Embossing UV ink application and formula

Embossing UV ink is widely used in the printing of gold and silver cardboard, synthetic paper and processed PP, PE and other substrates. Its print quality is good (compared with ordinary ink), and it is easy to arrange the production of the post-process immediately, and it becomes a streamlined operation with high production efficiency. At present, most of the large color and thick ink layer patterns of cigarettes and wine packaging are printed using letterpress UV inks. In addition, high-quality, high-required labels, etc., and examples where UV inks are used for embossing and printing are not uncommon.

According to the composition of the UV ink, the UV offset ink is similar to that of a UV offset ink. The difference is that the former has a lower viscosity, and the ink rheological requirements are not stricter than the latter. The general formula is as follows

Embossing UV ink formulation

EA resin 18-30 (wt%),

PUA resin 15-20

Initiation system 5-10

Pigments 15-22

Wax 2-5

Bentonite 2-5

The application of embossing UV inks has focused attention on the issue of "durability". The reason is that these prints are often used in the plastic packaging of detergents, shampoos, medicines, and cosmetics. Certain chemical substances (ethanol, acetone, surfactants, etc.) in the packaging are highly erosive to the cured ink film. Therefore, the chemical resistance of the ink will directly affect the durability of the printed matter. In this regard, the inexpensive epoxy oligomers, epoxy bis acrylates, have often been used in ink formulations to convert them to highly costly and chemically resistant polyurethane bisacrylates.

The thickness of the ink layer printed with the embossed UV ink is generally inconsistent, that is, the thickness of the edge portion of the ink is large and the thickness of the intermediate portion is small. At the time of exposure, the ink film in the middle has been cured, and the ink film on the rim is still insufficiently cured. In this regard, how to increase the cure rate of UV printing ink is one of the issues that should be taken seriously. In practical applications of embossing UV inks, in addition to the use of photoinitiators, a small amount of photosensitizers (such as triethanolamine, etc.) must also be used. The introduction of the photosensitizer can not only increase the curing rate of the ink film, but also improve the overall performance.

Braille transparent oil formula

EA epoxy resin 20

TDI Polyester PU 50

Special monomer 15

TPGDA 5

184 4

BP 2

Modified active amine 8

BYK450 0.3

N (defoaming) 0.2