2013/10 – Handling printing inks

Pad printing inks are easy to use and quickly made ready to print. Thinner addition is by weight, the weighing is done with solvent-resistant scales. We always recommend using scales that are adjusted for printing inks, or measuring instruments with glass plates. Important: The pad printing ink should have been stored at production temperature for at least 24 hours before use.

The process reliability for constant print quality can be achieved by determining the viscosity of the ready to print ink. Our TampoVisco viscosity measuring instrument is quickly set up and easy to use. Untrained personnel can be integrated into the process chain by using the documentation and orientation on the result of a single measurement of optimally stirred inks.
Pad printing ink must be thoroughly stirred before use, as the ink pigments sink to the bottom of the container after only a short time in storage. The ink pigments and the binding agent must be stirred into a homogeneous mass with the help of a stirring spatula (ideally metal, with a long, wide blade).

Any “hardener” used must be added first to the printing ink, in accordance with the specified mixing proportions. Caution: The thinner is stirred in after the hardener has been mixed in. Please refer now to the “pot life” specifications. When the “pot life” has expired, the ink may still appear to be printable, but the chemical reaction for the fast hardening of the ink on the printed part is already complete. There is now no guarantee of a good chemical and mechanical durability. Warmth accelerates the chemical reaction. Therefore the “pot time” specifications are for room temperature. If the surrounding temperature is higher, the “pot time” is shorter.

 

rotary pad printing colours

Colors, thinner and hardener for rotary pad printing

Pad printing color

Testing viscostiy of pad printing ink

 

Use the ink containers quickly after opening.

The pad printing inks should be stored at room temperature. The containers must be stored upright and protected from direct sunlight. When opening a container, take care that no dirt from the lid falls into the pad printing ink. Dirt on the container edge should be removed so that the lid is airtight. Clean the coloured components and spatula immediately after every use. Pad printing ink dries quickly, which leads to laborious cleaning.

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