What are the key points to pay attention to when using water-based varnishes?The application of water-based glazing oil must be comprehensively considered according to different glazing methods, paper types, product quality requirements and other factors in order to achieve good results. The following aspects should be paid attention to when using water-based varnish:①Viscosity control. In the coating process, the viscosity and solid content of the varnish must be reasonably controlled. Therefore, the dilution can only be carried out within a certain range of solid content. The diluent of water-based varnish is generally ethanol and water, and the ratio is1:1The viscosity reduction effect is obvious and should be strictly controlled.②Select the paper type. Thick paper has good dimensional stability, while thin paper has poor dimensional stability. Dimensional stability is one of the key indicators for the quality of printed matter. It is related to the amount of water in printing, the humidity of paper, and the drying time and methodthe viscosity control is closely related, if the printed product is90g/m2When using the following paper, be careful with water-based varnish.③ Control of coating amount.The coating amount of water-based varnish is not easy to control, because the evaporation rate of ethanol in the coating varnish is very fast, and the water is colorless and transparent. It is difficult to distinguish the amount with the naked eye. It is very important to control the viscosity. The content of ethanol should also be increased in time to ensure the stability of the product.④ The use of anti-sticking agent. The use of anti-fouling agents can be completely eliminated or reduced when using water-based varnishes, because the water-based varnishes are fully cured and the surface is very smooth, rarely sticky dirty, different from other glazing agents, after glazing with a printing machine2Die cutting and creasing with a small feed of paper.⑤ Control of drying time. Solvent-based varnishes are almost always volatilized and dried, while the penetration drying of water-based varnishes has great utilization value. However, in multi-color printing, if the last color is coated with varnish, the drying time will be longer, because the inside of the paper has absorbed more ink and wetting water. If infrared water-based varnish is used, with the help of Drying in infrared drying devices is the most successful. During the drying process, the glazing oil is heated, and the bottom layer is quickly penetrated and dried. At the same time, the moisture in the glazing agent is heated and evaporated by high temperature, and is discharged through the exhaust pipe. The infrared drying device has a good drying effect and improves theAnother method of drying speed is to increase the content of ethanol, but it depends on the actual situation and the viscosity of the glazing oil, which cannot be arbitrarilyadjust.
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