Performance and Application of UV-PPC Inks

First, the performance and use of UV-PPC ink

The basic composition of UV-PPC ink is similar to that of other UV inks, but UV-PPC ink is widely used as a UV ink and can print PC, PS, ABS, PVC, paper, gold and silver cardboard, and Treated PET, PP and PE and some painted panels and other materials. UV-PPC ink is a kind of multi-purpose UV ink with low application cost, improved production efficiency and printing quality. The basic performance indicators are shown in Table 1.

Table 1 Basic Performance Indexes of UV-PPC Inks
Second, printing requirements and operating methods
1, the printing material, the need to fully remove the oil, dust.

2. Stir the ink thoroughly before use. As the temperature changes, the state of the ink will become thicker or thinner. At this time, the viscosity should be adjusted by a special UV thinner. Under normal circumstances, the amount of diluent added should not exceed 5% of the weight of the ink, otherwise it may reduce the ink curing speed.

3, when the need for stacked color printing, should pay attention to weakening the background of the UV light intensity or reduce the illumination time, in order to avoid over-curing due to the underlying color resulting in poor adhesion adhesion phenomenon.

4, the open can wait for the ink should be taken to avoid direct exposure to ultraviolet light or sunlight, yellow light is safe light.

5, the choice of screen. When printing black and white ink, the mesh size should not be less than 420 mesh. When printing other colored systems, the screen should be above 350 mesh. Scrapers should use a sharp PU blade with a hardness of 70 or more. When the blades of the scraper have worn out, it should be immediately reground or replaced with a new scraper. In the production of screen, the photosensitive adhesive should not be too thick, usually in the front, second time is appropriate. As mentioned above, the purpose of this selection is to control the thickness of the ink layer. We know that UV-PPC inks need to absorb UV light to generate energy during the curing process. The entire ink layer is from the surface to the deep layer, and the intensity of the received UV light is gradually decreasing. The deeper the UV light, the more acceptable the UV light is. The weaker it is, the harder it is to cure. If the printed ink layer is too thick, UV light can hardly penetrate the ink layer and reach the bottom of the ink layer due to the hiding property of the ink itself. This will result in deep penetration of the ink and cause the adhesion to decrease. On the contrary, if the thickness of the ink layer can be controlled, the UV light can easily penetrate to the bottom of the ink layer and rapidly solidify.

6, UV lamp power selection. UV lamp power can choose 3 ~ 8kW, this power is generally sufficient to meet the UV-PPC ink curing requirements, it is worth noting that the reflector should choose a semi-circular arc with light focusing function to increase the density of UV light .

7, the curing time control. There are many factors that can affect the curing time of UV-PPC inks. First of all, the color of the ink is different, and the curing time is not the same. In general, due to the high hiding power of white and black, the curing time is longer than other colored inks, and the power requirement for the lamp is also relatively high. Therefore, when the printing plant is operating, the white and black curing time is relatively slow compared to other colored inks, and the UV curing machine's transmission speed should be adjusted more slowly. Secondly, the size of printed graphics also affects the length of curing time. Some small texts and thin lines cure faster, because they can receive UV light from the front, rear, left, right and upper five directions. It receives more radiation energy. For some larger color blocks, the middle part can only receive UV light from the above direction, and receive less radiation energy. Therefore, the curing speed is relatively slow and the time is longer. In the printing factory application process, many will find such a phenomenon, in the same pattern, small text and lines, UV adhesion is high after curing, while a larger color fast, the middle part of the adhesion can not. This phenomenon is often caused by the above reasons. The solution is to increase the cure time. Third, the thickness of the ink layer will also affect the curing time, because the intensity of the UV light is gradually decremented during the penetration of the ink layer, and the UV light is weaker toward the bottom layer of the ink film. Therefore, if the ink layer is thicker, the curing speed is slower, and the faster is the opposite.

To sum up, to embody the advantages of UV-PPC inks in application, it is necessary to have close cooperation between screens, scrapers, UVs, and various elements of the operator. As long as you understand the curing mechanism of UV-PPC ink and control the thickness of the ink layer, applying UV-PPC ink will give you unexpected printing effects and convenience.

Third, application prospects
In recent years, UV screen printing ink, as an environmental protection and UV fast curing type ink, has been increasingly applied in the field of screen printing in the face of increasing demands for environmental protection and the desire to increase production efficiency. UV-PPC ink has obvious advantages in environmental protection application cost and production efficiency. Therefore, its application prospects must be very broad. In labels, signs, membrane switches, bottles, packaging, advertising, etc., have a wide range of uses.




Source: China Ink Technology Network