Precautions in the application of titanium dioxide

Titanium dioxide is an important fine chemical raw material. Its chemical composition is titanium dioxide (TiO2). It is a white inorganic pigment with wide application and great market demand. Titanium dioxide products are divided into two categories: one is rutile titanium dioxide, which has strong light resistance and weather resistance, and is mostly used in the production of outdoor coatings and products; The other is anatase titanium dioxide, which has worse light resistance than rutile. It is mainly used in the production of indoor coatings and products. Titanium dioxide is widely used in coatings, plastics, papermaking, printing ink, medicine, fiber, cosmetics and other fields because of its excellent performance.

Factors to be considered in the selection of titanium dioxide

Color factor

Color is an important technical index for marking pigments. Titanium dioxide is known as the "king of white pigment", and the color index of titanium dioxide is whiteness. Even titanium dioxide with the same chemical composition will have different colors due to different process routes, raw materials, equipment and technical level. Although the color light depends on the chemical composition, the more important and often decisive factors are its particle shape, size, particle size distribution, crystal form, impurity content, etc.

Hiding power factor

The optical essence of hiding power is caused by the difference between the refractive index of pigment and the medium around it. Rutile titanium dioxide has a refractive index of 2.71 and anatase of 2.55. It is the white pigment with the highest hiding power. The masking effect is mainly due to the scattering caused by titanium dioxide, or the absorption caused by the presence of colored substances, or when the intensity of incident light decreases due to the above two reasons. Therefore, the main reason for determining the hiding power of titanium dioxide is not only the chemical composition and crystal form, but also the particle shape, particle size and particle size distribution of titanium dioxide.

Coloring force factor

Coloring power is an important characteristic index of titanium dioxide, which is the ability of titanium dioxide to show its own pigment after mixing with another pigment. In other words, for a white pigment, the lighter the color of the mixture after it is mixed with a dark pigment, the stronger its coloring power (achromatic power).

Oil absorption factor

Oil absorption is also one of the important pigment properties of titanium dioxide, because it involves the filling state of titanium dioxide in the color developing agent and can explain its dispersion performance in the medium. In the paint industry, it is used to estimate the consistency of paint before mixing, guide the formulation of paint, and preliminarily calculate the pigment volume concentration (PVC (5680, - 40.00, - 0.70%) according to the following formula.

Chemical composition factors

The chemical composition of titanium dioxide determines the chemical properties of titanium dioxide. It is the main symbol of the difference between pigments. In addition to reflecting a series of pigment properties of pigments, such as whiteness, achromatic power, oil absorption, etc., it also plays a great role in its application properties, such as weather resistance, dispersion, etc.

Light and weather resistance factors

The light resistance and weather resistance of titanium dioxide is an important index to measure the application performance of titanium dioxide. It is meaningless to only refer to its light resistance and weather resistance. This index is meaningful only after titanium dioxide is applied to relevant application fields (such as automobile paint, profile, etc.). Therefore, the light resistance and weather resistance of titanium dioxide refer to its light resistance and weather resistance in a certain field. In addition, to measure the light resistance and weather resistance of titanium dioxide, we should ensure that the weather resistance of its application carrier is better than that of titanium dioxide. The main factors affecting the weather resistance index of titanium dioxide are its chemical composition, chemical form of coating material, crystal structure, application formula and so on.

Gloss factor

The gloss of titanium dioxide is an important index to measure the application performance of titanium dioxide. Generally, titanium dioxide has no luster, and it is meaningless to refer to its gloss alone. This index is meaningful only after titanium dioxide is applied to relevant application fields (such as automotive paint, ink, profile, masterbatch, etc.).

Volatile factor

The volatile matter of titanium dioxide is actually the water content. Because there are high energy and hydroxyl groups on its surface, its surface must always adsorb certain water to reduce its surface energy. The amount of adsorbed water is related to the organic treatment of titanium dioxide surface and the humidity and temperature of the surrounding environment. The volatile content of titanium dioxide powder can not determine the quality of the product, but depends on its application system. In general, the volatile content of aqueous system has little impact on the application, but for oily system and polyolefin system, the lower the volatile content is, the better, because the high volatile content will affect its dispersion performance in the system and product quality.

Dispersive factor

Dispersity is also called abrasive dispersity or abrasive wettability. When used in water as medium, it is called water dispersity, and when used in solvent and other coating systems, it is called oil dispersity. Dispersion index is an important application index of titanium dioxide. The dispersion not only affects the achromatic power, hiding power, oil absorption and other indicators of titanium dioxide pigment, but also affects the gloss and weather resistance of coating film-forming or profile forming. When grinding and dispersing in the coating factory, the dispersion directly affects the length of grinding and dispersing time, which is one of the important economic indicators in coating production. Moreover, if the grinding time is too long, it will increase equipment pollution and worsen the whiteness of products. In the production of plastic masterbatch or profile, the dispersion directly affects the cycle of replacing the head screen and the performance of the final product.

Main precautions in the application of titanium dioxide

Stability of quality

The stability of product quality is very important to any enterprise. Because the quality stability of titanium dioxide is directly related to the product quality stability of its downstream users. If some indexes of titanium dioxide are unstable, even if a certain index of titanium dioxide has been greatly improved, this is also the product that downstream users do not want, because downstream users must adjust the formula according to the changes of quality indexes of titanium dioxide in order to stabilize their product quality, otherwise the product quality will have problems. Therefore, this problem is of great concern to users.

Choose suitable titanium dioxide
It is very important to select titanium dioxide products suitable for this application field. At present, there are thousands of titanium dioxide models in the market, which are mainly divided into general type and special type. As the name suggests, general-purpose products are applicable in many fields, but there must be a certain gap between them and special-purpose products in a specific application field. Titanium dioxide for Plastic Color Masterbatch must be changed from unique hydrophilicity to hydrophobicity. Water based and oil-based coatings and plastics cannot be shared because of their different properties. If the special products used well in the plastic industry are used in the field of water-based applications, there will be major quality problems. Therefore, titanium dioxide manufacturers should know which field their products are suitable for and not suitable for. It is necessary to avoid recommending your products to application fields that are not suitable for our products, which will effectively avoid many quality objections. Downstream users of titanium dioxide should also have a certain understanding of the products recommended by titanium dioxide manufacturers. You can know whether there are enterprises in the same industry and how they are used; Moreover, a small test must be conducted before the new product enters the factory to determine whether the product is suitable, so as to reduce unnecessary economic losses caused by improper product selection.