The general uv varnish or ink formulation curing time is selected within 0.1-0.2S. However, the specific time after the formulation is determined, from the process and the following factors related to.
1, UV light intensity
UV light intensity is high, the curing time is short, and vice versa is long.
2, less oxygen, curing fast
Oxygen has a strong absorption of UV, filling nitrogen on the surface of the coating will accelerate the curing speed.
3、Add solvent
UV light oil added diluent, such as ethanol will reduce the curing speed.
4、Coating thickness
The surface of the coating cures quickly, but the surface layer cured strongly absorbs UV energy, UV (ultraviolet light, hereinafter are indicated by UV) strength decay, reducing the curing speed. Therefore the coating thin curing fast, and vice versa is slow.
5、Ambient temperature
The temperature of the coating is ideal at 50°C to 70°C. The UV mercury lamp contains a large amount of visible light and infrared components, which provides the ambient temperature for the coating surface. However, due to the high energy consumption of UV mercury lamps, short life, high temperature, environmental pollution, now gradually to UV-LED light curing replaced.
The specific curing time is selected in relation to the following.
According to the characteristics of UV coating machine, such as screen printing machine, printing speed of about 600 ~ 2000 sheets, with 350 mesh net coated with UV light oil, the power density used is not high, with a UV-LED irradiation light head can meet the requirements. With four-colour offset
printing machine printing UV offset ink, printing speed up to 7000 sheets / hour, with two UV-LED irradiation light head can meet the requirements.
