The quality of UPVC profiles is mainly determined by its design and manufacturing process. A good UPVC profile should be a reasonably designed multi-cavity body with thick walls. The formula contains anti-aging and anti-UV additives. From the outside, it should have a smooth surface and a bluish-white color.
Color is also an important indicator of quality. The color of high-end UPVC profiles should be white with a hint of blue. Such a color has good anti-aging properties and will not age, change color or deform after being exposed to wind and sun for 30 to 50 years. The mid-to-low-end profiles are white with yellowing. This color has poor sun protection. After a few years of use, it will become more and more yellow until it ages, deforms, and becomes brittle. The reason is that the profile formula contains too much calcium.