Odorous emissions of polyurethane raw materials and parts

Many articles of daily use are made of or contain polyurethane (PU), for instance clothes, mattresses, furniture filling, insulation materials or automotive interiors. Polyurethanes (PUs), as most synthetic materials can emit volatile organic compounds (VOC), some of which could be unpleasant odorous and may reduce the consumer acceptance or cause consumer anxiety. Therefore, the aim of the PU-industries was the development of low emission and low odor PU products. The prerequisite in order to do this was to reveal the odorant sources and to understand their formation pathways during manufacturing. In contrast to other plastics, PUs are not commercially available as pellets/granulate or semi finished products for subsequent processing. PUs are produced in situ in the PUfactory by the exothermal polyaddition reaction of a polyol and an isocyanate component in presence of catalysts and additives like blowing agents, cross linkers, surfactants, flame retardants, pigments or fillers in order to achieve specific end product properties. Therefore, PU properties and corresponding material emissions are influenced by both the main PU components (polyol and isocyante), additives and catalysts as well as by production conditions like the reaction temperature. In order to reveal the causes for odor formation during the PU manufacturing process, the raw materials and additives of a conspicuous odorous PU product were sensorially evaluated. The odor evaluation showed that exclusively low odor raw materials and additives were used.