Method for Measuring Static Potential on Moving Fabrics

Abstract

There is no clear explanation for static potential generation. There are many factors that affect charge generation such as environment (temperature, humidity), structural (polymer type, structure of fabric) and working factors (fabric speed, tension, and contact area between fabric and machine parts, material type that is in contact with fabric). With a good knowledge of these parameters, generation of static charge can be minimized.

During production, static potential on a moving web can cause web breakage, ignition of flammable atmosphere, or shock risk.

The main objective of this research is to develop a method to measure static electricity on moving nonwoven machine belts. In this project the instruments to measure and eliminate static potential on moving fabrics, design of test apparatus, relationship between charge decay values and charge generation of different fabrics, static potential measurements under different conditions are discussed. Spunbond technology is one of the nonwoven production methods have a high static charge generation problem; tests were done by using a spunbond belt on an actual spunbond machine. These belts are mostly made of woven fabrics with different structures (different number of layers, fabric design, structure of polymers used). A goal of manufacturing these belts is to reduce static electricity during production.

Among all parameters that cause static charge generation, tension is the most important one. A small amount of increase in tension can double the charge on belt. Separation is also a reason for charge generation and as roller-fabric friction increases —because of the increased contact area- more charge will be generated during separation. A new parameter, contact area, also needs to be considered.

Static charge generation may not be same at cross direction on a belt. As all areas are in the same situation (working and environment conditions) the only thing that was different was the tension. Because of the spunbond machine setup, tension —for this reason, static charge- was different in cross direction. The effect of this and other parameters can be seen more clearly when a non-conductive belt is used.