I. Can sun umbrellas protect against ultraviolet rays?
Sun umbrellas have certain anti-ultraviolet properties. Generally, sun umbrellas will use protective fabrics such as silver glue, pearl cloth, satin, etc., which can block some ultraviolet rays. And some ordinary sun umbrellas without UV protection coating also have a certain defensive effect, but the sun protection effect of this umbrella will be affected by the color of the umbrella.
II ??Principle of UV protection of sun umbrella
The principle of UV protection of sun umbrella is mainly to reduce its transmission part, so that the UV rays can be reflected or absorbed as much as possible. There are currently two main methods: the first is to make it reflect or scatter away. There are also two cases, one is metal coating, which belongs to mirror reflection and regular reflection; there is also a pearl effect fabric, such as some umbrella surfaces, which can scatter ultraviolet rays in the direction of reflection. The second method is to incorporate ultraviolet-absorbing materials into the fabric fibers, or to do post-finishing after the fabric is completed, infiltrating some ultraviolet-absorbing materials, such as nano-scale zinc oxide or titanium dioxide.
3. How to choose a sun umbrella
1. When choosing an umbrella surface, umbrellas with sparse fabrics generally have poor anti-ultraviolet performance, and consumers Buy carefully.
2. Due to the shrinkage of the fabric, when buying a sunshade, the umbrella surface should be large rather than small.
3. The color of the fabric is related to the UV protection performance. Under the same conditions, the darker the fabric, the better the anti-ultraviolet performance. In contrast, black, navy blue, dark green, light blue, light pink, light yellow, etc. have better anti-ultraviolet performance.
4. Check the protection grade mark carefully before purchasing. The ‘Assessment of Anti-ultraviolet Performance of Textiles’ issued by the General Administration of Quality Supervision, Inspection and Quarantine stipulates that only when the UPF (ultraviolet protection factor value) is greater than 30 and the UVA (long-wave ultraviolet) transmittance is less than 5 percent, it can be called an anti-ultraviolet product. The standard is ‘UPF30+’; when the UPF is greater than 50, it indicates that the product has excellent UV protection performance, and the protection level is marked as ‘UPF50+’. When purchasing, consumers should carefully check the protection level label, and then choose the umbrella that suits them according to the local sun exposure.
5. The UV protection performance can be preliminarily judged according to the fabric properties of the umbrella surface. Generally speaking, cotton, silk, nylon, viscose, etc. have poor UV protection, while polyester is better. Polyester-containing fabrics usually used to make umbrellas include satin cloth, mike cloth, etc. In addition, the anti-ultraviolet performance of satin fabric is the best, followed by twill and plain weave, the darker the better.