**3.2. Drylaid nonwoven**

The drylaid nonwoven process consists in fiber preparation, web formation, web bonding, and stabilization (Figure 4).

The fiber preparation is close to classical textile industry staple fiber preparation including bale opening, blending, coarse, and fine opening. Then the web forming machine is fed with the help of a chute in case of short staple fibers or with the help of a hopper in case of long staple fibers. The fibers fed by a chute or hopper condensed into the form of a lap are introduced into a carding machine. The carding machine separates fibers, starts the process of individu‐ alization, and delivers the fibers in the form of a web [24,25].

The web is then formed into the desired web structure by layering the webs extracted from the carding machine. Based on the final chosen weight and web structure, the layering can be completed by using longitudinal layering, cross layering, or perpendicular layering.

Web strengthening can be done mechanically with the help of needle punching which consists in bonding nonwoven web by mechanically interlocking the fibers through the web using barbed needles (Figure 4), with the help of stitch bonding which consists in consolidating fiber webs using knitting elements or with the help of hydro-entanglement which consists in locking the fibers together using fine high pressure water jets directed across the web.

**Figure 4.** SEM photomicrograph of needle-punched nonwoven (natural and synthetic fibers)

Mechanical bonding can be replaced with web chemical bonding which consists in applying the chemical binder to the web and curing it.

In case of thermoplastic and thermostable fiber blend web, the strengthening can be achieved by thermal bonding.
