17/06/2026
Why do some uPVC profiles turn yellow over time?
The primary cause is the degradation of PVC molecular chains under prolonged exposure to UV radiation and heat. When the stabilization system is insufficient or low-quality raw materials are used, dehydrochlorination can occur, leading to the formation of conjugated double bonds that gradually change the profile color from white to yellow.
Several factors can accelerate yellowing:
✔ Low-quality or insufficient TiO₂
✔ Poor heat stabilization during extrusion
✔ Excessive recycled material content
Preventing discoloration starts with the right formulation. High-quality TiO₂, efficient stabilizer systems, optimized processing conditions, and strict raw material control all play critical roles in maintaining long-term color stability and weather resistance.
At Haitec Profile, we focus on formulation balance and manufacturing consistency to help ensure our uPVC profiles remain bright, durable, and attractive for years of outdoor service.
