A PVC window profile is designed to last for decades in an outdoor environment. During this time, the material experiences cyclic stress from the sun, cold, humidity, mechanical stress, and atmospheric pollution. However, most degradation processes do not occur during the actual use of the product, but rather during the processing of the melt.
This is why the stabilization system is a crucial component of the formulation, as it determines the actual lifespan of the product. Calcium-zinc stabilizers perform multiple functions: they bind hydrogen chloride released during heating, stabilize the polymer chain, slow down photo-oxidative processes, and prevent the accumulation of structural defects.
Why does the PVC profile degrade quickly?
If the stabilizer is not properly selected, the window profile may appear perfect when it leaves the production line, but after a few months of use, it begins to show signs of degradation, such as changes in color, loss of gloss, and reduced impact strength. This is because the unstable material continues to degrade after processing.
Modern CaZn stabilization systems provide uniform thermal protection throughout the entire thickness of the profile. This is particularly important for multi-chamber structures and thick-walled products, where the inner areas take longer to warm up and are more susceptible to local overheating.
For profile manufacturers, this translates into practical benefits: the production line operates more smoothly, the torque of the extruder is predictable, the surface of the product is uniform, and the finished PVC profile maintains its properties throughout its lifespan.
For window systems, Reapak G-AV/9911 and Reapak G-AV/9913 stabilizers are used, which are designed for stable processing and long-lasting outdoor performance.
