The production principle and performance of anti-static fabrics (2)

The production principle and performance of anti-static fabrics (2)

3. Things that should be paid attention to when handling static electricity removal workwear are as follows

1. All work clothes should use anti-static fabrics, and linings are generally not used. When a lining must be used, the exposed area of ​​the lining should not exceed the inner surface of the entire work clothes. 20% of the area.

2. Different levels of anti-static fabrics and anti-static work clothes should be selected according to the electrostatic sensitivity of different cleaning objects in different places.

3. Cleaning of work clothes should be carried out in a simple manner, and work clothes should be avoided from being cleaned by strong mechanical and chemical operations.

4. It is prohibited to attach or wear any metal objects on anti-static work equipment.

5. It is not allowed to put on or take off work clothes at the site where static-sensitive products are operated (changes should be done in the designated locker room). Work clothes The buttons should be fully buttoned, and the amount should not be in a state close to being undressed.

6. Before wearing the anti-static work clothes purchased in batches, a few pieces should be randomly selected to test the charge level. After a certain period of wear, especially if the wearer feels an electric shock when taking off his clothes, a repeat test should be carried out. Test.

4. Performance testing of anti-static workwear

1. Purification performance testing: The pollution particles attached to the inside and outside of the clothing of antistatic work clothes used in clean rooms are measured using the following four methods: ASTM F-51 method (microscope method), F-51 revised certification method (counting method), HELMKE drum method (drum method, equivalent to ASTM test method) and vibration test method (vibration method).

(1)ASTM-F-51 method (microscope method) test probe Equipped with a filter membrane, directly connected to the suction metering pump, the amount of air passing through is 28L/min. During the test, the air is passed through the test clothing, and the dust-generating particles contained in the air are captured on the test filter membrane, and the air is passed through a 400x microscope. Watch and count dust particles.
Read the number of particles between 0.5-5 and above 5 on the filter membrane. There is a 3.08mm grid printed on the filter membrane, and the number of particles in a grid can be read

(2)ASTM-F-51 revised method (counting method) Use Air passes through the test clothing, and a particle counter is used to measure the size and number of dust-generating particles. Place the sample on a stand with a metal mesh, use a sampler (replaced with a 47mm filter holder) to contact and aspirate, and the amount of air passing through is 28L/min

(3)Helmke Drum Test Put the sample It rotates in a rotating drum with a side opening, and samples the dust particles from the particle drum. Use a particle counter to measure the number of particles and then determine the cleanliness level. The size of the rotating drum is 43cm × 33cm, and there are 4 holes on the inside of the barrel. blades, and the number of revolutions of the barrel is 10 rpm.

(4)Vibration method
The sample is placed in a small chamber, and particles are generated by vibration and twisting, and measured with a particle counter. At the same time, particles with large particle sizes (above 25) are captured on the filter membrane, and the number of particles is read. The air volume is 3.5 feet/min (0.099m/mim), and the number of vibrations is 150 times/min.

Our country currently has no national standards for dust-free performance testing of clean work clothes. You can refer to the Japan Air Cleaning Association Special Committee The studied Japanese Industrial standard JIS-B-9923, and AmericanIES standard RP-CC-003-87-T. For the evaluation of dust-free performance, various industries can The clean workshop standards stipulated in the international standard ISO/TC209 are used in combination with their respective cleanliness levels.

Antistatic performance testing Antistatic property is an important feature of antistatic workwear, especially in microelectronics and other industries, which have stricter antistatic performance requirements for workwear.
The test method can be based on the national standard of the People’s Republic of China GB/T12703-91 “Static Electricity Test Method for Fabrics”. Since the fabric used in clean work clothes is polyester filament fabric with inlaid conductive threads, the standard only contains frictional charging voltage. (Method B), charge area density (Method C) and frictional charging of work clothes (Method E) are suitable for testing the antistatic performance of clean work clothes. Others can also refer to the National Standard of the People’s Republic of China GB/T12059-89 “Performance and Experimental Methods of Synthetic Fiber Antistatic Silk for the Electronic Industry”.

(1)Frictional charging voltage method
The testing principle of this method is to rub the sample and the standard cloth against each other under certain tension conditions, and use the high voltage and average voltage generated at this time to evaluate the frictional charging relationship between the wearer and the outerwear. The method is to clamp the sample (4 pieces, 2 warp, 2 weft, size 4cm × 8cm) on the rotating drum (outer diameter 150±1mm, width 60±1mm), and the rotating drum rotates at 400rpm. Rub it with standard cloth (nylon or polypropylene) and test the maximum charged voltage (V) of the sample within 1 minute.

(2)Charge surface density method
After the sample is rubbed with nylon standard cloth in a specific way under specified conditions, a Faraday cylinder is used to test its charge amount, that is, the surface charge density.