The main component of titanium dioxide is titanium dioxide. More than 90% of the titanium resources in the world are used to make titanium dioxide. It is currently recognized as the best white pigment in the world and is widely used in industrial production.
The main application areas of titanium dioxide are: coatings, plastics, inks, papermaking, etc. (including cosmetics, chemical fiber, electronics, ceramics, enamels, electrodes, alloys, glass and other fields). In actual production and application, different properties of titanium dioxide raw materials need to be selected according to different industries and product uses in order to achieve high efficiency, low consumption, and low cost, and to ensure that the products produced can meet the quality and practical application requirements.
The editor of this article will introduce the specific properties of titanium dioxide in different application fields of titanium dioxide.
First, let's take a brief look at the composition types and properties of titanium dioxide.
There are two types of titanium dioxide used in industry, one is anatase (A type), and the other is Rutile (R type).
There are many factors that affect the quality and application effect of titanium dioxide. The following indicators are commonly used in industry to measure the properties of titanium dioxide: whiteness, refractive index, hiding power, decolorization, gloss, oil absorption, weather resistance, dispersion Wait.
1 Characteristics of ideal titanium dioxide in coating industry
Coatings made of titanium dioxide have an anatase-type crystal structure that is less dense than a rutile type and a refractive index lower than that of the rutile type, so its hiding power and discoloration power are 20-30% lower than those of the rutile type. Therefore, the coating industry mainly uses rutile titanium dioxide. Anatase titanium dioxide is easy to powder and yellow, and it is generally only used for indoor coatings or primers, and its amount only accounts for 30% of the titanium dioxide used in coatings.
①Whiteness: The whiteness of titanium dioxide will directly affect the appearance of the coating film.
② Hiding power: When the surface of the same area is coated, the greater the hiding power of the titanium dioxide, the thinner the coating film, and the less the amount of paint required, the less the amount of titanium dioxide is required. If the hiding power of titanium dioxide is Decreased, in order to achieve the same hiding effect, the amount of titanium dioxide required will increase, the production cost will increase, and the increase in the amount of titanium dioxide will cause it to be difficult to disperse and evenly aggregate in the coating, and it will also affect the covering of the coating. effect.
③ Light and weather resistance: coatings have high requirements on the weather resistance of titanium dioxide, especially outdoor surface coatings, which require high light weather resistance or ultra-high light and weather resistance type titanium dioxide.
④ Dispersibility: Poor dispersibility of titanium dioxide will directly affect its optical properties such as decolorization, hiding power and surface gloss in coatings, and it will also affect the storage stability, flowability, leveling, and durability of coatings. Application performance such as chemical resistance, corrosion resistance and electrical conductivity, in addition, it will also affect the production cost of coatings, because the energy consumption of grinding and dispersing operations is high, accounting for most of the total energy consumption in the coating manufacturing process, and the loss of instruments and equipment is large.
2 Characteristics of ideal titanium dioxide in the plastics industry
① Strong decoloring power: The decoloring power determines the amount of titanium white used in the same plastic product color. The strong decoloring power is the low addition amount. Compared with the use of titanium dioxide with poor decoloring power and high addition amount, it is more likely to reduce production. cost.
②Whiteness: determine the appearance of light-colored (white) plastic products with the same titanium content, and titanium dioxide with different whiteness can be reasonably selected according to the appearance requirements of plastic products.
③ High dispersibility: The greater the amount of pigments and fillers added in plastic products, the smaller the proportion of resin, the higher the strength of plastic products, and the lower the production cost, but the worse the compatibility and lubricity between the components ; This will easily lead to rough surface and uneven color of plastic products. The use of titanium dioxide with good dispersion can reduce production costs and improve the smoothness and gloss of the product.
④ Strong hiding power: Titanium white with good hiding power produces lighter and thinner plastic products.
⑤ Good temperature and weather resistance: The production and processing of plastic products generally need to be carried out in a high temperature molten state. This requires that the titanium dioxide used has good temperature and weather resistance, otherwise it will cause pigment migration and pores, which will affect the plastic products. Surface quality and physical strength. In addition, outdoor plastic products and plastic doors and windows must have anti-ultraviolet performance, and the light and weather resistance of titanium dioxide must be guaranteed.
