How to choose ink when plastic packaging is printed?
Printing conditions including printing speed, drying device (capacity) and position, the plate cylinder, printing chromatic number and printing sequence, printing workshop temperature and humidity, preheater cooler (roller) function. These conditions can directly affect the transfer rate of ink and drying speed, so the ink used in printing should be adapted to the printing conditions.Drying conditions include drying temperature, air volume (wind speed) and drying device structure, etc., which determine the drying efficiency. The speed of printing determines the drying time and the separation speed of the ink transfer. The temperature and humidity conditions in the printing workshop and the preheating condition have some influence on the drying and the reappearance of the ink. The cooling roller must be able to cool the ink film away from the outlet of the drying box in time. In addition, for low-speed printing presses, the quality requirements of the ink is relatively low. And the use of high-speed printing machine, you have to choose medium grade ink. Some poor quality ink transfer rate is low, it is difficult to adapt to shallow version.
Post press processing conditionsMost of the plastic gravure printing products after the completion of printing, but also through the complex, cutting, bag making or stamping, polishing and other finishing process to get the product. Before these processes, it is necessary to determine whether they are suitable for the performance of the ink, which is an important part of product quality assurance. The type of complex machining and adhesive with composite strength, heat sealing, heat resistance and ink (i.e. link resin in) is also closely related, and the resistance to boil boil sterilization, sterilization distillation retort resistance not only with the type of ink, and ink pigment the durability of the.
Printing quality requirementsThe quality requirements are mainly reflected in these aspects:Hue, lightness and purity, transparency, resistance, surface gloss, level effect, overprint state, surface printing or printing on the back (in India), there is no additional printing of light oil and other special quality requirements.The ink we choose should be in line with the customer's requirements in printing. But because of different manufacturers of ink in the ink, concentration, transparency, gloss, such as expression level is different, so the choice must be careful. When the printing effect is high, the ink with higher grade should be chosen accordingly. When the initial use of some ink made standard sample, and then another ink standard be very difficult, so the ink to the ink printing proofing is consistent with the actual printing.
SubstrateFor different substrates, should be used to adapt to the ink. For example, printing BOPP film can use ordinary ink, printing NY/PET film can choose polyurethane ink, and when the printing substrate for aluminum foil, it is best to choose aluminum foil dedicated ink.Gravure printing the most basic condition is to make the printing ink can adhere to the printing substrate, so the ink infiltration and polarity is very important performance. In order to improve adhesion, surface treatment of printed substrates is required (some inks are specially applied to base material for corona treatment). The adhesive force of the ink will affect the printing process and durability, so we must pay great attention to it.The type of substrate is the most important factor in determining the type of ink used. Even the same species are often different according to the variety and grade. Therefore, need to be as detailed as possible to investigate and understand the following: type of printing substrates (material composition), the manufacturer, has no thickness, antistatic agent and other additives, there is no pre-treatment, treatment method, printing surface.
