What are paint wetting impairment substances (LABS)?
LABS is the abbreviation for „paint wetting impairment substances“ and refers to substances or particles that reduce the surface energy of substrates so that they cannot be evenly wetted. Even the smallest quantities can cause surface defects such as craters, bubbles, wetting problems or matt spots. In industrial painting processes - particularly in the automotive, aviation and furniture industries - the absence of LABS is therefore a critical quality criterion. In the area of rubber composite parts, this generally concerns the application of Adhesion promotion systems on carrier materials.
Typical LABS sources
- Silicone oils (e.g. from lubricants, release agents or sealants)
- Greases and oils from production or assembly processes
- Plasticiser made of plastics or rubber parts
- Certain additives in elastomers or coatings
- Dust or particle contamination with greasy components
- Residues from cleaning agents
- Skin lipids
- Contaminated blasting material, e.g. during sandblasting
Significance in practice
In LABS-critical production areas, materials, auxiliary materials and Tools are specially tested and certified to ensure that they do not release any paint-wetting impairment substances. Elastomers such as EPDM or NBR can be formulated LABS-free, depending on the formulation, by avoiding certain Plasticiser or additives is dispensed with. Also Seals, rubber caps and Vibration dampers must be LABS-free in such environments in order to avoid surface defects in subsequent coatings. LABS tests analyse whether a material causes wetting problems when it comes into contact with a test coating. LABS-free certificates are often a mandatory requirement for use in certain production lines.