SOLVENT-BASED INTAGLIO PRINTING INK viscosity is too high, resulting in scratches, color, and version, from the “orange peel” and other printing problems.
In summary, in the design and manufacture of solvent-based intaglio printing ink, to choose the right pigment, resin, solvent matching, so that the ink to achieve the appropriate initial viscosity. The printing plant to use the right mix of solvents, preferably the original ink manufacturer to provide the diluent, the original ink adjusted to the appropriate “working viscosity” , can be printed on the machine, so as to get high-quality printing.
In addition, the printing process of ink viscosity and printing speed. Generally speaking, the faster the printing speed, the lower the viscosity of the required ink, otherwise the ink transfer effect is not ideal.
SOLVENT-BASED INTAGLIO printing ink belongs to the volatile dry ink, that is, when the solvent from the wet ink film overflow, the ink film will become solid from the liquid state. Therefore, the speed of solvent evaporation on the drying of ink has a direct impact.
In the design and production of solvent-based intaglio printing ink, the general choice of medium boiling point, low boiling point and high boiling point solvent mixture to meet the drying requirements of ink. If the resin is selected improperly, the softening point of the resin is low, the resin is not good for solvent removal, the pigment is not good for solvent release, too much high boiling solvent will soften the ink film, etc. , all of these will affect the volatile speed of the solvent, cause solidification of the ink film dried after the residual excessive solvent.
Preparation of solvent-based intaglio printing ink, generally choose resin, after the selection of solvents. When the dissolution parameters of mixed solvent are similar to those of the dissolved substance, it is easy to dissolve and the volatilization rate is faster. As a result of the ink made by the addition of pigments, the volatile speed of the mixed solvent will be greatly reduced, and the larger the pigment particles, the slower the volatile speed of the solvent, the drying of the ink. At the same time, the higher the pigment content, the slower the volatile rate of the mixed solvent, which is due to the mutual traction between the solvent and the pigment surface, which resists the solvent removal rate.
In addition, the higher the room temperature, the lower the relative temperature of the air, the faster the air circulation, the volatile speed of mixed solvents will be accelerated, otherwise slow down.
Due to the drying of ink due to improper printing faults mainly include:
(1) in a certain printing speed, ink drying too fast will cause the end of the product, scratches, ink whitening, gloss, leveling, and other problems.
(2) in continuous register printing, because the ink is too slow to dry, the next printing position will occur in the roll, but also cause the printing rewinding back stick. The volatile speed of solvent in ink depends not only on the factors such as the boiling point of Solvent, vapor pressure, latent heat of evaporation, but also on the printing environment temperature, relative humidity, air volume and ink layer thickness, etc. , adjust the volatile speed of solvent in ink at any time.
Under normal production conditions, if the ink drying too fast, should add a proper amount of slow-drying diluent; ink drying too slow, should add fast-drying diluent. If conditions permit, the printing environment temperature should be controlled between 18 ~ 25 °C, the relative humidity control below 65% , is conducive to the stability of ink performance.
Post time: Jun-09-2020