Fluorescent whitening agent can whiten, and titanium dioxide can also whiten. What is the difference between the principle of fluorescent whitening agent and titanium dioxide, and what is the relationship 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, etc. Also known as optical brightener, fluorescent brightener. Fabrics are often yellow because of color impurities. In the past, chemical bleaching was used to decolorize them. Now, fluorescent brighteners are added to the products. The function of the fluorescent whitening agent is to convert the invisible ultraviolet radiation absorbed by the product into violet blue fluorescent radiation, which complements the original yellow light radiation to white light, and improve the whiteness of the product under sunlight.
Fluorescent brighteners have been widely used in textiles, paper making, washing powder, soap, rubber, plastics, pigments and paints. Fluorescent whitening agents are generally divided into two categories, one is water-soluble whitening agents, and the other is water-insoluble whitening agents. The former can be used as whitening agent for paper, paint, washing powder and cotton fabric, and the other can be used as whitening agent for chemical fiber and plastic.
Introduction to titanium dioxide:
Titanium dioxide is a very good white pigment, and it has the functions of reinforcement, anti-aging, filling and covering. It is widely used in rubber products and plastic pipe profiles. Titanium dioxide is added to white and colored rubber products, which is resistant to sunlight, cracking, discoloration, high elongation and acid and alkali under sunlight. Titanium dioxide for rubber is mainly used for automobile tires, rubber shoes, rubber floors, 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 light with a wavelength less than 410nm. It has good heat resistance, weather resistance and strong UV shielding effect. It is one of the important raw materials to improve the weather resistance of profiles. Because the addition of titanium dioxide in polymer materials will increase the viscosity, reduce the fluidity, and increase the torque, resulting in processing difficulties, but generally only adding titanium dioxide can not meet the requirements of whiteness, so we recommend customers to add a small amount of fluorescent whitening agent.
Differences between fluorescent whitening agent and titanium dioxide:
1. Some functions are different: the whitening agent is a single whitening, brightening and brightening agent, while titanium dioxide is a pigment, which plays a filling and covering role in addition to whitening.
2. Different dosage: the dosage of fluorescent whitening agent is 0.01%~0.03%, and the dosage of titanium dioxide is about 2%.
3. The whitening principle is different: titanium dioxide is a pigment, which can whiten the background color and is often used as a base. The whitening agent can make the product white and bright by absorbing ultraviolet light and emitting fluorescence.
4. Price difference: the price of fluorescent whitening agent is relatively expensive, while the price of titanium dioxide is relatively cheap.
Relationship between fluorescent whitening agent and titanium dioxide:
Fluorescent whitening agent and titanium dioxide have different whitening principles, and they are often used together in the actual production process of many products, known as the golden partner. Titanium dioxide is generally used as the base color for whitening, and it can also cover some other color components to increase the whiteness. This is an effect that optical whitening can not achieve, but the disadvantage is that the whiteness value is not high. It is good when the zui reaches more than 80, and the dosage is also large. Fluorescent whitening agent is just to make up for this defect. When the dosage is very small, it can completely improve the whiteness value of the product to more than 95 in an instant through optical complementary color whitening, which is also irreplaceable by titanium dioxide. For example, customers who make porcelain white plastics usually combine the two whitening methods to achieve this ideal effect.