Marabu Pad printing ink
Although screen printing ink is able to be used by the pad printer. Appropriative pad ink is recommended by the pad printing expert because of steady surface tension and nice ink transfer result. There are three kinds of pad inks in Chinese pad printing market.
This glossy pad printing ink is distinguished by particularly high resistance. Being an one-component ink, it is very quick-drying and easy to be processed. To raise surface stability or other stabilities, hardener can be added. This pad printing ink can be widely used. On rigid PVC, polystyrene, ABS, acrylic glass, polyester, thermosetting plastics and varnished surfaces. Because of its high resistance, it can also be utilized for products subject to high mechanical stress, the effects of hand perspiration or cleaning agents, such as control knobs, camera housings etc. Under certain circumstances, this ink is also suitable for poly-acetal materials.
High-gloss, quick-curing two-component ink for high-demand adhesion, scratch resistance, mechanical and chemical resistance. By using a matte paste, the degree of gloss can be varied. Materials that are difficult to print on, such as pre-treated polyethylene and polypropylene, thermosetting plastics, metals and varnished surfaces, but also polyurethane, polyamide, melamine resins, powder-coated surfaces and suchlike are easily printed. It can also be used for polyacetal under certain circumstances.
Glossy, quick-drying pad printing ink with good resistance to many chemicals such as oils, greases, alcohol. Hardener can be added to further raise surface stability and other properties. Tampapol TPY is primarily used for printing on packaging made of pre-treated polyethylene and polypropylene, ABS as well as rigid PVC. It is also widely used for thermosetting plastics, metals and varnished surfaces.
The UV-curable pad printing ink Tampacure TPC is particularly suited to print onto · ABS · Rigid PVC · Polycarbonate (PC) · Polystyrene (PS) · Acrylic (PMMA) By adding hardener, TPC adheres excellently to many other substrates such as · Pre-treated polyethylene (PE), · Pre-treated polypropylene (PP), · polyamide (PA), · varnished surfaces. When printing onto metals, an addition of Adhesion Modifier UV-HV 1 may improve the adhesion of the ink. In the case of printing onto polyethylene and polypropylene, please make sure to pre-treat the surface of your substrate by flaming or Corona discharge as usual. As per our experience, you can achieve a good adhesion with the Tampacure TPC with a surface tension of at least 48 mN/m. On polypropylene, you can also apply a thin film of our colourless Primer P 2 for surface pre-treatment. Since all the print substrates mentioned may be different in printability even within an individual type, preliminary trials are essential to determine the suitability for the intended use.
The UV-curable Tampacure TPC is particularly suited when printed parts are immediately to be processed further, resp. when excellent mechanical and chemical resistances are required. With multicolour printing, it is important to note that Tampacure TPC can be printed weton- wet, without an intermediate UV-curing. When printing overlapping motives with opaque colour shades, however, the individual ink films must be cured one by one. If the different ink layers do not overlap, it is possible to cure all printed layers with one single pass through the curing unit. Due to their transparency, 4-colour process shades can also be cured with one pass through the curing unit. Nevertheless, preliminary tests are always essential.
According to the required curing speed, a UVcuring unit (medium-pressure mercury lamps) of 80-120 W/cm is necessary. The curing speed of the ink is generally dependant upon the kind of UV-curing unit
(reflectors), number, age, and power of the UV-lamps, the printed ink film thickness, colour shade, substrate in use, as well as the printing speed. The adhesion of the ink is usually tested by a tape test after the ink has been cooled down to room temperature (approx. 20° C).
UV Pad Printing ink contains solvents. Parallel to physical drying and the evaporation of the solvents
used, the actual hardening of the ink film is caused by a chemical cross-linking reaction started by the UV-light. UV Pad printing ink is a slightly post-curing UV ink which will achieve its best resistances after 24 hours. If hardener has been added, the curing speed will be reduced. Due to this, adhesion and scratch resistance should be tested only after 24 hours. A final curing of the ink film will be reached after approx. 48 hours.
The pot life (processing period) at room temperature (approx. 20°C) with hardener will be about 12-16 h. Higher temperatures reduce pot life. . If the mentioned times are exceeded, the ink's adhesion and resistance may be reduced even if the ink characteristics show no noticeable change.
When using hardener, the processing and curing temperature must not be lower than 15°C as irreversible damage can occur. Please also avoid high humidity for several hours after printing as the hardener is sensitive to humidity.
Pigments of medium to high fade resistance are used in UV Pad printing ink. Owing to this, all UV Pad printing ink shades are generally suited to a short-term outdoor use of up to one year related to the
moderate Central European climate.
After proper and thorough drying, the ink film exhibits outstanding rub and scratch resistance
and is resistant to a large number of chemicals, oils, greases, and solvents, as well as perspiration. These resistances can further be improved by adding 5% hardener.
UV pad printing ink is not press-ready and must therefore be adjusted to the required viscosity
with the corresponding thinners prior to printing. In the case of higher requirements to the ink’s resistance or reactivity, there are different additives available.