The comfort of clothing fabric is not only reflected in good air permeability and moisture permeability, but also in the tactility of the fabric. Smooth, rough, waxy and smooth are the basic tactile sensation of the fabric, and the friction between the fabric and the skin is the leading factor leading to the different tactile sensation. If fabric surface does not have proper friction coefficient, light human body feels coarse, have attrition feeling, heavy can stimulate the skin to cause a variety of diseases badly, this kind of phenomenon is highlighted more in motion. The friction of the fabric not only affects the tactility but also hinders the sewing process. During sewing, sliding friction often occurs between the fabric and the instrument metal. If the friction coefficient is too large, it will cause sliding difficulty and affect sewing efficiency.

The evaluation of fabric friction coefficient is usually based on the personal sense after touch. Sensory sensitivity varies from person to person, making evaluation somewhat subjective. In the modern environment that stresses scientific data, this subjective evaluation is gradually replaced by instrument testing. Research between fabric and the skin friction coefficient, due to the particularity of the skin, sample test is difficult to implement, therefore, the author use a relatively simple way of test instrument, namely, under the certain condition of positive pressure and friction speed, smooth fabric surface with a rigid surface rubbing against each other, the determination of dynamic and static coefficient of friction, this value as the fabric and the skin friction performance of reference data.

Engineers take a polyester fabric and cut 3 pieces of warp and weft samples, with the size of 200mm 80mm, to ensure that it has no crease, arch, hemming and other defects. According to the principle stipulated in FZ/ t01054-2012 "test methods for fabric surface friction properties", the sample is clamped flat on the sample table of the friction coefficient meter, with the test face up, so that the sample is in a state of elongation but not elongation. The rigid and smooth friction block is opposite to the test surface of the sample and applied with 450Pa vertical pressure. The relative friction coefficient of the instrument was set at a speed of 50mm/min, and the measured dynamic and static friction coefficients were 0.182 in the longitude direction and 0.179 in the latitude direction.

The friction property of the fabric surface is proportional to the roughness of the surface, and the roughness is related to many factors, such as fiber fineness, length, crimp, yarn structure, fabric state, tightness, processing technology, etc. The coarser the fiber, the higher the crimp and the higher the compactness, the rougher the surface of the fabric will be due to the processes such as raising, drawing and shrinking. In addition, different relative humidity states of the fabric will also show different friction properties. When the fabric is in an environment higher than 40%RH, water molecules will form a continuous water film on the surface of the fabric, thus generating hydraulic friction and increasing the friction coefficient of the fabric.

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