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Present view of static charges in textiles | textiles static charges


Present view of static charges in textiles textiles static charges is a variety of mechanisms may cause charge transfer to occur at surfaces in contact. Consequently, large charges will form on the surfaces, but these will leak away through the air, the material, or surface-dressings, and observed charges are much smaller. Leakage through the air occurs until the field near the charged surface is reduced to a value which the air can support. If the ratio of the conductance of the material to the speed of separation is high enough, current will flow the material and further reduce the charge.The leakage will take place from the material just beyond the point of separation, either across the gap to the other surface or to points on the material behind the point of separation. If other conductors are present in the neighbourhood, some current may flow to them.

The limiting condition for high static charges, and hence the susceptibility to troubles in use, has been shown to depend on the resistance of the material: low-resistance materials, such as cotton and viscose rayon will rarely give static troubles; higher-resistance materials like wool, silk, and acetate will give trouble more often; and very high-resistance synthetic fibers will give most trouble. The speed of the process is also important: thus, to avoid fog-marking in weaving, dissipation in 10 minute, needing a total current of o.003 microamps is adequate, but to avoid trouble in carding, dissipation must take place in 0.1 second, needing 0.07 microamps; to avoid trouble in warping, it must take place in 0.01 second, needing 5 microamps.

Methods of getting rid of static charges depend upon increasing the leakage- by lowering the resistance either of the material, or of the air, or by providing a conducting liquid at the separation. The resistance of the material may be lowered by raising the humidity or by moistening it. The resistance of the air may be lowered by ionizing it, either by using a high-voltage static eliminator or by the presence of a radio-active material. Safe concentrations of the latter are only sufficient to cause a slow discharge. The use of electrostatic eliminators in the textile industry has been described by Henry. The use of anti-static agents is discussed by Sagar and by Gotze et al.  Unfortunately, the hygroscopic salts which are the most effective anti-static agents are usually unsuitable for various other reasons.
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