LABS

Substances that interfere with paint wetting create defects on the surface of components to be painted. In the rubber industry, substances that interfere with paint wetting are mixture components that can be emitted, such as silicone, certain waxes, oils, CFCs and surfactants, which prevent even and defect-free wetting with paint on surfaces to be painted, such as body parts in automobile construction, and are manifested in a type of crater formation.

Due to the introduction of solvent-free paint systems on a water-soluble basis, it became necessary for automobile manufacturers such as VW, AUDI, OPEL to define the assessment of labs-free hoses, seals, molded parts, O-rings in test specifications (e.g. PV 3.10.7 of Volkswagen AG).

When testing for LABS-free products according to VW test specification PV 3.10.7, the components to be tested are wetted with a solvent mixture and rubbed on a test pad (it also works on a standard household aluminum foil) until the solvent has completely evaporated. The test pad is then sprayed with commercially available car repair paint. The tested component is LABS-free if the painted test pad does not show any craters.

Synonyms: Paint wetting impairment substances