Plastics are the second largest user of Titanium dioxide pigments, accounting for 18%-20% of the world's total demand for titanium dioxide. The amount of titania added to plastic varies with its variety and application, generally between 0.5% and 5%.
The application of China Titania in plastic products, in addition to its high hiding power, color reducing power and good performance in combination with other pigments, it can also improve the heat resistance, light resistance and weather resistance of plastic products to protect plastic products from The attack of UV light improves the mechanical strength and electrical properties of plastic products. It is used in almost all thermosetting and thermoplastic plastics, such as polyolefins (mainly low-density polyethylene), polystyrene, ABS (acrylonitrile-butadiene styrene copolymer), polyvinyl chloride, etc. It can be dry mixed with resin powder, or mixed with plasticizer-containing liquid, and in some cases, titanium dioxide is made into color masterbatch through an intermediate factory before use. Therefore, the properties of Rutile used in plastics are mainly fine particle size and uniform particle size distribution, so as to enhance the reflection ability of short-wavelength light and prepare plastic products with better hue. In addition, Titanium(IV) oxide pigments must have good heat resistance and high dispersibility. Therefore, the titanium dioxide used for plastics is generally treated with inorganic coating and organic coating. Like the coating system, the titanium dioxide used for outdoor plastics should be rutile, and others can be anatase.
Titanium dioxide for plastics requires fine particles and good dispersibility; good heat resistance and light resistance. It does not change color during the heating of plastic molding and the finished product during sunlight exposure and use.
With the continuous expansion of the application range of plastic products, many external plastic products, such as plastic doors and windows, building materials and other outdoor plastic products, also have high requirements for weather resistance. In addition to rutile titanium dioxide, surface treatment is required. This kind of surface treatment generally does not add zinc, only silicon, aluminum, zirconium, etc. are added. Silicon has a hydrophilic dehumidifying effect, which can prevent pores from evaporating when plastic is extruded at high temperature, but the amount of these surface treatment agents is generally not too much.
When titanium dioxide is used in polyolefins (such as polypropylene), it sometimes causes yellowing of plastics. This is because titanium dioxide reacts with phenolic antioxidants (BHT) in polyolefins. Appropriate organic surface treatment can reduce this yellowing effect.
In rigid PVC containing lead stabilizers, Titania will cause the resin to turn gray when exposed to ultraviolet light. This is because the titanium dioxide after ultraviolet light will be reduced to Ti2O3, making the lead in the lead stabilizer After precipitation, this reaction is reversible. However, it does not occur in soft polyvinyl chloride and hard polyvinyl chloride that uses tin stabilizers. It is also used in melamine formaldehyde resin. Because of the reducibility of the resin itself, coupled with the effect of ultraviolet rays, it can also change the melamine decorative board. (Gray) color, if you want to use it in the above materials, you must choose rutile titanium dioxide with low chemical activity and high weather resistance.