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As the second largest user of titanium dioxide, the plastics industry is the fastest growing field in recent years, with an average annual growth rate of 6%. Among the more than 500 titanium dioxide grades in the world, more than 50 grades are dedicated to plastics. The application of titanium dioxide in plastic products, in addition to using its high hiding power, high achromatic power and other pigment properties, it can also improve the heat resistance, light resistance and weather resistance of plastic products, so that plastic products are protected from UV light. Invasion, improve the mechanical and electrical properties of plastic products.
Since plastic products are much thicker than paints and inks, it does not require a high volume concentration of pigments, plus it has high hiding power and strong tinting power, and the general dosage is only 3% to 5%. It is used in almost all thermosetting and thermoplastic plastics, such as polyolefins (mainly low-density polyethylene), polystyrene, ABS, polyvinyl chloride, etc. It can be mixed with resin dry powder or with additive. The liquid phase of the plasticizer is mixed, and some are used after processing the titanium dioxide into a masterbatch.

Specific application analysis of titanium dioxide in plastic industry and color masterbatch industry

Most of the titanium dioxide for plastics has a relatively fine particle size. Usually, the particle size of titanium dioxide for coatings is 0.2~0.4μm, while the particle size of titanium dioxide for plastics is 0.15~0.3μm, so that a blue background can be obtained. Most resins with a yellow phase or resins that are easy to yellow have a masking effect.

Titanium dioxide for ordinary plastics generally does not undergo surface treatment, because titanium dioxide coated with inorganic materials such as conventional hydrated alumina, when the relative humidity is 60%, the adsorption equilibrium water is about 1%, when the plastic is squeezed at high temperature. During processing, the evaporation of water will cause pores to appear on the smooth plastic surface. This kind of titanium dioxide without inorganic coating generally has to undergo organic surface treatment (polyol, silane or siloxane), because titanium dioxide is used for plastics. Different from titanium dioxide for coatings, the former is processed and mixed in low-polarity resin by shearing force, and the titanium dioxide after organic surface treatment can be well dispersed under appropriate mechanical shearing force.

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 the use of rutile titanium dioxide, surface treatment is also required. This surface treatment generally does not add zinc, only silicon, aluminum, zirconium, etc. are added. Silicon has a hydrophilic and dehumidifying effect, which can prevent the formation of pores due to the evaporation of water when the plastic is extruded at high temperature, but the amount of these surface treatment agents is generally not too much.