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 the 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, scientific name 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 wool fabrics, nylon fabrics, soaps and detergents.
The largest domestic fluorescent brighteners are VBL, CXT and liquid brighteners for papermaking. Generally, brighteners are divided into two categories, one is water-soluble brighteners, and the other is water-insoluble brighteners. The former can be used as a brightener for paper, paint, washing powder and cotton fabric. Alternatives can be used for whitening chemical fibers, plastics, etc.
Brightening agent classification:
According to the 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 Used in acrylic fibers and other plastics such as polyvinyl chloride and polystyrene, it has red fluorescence; ⑤phthalimide type, used in polyester, acrylic, nylon and other fibers, has blue fluorescence.