Polyurethanes have been a minor player in the composite world. Unsaturated polyesters (UP) have the lion’s share among thermosets. But the outlook for polyurethane is very positive. There are sizable opportunities opening up as increased levels of concern over styrene emissions from unsaturated polyester and vinyl ester systems coincide with the need for fast, automated and consistent production quality.
Historically the material cost of polyurethanes was an issue, but this is now often offset by the increased productivity and/or possibility of slimming down moulded parts thanks to the superior toughness of PU composites compared to their rival technologies.
The versatility of polyurethane chemistry and innovations in fabrication machinery technologies are also combining into a wide array of solutions for composite manufacturers; from low volume serial production to massive production runs.
Physical properties such as tensile strength vary greatly with formulations and combinations of fibre reinforcement systems. Products with relatively lower strength produced using chopped-fibre-reinforced polyurethanes, to truly structural parts using continuous fibre reinforcements are…