The Study On Clothing Pressure, Extensibility And Elasticity Performance Of Spandex Elastic Knit Fabric

Nowadays, comfortable and healthy is the new idea and trend in people's clothing consumption. Clothing pressure is an important parameter of comfortable and healthy of clothing and knit fabric. For knit fabric producer, the cost of testing clothing pressure is expensive and the test is usually hard to carry out. So it is worthy of studying a convenient and feasible method to forecast the clothing pressure of knit fabric by testing the extensibility and elasticity performance of knit fabric.In order to make a profound comparison and analysis, three representative structures: plain stitch, rib 1×1 stitch, uneven twill weave and three kinds frequently-used spandex were selected to weave cotton knit fabric and spandex elastic knit fabric. This dissertation analyses the relationship between clothing pressure and performance of knit fabric base on a series of experiments.The test results of spandex performance indicate that the strain of the three kinds spandex is below 1.5cN when they are elongated to 300%. And the percentage of elastic recovery at 300% elongation is above 97%. So, during weaving process, equably controlling the strain of spandex at about 1.5cN is propitious to keep the high elasticity of spandex in the knit fabric. There are several unreasonable points in actual standards that are not suitable for testing the extensibility and elasticity of the new spandex elastic knit fabric. Based on a great deal experiments and analysis, it studies proper test parameters: when loading samples, in order to get the full extending curve with the elongation and tension beginning from zero, the pre-tension should ensure the sample stretched but no extended; 150mm/min drawing velocity can guarantee the precision and improve the efficiency of the test; noting 20s and 3min percentage of elastic recovery at specified elongation which can give the fast and slow-elastic recovery that are useful for clothing pressure analysis of the spandex elastic knit fabric. In the end, the essay sums up a new experiment method to test the extensibility and elasticity of spandex elastic knit fabric.Under other constant conditions, the relationship of the extensibility and elasticity of the fabric is that rib 1×1 stitch is higher than plain stitch , than uneven twill weave; weft is superior to warp; fabric having spandex is better than not; the better performance of the spandex, the higher the performance of the fabric. The relationship of the clothing pressure of the fabric is that: rib 1×1 stitch is lower than uneven twill weave, than plain stitch; weft is superior to warp; fabric having spandex is less than not; the better performance of the spandex, the lower of the of the fabric. For the same sample, clothing pressure increases with the increasing of sample elongation, and decrease with the increasing of the diameter of the clothing pressure test module.Further analyzing of the extensibility curve of the spandex elastic knit fabric, it is found that the curve can be characterization by relation of y=a~*x~^b(>0,b>0). The relationship of clothing pressure and elongation of the fabric can be fitting by y=a~*(x-b)( a>0,b<0), and the correlation coefficient is above 0.9. Finally, based on those conclusions and the range of comfortable clothing pressure and the relation of y=a~*(x-b)( a > 0,b < 0)which is concluded from test module with radius of 3.25cm, this dissertation gives the elongation range and tension range which would be reference data for the spandex elastic knit fabric producer to measure the clothing pressure of the fabric.