Factors Affecting Curability of UV Ink

1. Types and factors of materials
Some types and colors of materials have the property of absorbing ultraviolet rays, and the curing of these materials will slow down. In addition, the same type of material will have different curing properties due to different grades.
2. Color of ink (properties of pigment)
The curing of pigments that can absorb ultraviolet rays will slow down, and the more the content, the stronger the tendency. Therefore, the concentration of UV curable ink has a certain limit. During color mixing, there is no curing problem for various primary color inks, but the color mixing ink will have the problem of poor curing. Especially when it is composed of high concentration white and dark colors (black, blue, other), full attention must be paid.
3. Photocuring initiator
Adding photocuring initiator (curing accelerator JAR-2/JAR-8JAR-15) is an effective way to improve curing property. However, excessive addition of photocuring initiator will hinder curing. Therefore, attention should be paid to the addition amount (the addition amount is within 4%).
4. Iron printing film thickness
The thinner the printed film, the better the curability. Generally, colored inks can obtain sufficient curing performance in the film thickness range of 10-12um. If the film thickness exceeds 15um, poor adhesion will occur due to poor curing. Varnish inks, even more than 100um and thick films, have no problem with their curability.
5. Lamp intensity (W/CM2) and calculated light quantity (J/CM2)
The criteria for judging the hardening are the intensity and accumulation of the lamp. The intensity of the lamp is determined by the output of the lamp and the shape of the lamp room. The amount of integrated light varies from the number of this, the speed of the mesh belt, and the irradiation time. The overall judgment of hardening is determined by the amount of accumulated light, but the most important thing about the internal hardening of the thickness direction of the printing film is ultraviolet. When the ultraviolet intensity is low, the irradiation time is increased, the accumulated light amount is increased, and the internal hardening of the printing film bottom cannot be improved. In this case, the height of the lamp should be lowered, or the output of the bar lamp should be converted to high output.
6. Temperature during irradiation
The ambient temperature during UV irradiation has a great influence on the curing of UV ink. The higher the temperature, the better the curability. Therefore, if preheating is carried out, the curing property of the ink will be enhanced and the adhesion will be better.