
Viscous resistance
Viscous resistance is an important index in ink evaluation. Gravure printing is a printing method with a high ink supply, good step reproducibility and fast printing speed. The inks used in it are mostly solvent volatile drying inks. After the printing ink plate transfers to the substrate, through the drying path, the organic solvent quickly volatilizes after drying. When going through the high-temperature drying road after rewinding, the surface temperature of the printing film is generally between 40℃~60℃, at the same time, due to the existence of rewinding pressure, if the ink itself does not have good anti-viscosity, it will lead to serious rewinding adhesion accident or quality problem.
Re-solubility
In gravure printing, ink re-solubility is also a key indicator of ink performance. Especially in color ink printing, moderate solubility, not only can make the color show fully, but also can well solve the printing plate shallow screen block, overprint color problem.
Storage stability
Ink, if being placed for a long time in the container, is prone to appear problems like uneven concentration, decreased viscosity, changed color etc. that might affect its use. Proper resin added will help solve this problem effectively.