Cheap and ultra-light sun protection umbrellas sold in the market can hardly achieve the sun protection effect. To buy such a sunscreen umbrella, you must look for the manufacturer and brand. According to reports, the choice of anti-ultraviolet umbrella mainly depends on the fabric of the umbrella. The research shows that the fabric with thick umbrella cover has better ultraviolet resistance than the fabric with thin umbrella cover. Among the untreated fibers, polyester fiber has the best ultraviolet resistance, which is related to the absorption of ultraviolet light by benzene ring in its molecular structure. The ultraviolet resistance of cotton (nylon) and viscose (rayon and rayon) in chemical fibers and cotton and silk in natural fibers is not ideal. When choosing an anti-ultraviolet umbrella, try to choose a thicker fabric containing polyester fiber. At present, there are mainly jacquard satin, silver onion satin, transfer satin, marked cloth, concave-convex cloth and polyester cotton cloth on the market. In addition, the closer the fabric is, the stronger the light blocking ability is and the less ultraviolet rays are transmitted. In woven fabrics, the porosity of plain weave fabric is generally larger than twill, and twill is larger than satin, so plain weave fabric has poor ultraviolet resistance, while satin fabric is the best. Third, the darker the color of the fabric, the smaller the ultraviolet transmittance and the better the anti-ultraviolet performance. Therefore, when choosing an anti-ultraviolet umbrella, we should consider the fabric and the tightness, color and thickness of the fabric to obtain the best anti-ultraviolet effect. At present, the anti-ultraviolet umbrella cover is mostly nylon or polyester fabric, which is made after anti-ultraviolet treatment. Umbrella cover names include silver belt, gold belt and pearl glue. According to the test results, the protective effect of silver rubber umbrella cover is the best. I remember that I did use an expensive umbrella before. In summer, the temperature under the umbrella is lower, and I can feel cool.