What fields are optical brighteners used in?

■Paper
Whitening of paper is usually carried out in papermaking links such as beating, sizing, and surface coating. The method of directly adding the optical brightener to the pulp and then making paper is mostly used. It is also very economical and practical to add fluorescent whitening agent to the surface sizing solution for paper whitening. The whitening agent tends to stay on the surface of the paper, and the whiteness of the paper is easy to adjust.
In the field of food packaging paper, there are stricter regulations. For example, popcorn buckets, etc., must be made of food-grade white cardboard. In order to reduce costs, some businesses use recycled waste paper for production, but because the quality of the pulp is not good enough, they have to add a large amount of fluorescent whitening agent to achieve a beautiful effect. Under the UV analyzer, the popcorn bucket with a large amount of fluorescent whitening agent will appear bright and dazzling blue, while the qualified packaging made of food-grade white cardboard will appear natural milky white. Therefore, when people buy paper food packaging such as disposable paper cups, they should pay attention that the whiter the paper, the cleaner it is.
■Detergent
In the process of wearing many clothes, due to various reasons (including the partial loss of optical brightener  added in the dyeing and finishing stage), they will become old and yellow, such as the whiteness of white clothes will decrease, and the colored clothes will no longer be vivid. Although surfactants and builders play a role in decontamination in detergents, optical brightener themselves have no decontamination function. However, under the same decontamination function, the clothes washed with a laundry detergent with an appropriate fluorescent whitening agent will appear brighter in color.
■Textiles
Optical brighteners have been used in the field of textile fibers for nearly 70 years. Fibers are divided into three categories: cellulose fibers, protein fibers and synthetic fibers. Therefore, when using optical brightener , it is necessary to understand the chemical composition and physical properties of fibers in order to select a suitable fluorescent whitening agent. The fluorescent whitening agent used in the textile fiber industry should meet multiple conditions, such as no damage to the fiber, and good affinity with it; good water solubility; good chemical stability; good uniform whitening property Wait.
■Other
With the vigorous development of the plastics industry, people's requirements for the appearance and performance of plastic products are constantly increasing, so the use of optical brightener  to improve the appearance of plastic products has attracted more and more attention. In addition, optical brightener is also used in pearl whitening, paint, leather and other fields.