Phenomenon: there is no adhesive coating on the substrates

Reason 1: the surface of printed inks "crystallization."

Solution: the printing process to consider in the first polishing conditions to meet, to change the process or the preparation of special Varnish.

Reason 2: The printing ink in the supplementary material inappropriate.

Solutions: for ink manufacturers.

Reason 3: UV varnished surface tension with the printed material does not match the lack of adhesion.

Solution: pre-press surface pretreatment.

Reason 4: light-cured inappropriate conditions.

Solution: check the reason, the complete curing.

UV-curable options should consider the following factors:

(1) Photoinitiators absorption spectra of the light source as close as possible to match the output spectrum in order to maximize the use of radiation sources.

(2) intensity should be appropriate, too light, free radicals generated too fast, too high concentration of the reaction rate leading to increased cross-linking reaction to be adversely affected; intensity is too low, too slow to generate free radicals.

(3) The condenser should have a very good shade.

(4) as a result of irradiation in the ultraviolet light, the air will produce ozone, the location should have ventilation. The accurate measurement of UV energy metabolism to provide the necessary information to determine and maintain the most appropriate and effective conditions for curing. Food is commonly used measurement of radiation. As the radiometer data can be provided to control the real process. Boot a day after the first operator of radiation exposure in the UV system to record data to see if the necessary normal range.

(5) to double-check the UV-ray shielding devices, ensuring the air to flow into the UV light curing system at the same time to ensure that no excess leakage of UV light. Inlet air filter should be kept clean, and there is no dust and litter at the surface above. If in the course of UV light-cured using a quartz plate, quartz plate should then carry out periodic cleaning to ensure that the nature of transmission of UV light is still valid.

Reason 5: UV printing and UV coating not only the or can not be too thick, or UV ink and UV Varnish is not curing can not be good on the substrates.

The solution: according to the actual situation, craft, and operatives decision quality coating thickness.

6 reasons: low-temperature printing materials, curing slowly.

Solution: UV Varnish UV light after irradiation region, the temperature should be 50 to 60, because in this temperature fast-curing UV Varnish, strong adhesion after curing.

7 causes: non-absorbing materials did not go far enough to deal with the surface of corona.

Solutions: the general surface tension to achieve the above 3.8x10N can get good ink adhesion.

Caution should be taken when dealing with the use of corona:

(1) electrode in the 1mm gap around the corona can be a better treatment effect.

(2) the size of the output current of the corona treatment has great influence on the output current is too low, poor corona treatment; output current increases, enhanced corona treatment.

(3) increase in temperature, chemical reactions speed up, increasing the degree of reaction to deal with the effect of strengthening, but the temperature should not be too high, otherwise they will be weak in the formation of new interfacial layer, it actually resulted in decreased strength. ,

(4) air humidity, the treatment effect will deteriorate as a result of this is in the air to absorb water molecules.