How would you use a beach umbrella? I think most people will use it on the beach or in the yard, under the shade, and enjoy holiday time with their family. So can we think that the sunscreen effect of fabric for beach umbrellas is very important?
According to scientific research and analysis, there are three main types of anti-UV fabrics in the world, namely coatings, chemical fibers and pure cotton. The sun protection standard is specifically embodied as UPF (sun protection degree), which can generally be measured by a UV protection factor tester. . In addition, the anti-ultraviolet radiation performance of the fabric mainly depends on the fabric structure (fabric coverage factor and thickness), fiber type, finishing and so on.
1. Fabric structure
Fabric has many physical parameters, such as spinning method, yarn thickness, fabric structure, warp and weft density, thickness, tightness and coverage, etc., which all have a certain effect on UV light transmittance. As the density of the fabric increases, the ultraviolet light transmittance decreases; the heavier fabric has a smaller ultraviolet light transmittance; the fabric coverage increases, and the ultraviolet light transmittance decreases.
It can be seen from the influence of these physical parameters on the anti-ultraviolet radiation performance of the fabric that when the fiber types of the fabric are the same, the change of the physical parameters is mainly to change the reflection amount of the textile to ultraviolet light, thereby changing the energy of the ultraviolet light passing through the gap of the fabric. In this sense, the most direct physical parameter that affects the anti-ultraviolet radiation performance of the fabric should be the porosity and thickness of the fabric, and the most direct physical parameter that characterizes the porosity is the coverage of the fabric, so a preliminary conclusion is drawn, that is, the fabric The coverage and thickness have the greatest impact on UV radiation protection. This conclusion can be seen from the analysis of experimental data, the coverage rate and the transmittance of ultraviolet light show almost linear changes. In addition, the correlation coefficient between the thickness and the anti-ultraviolet radiation performance of the fabric is also relatively large. In other words, changes in fabric coverage and thickness have the greatest impact on the UV transmittance of the fabric.
Does your supplier state the square weight or density of the fabric when quoting it? This point needs to be paid attention to in procurement.
2. The composition of the fabric
Generally speaking, protein fibers such as wool and silk contain aromatic amino acids, and polyester molecules contain benzene rings. Their molecular activity is relatively large, and they have good absorption of ultraviolet light less than 300nm, and most polyester fibers are Contains matting agent, has high absorption rate for UVA (320-400nm) and UVB (290-320nm). However, cotton fibers and viscose fibers lack such active groups, so their ability to prevent ultraviolet radiation is low.
3. Fabric color
Dark>light>transparent. In the case of the same fabric, the darker the umbrella, the better the UVA effect. Generally, the darker umbrella cloth can block 95% of the UVA. However, the sun protection performance must first consider the fabric, except for the fabric to talk about color, it is all hooligans. 80% of the sun protection effect depends on the fabric, and the color does not account for much.
Anti-UV treatment method.
The sun-shading principle includes the UV shielding method with coating and the UV filtering method without coating
The coated umbrella uses UV blocking method (shading sunscreen), mainly black and silver coating. There are many applications of silver coating on beach umbrellas, but they tend to fall off over time, so they are usually cheap promotional beach umbrellas. The UV shielding method physically blocks the light source to achieve the principle of blocking ultraviolet rays. Basically, it is to cut off all light, so the quality of an anti-ultraviolet umbrella will be judged by opacity.
The more advanced uncoated umbrellas rely on UV filtering. The UV filter method is to add sunscreen agents to the fabric, so that each yarn can fully absorb the sunscreen ingredients, and the sun and rain will not fall off for a long time to achieve the sunscreen effect. Will your supplier state their fabric UV50+ in the quotation?