Titanium Dioxide is a kind of perfect white pigment which is widely used in PVC profile as light screening agent. Rutile Titanium Dioxide has the density of 4.26g/cm3 and refractive index of 2.72. It can reflect most visible light and absorb ultravioletlight with the wave length of less than 410nm. It has performances of heat and weather resistance and excellent ultravioletlight resistance property. Titanium Dioxide is an important ingredient used for enhancing the weather resistance of PVC profile and prohibiting extraction of HCl from Polyvinyl Chloride (PVC). However, the market price of Titanium Dioxide is relatively high, so some PVC profile manufacturers reduce the dosage of Titanium Dioxide to 3.6 PHR to lower the cost. But weather resistance of PVC profile will also be badly affected.
As is researched, coverage of Titanium Dioxide will reach the limit when the dosage of Titanium Dioxide is 8 PHR. In general, adding 5 PHR of Titanium Dioxide is enough. In addition, a little optical brightener can be added for better whiteness.