Performance testing of anti-static work
1, purification performance testing
The contaminated particles attached to the inside and outside of the clothing of the anti-static overalls used in the clean room are determined by the following four methods: ASTM F-51 method (microscopic method), F-51 revision method (counting method), HELMKE rotating method ( The drum method is equivalent to the ASTM test method) and the vibration test method (vibration method).
(1) ASTM-F-51 method (microscopy)
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) ASTM-F-51 amendment method (counting 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 (Helmke Drum Test)
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.
2.2 Antistatic performance test
Antistatic property is an important feature of anti-static overalls, especially in the microelectronics and other industries, the antistatic performance requirements of clothing are more stringent.
The test method can be based on the National Standard GB/T12703-91 "Textile Electrostatic Test Method". Since the clean work clothes are made of polyester filament fabric with embedded conductive yarn, only the frictional charging voltage is used in this standard (B). Method), charge surface density (C method) and frictional charging of work clothes (E method) are suitable for the antistatic performance test of clean overalls. In addition, it can also refer to the national standard GB/T12059-89 "Anti-static silk performance and experimental methods for synthetic fibers for the electronic industry".
(1) Frictional electrification voltage method
The test principle of the method is to rub the sample and the standard cloth under a certain tension condition, and the highest voltage and the average voltage generated at this time are used to evaluate the frictional electrification relationship between the wearer and the outer garment.
The method is to clamp the sample clamp on the rotating drum (outer diameter 150±1 mm, width 60±1 mm) with a sample (4 pieces, 2 passes, 2 wefts, size 4 cm×8 cm), and the drum is rotated at 400 rpm. Rub the standard cloth (nylon or polypropylene) and test the maximum value (V) of the sampled voltage within 1 min.
(2) Charge surface density method
The sample is rubbed with a nylon standard cloth in a specific manner under specified conditions.