The textile structure of a nonwoven fabric is produced by bonding or interlocking the fibers. This is accomplished by mechanical, chemical, thermal, or solvent methods, or by a combination of these methods.
The principal bonding methods are resin bonding and thermoplastic fiber bonding. In resin bonding, the resin is sprayed or applied as a foam directly onto the web of fibers as it emerges from the web-forming equipment. The web is then dried, heat cured, and, in some instances, pressed. In thermoplastic bonding, a thermoplastic (heat-setting) fiber, with a lower melting point than a base fiber, is blended with the base fiber in the form of a web. The web is pressed between heated rollers, bonding the plastic fibers to the base fibers.
The chief mechanical method of producing nonwoven fabrics is with a needle-punch machine, which was designed primarily to produce blankets. The machine uses small hooked needles to interlace and interlock the fibers.