Test steps:
1. From the samples that have reached a moisture equilibrium state, randomly cut 3 samples of size (120 ± 1) mm × (100 ± 1) mm along each direction. For woven fabrics, it is the warp and weft directions; for knitted fabrics and non-woven fabrics, it is the transverse and longitudinal directions. The test surface of the sample is the friction surface, which is specified by the relevant party. For samples with significant differences on both sides (such as coated fabrics), if there is no special indication, samples from both sides should be taken for testing, and this should be explained in the test report.
2. Cut a friction fabric of size (300 ± 1) mm × (300 ± 1) mm from the standard friction fabric that has reached a moisture equilibrium state.
Fold the friction fabric along the weft yarn (or transverse direction), then cover it on the friction unit surface, and fix it with a rubber ring.
3. After the friction fabric is used for 3 times, the surface should be turned to the un-used side.
Instrument for testing friction-induced charging voltage and voltage attenuation time
4 Move the sample table (Figure 1 structure 2) beneath the electrostatic field meter (Figure 1 structure 3).
5 Adjust the instrument so that the circular opening of the sample table (Figure 1 structure 2) and the center of the sample holder (Figure 1 structure 4) align with the measurement center of the electrostatic field meter (Figure 1 structure 3), and adjust the measurement height of the sample table and the electrostatic field meter to (50 ± 1) mm.
6 Install the sample on the sample holder (Figure 1 structure 4), flatten the sample and use tape to firmly fix it to prevent the sample from wrinkling, as shown in Figure 5.
7 Use the electrostatic elimination device to eliminate the static electricity in the sample and the friction fabric.
8 Turn on the switch of the test instrument controller (Figure 1 structure 5).
9 Adjust the pressure between the friction unit and the sample so that the center of the friction unit is compressed by about 3 mm after contacting the sample.
10 Turn on the motion switch of the friction unit and make it move automatically according to the description in Chapter 7.
11 Record the static voltage value (V) and the attenuation curve.
12 Based on the static voltage attenuation curve, measure the frictionally charged voltage and the half-life.
13 Replace the sample and repeat the test for the other two samples.
14 Replace the type of friction fabric and repeat steps 1 to 13.
Test the different directions of the sample. For woven fabrics, test the longitudinal and transverse directions; for knitted fabrics and non-woven fabrics, test the lateral and longitudinal directions. The test results should be expressed as the average value of 3 samples in each direction. The test results of the frictionally charged voltage are retained to the integer place, and the test results of the half-life are retained to one decimal place. The test results are shown in Appendix A.
