Lubricant varnish
The friction coefficient of many materials can be reduced by coating with special lubricant varnishes. The requirements regarding abrasion and bonding of lubricant varnishes are particularly high, since they are subject to frictional forces in regular operation where loosening or flaking off of the varnish would result in loss of functionality. When plastic or elastomer components are coated with lubricant varnish, high requirements are also made regarding the elastic properties of the varnish so that deformation of the component will not result in tearing of the varnish. Many elastomer sealing elements are coated with lubricant varnish. These elastomers are typically characterised by a high coefficient of static friction. In practical use, this often leads to the stick-slip effect which coating with lubricant varnish can prevent very effectively. Often, the low friction coefficient of the lubricant varnish is due to a proportion of fluoropolymers (e.g. PTFE). To ensure proper adhesion of the lubricant varnish, pretreatment in the form of plasma cleaning and plasma activation is almost always required.