1, the gloss is not good, the brightness is not enough

Main reason:

1) The viscosity of UV varnish is too small and the coating is too thin;

2) Excessive dilution of non-reactive solvents such as ethanol;

3) UV oil coating is uneven;

4) Paper is too absorbent;

5) The anilox roller is too thin and the oil supply is insufficient.

Solution: According to the different conditions of the paper, the viscosity and coating amount of the UV varnish should be appropriately increased. For the paper with strong penetration and absorption, a layer of primer can be applied first.

2. Poor drying, incomplete light curing, sticky surface

Main reason:

1) The UV lamp is aging and the intensity is weakened;

2) The storage time of UV varnish is too long;

3) Too many non-reactive diluents are added;

4) The machine speed is too fast.

Solution: When the curing speed is required to be less than 0.5S, it is necessary to ensure that the power of the high-pressure mercury lamp is generally not less than 12OW/cm, the lamp tube should be updated in time, and a certain amount of UV varnish curing accelerator should be added if necessary to accelerate dry.

3. UV varnish cannot be applied on the surface of the printed matter, and it becomes flowery

Main reason:

1) The degree of UV varnish is small and the coating is too thin;

2) The ink contains too much varnish or drying oil;

3) The ink surface has been crystallized;

4) There are many anti-sticking materials (silicon oil, powder spraying) on the surface of the ink;

5) The glued mesh roller is too thin.

Solution: Corresponding measures must be taken when printing products that require UV coating to create conditions. When applying UV varnish, apply a thicker layer. If necessary, you can solve the problem by applying primer or replacing special varnish.

4. UV glazing coating has white spots and pinholes

Main reason:

1) The coating is too thin;

2) The anilox roller is too fine;

3) Excessive addition of non-reactive diluents (such as ethanol);

4) There is a lot of dust on the surface of the printed matter.

Solution: The production environment and the surface of the printed matter should be kept clean, the thickness of the coating should be increased, and a small amount of smoothing agent can also be added. Dilution is best to use reactive diluents that participate in the reaction.

5. The surface coating is uneven, with streaks and orange peel.

Main reason:

1) The viscosity of UV varnish is too high;

2) The coating roller is too rough and not smooth;

3) Uneven pressure;

4) The coating amount is too large;

5) The leveling of UV varnish is poor.

Solution: reduce the viscosity of UV varnish, reduce the coating amount, adjust the pressure evenly, the coating roller should be ground and polished, and a small amount of leveling agent can be added.

6. The adhesion of UV varnish is not good

Main reason:

1) Crystallization of the ink surface on the printed matter;

2) The auxiliary materials in the printing ink are not suitable;

3) UV varnish itself has insufficient adhesion;

4) Improper light curing conditions.

Solution: The printing process should consider the glazing conditions in advance, and the printed products need to be coated with a primer to enhance adhesion.

7. The UV varnish becomes thicker and has a gel phenomenon

Main reason:

1) The storage time of UV varnish is too long;

2) Varnish is not completely protected from light storage;

3) The storage temperature is too high.

Solution: Pay attention to the effective use period of UV varnish, and store it strictly away from light. The storage temperature is 5-25C.

8. Great residual odor

Main reason:

1) Incomplete drying and curing;

2) UV varnish has poor anti-oxidative interference ability;

3) Too many non-reactive diluents are added to UV varnish.

Solution: UV varnish must be thoroughly dried and cured, ventilation must be strengthened, and UV varnish varieties should be replaced if necessary.