UV coating practical practice

When it comes to uv glazing technology, many printing companies lack the equipment and processes in this area. UV glazing refers to the use of a specially formulated ink, the use of ultraviolet light wave sensitization, so that the ink film and dry, and then through the humidification and pressure, in the paperboard surface to form a layer of bright film. It plays an important role in improving the quality and grade of the cardboard surface. The industry believes that UV glazing is pollution-free and is an environmentally-friendly product that can be recycled and reused. It is widely used in food, cigarettes, and other packaging, and is also recognized by foreign trade and export authorities. In addition to uv polishing, there is a method called polishing. The polishing process means that the surface of the polished product can be obtained by first applying the ink to the paper, drying and calendering (including heating and pressurizing). The polishing process is generally used in the label industry. In addition, in addition to uv polishing, polishing, and calendering. Its production process, equipment and Uv, polished the same, but supplies are not the same. Under normal circumstances, a UV polishing machine can be dry polished or dry pressed. From the perspective of packaging Ep, ~J companies, the application is still more uV glazing. In particular, in recent years, the surface treatment of pharmaceutical packaging boxes and cosmetic packaging boxes has been most frequently applied.

UV glazing is divided into two types: overall glazing and local glazing. The overall glazing equipment is cheap, and the local glazing equipment is expensive. For example, the Xinhua Printing Factory purchased a local coater, which was produced in Taiwan and sold at a price of more than 800,000 yuan. At the time of use, such a thing happened in production: after the whole UV coating on the East: Illl Pharmaceutical Factory, the adhesive was found to be not tightly bonded when it was bonded into a box. Open seam. The technical personnel found that it was because the glue applied on the back side of the UV coating did not bond directly to the paperboard. However, the adhesive strength between the film and the paperboard after the UV coating was low, which caused the adhesive to stick to the UV film. Combination, Uv film and cardboard from the problem. The solution is to replace the resin plate with a blanket of a printing press, and then remove the part of the box that is to be bonded on the side of the blanket by peeling off a layer at the corresponding position of the blanket so that the removed layer of blanket cannot be coated with the cardboard. This method is effective, the edge of the box will not be polished, the adhesive strength is greatly improved after gluing, but also reduces the cost of the use of the resin plate, two birds with one stone.

In uv polishing, the use of resin plates and blankets should generally follow the following principles: that is, to perform partial glossing on the product, a resin plate should be used to partially polish the product, and blankets can be used. The resin plate can guarantee accuracy and quality during plate making, so only a part of the surface of the product, such as trademarks and small patterns, can be polished. At this time, only the resin version can ensure the polishing accuracy, and the difficulty of the small-area partial coating on the resin plate making is also greatly reduced. Due to the large gloss area, it is difficult to level the resin plate. If the product (such as a pill box) has only the adhesive portion of the tongue seam not painted, the dimensional accuracy requirement is not high, and it is economical and convenient to use the blanket fabric.

About the effect of the varnish effect on the surface of ink and printed ink on printed matter. For example, for a certain batch of printed products, the surface decoration is a pattern that is symmetrical to each other, such as the two extended fingers, which cross each other on the table, and the colors of the two hands are not the same. After applying UV polish on the surface of the product, it was found that one hand was bright, while the other hand had a uniform small pit on the surface. What is the reason for the difference between a symmetrical pattern and a different color pattern? After analysis, it was found that the difference between the UV coating and the printing ink is different from that of the UV coating because of different ink formulations and different additives inside. Generate affinity and rejection. Among them, due to the different additives in the printing ink (such as No. 6 oil, thinner, etc.), the uv coating causes different results. In order to meet the requirements of the user's request that all parts of the symmetry pattern are polished, we have added a process of drying the prints first, and then polishing them, eliminating the phenomenon of inconsistency after pattern coating on both sides. Another time, when processing kits for the Northeast Pharmaceutical Factory, the trademark on the box also had similar problems when it was glazing. The method used was to bake it first, and the glazing effect was also very good.

(author Zhao Shushan Shenyang Xinhua Printing Factory)
Source of information: <China Packaging Industry>