| 摘要 |
<p>Polyurethane (PU) mouldings, produced by reacting (a) polyisocyanates with (b) polyols with an OH number of 100-500 mg KOH/g, a water content of 0-5 wt% and a viscosity of more than 2000 mPa.s (20 degrees C), is obtained by chemical cleavage of waste PU and/or polyurea materials. Also claimed are: (i) polyols obtained as above, with an OH number of 100-500, preferably 200-450, especially preferred 250-400, a water content of 0-5 (preferably, 0.2-2, especially preferred 0.5-1) wt.% and a viscosity of more than 2000 (preferably 3000-20000, especially preferred 5000-10000) mPa.s; (ii) a process for the production of PU mouldings by reacting (a) with recycled polyols (b) as above, optionally with other substances and additives etc.. Preferably the PU mouldings have a density of50-1500 kg/m<3>. Preferred products are foam mouldings, especially in the form of a composite with a PU core and outer layer(s) of plastic material (optionally fibre-reinforced). Polyols (b) have a viscosity of 5000-10,000 mPa.s at 20 degrees C, and are obtained by the glycolysis of scrap PU and/or polyurea. Preferably the process (ii) involves the production of sandwich elements by applying at least one outer layer of optionally fibre-reinforced plastic material.</p> |
