Factors affecting UV transmittance of textiles_China Textile Fabric,Uniform Fabric,Cotton Fabric Supplier & Manufacturer & Factory

The rapid development of human life and production activities has caused increasingly serious environmental problems, which in turn threaten human survival, such as ultraviolet damage.

Factors affecting the UV transmittance of textiles

The transmittance of ultraviolet light depends on many factors, such as tissue structure, coverage coefficient, color, chemical additives in processing and sample handling, etc.:

1. Fabric organization and structure: The denser the woven or knitted fabric, the smaller the amount of UV rays passing through. For the same fabric structure, the UV protection performance increases with the thickness and quality of the fabric, basically depending 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 fabrics have greater transmittance. Wool fabrics and silk fabrics have high UV absorption capabilities. Polyester, due to its aromatic ring structure, has high UV absorption capacity. Materials with matting agents are more likely to absorb ultraviolet rays. Nylon fibers pass UV radiation fairly easily.

3. Fabric color and color depth: Many dyes absorb ultraviolet rays. Generally speaking, dark colors have better protective properties. Black and dark blue have lower UV transmittance.

4. Post-finishing: Repeated washing of anti-UV treated fabrics will affect its anti-UV properties. Clothing without UV treatment will improve its UV resistance after shrinking.

5 Moisture content: Wet clothes have lower UV transmittance than dry clothes.

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 transmitted through fabrics. There are several main ways to reduce the amount of ultraviolet rays transmitted through fabrics.

Ways to Reduce Ultraviolet Transmission

1High temperature and high pressure exhaustion method

The high-temperature and high-pressure exhaustion method is similar to the high-temperature and high-pressure dyeing of polyester. This is because some ultraviolet absorbers that are insoluble or poorly soluble in water have very similar molecular structures to disperse dyes and can penetrate into the fiber under high temperature and high pressure conditions. Fixed. The high-temperature and high-pressure exhaustion method is suitable for polyester, nylon and other synthetic fiber fabrics. This method mostly uses disperse dye dyeing and anti-UV finishing in the same bath.

2Normal pressure suction method

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

3. Dip method

Since most UV shielding agents are insoluble in water and lack affinity for natural fibers such as cotton and linen, the exhaust method cannot be used. Instead, the shielding agent is fixed on the surface of the fabric by bathing it with the resin. Padding fluid consists of UV shielding agent, resin, softener, etc. However, after heat treatment, the holes in the fabric are easily covered by resin, which will affect the style, water absorption and breathability of the finished fabric.

4 coating method

Generally, an appropriate amount of UV shielding agent is added to the coating agent, and an applicator is used to apply a precise fine coating on the surface of the fabric. Then, after drying and necessary heat treatment, a thin film is formed on the surface of the fabric. Although this type of method affects the washing fastness and hand feel, it has wide applicability to fiber types, low processing cost, and does not require high application technology and equipment. Most of the UV shielding agents used in the coating method are highly refractive inorganic compounds.

5Microcapsule technology and printing method

Microcapsule technology has been widely used in industrial fields. It is a special form of packaging. The substances in the capsule can be solid particles, liquid droplets or bubbles. The anti-UV finishing agent can be injected into the capsule, so that the outer layer of the capsule will rupture due to friction during the wearing of the garment, achieving the effect of slow release of the anti-UV finishing agent; if photosensitive color-changing crystals are added to the capsule, the fabric can change color. Function. In addition to increasing the aesthetics, photosensitive color-changing clothing also enhances the anti-UV function and can resist long-term UV radiation.
The printing method is to mix the ultraviolet shielding agent or absorber into the printing paste. After printing, it is fixed on the fabric by steaming. This method is suitable for fabrics that do not require high ultraviolet shielding rate.

6sol—gel technology

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