Non-woven fabrics are made bonding fibers together by chemical, heat, mechanical or solvent treatments. Both staple fibers (short) fibers and continuous long fibers are used in non-woven materials. It is basically a sheet of fibers (staple and continuous), that have been formed into a web, bound together by various means, other than weaving or knitting.
The term non-woven was coined in 1942 and were first were known to be produced in the US. The first non-woven fabrics were formed by adhesively bonding fiber webs together.
Fig: Non-Woven Fabric Processing Machine
Manufacturing Processes for Non-Woven
Non-woven fabrics are typically made by putting small fibers in a form of a sheet or web, and binding them together in that form, through various mechanical, adhesive, thermal, solvent, or chemical treatments. The choice of manufacturing process depends on the properties required in the final product. There are mainly four manufacturing processes used to produce non-woven, namely:
Spun-bond/ Spun-laid process
This process includes melting of raw material, which is formed into filaments then laid as a web, to be bound together by using heat rollers and embossing.
Melt blown process
in this process also, polymer fibers are melted, stretched into long thin fibers, and formed into a web, which is then bonded together. The only difference between this process and the spun-bond process is that the melt-blown process produces a non-woven fabric with low intrinsic strength but offers much smaller size, which can be used for certain applications.
Needle punching process
This process is mainly used for manufacturing felt. Here, fibers used are interlocked together by using serrated needles to increase the inter-fiber friction, which gives stronger strength in the resultant fabric.
Spun-Lace (Hydro-entangling) process
This process uses a high-pressure liquid stream to bond the fiber web together and impart a pattern to the resulting fabric. Here, staple fibers (e.g. cotton) are formed into a dry laid web, by carding operation. This web is then passed through a high-pressure liquid stream, which in turn entangles the staple fibers, forming the non-woven fabric.
Difference between Wovens and Non-Wovens
The production process of nonwoven fabrics is much smaller than that of woven fabrics, making nonwovens comparatively less expensive to produce. Moreover, the fabric structure of woven fabrics provides it much more default durability and strength, as compared to nonwoven fabrics, although the choice of raw material will also affect these properties. Nonwoven fabrics are mostly used for interlining or to make hats or other handicrafts.
Fig: Fabric Structure of Woven and Non-Woven Fabric