⑥Dry powder has strong fluidity: Most plastic products are processed in assembly lines during the production and processing process. If some powders have poor fluidity, they will stagnate or block the screen holes on the conveyor belt, affecting the quality of plastic products.
3 Characteristics of ideal titanium dioxide in ink industry
In ink production, the specific quality requirements of different types of ink products for titanium dioxide are different, but because rutile titanium dioxide has better hiding power than anatase titanium dioxide, rutile titanium dioxide is generally used in ink production. .
①Good whiteness: The ink made of titanium dioxide with good whiteness is durable and not yellowing, which can keep the color of printed products bright and vivid under various environments.
②Good decoloring power and hiding power: In order to get the colorful and beautiful effect of printed materials during the printing of gravure composite film ink, it is necessary to use white ink as the base and then perform color printing. This requires titanium dioxide to have good tinting power and hiding power, otherwise the effect will be poor.
③ High refractive index: The higher the refractive index of titanium dioxide, the stronger the tinting power, and the stronger the ink hiding power.
④ The particle size is suitable and uniform: the size of the titanium dioxide particles should be controlled to 0.2 ~ 0.4μm, which is equivalent to about 1/2 of the visible light wavelength, so as to obtain high scattering ability and make the color appear whiter. When the particle size is less than 0.1 μm, the crystal is bright. If the particle size exceeds 0.5 μm, the ability of the pigment to scatter light will be reduced, and the whiteness of the ink will be affected.
⑤ Good light and weather resistance: If it is printed for a long time, it must be ensured that the titanium dioxide has good light and weather resistance, otherwise the ink will turn yellow and powder.
⑥ Good heat resistance: For baking type iron printing inks, the baking temperature during printing can reach about 180 ° for up to 2 hours. Such printing conditions require the titanium dioxide in the ink to have excellent heat resistance, otherwise the white ink will turn yellow, lose its luster at high temperatures, and even cause the printed matter to be scrapped.
⑦Good anti-emulsification and hydrophobicity: In the printing process of offset printing inks, the principle of "oil and water repellence" is usually used to complete the printing process during offset printing. Therefore, titanium dioxide for offset printing inks must have good demulsibility and hydrophobicity.
Oil absorption: With the improvement of printing speed and technology, inks with reduced viscosity are required, and the oil absorption of titanium dioxide becomes the key. Under the condition that the color density is not changed, try to reduce the oil absorption as much as possible, which is conducive to the formulation of viscosity-enhancing inks.
4 Characteristics of ideal titanium dioxide in textile and chemical fiber industry
Titanium dioxide for chemical fiber is mainly used as a matting agent. Because anatase is softer than gold-red, anatase is generally used. Titanium dioxide for chemical fiber generally does not require surface treatment, but some special varieties need surface treatment in order to reduce the photochemical effect of titanium dioxide and prevent the fiber from degrading under the photocatalytic effect of titanium dioxide.
①Strong chemical stability: The selected titanium dioxide must not react negatively with the raw materials of synthetic fibers, otherwise impurities will be generated and the fiber quality will be affected.
② Good temperature and weather resistance: The vast majority of chemical fiber production and processing processes need to go through a high temperature environment, so the titanium white used must have excellent temperature and weather resistance, and cannot be decomposed, discolored or reacted to produce impurities at high temperatures (260-300).
③ Good dispersibility: ensure that the titanium dioxide can be evenly distributed in the polymer
④ Fine and uniform particles: If the titanium dioxide used contains coarse particles, it will damage the fiber strength, even cause hazards such as broken filaments, blocked spinnerets and frequent replacement of filters, which will affect the production process, cause loss of raw materials and increase costs.
5Characteristics of Ideal Titanium Dioxide in Paper Industry
Titanium dioxide is mainly used in high-grade paper and thin paper. Adding titanium dioxide to paper can make the paper have better whiteness. For papers with high ash content and anti-aging requirements, rutile titanium dioxide must be used, and papers that require opacity, such as Bible paper and banknotes, generally use anatase titanium dioxide.
