Influencing factors of fabric UV transmittance

Influencing factors of fabric UV transmittance

In recent years, studies have found that anti-ultraviolet fibers can prevent the harm of ultraviolet rays. Therefore, there are more and more anti-ultraviolet fabrics. Generally, ultraviolet finishing agents are added to the fabric. For processed anti-ultraviolet fabrics, how to test the UV transmittance? What are the current domestic and international testing methods, and their similarities and differences. How is the problem that people have been paying attention to.

1. Factors affecting the UV transmittance of textiles

The transmittance of ultraviolet rays depends on many factors, such as organization structure, coverage factor, color, chemical additives in the process and processing of samples, etc.:

1. Fabric organization and structure: the denser the woven or knitted fabric, the smaller the UV throughput. In the same fabric, the UV protection performance increases with the thickness and quality of the fabric, and it basically depends on the coverage factor of the fabric.

2. Types of fabric fibers: different materials have different UV absorption properties. Both cotton and viscose fabrics have high UV transmittance. Bleached cotton fabric has a greater transmittance. Wool fabrics and silk fabrics have high ultraviolet absorption capacity. Polyester, due to its aromatic ring structure, has high UV absorption capacity. Materials with matting agents are easier to absorb ultraviolet rays. Nylon fibers are relatively easy to pass ultraviolet radiation.

3. The color and depth of the fabric: Many dyes absorb ultraviolet rays. Generally speaking, darker colors have better protective properties. Black and dark blue have low UV transmittance.

4. Finishing: The anti-ultraviolet treated fabric will affect its anti-ultraviolet performance after repeated washing. Clothing without UV finishing will improve its UV resistance after shrinking.

5. Moisture content: wet clothes and drier clothes have lower UV transmittance.

According to scientific analysis, in order to reduce the damage of ultraviolet rays to the skin, it is necessary to reduce the amount of ultraviolet rays passing through the fabric, and there are several ways to reduce the amount of ultraviolet rays passing through.

2. Ways to reduce the amount of ultraviolet light transmitted

1. High temperature and high pressure exhaust method

The high temperature and high pressure exhaust method is similar to the high temperature and high pressure dyeing of polyester. This is due to some insoluble or hardly water-soluble ultraviolet absorbers. Their molecular structure is very close to disperse dyes, and can enter the interior of the fiber under high temperature and high pressure conditions. Fixed. The high temperature and high pressure exhaust method is suitable for polyester, nylon and other synthetic fiber fabrics. This method is more commonly used for dyeing with disperse dyes and anti-ultraviolet finishing in the same bath.

2. Atmospheric exhaustion method

The atmospheric exhaustion rule is mainly suitable for the anti-ultraviolet finishing of natural fiber fabrics such as cotton, linen, wool, and silk. The atmospheric exhaustion method must use water-soluble UV absorbers. For example, some benzophenone-based water-soluble UV absorbers have multiple meridian groups in the molecular structure, which have good adsorption capacity for cotton and other natural fibers. Therefore, it can be used for anti-ultraviolet finishing of such fabrics under normal pressure.

3. The dip method

Since most UV shielding agents are insoluble in water and lack affinity for natural fibers such as cotton and linen, the exhaustion method cannot be used. Instead, the shielding agent can be fixed on the surface of the fabric in the same bath with the resin. The padding liquid is composed of ultraviolet shielding agent, resin, softener and so on. However, after heat treatment, the holes on the fabric are easily covered by resin, which will affect the style, water absorption and air permeability of the finished fabric.

4. Coating method

Generally, an appropriate amount of ultraviolet shielding agent is added to the coating agent, and a coater is used to make a precise fine coating on the surface of the fabric, and then after drying and necessary heat treatment, a film is formed on the surface of the fabric. Although this kind of method affects the washing fastness and hand feel, it has wide applicability to fiber types, low processing cost, and low requirements for applied technology and equipment. Most of the ultraviolet shielding agents used in the coating method are some high-refractive inorganic compounds.

5. Microcapsule technology and printing method

Microcapsule technology has been widely used in industrial fields. It is a special packaging form. The substance in the capsule can be solid particles, droplets or bubbles. The anti-ultraviolet finishing agent can be injected into the capsule, so that the outer layer of the capsule will be broken due to friction during the taking of the clothing, so as to achieve the effect of slow release of the anti-ultraviolet finishing agent; if the capsule is added with photosensitive color-changing crystals, the fabric can be discolored Features. In addition to increasing the aesthetics, photosensitive color-changing clothing also enhances the anti-ultraviolet function, which can resist long-term ultraviolet radiation.

The printing method is to modulate the ultraviolet shielding agent or absorber into the printing paste, and after printing, it is fixed on the fabric by steaming treatment. This method is suitable for fabrics that do not require very high ultraviolet shielding rate.

6. Sol-gel technology

The washing fastness of general shielding agents is relatively poor. As a new multi-purpose tool, the sol-gel technology can coat a transparent metal oxide film on the surface of the fabric, which greatly improves the washing fastness. At the same time, the anti-ultraviolet performance is also very good.

The above is an introduction to the "factors affecting the ultraviolet transmittance of fabrics", I hope it can bring you some help. If you have any questions, you can consult QINSUN online customer service or call our technical service number 15618748368 for consultation. Here are our professional engineers to answer for you, hoping to find the answer you want.

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