Double-belt laminators are widely used to produce prepregs and unidirectional tapes with fiberglass or carbon fiber reinforcement. Such equipment also is used to consolidate glass fiber and carbon fiber mats, webs, or cross-ply reinforcements (including fabrics and nonwovens using commingled polymer-based fibers) with thermoplastic or thermoset matrices.
When older IR ovens are used with traditional nonwovens, fibers are exposed to heat throughout the thickness of the web (not just on top and bottom surfaces) and for a longer duration than typically is seen with contact heating, the preferred method. This can prove problematic for unconsolidated non-wovens – especially thermally sensitive formulations containing natural fibers (which can burn/carbonize) or thermoplastic fibers like polypropylene (which can shrink, sag, or even melt) during the preheating cycle. In cases where molders cannot justify the capital expense of installing contact heating systems, changing to pre-impregnated and preconsolidated non-wovens provides several benefits. First, thermoplastic fibers experience less shrinkage, so molders need not buy as wide a roll or sheet of product, thereby saving money. Second, the preconsolidated products heat faster, which reduces both time and energy requirements during preheating and molding while reducing risk of damage to the materials.