In principle we have to differ between physical drying and chemical curing/ film building. In the following, the four main mechanism are shortly described.
- Physical drying process
- Printing material absorbs the thinner of the ink
- Drying in seconds
- Part of drying process in printing inks and water based varnishes in cold-set the only drying process. For example, news paper web offset.
- Chemical film building
- Parts of the printing ink react with oxygen
- Dryer compounds speed up film building
- Film building in hours
- Oxidative film building is a partial process in conventional printing inks.
- The water particles of the varnish are transformed in a steam like condition
- The steam, or respectively, the steam saturated air will be exhausted
- Drying in seconds or up to minutes
The evaporating drying is a partial process of the drying of varnishes. The drying process of water based varnished will be explained in the following.
- UV radiation and photo initiators are starting the series of polymerization processes
- Curing process in milliseconds