Evaluation standard for antistatic fabric
Test method based on fabric selection
The evaluation of the antistatic properties of textiles should be based on the different properties of the fabric, and the test items vary from method to method. Electrostatic testing includes hazardous static power parameter testing, static testing of materials and products, and testing of electrostatic susceptibility of flammable and explosive materials. The main parameters characterizing the electrostatic properties of materials or products are resistivity, leakage resistance, charge density and half-life, triboelectric charging voltage and half-life. The evaluation of the electrostatic properties of textile materials mainly includes resistance index, electrostatic voltage and half-life, charge surface density and other indicators, as well as simple low-precision test indicators such as suction test, Zhangfan test and adsorption metal sheet test.
Type of test method
China's current national and industry standards for antistatic performance testing of textiles and clothing mainly include: GB/T12014-1989 "Antistatic Workwear", GB/T12703-1991 "Textile Electrostatic Test Method", FZ/T01042-1996 "Textile Materials" Determination of Static Voltage Half-Life of Electrostatic Properties", FZ/T01044-1996 "Determination of Fiber Leakage Resistance of Electrostatic Properties of Textile Materials", FZ/T01059-1999 "Method for Measuring Electrostatic Adsorption of Fabric Friction", FZ/T01060-1999 "Friction Friction and Charge Method for Measuring Charge Density", FZZY01061-1999 "Method for Measuring Frictional Electric Voltage of Fabrics".
It must be noted that the applicability of different test method standards is different. Taking GB/T12703-1991 "Textile Electrostatic Test Method" as an example, this method provides several different test methods. Not only the test items are different, the technical conditions are different, and the applicable products are also different, and the meanings are different. Such as:
Method A (half-life method, same as FZ/T01042-1996): The sample placed on the optional metal platform was discharged with a high voltage of +10 kV for 30 s, and the half-life (s) of the induced voltage was measured. This method can be used to evaluate the electrostatic attenuation characteristics of fabrics, but the contact state of the samples containing conductive fibers on the grounded metal platform cannot be controlled. When the conductive fibers are in good contact with the platform, the charge leaks quickly, and the attenuation rate of the contact is poor and the ordinary textiles. Similarly, the test results obtained by the same sample under different placement conditions are extremely different, so it is not suitable for the evaluation of antistatic properties of fabrics containing conductive fibers.
Method B (triboelectric voltage method, basically the same as FZ/T01061-1999): 4 pieces of sample (2 by 2 latitude, 4 cm × 8 cm) are placed on the drum, and the drum is rotated at 400 r/min. Standard cloth (nylon or polypropylene) friction, test the maximum value (V) of the sample charging voltage within 1 min. Because the sample size is too small, the distribution of conductive fibers will vary greatly with the sampling position for fabrics with embedded conductive fibers, so it is not suitable for the evaluation of antistatic properties of textiles containing conductive fibers. .
Method C (charge surface density method, basically the same as FZ/T01060-1999): The amount of charge measured by the Faraday cylinder after the sample is rubbed with the nylon standard cloth in a specific manner under specified conditions, and the charge surface density is obtained according to the sample size. (μC/m2). The charge surface density method is suitable for evaluating various fabrics, including the difficulty of accumulating static electricity by friction-containing fabrics, and the measured results have a close correlation with the degree of ash absorption of the samples. Since the triboelectric charging between the sample and the standard cloth is realized by manual operation, the consistency of the test conditions, the accuracy and reproducibility of the test results are susceptible to the operation method.
D method (clothing charge method when **): After the work clothes are rubbed against the chemical fiber underwear in a specific way, the work clothes are taken off, and the Faraday tube is put into the tube to obtain the charge amount (μC/piece). The test object of this method is limited to clothing, but because the material of the underwear is not specified, the friction method is difficult to be consistent and lacks comparability.
Looking at the existing national standards and industry standards for electrostatic testing of textiles, the practical method for testing the electrostatic properties of fabrics containing conductive fibers is only the charge surface density method in GB/T12703-1991 or FZ/T01060-1999. Therefore, the evaluation of the antistatic properties of textiles does not insist on finding a certain correlation between different indicators, but should establish a complete and multi-faceted evaluation system to reflect the textile under different test conditions and conditions. Antistatic properties and actual use. Some experts suggest that for the existing charge surface density method, the relevant test technical conditions should be further studied and improved, and the artificial friction should be changed to automatic operation to further improve the accuracy and reproducibility of the test.