Definition of fluorescent whitening agents
Fluorescent brighteners, sometimes referred to as optical brighteners, are colorless to light colored organic compounds. Absorb the mainly invisible ultraviolet light within the range of 300-400 nano meters (nm) and convert it into visible ultraviolet to blue fluorescent light to produce a brighter and fresher appearance. Their design is to achieve brighter colors or cover yellowing in plastics, paint, pigments, ink, photo processing solutions, and fibers.
Classification of fluorescent brighteners
1) Classification by application
Here, we can use the classification of optical brighteners as a general guide, and we can know that if we choose the correct type of optical brightener for our application
Optical brighteners for detergents
Including optical whitening agents CBS-X, DMS/AMS
Optical whitening agents for paper
Including optical brightener PC, BBU/BBU, VBL/VBL l
Optical brighteners for optical fibers and textiles
Including optical whitening agents 4BK, ER-I, ER-II, PF/DT, BA, CXT, SWN
Plastic optical brightener
Including optical brighteners OB, OBR, OB-1, KSN, KCB, KSB, FP-127, CBS-127, PF
2) Classified by chemical structure.
1. Styrene type, blue fluorescent, used in industries such as cotton fiber, synthetic fiber, paper making, soap, etc.
2. Coumarin type, with a coumarinone structure and strong blue fluorescence, used in celluloid and PVC plastics.
3. Pyrazoline, green fluorescent, used in wool, polyamide, and acrylic fibers.
4. Benzo nitrogen type with red fluorescent light, used for acrylic, PVC, PS.
5. Phthalenephthalimide, blue fluorescent, used for polyester, acrylic fiber, cotton fiber.
3) Classification of fluorescent brighteners for plastics
1. Benzoxazole has the following chemical structure, and OB, OB-1, KSN, and KCB all belong to this chemical structure
2. Benzcoumarin, with the following chemical structure
3. Diphenylene biphenyls, with the following chemical structure, CBS is related to this chemical structure