What issues should be noted when coloring and whitening white profiled materials?

What issues should be noted when coloring and whitening white profiled materials?

Rutile type (R type) titanium dioxide is the best pigment for white profiles. It is also an excellent light shield, which can enhance the weather resistance of profiles. At the same time, it has the effect of inhibiting the dehydrochlorination of PVC and delaying the decomposition of PVC. However, generally, adding about 5 parts is sufficient. When the titanium dioxide content in the product is 8%, its covering rate tends to balance. Adding more beyond this range is not beneficial and will increase the viscosity of the material, reduce its fluidity, and increase the torque, causing processing difficulties.
If the whiteness of the profile is insufficient, a small amount of fluorescent brightener can generally be added to increase the surface brightness of the product, make the color clearer and more vivid, and achieve a "radiant" whitening effect. Domestic common brighteners such as PF type have a low decomposition temperature, with an initial decomposition temperature of 178℃ and a maximum absorption wavelength of 363nm. They also have sublimation phenomena. Although they are low in price, their effect is not satisfactory. If type 0B is selected, the melting point is 196 to 203℃, the decomposition temperature is higher than 220℃, and the maximum absorption wavelength is 375nm. "0B-1", melting point 353-359℃, maximum absorption wavelength 374nm, maximum fluorescence emission wavelength 434nm; Among them, "127" is particularly suitable for PVC products.
A small amount of blue pigment can also be added to the white profiles to "cover the yellow" in order to achieve the purpose of whitening. However, it should be noted that when choosing blue pigment, ultramarine has poor acid resistance and generally cannot be mixed with heat stabilizers containing lead, tin and cadmium. However, phthalocyanine blue has a strong coloring ability and is prone to causing uneven coloring.