1. What is fluorescence
Fluorescence is just a physical phenomenon of cold luminescence. It is absorption a certain wavelength of incident light (usually ultraviolet or x-rays) gives off a longer wavelength of outgoing light (usually visible light) . For example, absorbing blue light emits green light, absorbing green light emits red light, and most commonly, absorbing ultraviolet light emits blue light. Once the incident light stopped, the phenomenon of luminescence will disappear.
2. What is a fluorescent whitening agent
Fluorescent Whitening Agents, or Fwa, are a class of organic compounds that absorb ultraviolet light and thus emit blue or blue violet light. Fluorescent Whitening agent is a colorless fluorescent dye, under the irradiation of ultraviolet light, can stimulate blue, violet, and yellow light on the substrate complement and have whitening effect, colloquially speaking, fluorescent Whitening agent is the use of optical complementary color to make white or light-colored articles (such as textiles, plastics, paper, etc.) whitening or brightening, it does not have a chemical reaction with the articles, instead, it relies on optical effects to increase the whiteness of objects, using fluorescence to increase the visual sense of whiteness. Therefore, the fluorescent whitening agent also known as optical whitening agent, white fluorescent dyes. Fluorescent brighteners are deliberately manufactured by human beings for the production of fluorescent substances, natural fluorescent substances are not included, the purpose and use is not used for the production of fluorescent substances are also not.
3. What are the types of fluorescent whitening agents
There are many kinds of fluorescent whitening agents. They are commonly divided into fluorescent brighteners for detergents, for textiles, for paper making, for plastics and synthetic materials, and for other uses. According to dissociation properties, fluorescent whitening agents can be divided into non-ionic whitening agents, anionic whitening agents, cationic whitening agents and amphoteric whitening agents.