Outdoor clothing is mostly made of chemical fiber fabrics. When the outdoor environment is relatively dry, static electricity problems can occur, manifested as clothing being prone to fuzzing and pilling, being prone to dust and dirt, and generating static electricity adsorption close to the skin. If carrying precision electronic instruments such as electronic compasses, altimeters, GPS navigators, etc., there is a possibility of errors caused by electrostatic interference from clothing, resulting in serious consequences. [1]
Anti static fabrics are divided into two types: non durable and durable. The commonly used testing methods in China include static voltage half-life method, static charge surface density, and point charge amount. GB/T12703 "Evaluation of Electrostatic Properties of Textiles" includes 7 parts, of which 3 have been implemented, and the rest are still in the process of development. The principle of GB/T12703.1 "Evaluation of electrostatic properties of textiles - Part 1: Static voltage half-life" is to make the sample charged to a stable state in a high-voltage electrostatic field, disconnect the high-voltage power supply, and let its voltage naturally decay through a grounded metal platform. The time required for its voltage decay to half the initial value is measured in seconds, and a smaller value indicates better anti-static performance. The standard stipulates that a level ≤ 2.0s, b level ≤ 5.0s, and c level ≤ 15.0s. For non durable anti-static textiles, this requirement should be met before washing; For durable anti-static textiles, this requirement should be met before and after washing. The principle of GB/T12703.2 "Evaluation of electrostatic properties of textiles - Part 2: Charge surface density" is to insert a sample that has been rubbed by a friction device into a Faraday cylinder to measure the charge surface density of the sample. The electrification method of this method reflects the actual frictional electrification of the fabric when worn, and the peeling process is similar to the stripping process, which can reflect the corona discharge ability of the fabric when electrified. It is suitable for testing anti-static fabrics with added conductive wires, but the test results will be affected by human factors and the position of the tested fabric in the electrostatic potential sequence. The smaller the charge surface density, the better the anti-static performance. The standard requires non durable anti-static fabrics with a surface charge density not exceeding 7.0 before washing? C/m2; The surface charge density of durable fabrics before and after washing should not exceed 7.0? C/m2. GB/T12703.3 "Evaluation of Electrostatic Properties of Textiles - Part 3: Charge Quantity" The principle of measurement is to simulate the frictional electrification of a sample using a friction device, insert the sample into a Faraday cylinder, and measure its point charge quantity. The smaller the charge, the better the anti-static performance. Standard requirement: Non durable anti-static textiles with a pre wash charge not exceeding 0.6? C/piece; For durable anti-static textiles, the charge before and after washing should not exceed 0.6? C/piece.
Comparing existing national and industry standards, the evaluation indicators of each method are different, and the results obtained using different testing methods are not comparable. The charge surface density method can effectively simulate the electrification process of outdoor clothing during actual wearing, and is a suitable method for testing the anti-static performance of outdoor clothing.
UV resistance
The evaluation parameter for textile protection against ultraviolet radiation uses the ultraviolet protection coefficient upf value, which represents the ratio of the average effect of ultraviolet radiation calculated when the skin is not protected and the average effect of ultraviolet radiation calculated when the skin is protected by fabric. GB/T18830-2009 "Evaluation of UV Protection Performance of Textiles" specifies the test methods, expression, evaluation, and identification of the UV protection level of textiles against sunlight. The testing principle is to use monochromatic or multi-color UV radiation samples, collect the total spectral transmission rays, and determine the total spectral transmission ratio t( λ), And calculate the UV protection coefficient upf value of the sample. Parallel light beams can be used to illuminate the sample, and an integrating sphere can be used to collect all transmitted light; Alternatively, a hemisphere of light can be used to illuminate the sample and collect parallel transmitted light. In practical operation, the detection instrument can automatically calculate the upf value and t of the sample( λ). When the upf value of the sample is greater than 50, it is represented as "upf>50". According to this standard, when the upf of the sample is greater than 40 and t (uva) av is less than 5%, it can be called a "UV resistant product".