First, the color
Color is an important technical indicator for marking pigments. Titanium dioxide is known as the “king of white pigments”, 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 levels. Of course, the shade depends on the chemical composition, but the more important and often decisive factor is its Particle shape, size, particle size distribution, crystal form, impurity content, etc.
Second, the covering power
The optical nature of hiding power is caused by the difference in refractive index between the pigment and the medium in which it exists. The refractive index of rutile type titanium dioxide is 2.71 and that of anatase type is 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 the above two reasons to reduce the intensity of the incident light, and the masking phenomenon occurs. 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.
Third, tinting strength
Tinting strength is an important characteristic index of titanium dioxide, that is, after titanium dioxide is mixed with another pigment, the ability of the mixture to display its own pigment can be obtained. That is to say, for a white pigment, after it is mixed with a dark pigment, the lighter the color of the mixture, the stronger its tinting power (achromatic power).
Fourth, oil absorption
Oil absorption is also one of the important pigment properties of titanium dioxide, because it relates to the filling state of titanium dioxide in the vehicle and can explain its dispersion performance in the medium. In the paint industry, it is used to estimate the consistency of the paint before mixing, to guide the formulation of the paint, and to preliminarily estimate its pigment volume concentration (pvc).
Fifth, chemical composition
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., its application The performance effect is also great, such as weather resistance, dispersibility and so on.
Sixth, light and weather resistance
The light resistance and weather resistance of titanium dioxide are important indicators to measure the application performance of titanium dioxide, and it is meaningless to refer to its light resistance and weather resistance alone. This indicator is meaningful only after titanium dioxide is applied to relevant application fields (such as automotive paint, profiles, etc.). Therefore, the light resistance and weather resistance of titanium dioxide refers to its light resistance and weather resistance in a certain field. In addition, to measure the light resistance and weather resistance of titanium dioxide, it is necessary to 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, etc.
The gloss of titanium dioxide is an important indicator to measure the application performance of titanium dioxide. Usually titanium dioxide has no gloss, and it is meaningless to simply refer to its gloss. This indicator is meaningful only after titanium dioxide is applied to relevant application fields (such as automotive paints, inks, profiles, masterbatches, etc.).
Eighth, volatile matter
The volatile matter of titanium dioxide is actually the water content. Because of the high energy and hydroxyl groups on its surface, its surface always has to adsorb a certain amount of water to reduce its surface energy. The amount of adsorbed water is related to the organic surface treatment of titanium dioxide and the humidity and temperature of the surrounding environment. The level of volatile content of titanium dioxide cannot determine the quality of the product, it depends on its application system. In general, the level of volatile content in water-based systems has little effect on the application, but for oil-based systems and polyolefin systems, the lower the volatile content, the better, because high volatile content will affect its dispersion performance in the system and products. quality.
Dispersibility, also known as grinding dispersibility or grinding wettability, is called water dispersibility when used in water as a medium, and oil dispersibility when used in solvent and other coating systems. The dispersibility index is an important application index of titanium dioxide. The quality of dispersibility not only affects the achromatic power, hiding power, oil absorption and other indicators of titanium dioxide pigments, but also affects the gloss and weather resistance of coating film formation or profile forming. When grinding and dispersing in a paint production plant, the quality of dispersibility directly affects the length of grinding and dispersing time, which is one of the important economic indicators in the production of paints, and if the grinding time is too long, it will increase equipment pollution and make the product whiteness. Difference. In the production of plastic masterbatch or profiles, the quality of dispersion directly affects the replacement cycle of the machine head screen and the performance of the final product.
Post time: Sep-22-2022