Paper for teaching auxiliary materials refers to the general term for books, exercise books, and test papers that students need to use in the process of learning, including offset printing paper, copy paper, and writing paper. At present, in the market of paper for teaching auxiliary materials, the consumption guide is that the whiter the paper, the better, the higher-end it is, This is a wrong consumption concept.
According to the application survey, in order to improve the visual whiteness of the paper used for teaching auxiliary materials, paper mill enterprises use a large amount of fluorescent whitening agents, which causes not only environmental pollution but also damages human health, especially for young people in the learning and growing period.
Fluorescent whitening agent, also known as white dye, is a color conditioning agent with brightening and whitening effects, widely used in textiles, washing, papermaking, plastics, leather, and other industries. Fluorescent whitening agents can absorb invisible ultraviolet light (wavelength range of about 60-380 nm) and convert it into blue or violet visible light with longer wavelengths, thus compensating for the unwanted yellowishness in the matrix, and at the same time reflecting a higher wavelength than the original one. So that the dyed material appears white and bright. When it is applied to paper, it can make people visually feel that the paper is whiter, but it is only a visual effect. In fact, it does not dye or bleach the paper but is only a result of optical action.
In the process of papermaking, in order to improve the visual whiteness of the paper, a large amount of fluorescent whitening agent is used, and its additional amount can even reach more than 20 kg/ton of paper so that the whiteness of the paper can be directly increased from about 85% to more than 104%. The amount of fluorescent whitening agent added to the paper is a positive example of the whiteness of the paper. Within a certain range, the more the amount of fluorescent whitening agent added, the higher the whiteness of the paper.
At the end of 2010, the state issued the "Maximum Limit of Brightness (Brightness) of Paper and Cardboard" GB/T 24999-2010, which has clearly stipulated the maximum whiteness value of various paper types, offset paper brightness (whiteness) ≤ 90.0%, copy paper Brightness (whiteness)≤95.0%, writing paper brightness (whiteness)≤85.0%. Its purpose is to limit the whiteness of the paper and the use of fluorescent whitening agents by enterprises.
People often come into contact with fluorescent whitening agents in their daily life activities, which generally do not cause harm to the human body. However, if they are exposed to excessive amounts, because fluorescent whitening agents are not as easily degraded as general chemicals, over time, it will have many harmful effects on the human body and greatly reduce the human immune system. Fluorescent whitening agents bind to proteins in external wounds, slowing wound healing. Once it enters the human body, the fluorescent whitening agent can mutate human cells, and its toxicity accumulates in the liver or other important organs, which will become a potential carcinogenic factor and cause cancer.
Offset paper/woodfree paper has four colors: super white, nature white, cream color, and yellow color. The specific whiteness will depend on the product's technical data sheet. The specific whiteness will depend on the product's parameter table. For the sake of the reader's health and eyesight, it is recommended to use suitable white offset paper for learning materials and books.
Post time: Jun-20-2022