Chemical Resistance
Test Methods and Standards for Chemical Resistance
Various resistance tests serve to determine, in an accelerated manner, how a material reacts to external influences. We conduct tests according to many common standards and OEM specifications.
Media Resistance Testing
During use, a component surface is exposed to various media present on hands, such as sweat, oil, grease, or hand cream. Sunscreen residues, in particular, are known to leave stains on painted surfaces. However, further hazards lurk in a vehicle interior, such as spilled beverages (coffee, cola, or juice) or food residues (e.g., ketchup) on component surfaces. Finally, the component must withstand various cleaning agents or solvents without changes. In the simplest tests, the test medium is applied to the surface only for a defined period; under more stringent conditions, an elevated temperature or simultaneous abrasive stress may be required.
A media resistance test allows for the early detection of potential damage (such as paint adhesion problems, gloss and color effects, reduction in strength, etc.).
Stress Crack Resistance
Many plastics can be destroyed by the simultaneous action of a load (mechanical stress) and a crack-inducing medium. The stress crack resistance of plastics is usually tested according to the bent strip method in accordance with DIN EN ISO 22088-3. For this purpose, the test specimen is fixed with a predetermined radius of curvature and exposed to the test medium (e.g., a solvent). More stringent tests are conducted under elevated temperatures. After the corresponding exposure time, potential changes are first assessed visually. Additionally, mechanical tests on the treated specimens may follow.
Soiling and Cleaning Behavior
Soiling and cleaning behavior is particularly important for textiles (seat covers). A defined standard amount of dirt is applied to the textile and rubbed into it. Subsequently, the textile is cleaned with specified cleaning agents, and deviations from the initial state are assessed.
Corrosion Testing / Salt Spray Testing
Corrosion is a widespread problem with metallic materials. It occurs particularly in tropical climates with high humidity and temperature, which is simulated by a condensation test. In system assemblies, interactions between the materials used can also occur. For example, water could leach flame retardants from a plastic, leading to corrosion on electronic contacts. Increased corrosion occurs with the involvement of salts. In a salt spray chamber, component stress near the sea or due to road salt contact is simulated. Primarily, optical changes to the surface (e.g., of chrome plating) are assessed.