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Gravure printing products did not dry, affecting the quality?
Promulgator: admin
Gravure printing products are not dry, prone to back sticky, the quality of printed matter is very large. The following summarizes the gravure printing products are not dry 7 reasons for your reference.
Gravure printing because the ink layer is thicker, so dry problems always exist. Gravure printing characteristic is wet, although the oven has longer, but when the color gravure in laminated color group ink does not dry, just in the ink layer of a thin film formed on the surface, to prevent the color group ink in laminated color when put color ink anti sticky.
凹印产品没干透的七大原因
1, gravure mesh hole is deeper, sometimes depth to 60 m, large amount of ink, drying will be difficult.2, in order to ensure high light, small dot printing, gravure printing process must be added slow drying agent, this will also affect the drying effect of ink.3, the comprehensive balance of mixed solvents is not easy to master, resulting in a large number of slow dry agent retention.
4, some interior printing process, and finally the same color printed white ink, and then close the volume, drying and winding station between the distance is too short, dry difficult. White ink and ink with backing zhegaili good, only thicker ink layer. In general, the amount of ink on white ink is the largest in all colors.
5, when the film printing, drying device temperature can not be too high, drying Road can not be too long, otherwise the film will occur tensile deformation, affecting the overprinter accuracy and product length. The commonly used method is to use low temperature and large air volume, and adopt evaporation method in the drying process, and abandon evaporation.6, the dependence of solvent evaporation on environmental conditions, when the atmospheric pressure is relatively low, it is difficult to control the drying efficiency with mechanical exhaust device.
7. The ink layer on the surface of the print has a boundary layer with the contact surface of the atmosphere. It is a mixture of hot air and solvent vapor, which has higher temperature. When the ink is dry, at high temperature, the liquid solvent will evaporate and move to the boundary layer. If there is no solvent in the boundary layer, the solvent vapor will easily be transferred to the atmosphere. But with the increasing of solvent vapor concentration in the boundary layer, the evaporation ratio of the solvent will decrease. When the solvent vapor in the boundary layer becomes saturated, the evaporation process will stop. The traditional process of gravure printing drying did not attach importance to boundary layer, ignoring the evaporation in the drying process, while the industry of gravure printing machine drying curve was improved, reduce the drag, improve the air volume, but because of this layer with boundary layer air flow exists in some residual solvent ink the volatile still wrapped in them.
