As far as several major printing techniques are currently available in the market, due to different types of printing, different materials, different ink materials (systems), different printing machines, different printing speeds, and different environmental temperatures and humidity, The brand used is different, the viscosity of the ink is different, and the skill of the packaging and printing operator is different, which often causes such a printing failure. Introduced "Scientific understanding of ink manufacturing, ingenious handling of printing problems" serial articles, 11 questions for you to answer printing problems and failures.
In recent days, many manufacturers have been writing letters to reflect the problems in ink printing. The author can only respond to the following points in order to communicate and discuss with colleagues.
Q: The printing ink of a factory's printing ink on PVC is very good, but our factory is very poor. What is the reason and how to solve it?
A: This is because the solubility of the ink is reached, but the hydrogen bond value is not similar to that of PVC. The easiest solution is to increase the hydrogen-bonding value of the ink by two percentage points. It is also possible to increase the true (ketone) solvent in the ink system, and also to replace the PVC special ink.
Q: After the Indian ink printing OPP composite PE, there is a little (adhesion) force in the place where the ink is present, and there is no point in the film (adhesion). Is it a problem with the printing ink?
A: It is not an ink problem. It is mainly the problem of compound glue, followed by OPP that is not treated/that is, the surface tension is small.
Q: I have used trichloric acid as the ink. After the printing, the gloss is not good. The gloss of the aldehyde and ketone resin is not significantly improved. It is a screen ink. Is there any way?
A: Because aldehydes and ketones lose light with the miscibility of trichloric acid, please use high-molecular-weight acrylic varnish to improve the gloss.
Q: How many microns is required for filter bag filter inks?
A: In the past, the ink was generally controlled at a fineness of 20 to 25 microns, but the transfer rate of the ink was usually 60%. Wentuo's laser engraving machine at Wenzhou Plate Printing Plant improved a step and the transfer rate of the ink was comparable. 80%, therefore, the fineness of the ink, that is, most of the filter bags are required to be controlled at 2 to 10 microns.
Q: Is there any difference between raw materials used in table printing inks and printing inks?
A: Generally speaking, no, this is mainly determined by the printing objects - the use of substrates and packaging and printing products. For example, general-purpose surface printing inks mostly use polyamide resins, toluene, butanone, and ethyl esters. The strict difference is a very difficult one.
Q: The woven bag cast film extruded composite ink, printing is fast, horizontal lines appear; printing is slow, vertical lines appear, what is the problem? How to solve it?
A: The printing is fast and linear, indicating that the printing plate is not caused by the passing of the heart. Because of the rapid vibration of the printing machinery, unacceptable printing plate problems are exposed. The water-streak-like printing occurs slowly, indicating that the ink viscosity is low. Specifically, the concentration is not enough, and the ink does not stand up, that is, there is no thixotropy. It is recommended that the following measures be taken: appropriate adjustment of the printer or re-plate; add TM-27 coupling agent or thixotropic thickener to the ink.
Q: After using the alcohol-soluble extruded (cast film) white ink, the white film was printed as a full-size print. After the cast was squeezed, all of the white ink migrated to the plastic woven bag. What is the problem? How to deal with this?
Answer: If white ink migrates to the woven bag after printing, one is that the surface active agent or the softening point of the connecting material in the ink system is too low; or the ambient temperature of the production is too high.