Environmental Simulation
Climate tests simulate the long-term behavior of products under artificially intensified conditions to qualify them for specific environmental conditions. Here, the parameters temperature, humidity, and radiation are varied.
We Simulate Environmental Influences
Technical products are exposed to a variety of environmental influences throughout their entire service life. These can affect the function and/or appearance of a component, thereby reducing its service life. Artificial aging in climate tests simulates long-term behavior under intensified external conditions, thus qualifying a product for given environmental conditions. The goal of environmental simulation is to quickly and effectively identify weak points in products and prevent complaints. Environmental influences refer to all forms of physical, chemical, or other effects on the object under investigation.
Thermal Aging – Cold Aging – Temperature Cycling Test
Plastics are subject to aging, which is often attributable to temperature effects. Stresses in plastic, for example, can lead to component deformation (warpage) under heat exposure, thus causing problems with fit accuracy within an assembly. Different coefficients of thermal expansion (e.g., metal and plastic) can cause cracks or material delamination, especially with frequently changing temperatures in a temperature cycling test. A change in mechanical strength or material embrittlement is also frequently observed. It is therefore advisable to combine storage tests with a verification of product properties such as strength, hardness, adhesion (cross-cut test) before and after the climate test.
The temperatures and duration of a climate test are adapted to the product’s operating conditions and its expected service life. For example, temperatures ranging from -35°C to +85°C are common in the automotive sector. However, significantly lower or higher temperatures are also possible depending on the application area.
Humidity Aging – Condensation Constant Climate Test – Hot Water Test – Hydrolytic Aging
Polar plastics with functional groups, such as polyamides, polyesters, or polyurethanes, are particularly susceptible to hydrolytic aging. In this process, the functional group of these polymers is cleaved under the influence of water. The resulting cleavage of the molecular chains alters, among other things, the mechanical and thermal properties of these plastics. Furthermore, the temperature to which the plastics are exposed during hydrolytic aging has a strong influence. Therefore, simple humidity storage of plastics provides only limited information regarding hydrolysis resistance. For more comprehensive statements, condensation constant climate tests and hot water tests are also conducted to examine the influence of water and temperature on the plastic and to derive a property profile from this.
Lightfastness Test – UV Resistance – Hot Light Aging – Sunlight Simulation Test
Under the influence of light (especially UV radiation), plastics can also undergo aging. Color pigments can fade due to a lightfastness test, leading to a color change or yellowing. Therefore, after each lightfastness test, an assessment of color and gloss is performed. More serious than optical changes are possible structural changes within the plastic itself, which can, for example, negatively alter the mechanical properties of the material. Cleavage of molecular chains or post-crosslinking can, for instance, cause material embrittlement. Exposure tests are sometimes also carried out in conjunction with temperature and/or humidity.