Mejoel：How to prevent UV varnish from curing on the coating roller?

Avoid exposure to ultraviolet radiation
Reasonable placement of equipment: The polishing machine should be avoided from being placed in direct sunlight, as ultraviolet light in sunlight can accelerate the curing of the varnish, causing it to solidify on the coating roller and affecting the polishing effect. If direct sunlight cannot be avoided, shading measures such as red and black curtains can be used to reduce the impact of ultraviolet light on UV varnish.
 
Control environmental factors
 
Temperature control: Ensure that the UV varnish is within the normal operating temperature range of 50-55 ℃. During low temperatures in winter, constant temperature water can be used to circulate and heat the varnish to its designed viscosity, promoting leveling and rapid solidification. When UV varnish passes through the UV lamp irradiation area, the optimal temperature should be controlled at 50-60 ℃. Excessive or insufficient temperature can affect the curing speed and adhesion.
 
Maintain air circulation: During the curing process, it is important to ensure good air circulation in the work area to avoid strong absorption of UV light by oxygen, which can affect the normal curing of the varnish and reduce abnormal curing on the coating roller.
 
Reasonable use of varnish and diluent
 
Control the dosage of diluent: Adding diluent to UV varnish can reduce its viscosity, but excessive diluent can prolong the curing time and reduce the curing effect, and may also cause the varnish to solidify on the coating roller. Therefore, the amount of diluent added should be strictly controlled to ensure that it does not have adverse effects on the curing process.
 
Pay attention to the storage of varnish: avoid storing varnish for a long time to prevent the failure of the photoinitiator. For light oil that has been stored for too long, it should be tested and replaced with a new batch if necessary. At the same time, attention should be paid to the storage conditions of the varnish, strictly avoiding light storage, and the storage temperature should be between 5-25 ℃.
 
Keep the equipment clean and in good condition
 
Regularly clean the coating roller: During the production process, it is necessary to regularly clean the coating roller to remove residual impurities such as varnish and ink, and prevent their accumulation from causing poor curing of the varnish. Special cleaning agents and tools can be used for cleaning to ensure that the surface of the coating roller is clean and smooth.
 
Check equipment components: Regularly inspect the condition of equipment components such as coating rollers and mesh rollers to ensure that they are not damaged, worn, or blocked. If there are any problems, repair or replace them in a timely manner to ensure the uniformity of coating and the normal curing of varnish.
 
Optimize operational processes
 
Adjust the coating amount and speed: Adjust the coating amount according to the paper type and printing requirements. Insufficient coating amount may result in insufficient glossiness, while excessive coating amount may lead to the flow of varnish or poor curing. At the same time, it is necessary to control the coating speed reasonably to avoid affecting the leveling and curing of the varnish too quickly or too slowly.
 
Control the surface condition of ink: Before applying UV varnish, the anti sticking materials such as silicone oil and powder on the ink surface should be thoroughly removed to ensure that the varnish can adhere evenly. If the surface of the ink has crystallized, methods such as roughening, removing grease, or adding 5% lactic acid can be used for treatment.