What are the factors affecting the breathability of fabrics?

What are the specific factors that affect the breathability of fabrics? As we all know, the breathability of fabrics is affected by a lot, but if you want to ask what are the specific ones, I am afraid many people do not know! It doesn't matter, I will explain it to you one by one below. 1. Influence of fabric material on air permeability Five types of fabrics of cotton, linen, wool, nylon and polyester with similar organizational structure and thickness are selected, and YG(B)461 type digital fabric air permeability meter is used respectively according to GB/T5453—1997 Test air permeability (the same below). Fabric material is one of the main factors affecting breathability. In general, the air permeability of natural fiber and protein fiber fabrics such as cotton, hemp, wool is better than that of synthetic fiber fabrics such as nylon and polyester. 2. The influence of fabric structure on air permeability The fabric structure is also an important factor affecting the air permeability of fabrics. It can be seen from Table 1 that the air permeability relationship of fabrics with different organizational structures is: perforated fabrics>satin fabric>twill fabric>Plain weave. This is because the warp and weft threads of the plain weave are interlaced the most, the pores between the yarns are smaller, and the air permeability is smaller; Due to the change of fabric structure and density, when the float length increases, the air permeability of the fabric also increases. When the warp and weft yarn count of the fabric remains unchanged, the warp density or weft density increases, and the air permeability of the fabric decreases. Within a certain range, the twist of the yarn increases, the weight per unit volume of the yarn increases, the diameter of the yarn and the tightness of the fabric decrease, and the air permeability of the fabric increases. 3. The effect of processing method on air permeability Use the same specification of pure cotton plain weave fabric (11.7tex)×11.7tex315/10cm×267 pieces/10cm), and were respectively subjected to post-finishing such as soft, liquid ammonia soft, non-iron, liquid ammonia non-iron, liquid ammonia moisture cross-linking and three-proof, and compared the effect of different finishing methods on the air permeability of the fabric. Liquid ammonia finishing can improve the air permeability of fabrics. Liquid ammonia moisture cross-linked fabrics have the best air permeability; ordinary soft and non-iron finishing have relatively poor air permeability. The breathability of the Ammonia Soft and Liquid Ammonia No-Impression fabrics is 20% higher than that of the corresponding soft and easy-care fabrics. This is because after the cotton fabric is treated with liquid ammonia, the fibers become thinner, the hollow tubes and holes become smaller, the flat ribbon distortion is reduced, and the fibers become thinner, which increases the air permeability of the fabric. The air permeability of the three-proof finishing fabric is the worst, because the three-proof finishing coats the waterproof and oil-proof finishing agent on the surface of the fabric, and chemically reacts with the fiber to cross-link on the yarn surface to form a film, preventing water and oil from entering the fiber. At the same time, the amount of air passing through the fabric is also reduced.