**2. Fibrous materials**

Nonwovens have three key features and are as follows:


While manufacturing nonwovens some conventional textile operations, such as carding, drawing, roving, spinning, weaving, or knitting, are partially or completely eliminated. For this reason, the choice of fiber is directly related to fabric quality [1-6, 8-11].

All kinds of fibers can be used to produce nonwoven fabrics. The selection of fibers is based on the following features[1,6]:


The commonly used fibers include natural fibers (cotton, jute, flax, wool), synthetic fibers (polyester (PES), polypropylene (PP), polyamide, rayon), special fibers (glass, carbon, nano‐ fibers, bicomponent, superabsorbent fibers), etc [1,6,8-10,12-15,16].

Two or more types of fibers are typically utilized. The fibers are usually blended or mixed in order to improve performance properties of nonwovens, such as strength and other properties. The fiber blend or mix can be natural/natural, synthetic/synthetic, or natural/synthetic [6,8-10].

Man-made fibers are the most widely used in the nonwoven industry. Owing to impurities and higher costs, natural fibers are of minor importance for the production of nonwovens.

Fiber characteristics influence not only nonwoven fabric properties but also processing performance. Web cohesion, fiber breakage, and web weight uniformity are the key quality parameters and are influenced by fiber diameter, fiber length, fiber tensile properties, fiber finish, and crimp. The properties of nonwoven fabrics are largely dependent on fiber properties and fabric structural geometry.
