Properties of Glass Fiber for Filtration: Influence of Forming Process

Abstract

Glass fiber used in filtration applications is typically produced by either of three types of processes: (1) continuous draw, (2) centrifugal (rotary) spinning, or (3) flame attenuation. Each process imparts to the fiber a unique set of characteristics such as diameter, length, and surface chemistry and structure. These in turn dictate the key performance properties of the fiber in nonwoven products. Diameter distribution is perhaps the most fundamental to filtration efficiency; this can vary appreciably with fiberization process even for fibers of the same bulk chemistry and “mean” diameter. Likewise length distributions are unique to each process and, for discontinuous fiber, have a distinct correlation to the diameter distributions. Complete characterization, therefore, often requires bivariate analyses. Finally, glass surface chemistry and structure, which are critically important for key properties such as fiber tensile strength, chemical durability / reactivity, and dispersability, are also highly dependent upon the fiber forming process. By controlling initial glass chemistry and fiberization process parameters, a wide range of fiber dimension, morphologies and surface properties can be achieved. As such glass fiber has some unique opportunities in meeting existing and new demands in filtration markets.