Performance testing and standards for anti-static dust-free clothing
Clean clothes are also called anti-static clothes and clean clothes. The fabric is made of polyester filament fiber, and the Belltron series of conductive fibers are embedded in the warp or warp weft. It has excellent anti-static and dustproof properties and is widely used in anti-static areas and dust-free clean areas.
One: anti-static performance test
Anti-static is an important feature of clean clothes, especially in the microelectronics and other industries, the antistatic performance requirements of clothing are more stringent. The general test has two parts: surface resistance test and friction voltage test.
Surface resistance test
Principle: This test verifies the electrical conductivity of the conductive filament and the requirements of the stitching process before the fabric and the fabric, such as the connection between the conductive filaments.
Test conditions: Temperature: (20 ± 5) 0 C Relative humidity: (35 ± 5)% Test voltage: (100 ± 5) V test time 15S.
Test method: put the tested work clothes on a special test bench (table resistance is greater than or equal to 103Ω), test it with a resistance tester, usually need to test different points of the work clothes, like a piece of cloth, different Between the cloth blocks, between the sleeves and the sleeves, between the pants and the pants.
Test result: Take the geometric mean of 5 measurements.
2. Friction voltage test
Principle: This test is mainly to verify whether the fabric itself can reach a specified stable value in a short time after accumulating some voltage after friction.
Test conditions: Temperature: (20 ± 5) 0 C relative humidity: (35 ± 5)%.
Test method: On a dedicated ESD test bench (via grounding), the tester rubs the surface of the fabric several times (usually 5-10 times) with a certain amount of force and speed, and then separates the probe of the dedicated voltage tester by 5 cm. Align the rubbed portion to the left and right and read the voltage value after the 5th second.
Test result: friction voltage should be less than 100V
Two: cleanliness test
The contaminated particles attached to the inside and outside of the clothing of the clean overalls used in the clean room are determined by the following four methods:
1. Microscopy (ASTM-F-51)
The test probe is equipped with a filter diaphragm and is directly connected to the suction metering pump, and the amount of air passing through is 28 L/min. During the test, air was passed through the test cloth, and the dust particles contained in the air were collected on the test filter, and the number of dust particles was observed and counted by a 400-fold microscope. The number of particles of 0.5-5 and 5 or more on the upper surface of the filter was read. A 3.08 mm grid is printed on the filter to read the number of particles in one grid.
2. Counting method (ASTM-F-51 amendment method)
The air was passed through the test cloth, and the size and number of the dust particles were measured by a particle counter. The sample was placed on a gantry with a metal mesh and contacted with a sampler (replaced with a 47 mm filter holder) with a passing air volume of 28 L/min.
3. Rolling bucket method (HelmkeDrumTest)
The sample is placed in a rotating drum with a side opening, and the dust particles are sampled from the barrel, and the number of particles is measured by a particle counter to determine the level of cleanliness. The size of the rotating drum was 43 cm x 33 cm, and there were 4 blades on the inside of the barrel, and the number of revolutions of the barrel was 10 rpm.
4. Vibration method
The sample was placed in a small chamber, and particles were generated by vibration torsion and measured by a particle counter. At the same time, particles having a large particle size (25 or more) are collected on the filter membrane, and the number of particles is read. The air volume was 3.5 ft/min (0.099 m/mim) and the number of vibrations was 150 beats/min. At present, there is no national standard for the dust-free performance test of clean overalls. For reference, the Japanese Industrial Standard JIS-B-9923, which is studied by the Japan Air Clean Association Special Committee, and the American IES Standard RP-CC-003-87-T. For the evaluation of dust-free performance, each industry can be used according to the clean factory standards specified in the international standard ISO/TC209, combined with their respective cleanliness levels.