skinning time

The skinning time describes the time in which a "solid" skin forms on the adhesive.

This term is mainly used for adhesives that react with atmospheric moisture from the outside inwards.

During this period, the surface of the coating begins to air dry to form a skin. The length of skinning time depends on various factors such as the type of coating, ambient temperature, relative humidity and air movement. As a rule, the skin formation time is specified by specifying a dry film thickness and a time specification, for example "2 hours at 20° C. and 50% relative atmospheric humidity". Accurately determining skinning time is important as it affects total drying time and coating adhesion. If skinning occurs too quickly, it can cause cracks or bumps on the surface, while too long a skinning time can compromise adhesion and increase overall drying time.

If the skin has already formed too far before joining, the wetting of the second part to be joined will be more difficult or may not take place at all. The joining must therefore be completed before the skin formation time has elapsed.

Colloquially, chemically not completely correct, the skin formation time is also sometimes used as a synonym for open time, pot life and processing time.