What are the Air Permeability Impacts of Fabric Construction?

Fabric permeability is commonly expressed by ventilation property, ventilation property refers to both side of fabric under specified pressure difference,within unit time the air volume of flowing in the fabric unit area. Taking the fabric permeability is closely related to the heat preservation and comfortability, some industrial textiles have very strict request for fabric air permeability, so research for the fabric permeability has important practical significance.

 

After many test we got conclusion:

 

1, factors affecting the air permeability of the fabric: latitude and longitude tight ratio,cotton yarn count, the total fabric tightness, average float, float variance;

 

2, Compared with the 95% and 90% significant level,warp/weft tightness ratio and cotton yarn count influence on fabric permeability is more significant,fabric total tightness and average float influence on fabric permeability is more significant.

 

3, After comparing of each factor, the influence rule of various factors on the fabric permeability volume are as follows:

 

(1) Within the scope of the lesser average float, with the average float increases, alternating frequency decreases,big covering area of yarn, poor degree of gathered into a bundle,fabric gap decreases, so breathable performance become bad, but with the average float is further increased, the fabric becomes soft, too little interlacing times so that the binding force of mutual yarn is bad, then easy to produce yarn slipping and holes are formed, so air permeability has upward trend;

 

(2) With the increase of total tightness,cover area of yarn increases,that means total number of yarn increase in a certain area,so cause the increase of surface filling degree, so fabric pore area is reduced, so that the constitution between the yarn gas passage becomes smaller, so that the gas way between the yarn is increased, so that the flow of air perpendicular to the viscous resistance of the fabric is increased, so the larger the total tightness, the less permeability; but when the tightness increases to a certain extent,the rate of air permeability decreases is in reduction,which because when the total tightness increased to a certain extent, the fabric yarns have very small pores, add fabric tightness can only increase the fabric yarn extrusion and little change in porosity, ventilation volume reduction rate is also reduced.

 

(3) With the increase of warp/weft density, the fabric warp/weft density difference is becoming more and more big; for the same tightness of fabric, when warp/weft tightness ratio is 1, the value of warp or weft is equal, so make fabric tied each other between the yarn in both the warp and weft, and not easy to slip to produce a gap, so permeability is very poor; when warp/weft tightness ratio is 2.5,warp cover factor is much larger than weft cover, so make the weft cover is very small, then the binding force of weft is poor,easy to produce slipping and formed hole,so air permeability is very big. With the increase of warp/weft density ratio ,slipping of weft yarns is more easy to produce, that is the hole is more easily formed, so the rate of permeation volume increasing is bigger and bigger, similar,when warp/weft tightness ratio is 1, air permeability of fabric is worst. That means,with the increase of warp/weft density ratio increases,air permeability is rising;

 

(4) Flame retardant fabric permeability increased with the increase of cotton yarn count, that means the thinner yarn, the poor fabric permeability.

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