Printing ink type, application and its advantages and disadvantages

The one-component ink is added with thinner to obtain the desired printing viscosity. The drying method is physical evaporation type. Some thermoplastic substrates such as PS, PC and PVC will be slightly dissolved. This dissolution will cause the ink and the substrate to directly adhere to each other. Scratch resistance, good adhesion.

The chemical resistance of two-component inks is higher. Generally, hardeners are added to the inks, but care must be taken to add them before printing. If the addition time is too long, the effect is not good. In addition, whether or not it is completely dry depends on the ambient temperature. It takes several days to dry at room temperature at 20°C, so do not perform scratch resistance and adhesion tests prematurely.

Thermosetting inks are generally two-component inks. The resin bonding of such inks does not occur at room temperature and only occurs at high temperatures.

Oxidation type inks react by air oxidation, and the reaction speed is generally slow. It is 1 to 2 days at room temperature.

The transfer of the printing ink mainly relies on the evaporation of the solvent, the evaporation causes the ink film to adhere, and the adhesion of the ink is adjusted. Good hiding power is achieved through the transfer of the ink film layer. Due to the lack of solvents in UV inks, the ink film layer cannot be changed. This shift is "water transfer" and the transfer is difficult.

UV curing inks are generally used for high quality printing. Advantages of UV inks: Ink on steel stencils is not dry; quality is guaranteed; less wear on steel stencils; faster drying speed; solvent-free. The disadvantages of UV inks are: high energy requirements, UV curing equipment; high requirements for cleaning rubber heads; viscosity requirements are not as good as solvent inks; fineness printing is not as good as solvent inks.

Water-based inks have not been used for pad printing because of the low yield, drying speed, viscosity, adhesion, and evaporation rate are not as good as solvent inks.