The influence of UV glazing on the color of printed matter
printing materials with UV glazing sometimes appear yellowing, which is mainly caused by two reasons: first, the UV glazing oil itself turns yellow; Second, in the glazing process, the glazing oil only solidifies on the surface of the printed matter. The interior is not completely cured the yellowing of glazing oil is related to the fact that the oligomer and active diluent used have a certain yellow color, so colorless oligomer and active diluent should be selected to prepare glazing oil. In addition, the influence of photoinitiators is also great. Some photoinitiators will make the system yellow after curing, such as benzoin dimethyl ether, so it should be avoided to use this kind of photoinitiators to prepare glazing oil. in the glazing process, when the interior of the glazing oil is not completely cured, the interior of the glazing oil diluent will gradually be absorbed by the ink and paper, and will have an effect on the binder in the ink, The oil is lost, the pigment is not adequately protected, and the pigment particles are free. At this time, the smoothness of the paper coating and ink layer surface will be reduced. The rough surface will produce diffuse reflection of light, which will add some white components to the color, making the brightness increase and the saturation decrease. It explains to Ian that people feel yellowish and pale as a whole. Therefore, we should improve the curing speed of UV varnish or choose an efficient UV curing light source. In addition, using water-based UV glazing oil can avoid the chemical action of diluent Liu ink layer and paper coating, and can avoid the yellowing phenomenon of printed matter. Metallographic microscope is a microscope that inspects metal samples with incident lighting. This batch of joints is the surface (metallographic structure) of unqualified products
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