Fabric Fiber Types

Until the 1950's and the advent of synthetic fibers, natural fibers such as cotton and wool were used almost exclusively in industrial liquid filtration. As synthetic fibers were developed and made readily available, they began to replace natural fibers and today are the primary fiber type used in liquid filtration. Nylon was the first important wholly synthetic fiber to be manufactured, followed by polyester, acrylics and more recently polyethylene, polypropylene, fiberglass, PTFE and aramid. Synthetic fibers are manufactured in three forms:

Monofilament Filter Fabric Monofilament: This consists of unbroken lengths of fiber extruded into one continuous filament fiber. Monofilament fabrics are characterized as having the best cake release, the highest flow rates, less likely to blind, and by comparison would have the poorest retention (filter efficiency.)
Continuous Multifilament Filter Fabric Continuous Multifilament: This consists of several fibers of unlimited length twisted tightly together to produce a completely smooth yarn. Compared to monofilament fabrics, miltifilament fabrics have poorer release qualities, better retention (filter efficiency), lower throughput, and may be more likely to blind.
Spun Filter Fabric Staple Fiber (Spun): The continuous fiber as extruded is cut into short lengths similar in appearance to natural fibers, such as cotton. The fiber is then carded and spun into a yarn before it can be woven into a fabric. Spun fabrics tend to be rated with the best efficiency or retention, have generally lower flow rates, are more likely to blind, and have the poorest cake release.
Effect Of Yarn Type On Filtration Media Performance
Order of Preference
Maximum Filtrate Clarity spun multifil monofil
Minimum Resistance to Flow monofil multifil spun
Minimum Moisture in Cake monofil multifil spun
Easiest Cake Discharge monofil multifil spun
Maximum Cloth Life spun multifil monofil
Least Tendency to Blind monofil multifil spun