UV ink curing is not complete, the surface of what are the reasons for how to solve? (1) lamp aging. Flexographic UV inks absorb UV light at wavelengths of 200-400nm, and generally require more than 150W/cm to completely cure. The medium-pressure mercury lamps currently used have an average service life of 1,000-1500 hours, gradually decomposing as the electrodes of the lamps are used. The inner wall of the lamp tube is deposited, and the transmittance of the transparency and ultraviolet light is gradually weakened. Therefore, the lamp tube should be tested regularly and the lamp tube should be replaced in time. (2) The power of the light source is not enough. The fast printing speed is also the cause of incomplete UV ink curing and surface stickiness. This can reduce the printing speed or increase the power of the light source. (3) The UV ink itself cures slowly. Can add photo-curing accelerators, reduce printing speed or find ink suppliers to solve. (4) Some manufacturers use ethanol to dilute UV inks, and excessive ethanol will affect the degree of light curing, resulting in incomplete photocuring and surface stickiness. Therefore, it should be avoided to use ethanol dilution. If it is necessary to reduce the viscosity of ink, UV ink thinner can be used. When printing films of PE, BOPP, PET, etc. with UV inks, why does the phenomenon of unsatisfactory adhesion occur?
(1) The corona treatment on the surface of the film is not enough. Generally, the surface tension should be 3.8x10N-2/m or more in order to obtain good adhesion of the ink. (2) UV ink is not cured enough. Therefore, it is necessary to ensure that the UV ink is completely cured. (3) UV ink shrinkage greatly affects adhesion. Adding a certain amount of monofunctional reactive diluent or a small amount of filler can increase the adhesion. In addition, the addition of a UV ink adhesion promoter can increase the physical adsorption of UV inks and substrates, thereby increasing adhesion. How to solve the problem of poor stability in the UV ink storage process (1) UV inks are exposed to light or cross-linked when exposed to heat, so they should be avoided in the use of direct light, can not be stored in the environment above 30C for a long time, must Under 16-28C ventilated, protected from light. (2) In order to increase the speed of photo-curing, adding an excessive amount of photoinitiator also affects the stability of the UV ink. Therefore, excessive photoinitiators should be avoided. (3) Improper mixing of UV inks produced by different manufacturers can also cause changes in the stability of UV inks. Therefore, when the ink needs to be mixed, it must be tested first, and it can be mixed without any reaction.
(1) The corona treatment on the surface of the film is not enough. Generally, the surface tension should be 3.8x10N-2/m or more in order to obtain good adhesion of the ink. (2) UV ink is not cured enough. Therefore, it is necessary to ensure that the UV ink is completely cured. (3) UV ink shrinkage greatly affects adhesion. Adding a certain amount of monofunctional reactive diluent or a small amount of filler can increase the adhesion. In addition, the addition of a UV ink adhesion promoter can increase the physical adsorption of UV inks and substrates, thereby increasing adhesion. How to solve the problem of poor stability in the UV ink storage process (1) UV inks are exposed to light or cross-linked when exposed to heat, so they should be avoided in the use of direct light, can not be stored in the environment above 30C for a long time, must Under 16-28C ventilated, protected from light. (2) In order to increase the speed of photo-curing, adding an excessive amount of photoinitiator also affects the stability of the UV ink. Therefore, excessive photoinitiators should be avoided. (3) Improper mixing of UV inks produced by different manufacturers can also cause changes in the stability of UV inks. Therefore, when the ink needs to be mixed, it must be tested first, and it can be mixed without any reaction.
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