Customers often look for "fluorescent brighteners". So, does this kind of additive really exist?
Since it is a brightener, let's start with the concepts of "whitening" and "bleaching".
"Bleaching", my understanding is to wash the face, whether it is a facial cleanser or a facial cleanser, when used on the fiber is to remove the coloring substance from the fiber by reducing or oxidizing chemical substances. For example, the commonly used hydrogen peroxide belongs to oxidative bleaching, while sodium hydroxide is a reducing bleaching agent.
And "whitening" refers to whitening cream or lotion that looks white after washing the face, and the whitening on the fiber is achieved by fluorescent whitening agent, which is a kind of It absorbs the invisible ultraviolet light in the light and reflects the visible blue light, which is superimposed with the yellow light on the fiber to form a white light, which increases the white light on the fiber and increases the whiteness to the naked eye.
So is there any brightener without fluorescence?
If it does not contain fluorescence, which means that the substance cannot absorb ultraviolet light in the light and emit blue light, it cannot be regarded as a fluorescent whitening agent. So what is the whitening principle of this non-fluorescent whitening agent? Is a bleach replaced the concept?
In fact, in the printing and dyeing auxiliaries market, scouring enzymes without enzymes have been selling well for so many years, and soap washing enzymes without enzymes are also in use.
Some people will say that what can be sold is successful, maybe!
Let's spread a little knowledge of fluorescent whitening agent:
1. The discovery of fluorescent dyes was first discovered in 1921. Lagorio discovered that fluorescent dyes have the ability to convert invisible ultraviolet light into visible fluorescence, and inferred that the whitening of natural fibers can be improved by aqueous solutions of fluorescent substances.
2. In 1929, Krais put yellowing viscose fiber into the solution of 6,7-dihydroxycoumarin glycoside, and the whiteness of viscose fiber was greatly improved.
3. Types of fluorescent whitening agent on different fibers:
Cellulose fiber: mainly stilbene, such as commonly used CBS (stilbene biphenyl) and 33# (bistriazine amino stilbene).
Polyester fiber: phthalimide type
Acrylic fiber: benzoxazide type, phthalimide type, pyrazoline type
Nylon: pyrazoline type
Protein fibers such as wool: pyrazoline type
4. Fluorescent brighteners were originally classified as printing and dyeing auxiliaries in China, and then classified as dyes (the brighteners contain dyes to tint the light), and then they were classified as a large group with the increase in dosage class.
5. Detergents, paper and textiles are the three major users of optical brighteners.