① Strong hiding power: the ability of paper containing the same titanium dioxide to cover the background color, this index determines the cost-effectiveness of titanium white. To put it simply, titanium white with high hiding power is generally expensive, but the amount used is small, so the cost of titanium white per ton of paper may be lower; although titanium dioxide with low hiding power is low in price, it is used in large amounts, resulting in per ton. The cost of titanium white in paper increases.
②Whiteness: The whiteness of titanium white determines the appearance of the paper after molding. The titanium white powder filler can be selected according to the whiteness of the specific paper.
③ Good wettability: Highly wettable titanium dioxide can reduce its viscosity in the pulp system and reduce the tendency of titanium dioxide to self-agglomerate, reduce the surface tension of titanium dioxide in the pulp system, and improve the surface wettability of titanium dioxide. Ensure that the titanium dioxide is dispersed quickly and evenly in the pulp.
④ High paper retention rate: In order to ensure the uniformity and opacity of the paper, the titanium dioxide must exist uniformly and stably in the entire papermaking process. The higher the retention rate of titanium dioxide, the better the permeability of the paper, and the less titanium dioxide needed to achieve the same use effect.
6 Characteristics of Ideal Titanium Dioxide in the Cosmetics Industry
① Suitable particle size: In sunscreen products, the ability to resist ultraviolet rays is particularly important. The size of titanium dioxide particles often determines the strength of the ability. When the particle size is equal to or less than half of the wavelength of the light wave, the titanium dioxide has the strongest light reflection and scattering ability, and the best shielding effect. Because the wavelength of ultraviolet rays is between 190-400nm, the particle size of titanium dioxide cannot be greater than 200nm, and preferably not greater than 100nm. But it is not that the smaller the particles, the better. Generally speaking, in the particle size range between 30-100nm, the effect of shielding ultraviolet rays is the best. The rutile type has a strong ability to reflect and scatter ultraviolet rays, but has a weak absorption power, so rutile is the main source of titanium dioxide for sunscreen cosmetics.
②Whiteness and hiding power: For example, foundation makeup powders and other foundation makeup products that have high concealing and whitening effects have higher requirements for the whiteness and hiding power of titanium dioxide. Anatase titanium dioxide has a good whiteness, so if it is used only as a basis for white additives, anatase titanium dioxide can be used; however, the hiding power and light resistance of anatase are far inferior to those of rutile, which can be flexibly selected according to demand.
③ Low content of harmful heavy metals: cosmetics directly contact human skin, if there are harmful heavy metals exceeding the standard will cause serious adverse consequences, it is necessary to ensure that titanium dioxide is non-toxic and harmless, high-quality cosmetics will use food-grade titanium dioxide.
7 Characteristics of Ideal Titanium Dioxide in Rubber Industry
Titanium dioxide for rubber, such as rubber shoes, rubber flooring, gloves, sports equipment, etc., is generally anatase type. However, a certain amount of rutile products are often added to the production of automobile tires to enhance their resistance to ozone and ultraviolet rays.
①Good heat resistance: The rubber production process requires high temperature environment. Titanium dioxide should have good heat resistance. It should be vulcanized at 110 ℃ to 170 ℃ without yellowing.
②Good light and weather resistance: The anti-aging agent used in white and light-colored rubber products has weak protection and is easy to age under light. Titanium dioxide has a strong ability to absorb the most destructive ultraviolet rays in the sun and has good light and weather resistance Titanium dioxide can strengthen the anti-aging ability of rubber products, not easy to crack and discolor.
③ Good stability: Good stability to sulfur and other additives, should not have adverse effects on the performance of rubber products.
8Ideal titanium dioxide characteristics of enamel industry
① Strong refractive index and decoloring power: Titanium dioxide is used as the strongest opacifying agent in porcelain glaze. The opacifying strength of porcelain glaze is related to the refractive index of the opacifying agent. Titanium dioxide has a high refractive index, so that the titanium white porcelain glaze coating can be thin and white.
② High whiteness and purity: If impurities such as Fe₂O₃ and Cr₂O₃ are contained, the product will produce yellow shading.
③ The particles are fine and uniform: it is easy to mix with other materials during melting and easy to control during melting in the melting process.
Enamel pots are corrosion-resistant, abrasion-resistant, heat-resistant, beautiful and lightweight, and are widely favored by consumers.