| abstract |
Hydrolytic liquefaction of polyurethanes, polyurethane-ureas and/or polyureas (A) comprises (1) heating (A) with (B) water, (C) amino cpds. of mol. wt. 17-399, opt. (D) mono-, di- and/or polyhydric alcohols of mol.wt. 32-250 and opt. (E) other mono-, di- and/or polyhydric alcohols of mol.wt. 251-20,000 for 1 min. - 72 hrs. at 120-250 deg.C, with wt. ratio (A):(C+D) = (3:1)-(1:10), and (2) at least partly removing components (C), (D) and (E). (A) Are polyurethane-urea and/or polyurea plastics prepd. by the RIM process from (a) MDI-series isocyanates, (b1) DETDA or (b2) ethylene glycol and/or butane-1,4-diol, (c) polyether-polyols of mol.wt. 400-20,000 with terminal OH and/or amino gps. and opt. (d) normal additives, etc. (A) is first dissolved by heating with (C) and opt. (D) and (E), then water (B) is added dropwise to produce a steady evolution of gas. USE/ADVANTAGE - Provides a simple process for the prodn. of NCO-reactive components (I) from polyurethane-type plastic scrap, esp. based on MDI and/or TDI, by heating for short periods at relatively low temp. and atmos. pressure; the process enables max. recovery of (I) for recycling, with complete recovery of (C). |