Precautions for applying water-based varnish.

Environmentally friendly water-based adhesives (water-based varnishes) are suitable for the packaging and printing industry. Water-based products are non-toxic, pollution-free, odorless, water-resistant, weather-resistant, acid and alkali resistant, and have high bonding strength. It features low dosage, fast curing time, anti-aging, good flame retardancy, simple operation and easy equipment cleaning. It provides ideal raw materials for the high-quality development of various industries and is a new generation of environmentally friendly high-quality product (water-based varnish). But do you know what to pay attention to when applying water-based varnish?

When applying water-based waterproof varnish to cartons, the following points should be noted:

I. Drying Equipment: The UV irradiation light source generally adopts high-pressure mercury lamps or metal halide lamps, and the power of the light source also needs to be stable. The output power of high-pressure mercury lamps is generally 80 to 120W/cm to ensure that the curing speed of the coating is less than 0.5 seconds.

2. Smoothness: If the coating roller of the varnishing machine is damaged or the viscosity of the varnish is high, the roller should be replaced or reground to reduce the viscosity of the varnish on the carton.

Iii. Whitening of the coating layer: Whitening of the coating layer may be related to improper use of the thinner, especially in summer when alcohol solvents evaporate quickly. In such cases, the thinner should be replaced or ester-based thinner should be used instead.

4. Ink Bonding: When applying varnish, it is also necessary to pay attention to the bonding issue between the carton coating and the ink. If necessary, apply a layer of primer first.

V. Poor Brightness: If the brightness of the carton is too poor after being coated with varnish, the following three reasons can be considered

(1) If the quality of the paper is poor or its surface is rough and it has a high oil absorption capacity, a higher grade of paper should be used instead. If the coating is uneven or the varnish is diluted too thinly or its viscosity is too low, the varnishing machine should be adjusted and the viscosity of the varnish should be increased.

(2) Poor adhesion, crystallization of the ink layer on printed matter or improper use of ink additives and anti-slip agents, etc. The printing process should be improved to avoid or minimize the use of ink additives.

(3) The viscosity of the varnish is too low. The varnish machine should be adjusted and the viscosity of the water-based waterproof varnish should be increased.