Approach to analyzing defects

Clearly identify the causes

In the Coating Systems and Painting Technology Department, the development and application of paint-related analytical testing methods is a key area of expertise. The focus of our work is on organic coating materials, their material properties and application fields.  These range from coatings for wood through wall paints right up to functional and decorative paints for the automotive industry.

There are many causes of paint defects in decorative and functional coatings. Among others, these include curing deficiencies, incorrect mixing ratios for 2-component paints, contamination by substances that impair wetting properties, the inclusion of foreign particles and defects in substrates.  In some cases, two unintentional changes in the system or even more may be identified. On their own, they do not cause any damage but combined they can lead to significant reject rates.  Each cause of damage is unique in its nature. This calls for an approach tailored exactly to the profile concerned to search for the problem.  In our laboratories we have a range of analysis methods at our disposal. Accredited according to DIN EN ISO/IEC 17025, these include infrared spectroscopy, Dynamic Mechanical Analysis (DMA), Differential Scanning Calorimetry (DSC) and Thermo-Gravimetric Analysis (TGA).

 

Examples of identified causes of defects (extract)

  • Flaws in the substrate
  • Inadequate substrate pre-treatment
  • Incorrect mixing ratio for a 2-component system
  • Impurities in paint materials and coatings
  • Inadequate cleaning processes or the presence of surface contamination
  • Delamination, poor adhesion
  • Sub-optimal curing process
  • Coating subjected to mechanical stress
  • Environmental influences
  • Typical painting flaws such as bubbles, craters, specks, drips, particles, etc.

 

Our testing methods and techniques (extract)

  • Infrared spectroscopic tests: Characterization of binders and fillers, detection of surface contamination, infrared microscopy
  • Thermal analytics (DSC, TGA, DMA)
  • GC-MS: Analysis of volatile components
  • Determination of the surface energy of a substrate (Sessile Drop) and paint (Pendant Drop)
  • Laser scanning microscopy
  • SEM / EDX / FIB (scanning electron microscope (SEM) with energy-dispersive x-ray spectroscopy (EDX), Focused Ion Beam)
  • Rheological tests