Factors affecting the permeability of fabrics
The permeability of fabric is the permeability of liquid water from one side to the other. Generally speaking, there are three main factors for the waterproof and permeable fabric:
1, fiber surface infiltration
When the fibers are in contact with theta less than 90°, the fiber aggregate material is a water conducting material, and the tight structure only leads to more water absorption by the capillary core. When theta > is 90°, the fiber is waterproof, and the tighter the fabric structure (i.e. the smaller the pores), the better the waterproof effect. Therefore, only when the contact Angle of the fiber is known, it is better to discuss the waterproof or permeability of the fabric.
2, fabric coating
The surface of the fabric is coated with a layer of impermeable and insoluble continuous film layer, which reduces the water permeability of the fabric, so the fabric is impermeable. It is not suitable for clothing, but can be used for canopies or ponchos. If the use of waterproof, multi-porous coating film, can form excellent water resistance, and permeability, permeability of good coating fabric.
Water-repellent fabrics or coated fabrics are mostly made of non-hygroscopic fibers or coated materials, so the change of relative humidity will not affect their waterproof properties. And water - conducting fabric is mostly hygroscopic fiber material. As the relative humidity increases, the moisture absorption of the fiber increases, the fiber expands and the capillary effect increases, so the water conductivity of the fabric increases. Temperature has the same effect as humidity. Therefore, the environment has a great influence on the water-conducting fabric.