Fabric permeability
May 14, 2019
Definition: The performance of gas molecules through fabrics is the most basic property of fabric permeability.
Mechanism: When there is a certain pressure on the air on both sides of the fabric, air flows from the higher pressure side through the fabric to the lower pressure side.
Relationship with clothing comfort:
Summer clothing fabrics, good breathability, clothing wear has a cool sense of comfort; winter outerwear fabric, breathability is small, the clothing has more static air, with wind and warmth. Index: Air permeability, which refers to the amount of air passing through the unit area of the fabric per unit time under conditions of maintaining a certain pressure difference on both sides of the fabric.
Factors affecting gas permeability:
Fabric structure
Such as: plain, twill, satin, porous tissue
Warp yarn density, fabric tightness, fabric texture, fabric finishing, general gas permeability reduction
2. Fiber properties and yarn structure
The moisture regain of the fiber has a significant effect on the gas permeability. As the wool fabric increases with moisture regain, the gas permeability decreases significantly. Most heterogeneous fiber fabrics have better gas permeability than circular cross-section fabrics. The surface shape and cross-sectional morphology of the fiber increase the resistance of the airflow due to the increase in the shape of the barrier and the specific surface area. Therefore, the shorter the fiber, the greater the rigidity, the greater the probability of hairiness, and the more the barrier and channel changes are formed, so the gas permeability is smaller.
3. Environmental conditions
When the temperature is constant, the air permeability of the fabric decreases with the increase of air humidity. When the relative humidity is constant, the air permeability of the fabric decreases as the ambient temperature increases. When the temperature and relative humidity are constant, the change in the air pressure difference between the two sides of the fabric affects the measured flow rate and is non-linear.
