The difference between fluorescent brightener and dyestuffs:
Fluorescent brightener or fluorescent whitening agent on the fabric treatment is similar to dyes, but it is different from the general nature of dyes. The main differences are as follows.
① The amount of color given by dyestuff to fabric dyeing is directly proportional to the dosage of dyestuff. While for fluorescent brightener, when it is used in low dosage, its whiteness is directly proportional to the dosage. When the dosage exceeds a certain limit, the increasing dosage will not give improvement in whiteness, instead, it will make the fabrics yellow. This “certain limit” is called the peak point or the yellowing point.
② The deeper the dye is, the more it can cover the fabric stains. The better the whitening effect of the fluorescent brightener is, the more obvious the stains will be.
③ Fluorescent brightener itself and its aqueous solution in daylight fluorescence effect is not obvious. It shows a strong whitening effect only when it is dyed on the fiber.
The classification of fluorescent brighteners according to ionic type
According to their different properties and performance, the fluorescent brighteners can be divided into cationic type, anionic type, and non-ionic type.
Cationic and anionic type fluorescent brightener is generally a yellowish solid powder, easily soluble in water, in water is a slightly yellow fluorescent solution and can be adsorbed by the fiber. They have excellent directness and leveling properties to fibers, and are more convenient to use. Ionic whitening agent can not be applied in the same bath with dyes or auxiliaries of the opposite ionic type, otherwise it will reduce the whitening effect or even lose the whitening effect completely. In addition, the pH of the medium has a great influence on the whitening effect of the ionic whitening agent.
Non-ionic type fluorescent brightener is a class of insoluble in water or slightly soluble in water compounds, its commercial dosage forms are dispersed suspension, organic solution, and ultra-fine powder. It can not only be used for the whitening of fabrics, but can also be directly added to the synthetic fiber resin in the original liquid, becoming a “permanent whitening agent”.
The main applications of fluorescent brightener
Fluorescent brightener has a wide range of applications, the demand is also increasing. It has penetrated various industrial sectors and is closely related to our lives. Their main uses are as follows:
- Used for whitening and brightening various textile products.
- Used for synthetic detergents to increase the washing effect of detergents.
- Used for whitening paper to improve the whiteness and commodity value of paper.
- Used for whitening plastics to increase their aesthetics.
- Used for whitening paints or coatings to increase the whiteness and vividness.
