Views: 0 Author: Site Editor Publish Time: 2022-11-21 Origin: Site
Excessive ultraviolet rays will cause serious damage to the skin. The shorter the wavelength of ultraviolet rays, the greater the harm to human skin. Short -wave ultraviolet rays can pass through the leather, and the mid waves can enter the leather. Excessive ultraviolet rays can cause the DNA in the skin cells to cause sunburn and produce pigmentation. If the increasing DNA damage of the epidermal cells increases, it will cause the skin to cause cancer. The research of anti -ultraviolet tidal agents has earlier attracted people's attention. According to the anti -ultraviolet mechanism, it can be divided into: reflective anti -ultraviolet tidal agent, absorbing ultraviolet tidal agent and nano -type anti -ultraviolet tidal agent.
1. Reflective anti -ultraviolet tidal agent
The reflective anti -ultraviolet tidal agent has no absorption of ultraviolet rays, but it only rely on the reflection effect of light to reduce the passage of ultraviolet rays. Also known as ultraviolet shielding agent. Such shielding agents are non -toxic, tasteless, non -irritating, good thermal stability, no decomposition and volatilization, etc. Most of them are metal, metal oxides and salt. Typical ones such as TI02, Zn0, Al02, kaolin, talc Powder, carbon black, iron oxide, leader-oxide, and CAC03, etc., UV reflectivity with wavelengths of 310-400nm can be as high as 95%.
Although the ultraviolet shielding agent has a unique advantage, the air permeability, feel, and washing resistance of the fabric after finishing the fabrics are poor, and the color, fastness and whiteness of the fabric have decreased, and some even cause the human body to have an allergic reaction. Therefore, most of these finishing agents are used for parasols, tents, etc., and are rarely used for clothing fabrics.
2. Absorbing anti -ultraviolet tidal agent
The absorption anti -ultraviolet tidal agent is also called ultraviolet absorbers, which can strongly and selectively absorb high -energy ultraviolet rays. It is released in other lower energy forms (such as long wavelengths of light or calories) to avoid ultraviolet rays to pairs Human skin damage, and the absorbent itself is not damaged by ultraviolet rays. The principle of its absorbers is generally considered to be the transfer of molecular end proton: the hydroxyl group in the structure forms a six -dollar ring in the molecular of the hydrogen bond with the N or O atoms in the nearby structure. The conversion of hydol -type and ketone structure will convert harmful energy into harmless light waves or thermal energy release, and the six -yuan ring is closed and recovered.
UV absorbers as fabrics should have the following conditions
(1) Safe and non -toxic, no allergies to the human body, and cannot threaten human health;
(2) Comply with environmental protection requirements;
(3) Good solvent and washing resistance;
(4) No coloring after absorbing ultraviolet rays;
(5) Do not affect the whiteness, fastness, strength and feel of fabrics and fabric styles of the fabric;
(6) There is a certain degree of stability.
Common ultraviolet absorbers include
1 Twozozoone ketone -type combination
It is the earliest ultraviolet absorbent. The cymbal group and the hydroxyl group in this type of compound molecules form the hydrogen bonding of the molecular intramolecularly, forming a chewing structure. After absorbing ultraviolet rays, the hydrogen bonds oscillated, the stable chelating ring was opened, and the absorbed energy was released in the form of thermal energy. Mutual mutation, which also consumes a part of energy.
Such compounds are: 2-hydroxyl groups. 5 chlorobenolone, 2-4 dihydroxyl diode ketone, etc. Such compounds have multiple hydroxyl groups, and have better adsorption capacity for fibers to absorb 280 to 400nm ultraviolet rays, mainly used for polypropylene, polyester, cellulose and other fiber. However, it has almost no absorption of ultraviolet rays below 280nm, sometimes easy to turn yellow, and the price is more expensive, so it uses very little in the market.
The salicylate ultraviolet absorbers also have internal hydrogen bonds in molecules. At the beginning, the absorption capacity of ultraviolet rays is low, and the range of absorption is narrow (less than 340nm), but after a certain period of time, the absorption gradually increases. The reason is that under ultraviolet irradiation, the molecular discharge of the molecular discharge has formed a diopizomone structure with strong ultraviolet absorption capacity, which strengthens its absorption capacity for ultraviolet rays. After the reunion, the bivioxylbenzoone and its derivatives can be visible to see yellow. As a result, the fabric is yellowed after finishing. In addition, the melting point of such absorbers is low, easy to sublimate and absorb coefficients, so less use.
3 benzene combined tatoram
The principle of the action of benzene-mourning ultraviolet absorption agent is similar to the dysophenyl ketone: the ultraviolet absorption effect of benzazole-like is better than that of diekeyle ketone ultraviolet absorbers, which can absorb 300-400nm light, and not Absorb light above 400nm wavelength, so it will not be yellowed, and has the advantages of volatility and oil resistance. The structure and decentralized dyes of benzene -pyramazole absorbers are very close. Therefore, the application range is limited. It can be treated with high temperature and high -voltage method to polyester. Appropriate quantity of sulfate group.
Both triazine and tatromazine ultraviolet absorbers contain N. The conversion of molecular hydrogen bonds and hydrogen alcohol and ketone structures formed by N and H is effectively absorbed. ability. The absorption effect of triazine absorbers is proportional to the number of hydroxyl groups. Therefore, the absorption capacity is stronger than that of benzal and tatromazole. Its disadvantages are that the compatibility of the polymer is poor.
5 Organic nickel:
Organic nickel polymers are different from the above -mentioned 4 absorbers as ultraviolet absorbers. They often classify it in the quieter (also known as reducing active, eliminating agent, laser -state hate, or energy quieter) Essence
The absorption capacity of organic nickel absorption agents is low. When the energy of organic nickel polymer molecules accepted ultraviolet light is stimulated to become excited. When ultraviolet light is lost, it returns from inspiration to the base state and transforms ultraviolet energy into a low -energy spectrum. Express. This reduces the passage of ultraviolet rays. Organic nickel absorption agents can form chelated collaterals with some fiber fabrics under certain conditions, but often have colors and limited use.