The quality of post press consumables varnish
theoretically speaking, the chemical composition of varnish should be determined. From the perspective of application, it is a simple way to check the quality of the glazing oil purchased by users
① smell. The solid content of UV oil is more than 95%, and the volatility of solid content substances is very small. Therefore, the smell of good glazing oil is very small, which should be less than that of printing ink. The smaller the smell after curing, the better
② measure the solvent content. Put the glazing oil into a graduated vessel (diameter less than 50mm), place the paper for 12h, and observe how much volatilization it has. Generally, the decline of the surface position cannot be seen. If a decrease is obviously observed, it indicates that there is too much solvent in the glazing oil, which is a fake product with diluent added to the original glazing oil
③ UV glazing oil is non conjunctival, like edible oil, the surface will not peel after long-term storage. Place a small amount of glazing oil on the surface of the glass sheet, and observe whether there is scaling after placing it in the dark place for 24h. No peeling means UV oil, otherwise it is fake UV oil
④ skin irritation. Put a small amount of polish on the back of your hand and observe for about 20min to see whether the skin turns red or blisters. Good polish skin basically fails to respond, while general polish will appear erythema, and bad polish will make the skin blister
⑤ observe the color of UV oil (2) dig a hole downward at the installation position of the experimental machine. Place UV ink in transparent glassware for observation. The lighter the color, the better the quality can be divided into manual mode and automatic mode
⑥ viscosity. Different tensile testing machine viscosities are selected according to different glazing models, such as the viscosity of ordinary three roll and teeth polishing machine is 30~40s
⑦ leveling. Check the printed matter after UV curing. If there is ripple, it indicates that the leveling property is not good. The first solution is to require the alloy to have as high static strength as possible, reduce viscosity, heat or add diluent; The second is to extend the time of coating and curing to make it fully leveled before curing
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