Catalyst for Resistant Prints

Description

For durable and resistant prints, we recommend adding a hardener to the ink or varnish. The hardener in the printing inks acts as a catalyst that aids the curing process. This often makes the prints more durable, providing greater wear resistance. For example, if you add a hardener to the ink to print on glass cups, it will withstand the effects of washing in the dishwasher.

The hardener does not always have to be added to the printing inks, - sometimes the flexibility of a one-component ink is more beneficial, - but it can be used to increase the general durability of the ink layer.

What is the ink hardener?

Hardener is a catalyst that is added to various inks and its mixtures. It increases adhesion on different surfaces and helps protect prints from outdoor/weather conditions. It also increases resistance to chemicals, such as cleaning agents. It is important to check the correct mixing ratio of the hardener and the ink, this varies depending on the ink family and the type of hardener. For example, for printing Pens / Lighters / Caps to Dynapoll inks that recommended for printing these items suggested to add 5%, while to high-gloss Polycure inks, that recommended for shaker dishes suggested 8% NB Catalyst hardener for good dishwasher resistance. (manufactured by Apollo Colurs LtdUnited Kingdom)

Higher density materials may require a hardener for good adhesion. For example, most of hard plastics are difficult substrates in terms of adhesion. Therefore, the addition of a hardener is recommended for durable and resistant prints.

A good feature of hardeners to improve the durability of the prints. At the same time, they reduce the so-called "pot time". This is usually 6-8 hours, i.e. the mixed ink and varnish must be used up during this time.

All hardeners are sensitive to moisture. Therefore, during the drying process, the lowest possible ambient humidity must be ensured in the first 24 hours. Otherwise the hardener will partially react with the moisture instead of the ink. Contact with moisture must also be strictly avoided during storage of the hardener (containers must always be tightly closed after use!). Furthermore, the degree of crosslinking of the hardener and the ink, and then the chemical and mechanical resistance of the printed two-component ink, depends to a great extent on the temperature.

Tip for maximum resistance
Forced drying of the ink at 140-150°C for 20-30 minutes, immediately after printing, achieves the best possible cross-linking and thus the greatest resistance. On substrates that are difficult to print on, such as glass, some metals, thermosetting plastics, and for high resistance requirements (such as dishwasher resistance), forced drying of the ink layer is strongly recommended.

When should we add hardener to the ink?

The use of the hardener depends on the needs of the end user. Is the resistance of the one-component ink is adequate, or requested that the print has greater abrasion resistance?

First of all, important to check the data sheet for how much hardener you need to add to ink or varnish. Printing ink series can be one-component (does not require a hardener) or two-component (requires the use of a hardener). - But most inks series can also be used as one- or two-component inks, so, if you want, you can use a hardener.