By Janice Kleinschmidt
Woven fabrics begin with twisting fibers together and then weaving those yarns together. Nonwovens begin with the arrangement of fibers into a web by entangling them. There are three basic methods of binding the web to give it structure: chemical, thermal and mechanical.
In chemical bonding, polymers or copolymers are applied by impregnating, coating or spraying the fibers.
There are several methods of thermal bonding, which uses the thermoplastic properties of certain synthetic fibers to form bonds under controlled heating.
Mechanical bonding involves either needle punching or spunlacing (hydro-entangling fibers with high-pressure jets of water). Spunlaced nonwovens are the most durable, softest and most drapable nonwovens.
Once bonded, nonwovens can be cut without unraveling, laminated to other materials and finished to add functions, such as flame retardancy.