What is the cause of cratering?

Cratering defects also called fish eyes, are generally caused by the antifoam agent present in the ink or by the presence of non-compatible substances. Disproportionate addition of antifoam or its low compatibility may generate this kind of defect and the effect is more visible on low or not absorbent supports, such as glossy paper or plastics. Therefore, it is appropriate to use an antifoam which is suitable for the kind of support to be printed on, and to be used in the right proportion. In order to solve this problem, it is necessary to add products able to increase the wetting of the...

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In terms of long-term production, the ink sometimes tends to produce foam. How can the problem be prevented?

Foam can be defined as gas which has been stabilized in a liquid medium. The formation of foam primarily occurs in water-based inks that contain surfactants (used to improve wetting of the support, the dispersion of pigments and the emulsification of resins), especially with pumping systems (that blow air into the ink) and during long-time production. The addition of low quantities of antifoaming agents (better if predispersed in water in a ratio 1:1 and directly sprayed on the foam) causes the destruction of the foam layer and reduces the problem. Sometimes it is very difficult to demolish...

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What means of personal protection needs to be adopted during the use of ink printing?

The means of personal protection equipment that has to be adopted during the use of chemical mixtures are listed at point 8 of the Safety Data Sheet. The use of masks and respiratory protection systems has to be evaluated within the function of the concentration of volatile substances in the atmosphere of the working place (determinable by theoric or analytical methods). It is important to remember the inks are chemical mixtures, although they are not dangerous they have to be used with caution avoiding contact to the skin, not to drink, eat and to smoke whilst handling...

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