UV Backlight Ink

UV light-emitting ink is a kind of special functional ink prepared by adding luminescent material in transparent ink, which has been widely used. General luminescent ink is made of heat curing ink doped with luminescent materials, and the luminescent products are prepared by heat curing, which is difficult to use in UV ink, which is determined by the special characteristics of luminescent materials. Luminescent material that is long afterglow light-emitting materials is a particle size of 10 ~ 60μm inorganic powder materials, in special conditions and even larger particle size, this powder material has a certain body color and opaque, in practice, you need to print a certain thickness in order to reflect a better light-emitting effect, these problems to the use of UV-cured luminescent inks bring certain difficulties.

Luminescent powder into the ink is a common method of preparing luminescent inks, in the past are heat-curing ink and luminescent powder mixed preparation of luminescent inks. With the development of UV technology, the combination of luminescent powder and UV ink to prepare UV light-emitting ink has been gradually adopted by the majority of printing manufacturers, especially in the production of light-emitting signs with UV light-emitting ink instead of heat-setting light-emitting ink has considerable advantages. The printing of UV light-emitting ink by screen printing technology is a common method to prepare light-emitting signs.

① Luminous Powder Selection: UV luminescent ink should consider the selection of luminescent powder in screen printing, the basic requirement of luminescent powder is high brightness and moderate particle size. Large particle size can not be missed from the screen, small particle size printing thickness is not enough, you need to increase the number of prints to achieve the thickness requirements, labor and time consuming, generally use 50 ~ 80μm of the luminescent powder is more appropriate. Rare earth luminescent powder is light yellow-green, so choose to make the signage substrate to blue or green is appropriate.

②网版制作。发光标牌一般要求发光层印得较厚，所以通常采用 80 目涤纶单丝网版，这样可以使发光粉通过网版，同时印出的发光层也较厚。在制版时应考虑到一般标牌产品如一些地名标牌往往同一图案不会连续印刷多次，在这种情况下，可以选择低档耐油的感光树脂，可以节约成本。

③ pre-coated primer. In the printing of light-emitting layer before the need to print a white substrate, light-emitting layer printed on the white substrate. Printing substrate layer is one of the necessary steps for printing luminescent ink, pre-coating the substrate surface will help to improve the luminescent performance of luminescent ink. The use of different pigments of the substrate layer on the luminous performance of the ink is not the same, adding titanium dioxide white substrate layer is most conducive to improving the luminous performance of luminescent inks, this is because the white substrate layer can make through the ink layer of the incident light as well as emitted fluorescence more fully reflected, maximize the role of the luminescent inks.

需要注意的是，UV 发光油墨需要在白色基材上有良好的附着力，否则固化后发光油墨层容易脱落，一般采用白色 PVC 油墨，因为大多数 UV 油墨在 PVC 油墨层上有良好的附着力，从而避免了发光层从标牌上脱落的现象。

④ Pay attention to the interlayer adhesion when printing and curing for several times. The use of UV light-emitting ink should pay attention to a very important issue, the production of signs often need to light-emitting layer to reach a certain thickness, which requires a number of printing to achieve the thickness requirements. As the UV ink is printed once immediately after curing, cured surface smooth, in the next printing is carried out on the basis of the previous layer, this time the need for UV ink between each layer has a good adhesion, can not appear delamination phenomenon. Therefore, in the selection of UV ink should pay special attention to the problem of interlayer adhesion.

长余辉发光材料与 UV 油墨结合印刷使用需要注意以下问题。

长余辉发光材料是一种无机粉体材料，发光材料密度大易析出，使用前需搅拌均匀，同时发光材料易与铁锈、重金属等发生反应，因此在分散研磨过程中不宜使用金属棒，也不宜存放在金属容器中，否则会导致材料变黑，影响材料的使用效果。容器选用玻璃、陶瓷、搪瓷衬里、塑料容器为宜。

发光油墨成膜后，发光吸光功能是由发光材料颗粒实现的。由于要求通过发光材料粘合在一起的树脂应具有良好的透光性，无遮盖力，所以选用的树脂、清漆应以无色或浅色透明为宜。

③ The higher the content of luminescent material, the brighter the luminosity, but in order to make the luminescent material have proper adhesion with the coated products, the proportion of resin should not be less than 10% at least. Of course, the higher the proportion of resin, the higher the smoothness and finish of the luminescent coating. Therefore, the dosage of luminescent material is generally 20%-60% of the total mass or 10%-35% of the volume, or the dosage of luminescent material is determined according to the requirement of luminescent brightness.

④UV Luminescent Ink in screen printing to consider the choice of luminescent materials, luminescent materials, the basic requirements of high brightness, particle size moderate. Particle size can not leak from the screen, particle size of small printing thickness is not enough, need to increase the number of prints to achieve the thickness requirements, waste of time, the use of 20 ~ 80μm of luminescent powder is more appropriate. Luminescent materials are more colorful, the production of sign products generally choose light yellow-green luminescent materials.

生产过程中，发光材料不能研磨，不能使用三辊研磨机，配制发光油墨时，只能使用高速分散机或搅拌机。具体方法是将树脂或清漆放入容器中，加入添加剂，开启搅拌器，加入防沉剂，在缓慢搅拌状态下依次加入发光材料。加入发光材料后，提高转速，直至发光材料均匀分散在材料中，然后过滤得到产品。

不得将重金属化合物用作添加剂。

Pay attention to the choice of mesh size. General light-emitting materials due to the larger particle size, the need for a smaller mesh screen, usually using 100 mesh screen printing is better. The degree of curing of the product after printing also has an impact on the final quality of the product, test whether the curing is complete in the following four ways. First, the pencil hardness meter for testing, generally 3 ~ 4H, can be considered to have fully cured ink. The second is to test the method of dropping solvent, but also to test the solvent resistance, the propionic acid drops on the surface of the print after 20min, such as no change to prove that it has been fully cured. Third, the compression method test, that is, the cotton fiber placed on the surface of the print, with a smooth bottom 500g weights pressed on the surface of the cotton fiber 2 ~ 3min, and then remove the weights, if the cotton fiber does not stick to the surface of the print to prove that it has been fully cured. Fourth, the grid test method, the use of the grid force in the print surface cross, and then use the tape to stick to the surface of the cross, if there is no sticky ink, indicating that the curing is complete and the adhesion of the ink layer after curing is relatively good.