UVLED curing principleread count [495] release time：2019-12-30 20:43:00
In recent years, whether it is the inkjet printing industry, offset printing industry or silk screen printing industry, UVLED The use of light-curing inks is becoming more and more widespread. As we all know, compared with traditional solvent-based inks, UVLED light curing The ink has many advantages such as good gloss, strong three-dimensional effect, and no harmful solvent volatilization, especially in the curing of the ink. dry On the other hand, UVLED light-curing ink can achieve instant curing under ultraviolet light irradiation, avoiding the shortcomings of traditional solvent-based ink such as long drying cycle and large floor space, thus greatly improving the efficiency and quality of work. UV light curing After printing, the ink needs to be cured instantly through UV light curing equipment. The main factors that affect the quality of light solidification include the wavelength and energy of the UVLED lamp, the speed of the conveyor belt, and the cooling system of the UV machine.
one, UV curing Principle, UV lamp and related technical parameters:
1. UV curing principle: A photoinitiator (or photosensitizer) is added to a specially formulated resin. After absorbing the high-intensity ultraviolet light in ultraviolet (UV) photocuring equipment, active free radicals are generated, thereby initiating polymerization, cross-linking and grafting reactions, converting the resin from liquid to solid within seconds.
2、UV curing lamp : The UV equipment light sources currently used in industry are mainly gas discharge lamps (mercury lamps). According to the pressure of the gas in the lamp cavity, it is divided into low pressure, medium pressure, high pressure and ultra-high pressure. High-pressure mercury lamps are usually used for industrial production and curing. High-pressure mercury lamps can produce characteristic ultraviolet (UV), visible light and infrared light (IR) with strong radiation of 310nm, 365nm, 410nm and other wavelengths. The wavelength of 365nm as the main peak is a band commonly used in countries around the world for curing and drying (the UV lamp referred to below refers to the 365nm high-pressure mercury lamp).
2. The influence of relevant parameters on curing quality
1、UVLED light curing machine Power: Generally, the power required for UV light-setting ink is 80-120w/cm. Too high light-setting energy will cause the ink to become brittle, and too low light-setting energy will not achieve the light-setting effect.
2、UV LED light solid Machine wavelength: The spectrum of the 365nm band is suitable for general light-curing inks (not suitable for inks with special spectral requirements such as ice flowers, wrinkles, etc.). Too much stray light from UV lamps will affect the light-curing effect.
3. Air suction device: While the UV lamp emits ultraviolet rays, it also generates a large amount of heat, which continuously increases the temperature inside the machine. The light curing machine is equipped with an air suction device above the UV lamp tube, and the ozone generated during the curing process is discharged to the outside through the air duct to achieve the purpose of cooling. When the substrate is too thin or the temperature resistance requirements are very low, a light-curing test is required to determine whether it can meet the requirements. For substrates with higher temperature requirements, we can undertake special processing and install a quartz glass plate under the lamp to cool down and further filter stray light.
