Common problems and solutions of the hottest water

2022-08-03
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Common problems of water-based varnish and their solutions

the factory viscosity of general water-based varnish is within seconds (25 ℃, measured by "coating -4 cups"), and the printing factory can dilute it according to actual needs. The dilution method has a great impact on the overall performance of the varnish. The diluent used for water-based varnish is generally a 1:1 alcohol aqueous solution (i.e. alcohol and water can be inched and mixed by 1:1). When the proportion of alcohol is high, the drying time is faster; When the proportion of water is high, the drying time is slower. The printing plant shall make appropriate adjustments according to the conditions of its own printing machine. Generally, the best dilution of varnish is about 20%. Excessive dilution will reduce gloss and wear resistance. If you have special requirements for viscosity of AC foaming agent 0.3~0.5, you can contact the varnish manufacturer to provide products with specific viscosity. Main reasons for slow drying of varnish: a. the proportion of water is too high. B. The oven temperature is too low C, the polishing speed is too fast D, the varnish viscosity is too large, the film thickness is too thick e, the varnish itself is too slow to dry solution: A. increase the alcohol content in the diluent B. increase the oven beam will automatically return to the zero temperature C, reduce the polishing speed D, appropriately increase the diluent, reduce the viscosity, reduce the film thickness e, replace the varnish with a faster drying speed. The main reasons are: a The alcohol content in diluent is too high B, the polishing speed is too slow C, the varnish dries too fast solution: A. increase the water content in diluent B, improve the polishing speed C, replace the gloss of the varnish is not ideal main reasons: a. the gloss is diluted too much B, the substrate is too absorbent, the absorption of the gloss is too large C, the gloss is not leveled too fast D, the gloss is not good solution: A. reduce the dilution B Increase the glazing thickness, or apply a layer of primer first. C. Adjust the drying speed D. replace the polishing oil. Main reasons for poor wear resistance: A. excessive dilution B. incorrect polishing oil type C. poor wear resistance of the polishing oil itself. Solutions: A. reduce the dilution B. select appropriate polishing oil. C. The main reasons for choosing the varnish with good wear resistance are that the residual odor is too large: a. the varnish is not completely dry; B. the drying channel is too short, and the odor is too late to volatilize; C. the solution to the problem of the varnish itself: A. increase the drying channel temperature, completely dry; B. properly adjust the polishing speed; C. The main reasons for wrinkles in the polishing layer of the replaced varnish: a. the ink is not dry, or the wet and dry polishing oil is used in the wet and wet polishing. B. The printing ink is not completely dry. C. There is a problem with the resin of the varnish itself. Solution: A. let the ink layer dry before polishing, or select wet wet polishing oil B. appropriately reduce the drying channel temperature C. replace the polishing oil

source: 21st Century Fine Chemicals

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