Fluorescent whitening agents can whiten, and titanium dioxide can also whiten. So, what are the differences in whitening principles between fluorescent whitening agents and titanium dioxide, and what are the connections between the two?
Introduction to fluorescent whitening agent: (For details, please refer to the article "What is fluorescent whitening agent?" in this official account)
Fluorescent whitening agent is an organic compound that can improve the whiteness of plastics, fiber fabrics, paper, detergents, and other materials. Also known as optical whitening agent, fluorescent whitening agent. Textiles and other materials often turn yellow due to the presence of color impurities. In the past, chemical bleaching was used for decolorization, but now the method of adding fluorescent whitening agents to products is adopted. The function of fluorescent whitening agents is to convert the invisible ultraviolet radiation absorbed by the product into purple blue fluorescent radiation, which complements the original yellow radiation to become white light, improving the whiteness of the product under sunlight.
Fluorescent whitening agents have been widely used in textiles, papermaking, laundry detergent, soap, rubber, plastics, pigments, and paints. Fluorescent whitening agents are generally divided into two categories: water-soluble whitening agents and water-insoluble whitening agents. The former category can be used as whitening agents for paper, coatings, laundry detergent, and cotton fabrics, while the other category can be used for whitening synthetic fibers and plastics.
Introduction to Titanium Dioxide:
Titanium dioxide is a very good white pigment, which has the functions of reinforcement, anti-aging, filling and covering. It is widely used in rubber products, plastic pipes and profiles. Adding titanium dioxide to white and colored rubber products, it is resistant to sunlight exposure, does not crack or change color, has high stretchability, and is acid and alkali resistant. Titanium dioxide for rubber is mainly used for car tires, rubber shoes, rubber flooring, gloves, sports equipment, etc.
Secondly, titanium dioxide is also a very good light shielding agent. Rutile type (R-type) titanium dioxide has a relative density of 4.26 and a refractive index of 2.72. It can reflect or refract most of the visible light and completely absorb ultraviolet rays with wavelengths less than 410nm. It has good heat resistance and weather resistance, and strong UV shielding effect. It is one of the important raw materials for improving the weather resistance of profiles. Due to the addition of titanium dioxide to polymer materials, viscosity increases, fluidity decreases, and torque increases, making processing difficult. However, generally adding only titanium dioxide does not meet the required whiteness. Therefore, we recommend that customers add a small amount of fluorescent whitening agent.
The difference between fluorescent whitening agents and titanium dioxide:
1. Partial functions are different: whitening agents are single whitening, brightening, and enhancing agents, while titanium dioxide is a pigment that not only whitens but also serves as a filling and covering agent.
2. The usage varies: the amount of fluorescent whitening agent is between 0.01% and 0.03%, while the amount of titanium dioxide is around 2%.
3. The whitening principle is different: titanium dioxide is a pigment that can whiten the base color and is commonly used as a base. Whitening agents absorb ultraviolet light and emit fluorescence to make the product whiter and brighter.
4. Price difference: Fluorescent whitening agents are relatively expensive, while titanium dioxide is relatively cheaper.
The relationship between fluorescent whitening agents and titanium dioxide:
Fluorescent whitening agents and titanium dioxide have different whitening principles and are often used in combination in the actual production process of many products, known as the golden partner. Titanium dioxide is generally used as a base color whitening agent, and can also cover up some other colored components to increase whiteness. This is an effect that optical whitening cannot achieve, but the disadvantage is that the whiteness value is not high. A maximum of 80 or above is already very good, and the dosage is also relatively large. Fluorescent whitening agents are precisely designed to compensate for this deficiency. With a small dosage, optical color correction can instantly increase the whiteness value of the product to over 95, which cannot be replaced by titanium dioxide. For example, customers who make porcelain white plastic usually combine two whitening methods to achieve this ideal effect.