Pure Cotton Sunscreen Is Weaker Black And More Sunscreen.

Sunscreen is the most important task of summer beauty lovers. In order to block the body, sunscreen, mask and sunscreen are all kinds of sunscreen. Spin The application of products is more and more. How to choose and use sunscreen textiles reasonably has become the knowledge that beauty lovers are eager to understand. This summer, the colorful "skin clothes" have almost become the required equipment for every beautiful person. But have you really chosen the right "skin clothes"?

　　 UV or disease, sunscreen is more related to health.

People all know that basking in the sun can promote the synthesis of cellulose D and bone development. Children can bask in the sun more effectively to prevent rickets. Red and black skin is a symbol of sunshine and health.

Sun protection for most people's understanding is to prevent sunlight, but is it against all sunlight? According to Dr. Zhang Bin, associate professor of the Key Laboratory of textile technology of the textile School of Donghua University, the main effect of sunlight on the human skin is ultraviolet radiation. Although its radiation energy accounts for only 6% of the total solar radiation, it is the main light of sun protection.

"If our skin is exposed to ultraviolet rays too much, it will be black and rough and lose its elasticity. This will only affect the appearance, and more importantly, accelerate the formation of cataracts, cause keratitis and conjunctivitis, induce skin diseases and even skin cancer, and bring about many health problems. Therefore, sunscreen is not only related to skin fair, but also to health." Zhang Bin said.

According to the introduction, ultraviolet light can be divided into long wavelength ultraviolet UVA (wavelength 320 to 420nm), ultraviolet UVB (wavelength 275 to 320nm) and short wave ultraviolet UVC (wavelength 200 to 275nm) according to wavelength. UVA can penetrate the epidermis to attack the dermis, and more than 95% of the ultraviolet rays from the skin are UVA. It is easy to cause skin damage and aging. Long term irradiation can cause melanin formation and deposition, making the skin dark and dull, so it is called the tanning section. UVB is known as the dry red section. Long time exposure to the sun will cause skin to become red and painful. It can cause immediate skin burn. This is the main band that needs to be prevented. UVC has been absorbed by the ozone layer before reaching the ground, and has no effect on the skin. Therefore, sunscreen is mainly against UVA and UVB.

In recent years, due to the massive emission of fluorine derivatives such as Freon, human beings are increasingly destroying the atmosphere above the earth, and the ozone layer is thinning and thinning. The amount of ultraviolet radiation reaching the ground is gradually increasing, and the related diseases caused by it are also increasing. Therefore, sunscreen has become a matter of concern to people. In view of this, sunscreen textiles emerge as the times require. Whether or not we can effectively prevent ultraviolet radiation has become the main consideration for people to choose sunscreen textiles.

　　 Pure cotton sunscreen is weak, black is more sunscreen.

According to Zhang Bin, ultraviolet radiation is applied to textiles, part of which is absorbed, part of which is reflected, and part of it is passed through the fabric. Only through ultraviolet radiation of fabric can it affect the skin. If the more absorption and reflection, the less ultraviolet radiation is, the better the protective performance. "Therefore, the identification of textiles against ultraviolet radiation depends on whether it improves the reflection and absorption of ultraviolet radiation. The UV protection ability of textiles is related to the type and structure of fiber, yarn structure, fabric structure and specifications and color.

According to the introduction, at present, the commonly used textile fibers, such as benzene ring in polyester molecule and amino acid in wool molecule, have good absorbability to ultraviolet light with wavelengths less than 300nm. fibre The polarization structure of the pectin and the existence of grooves and cracks can effectively eliminate the light wave. Cotton fabric has relatively poor UV protection capability and is the most easily woven fabric. Therefore, if there is no targeted processing of pure cotton products, its UV protection performance is poor.

In terms of the original yarn structure, the UV protection performance of textiles is as follows: short fiber fabric is better than filament fabric; fine fiber fabric is better than coarse fiber fabric; general profiled fiber fabric is better than circular section chemical fiber fabric; twisting filament yarn product is better than twisted filament product. Fabric structure is also one of the factors that determine the UV radiation resistance of textiles. The heavier the fabric is, the lower the porosity is, the lower the UV transmittance, the greater the protective effect of textiles on the human body. "Therefore, it is not difficult to understand why people pay attention to sunscreen in summer and less care in other seasons."

According to Zhang Bin, at present, the sun protection clothing on the market is mostly translucent light and thin fabric. If it does not make any design and processing for UV protection, it can only cover the body, and it is difficult to screen ultraviolet. But heavy and compact fabrics have poor air permeability, moisture permeability and sweat perspiration, so they must balance each other with the cool and comfortable clothing. So, how to choose the textile suitable for summer? For this reason, Zhang Bin suggested that light, cool and comfortable should be considered.

"After dyeing, the UV transmittance of the fabric decreases with the deepening of the fabric color, which means that the UV protection performance is improved. In different colors, black has better UV protection performance, followed by Navy, red, dark green and purple, while green, light red, light green and white are poorer, especially white. If the fabric is white, the UV protection performance will be worse. Zhang Bin said.

"If it is not treated specifically against UV, it is difficult to obtain better sunscreen properties. But after UV treatment, the wearability of textiles will be reduced, such as physical and mechanical properties, handle and comfort. Generally speaking, the UV resistant textiles made by the finishing method are generally not resistant to washing. Therefore, it is suggested that sunscreen textiles should not be washed or washed as little as possible, so as not to affect their UV protection properties. In addition, such as anti UV sunshade products, rain, such as rain directly exposed to the anti ultraviolet layer, its UV protection performance will be reduced, it is recommended not to use rainy days.

In order to help people get better sunscreen, the pace of scientific researchers has not stopped. It is understood that in order to improve the cleaner production capacity of textiles, researchers at Donghua University have developed an ecological natural UV protection finishing agent, which has been successfully applied to silk and goat hair products because of its high compatibility with the human body and the environment. In silk products, it can not only significantly improve the UV protection performance of silk products, but also improve the non sun resistant properties of silk fabrics.