After the non -woven fabric is immersed or washed in room temperature, the size of the size of the two directions is called shrinkability. Generally, if the fabric is dropped or washed, there will be a certain degree of contraction, especially the thin non -woven fabric bonding lining. If the shrinkage rate is too much, it will affect the performance.
There are two types of testes: immersion and laundry. The impregnation method is static, and the washing machine method is dynamic.
Non -woven fabrics are often impregnated when testing its shrinkage. Before testing, the three samples with three sizes of 250mmx250mm were cut, and 200m × 200m and centers were drawn with strokes on the samples to mark the vertical and horizontal direction. Then wet the sample for 24 hours under the standard atmospheric conditions, and then measure the length of the three -back line length of the samples according to the longitudinal and horizontal measurement of the sample, which is accurate to 0.5mm.
During the test, soak the sample in water with a temperature of 25 ° C, take it out after being soaked for 20min, put it on the platform flat, and dry it naturally. You can also immerse the sample in a neutral soap liquid with a temperature of 50 ° C and 0.5 % (the bath ratio is 1:50), remove it for 20 minutes, rinse at a temperature of 50 ℃ ± 1 ℃ for 20 minutes, and then remove it. Dry naturally on the platform. After 24h wet treatment, the three sample vertical and horizontal labeling lines are measured, and the length of the sample is 0.5mm accurately. Press the formula:
Shrinkage = (L-L ')/L*100%