Common problems and troubleshooting of water soluble varnish
1、 Poor smoothness and insufficient chromaticity
Common faults: A. The paper plate is too thick, and the penetration speed is too strong; b. The coating is not enough and the coating is too thin; c. The viscosity of the upper light oil is very small, and the solid content is too low; d. Printing ink on the surface of printing material is not dry; e. The quality of Shangguang oil is poor;
The removal method: a. the viscosity of the upper light oil should be increased appropriately; b. Increase the coating amount; c. Before applying polish, the ink should be dry enough; d. The paper plate is too thick, but first wipe a layer of adhesive; e. To replace water-soluble light oil with high cost performance;
2、 Not very dry, sticky surface
Common faults: a. the coating of water soluble light oil is too thick; b. The viscosity of light oil is higher; c. The temperature and heating of the curing furnace are not enough; d. The working pressure of coating is uneven, and part of coating is too thick; e. The machine speed is too fast, especially the surface of the plate is not fast and instant;
The removal method: A. reduce the viscosity of light oil, use 50% alcohol solution as paint diluent; b. Moderate reduction of coating amount; c. Adjust working pressure to make coating uniform; d. Increase heating capacity and increase curing furnace temperature; e. Reduce the speed of the machine; f. Remove the fast dry water soluble light oil;
3、 Uneven surface coating, ash spots and orange peel condition '
Common faults: A. viscosity of light oil is too high; b. Too much light oil coating; c. The pressure adjustment of coating is not suitable; d. The surface of coating roller is too smooth and uneven; e. The light oil is too fast to dry; f. The ability of varnish of the light oil cover is poor; g. Ink does not dry and resists light oil
The way of exclusion: A. adjust the working pressure of coating to make the coating uniform; b. Coating roller is not smooth, brittle or deformed, and it should be reground or reset; c. Before applying polish, the ink should be dry and impetuous; d. The viscosity of light oil should be reduced; e. Moderate reduction of coating amount; f. Remove and replace the water-soluble light oil with good leveling property
4、 Wear resistance is not very good
Common fault reasons: A. too much diluent; b. The wear resistance of the light oil is poor
The elimination method: A. reduce the diluent quantity; b. Choose the light oil with good wear resistance
5、 Light off
Common faults: a. the epoxy resin (interconnecting material) in ink is too few, and the color paste particles are lost maintenance and dispersed; b. Light oil has the dissolving effect on ink layer
The method of exclusion: a. the color paste is coated with sufficient ink by epoxy resin; b. Select light oil without dissolving ink
