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What are the Factors Affecting Curability?

Jul. 13, 2021

As a Uv Ink Manufacturer, share with you.

(1) Type and color of material

There are some types of materials with colors that can absorb ultraviolet rays, and the curing of these materials will slow down. In addition, the same type of material will have different curability due to different grades.

(2) The color of the ink (the nature of the pigment, the problem of toning)

The pigment that can especially absorb ultraviolet rays will slow down its curing. The more the content, the stronger the tendency. Therefore, the concentration and concealment of UV curable inks have a certain limit. Especially when toning, the various primary color inks have no curing problems, but the toning inks will have the problem of poor curing. Especially when using high-concentration white and dark colors (black, blue, other) in combination, you must pay full attention.

UV Curable Ink

UV Curable Ink 

(3) Light curing initiator

Adding photocuring initiators (curing accelerators JAR-2, JAR-8, JAR-15) is an effective way to improve curability. However, excessive addition of the photocuring initiator will hinder curing. In addition, the odor will remain after irradiation, please pay attention to the specified addition amount (addition amount is less than 4%).

(4) Printing film thickness

The thinner the printed film, the better the curability. General colored ink can obtain sufficient curing performance in the film thickness range of 10-12μm. If the film thickness exceeds 15μm or more, poor adhesion may occur due to poor curing. Varnish-based inks have no problem in curability even if they are thicker than 100μm.

(5) Ultraviolet intensity W/cm2 and accumulated light quantity J/cm2

is the standard for judging the curability of ultraviolet rays and the amount of accumulated light. The intensity of ultraviolet rays is as described in 2-①, which is determined by the output of the lamp and the shape of the lamp house. In addition, the data of cumulative ultraviolet intensity and irradiation time is the cumulative amount of light. The amount of accumulated light varies with the number of lamps, the speed of the mesh belt, and the irradiation time.

The overall judgment of curability is determined by the amount of accumulated light, but for the internal curability of curing in the thickness direction of the printed film described in (4), the important thing is the intensity of ultraviolet rays. When the ultraviolet intensity is low, increasing the irradiation time and increasing the accumulated light quantity will not improve the internal hardening of the bottom of the printed film. In this situation, please lower the height of the lamp or change the lamp output to higher output. solving issues.

(6) Temperature and preheating 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 performed, the curability of the ink will be enhanced and the adhesion will be better.

Our company also has UV Curable Ink on sale, welcome to contact us.