Views: 84 Author: Site Editor Publish Time: 2022-07-14 Origin: Site
The main reason and solution: In the multi-color hot stamping, the anodized aluminum pulls off the printing ink or the varnish of the printed parts.
The main reasons for this failure are as follows:
① Mainly because the ink on the surface of the printed product is not dry or the UV varnish on the surface of the printed product is not properly processed, which causes the ink and UV varnish on the surface of the printed product to not be firmly bonded to the paper surface, and its adhesion cannot withstand the adhesion and tension of the electrochemical aluminum foil layer. Peel force during separation. Solution: bronzing after the printed product is dry. Quick-drying ink can be used or an appropriate amount of desiccant can be added to the ink to ensure that the drying speed of the ink can be adapted to the requirements of hot stamping, and the hot stamping time can be appropriately extended or the drying rack can be used to dry before hot stamping. In addition, anodized aluminum with low separation force and excellent heat transfer can be selected.
②Insufficient pressure or uniform pad during printing, so that the printing ink layer is too thick, and the ink does not penetrate into the fiber structure of the paper, but floats on the paper surface. This requires that the printing pressure should be controlled during printing. For relief printing products, the pad should be flat and uniform, and the bottom support should be made of metal materials to ensure that the printing pressure is solid, uniform and sufficient.
③The viscosity of the ink itself is too low, less than the viscosity of the anodized aluminum foil layer. Attention should be paid to the selection of fast-setting inks with a viscosity that meets the requirements, and attention should be paid to controlling the amount of anti-sticking agent added in the ink to ensure that the ink viscosity meets the requirements.
④When preparing light-colored inks, inks with coarser pigment particles (such as white inks) are used. The bonding force between this ink and the binder is poor. After printing, the binder in the ink is easily absorbed by the paper surface, causing The pigment is suspended on the paper surface, causing chalking, which is easy to cause the disadvantage of color fading. In this way, the electrochemical aluminum foil layer cannot be peeled off smoothly during hot stamping, but the ink layer on the printed product will be pulled down.
Therefore, it is necessary to dilute with titanium white ink as little as possible or use a mixture of diluting agent and white ink. In addition, when designing, we should fully consider avoiding large-area hot stamping on the light-colored ink layout as much as possible. In addition, some measures can be used to remedy the phenomenon of chalking due to the ink layer of the printed product and the back-pull phenomenon caused by the excessive amount of white ink, such as using No. 991 bright lightening agent plus appropriate amount of white dry oil for blending, using on-site Hot stamping after the plate is stamped once can also improve the hot stamping effect.
