Teach you to correctly understand the fluorescent whitening agent

01What is an optical brightener?

Fluorescent whitening agent, also known as fluorescent agent or fluorescent bleach, is a fluorescent dye (white dye) that is mainly used in textile, paper, plastic and washing industries.

The principle of the action of fluorescent whitening agent: Under the irradiation of ultraviolet light, fluorescent whitening agent will absorb UV and emit blue fluorescence (about 410-480nm wavelength). The yellow reflection is visually offset, so that the surface of the object looks whiter, and it is an optical complementary color and brightening.

02What is the use of fluorescent whitening agent?

A long time ago, people made white objects mainly by traditional bleaching and blueing processes, but they gave people an old feeling. The use of fluorescent whitening agent, its whitening effect is incomparable with blue and white and chemical bleaching. After that, the application range of fluorescent whitening agent is more and more extensive, from the beginning of the textile industry to food and food contact materials. , cosmetics, paper products, cleaning supplies and other industries.

In the food industry, in addition to its obvious whitening effect, fluorescent whitening agents also have certain fresh-keeping and anti-corrosion effects. At present, fluorescent whitening agents are not allowed to be added to food. The use of fluorescent whitening agents in food contact materials can improve the whiteness and brilliance of products, thereby reducing packaging costs.

In the washing and textile products industry, fluorescent whitening agents restore the visual effect of washed white textiles to a white and bright state, which not only improves the appearance, improves the quality and grade, but also enhances its commercial value. Fluorescent whitening agents are becoming more and more important.

In the daily chemical industry, my country's regulations do not explicitly prohibit the use of fluorescent whitening agents in daily necessities and cosmetics, and the addition of an appropriate amount of fluorescent whitening agents is in line with regulations. Careful consumers will find that the optical brightener "disodium distyryl diphenyl disulfonate" is found in the ingredients of some international big-name products.

However, there are also some unscrupulous manufacturers who add excessive fluorescent whitening agents to the mask products for immediate whitening effect, which brings potential safety risks to consumers.

03 Fluorescent substances are called fluorescent whitening agents?

I am often asked that there is fluorescence in the VISIA test or under the illumination of the fluorescent detection pen, and it is suspected that the product has added fluorescent whitening agent.

How to distinguish between fluorescent reaction and fluorescent whitening agent

Fluorescent agents can produce fluorescent reactions, but the substances that can produce fluorescent reactions are not only fluorescent agents.

Fluorescence is generated by the electronic transition of the compound molecule in the ground state to the excited state of high energy orbital after absorbing the energy of ultraviolet or visible light. The molecule in the excited state transitions to the lowest vibrational energy level of the lowest excited state of the molecule through the vibrational relaxation or internal conversion process, and then radiatively transitions back to the ground state, and emits photons to generate fluorescence.

The necessary condition for generating fluorescence is that there are fluorescent groups in its structure, and the fluorescent groups are all groups containing unsaturated bonds. When these groups are part of the conjugated system of the molecule, the compound may generate fluorescence. When the molecular structure contains one or more substituents (such as -OH, -NH2, -COOH), the fluorescence can be enhanced or weakened.

Therefore, fluorescent whitening agents are not necessarily all fluorescent whitening agents! !

Which ingredients in cosmetics will produce fluorescent reaction

From the group of fluorescent reaction, it can be known that there are many kinds of substances that can generate fluorescence. Substances with fluorescent reactions commonly exist in nature, such as shrimp, crabs, jellyfish, fireflies and other animals; the human body also contains fluorescent substances, mainly amino acids, vitamins, proteins, hormones, etc.; soy sauce, Pu'er tea, liquor, black tea, coffee Other fermented foods can also produce fluorescent reactions.

Common ingredients in cosmetics such as salicylic acid, vitamin A, vitamin E, flavonoids, polyphenols, resveratrol, ellagic acid, and plant extracts such as chlorophyll, ginkgo flavonoids, and matrine alkaloids can all be exposed to ultraviolet light. Fluorescence reaction occurs under excitation.

04What are the hazards of fluorescent whitening agent skin care products?

Although the state does not prohibit the addition of fluorescent whitening agents to skin care products, cosmetics manufacturers should comply with relevant national regulations, standards and specifications when selecting raw materials, conduct safety risk assessments on raw materials, and assume responsibility for product quality and safety. .

Therefore, the addition of fluorescent whitening agents to cosmetics is not absolutely safe. Some unscrupulous manufacturers add a large amount of fluorescent whitening agents to their products to achieve instant whitening effects. The duller and yellower the skin, the better the effect. But what harm will long-term use of such products do to us?

The safety research of fluorescent whitening agent on human skin mainly includes the following aspects:

01Adsorption on the skin and percutaneous absorption

Luckhaus conducted related experiments with nude mice: the results show that the epidermis of nude mice is attached with fluorescent whitening agents, which may combine with the stratum corneum of the skin by a certain chemical bond and remain on the skin, thereby affecting the skin to varying degrees. healthy.

02 Skin irritation

Kplinger and Fancher et al. performed skin encapsulation tests on mice with 5-10 g/kg of fluorescent whitening agent solution, and the results showed that local skin had a slight erythema reaction.

03 Skin Sensitization

The Shanghai Institute of Occupational Health and Occupational Disease Prevention and Control reported 65 cases of occupational skin diseases caused by fluorescent whitening agents in garment workers. The report pointed out that these workers have a history of exposure to fluorescent whitening agents, and the number of sick people accounted for 73.9% of the total number of people examined, indicating that fluorescent whitening agents have strong sensitization.

04 Increased probability of facial dermatitis

Guangdong Dermatology Hospital found 7 cases of facial brightening agents detected by Visia skin detection system, including 3 patients with "explosive acne" and 4 patients with sudden aggravation of "melasma". All patients had long-term use of masks containing fluorescent whitening agents.

05What should I do if a fluorescent reaction is found in the test?

First of all, let's analyze, there may be two reasons:

First, the products used are added with fluorescent whitening agents, and long-term exposure to such products will increase the probability of allergic dermatitis;

The second is that the product contains ingredients that can produce fluorescent reactions, such as vitamins, flavonoids, and polyphenols. These are not fluorescent whitening agents and will not cause harm to the skin.

Secondly, if it is found that a fluorescent whitening agent is added to the product ingredients, there is no need to panic if it is a product of a regular manufacturer, and the safety risk is within the controllable range. If it is not a regular manufacturer, it is recommended to give up decisively, do not continue to use it, and re-purchase products from regular manufacturers, or products that do not contain optical brighteners in the product ingredients.

In a word, we can't "talk about fluorescent color change", and look at the fluorescent reaction rationally.