Optical Brightener

Overview

　　 Fluorescent brightener(Optical brightening agent) is a kind of fluorescent dye, or white dye, and it is also a kind of complex organic compound. Its characteristic is that it can excite incident light to produce fluorescence, so that the dyed material obtains a sparkling effect similar to fluorite, so that the material seen by the naked eye is very white, achieving a whitening effect.

It can absorb invisible ultraviolet light (the wavelength range is about 360-380 nm), and convert it into longer-wavelength blue or violet visible light, so it can compensate for the undesired yellowish color in the matrix, and reflect more than the original incident More visible light with a wavelength in the range of 400-600 nm makes the product appear whiter, brighter and more vivid. In daily life, there are many opportunities to be exposed to fluorescent agents. As long as it does not exceed a certain standard, it will bring many benefits to our lives. If too much contact with it, it will cause harm to the human body. Scientific experiments have shown that after being absorbed by the human body, fluorescent agents are not easily decomposed like ordinary chemical components. If there is a wound on the body, combining it with the protein in the human body will hinder the healing of the wound, and it is very difficult to remove it, only through the enzyme decomposition of the liver, which undoubtedly increases the burden on the liver, according to medical clinical experiments. Fluorescent substances can make cells variability, and mutated fluorescent substances can receive electromagnetic waves or radiation with visible light shorter than ultraviolet wavelengths, and convert these energy into visible light with longer wavelengths. In this way, if excessive exposure to fluorescent agents, there may be potential carcinogens. Although it has not been proved that the absorption of fluorescent agent will cause harm to human body, but fluorescent agent is listed as one of the potential carcinogens.

Brightener

　　 A class of organic compounds that can improve the whiteness of fiber fabrics and paper. Also known as optical brightener and fluorescent brightener. Fabrics are often yellow because they contain colored impurities. In the past, chemical bleaching methods were used to decolorize. Nowadays, brighteners are added to products. Its function 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, and improves the whiteness of the product under sunlight. Brighteners have been widely used in textiles, papermaking, washing powder, soap, rubber, plastics, pigments and paints.

The brightener has a cyclic conjugated system in chemical structure, such as: stilbene derivatives, phenylpyrazoline derivatives, benzimidazole derivatives, benzoxazole derivatives, coumarin derivatives , And naphthalimide derivatives. Among them, the production of stilbene derivatives is the largest. For example, 4,4'-bis(4,6-diphenylaminotriazinyl-2-amino) stilbene-2,2'-disulfonate sodium salt is a kind of A brightener with a wide range of uses, the trade name is brightener TA. Such brighteners have been widely used in papermaking, textiles, washing powder and soap industries. Brightener AD is a derivative of phenylpyrazoline, the scientific name is 1-(p-methylsulfonylphenyl)-3-(p-chlorophenyl)pyrazoline, mainly used in acrylic fiber spinning, textiles and plastics The product is in production. 4-Methyl-7-dimethylamine coumarin belongs to the oxaphthalone compound and can be used in products such as wool fabrics, nylon fabrics, soaps and detergents.

　　 The largest domestic fluorescent whitening agent is VBL, CXT and liquid whitening agent for papermaking. Generally, brighteners are divided into two categories, one is water-soluble brighteners, and the other is water-insoluble brighteners. The former type can be used as a brightener for paper, paint, washing powder and cotton fabric. Alternatives can be used for whitening chemical fibers, plastics, etc.

Classification of brighteners

According to chemical structure, it can be divided into five categories: ①Stilbene type, used in cotton fiber and some synthetic fibers, papermaking, soap making and other industries, with blue fluorescence; ②Coumarin type, having the basic structure of coumarone, Used for celluloid, polyvinyl chloride plastics, etc., with strong blue fluorescence; ③Pyrazoline type, used for wool, polyamide, acrylic and other fibers, with green fluorescence; ④Benzoxazide type, used It has red fluorescence in acrylic fibers and plastics such as polyvinyl chloride and polystyrene; ⑤phthalimide type, used in polyester, acrylic, nylon and other fibers, has blue fluorescence.

Application of optical brightener

　　 fluorescent whitening agent is used to synthesize washing powder. Its appearance whiteness, cumulative washing whiteness, chlorine bleaching resistance, color tone, and dispersibility are more than the same type of whitening agent. It is an ideal whitening agent for washing powder. It is also suitable for whitening and brightening various types of cellulose fibers.