Development of continuous compounded grades of fibre-reinforced composites based on non-acid cure phenolic resols

Commercial grades of dough moulding compounds (DMC) are typically based on glass fibre reinforcement, unsaturated polyester resins (UPR) and particulate inorganic fillers. Such systems are inherently inflammable and will emit dense smoke on combustion, therefore the more expensive fire retarded grades of UPR must be used for fire critical applications. The recently-introduced, second generation phenolic resols are intended for composite applications. These resins have in particular, excellent fire and smoke properties which gives them the potential to replace UPRs in DMC formulations: these phenolics are of comparative price. [Continues.]