GB1093884A - Method of recovering polyol and amine derivatives by the decomposition of polyurethane substances - Google Patents

Abstract

Polyurethane foams and elastomers are thermally decomposed, in the presence of an amine, to yield a polyol, which is the polyether or polyester from which the polyurethane was formed, and the amine derivative of the polyisocyanate. The amine also serves as solvent. Suitable amines include aliphatic e.g. di-n-butylamine, ethylenediamine, and triethanolamine, cycloaliphatic e.g. cyclohexylamine, piperazine and piperidine, aromatic e.g. aniline, benzylamine, the toluidines, anisidines and p-phetidine, o-phenylenediamine, and a -naphthylamine and heterocyclic e.g. pyridine, a - and b -picolines, N - methyl and N - ethyl morpholine, and pyrazole. After the decomposition, one or more layers appear, and each layer is distilled under reduced pressure, the polyol being obtained as the residue. The amine derivative is isolated by recrystallization of the distillate. In the examples, the preparation and decomposition of polyurethane foams is described together with tests to establish the identical nature of the products of decomposition and the reactants of preparation. A mixture of 2,4- and 2,6-tolylene diisocyanate is used for the preparation of the polyurethane in examples (1-8) and 2,4 and 2,6-diaminotoluene are obtained from the ensuing decomposition. Similarly 1,5-naphthylenediamine in Example (9) and 4,41-diamino diphenyl methane in Example (10) are also obtained from the decomposition. The polyols recovered by the above methods are reconverted to polyurethanes. The reformed polyurethanes are cured using 4,41-methylene bis (2-chloroaniline) in Example (8) and butanediol in Example (9). The polyols used are: (1) the product of polymerization of propylene oxide with glycerol; (3) the product of polymerization of propylene oxide with sorbitol; (4) a polyester obtained from adipic acid and diethylene glycol; (8) polytetramethylene ether glycol; and (9) a polyester obtained from adipic acid and ethylene glycol.ALSO:Polyurethane foams and elastomers are thermally decomposed, in the presence of an amine to yield a polyol, which is the polyether or polyester from which the polyurethane was formed, and the amine derivative of the polyisocyanate. The amine also serves as solvent. Suitable amines include aliphatic, e.g. di-n-butylamine, ethylenediamine and triethanolamine, cycloaliphatic, e.g. cyclohexylamine, piperazine and piperidine, aromatic, e.g. aniline, benzylamine, the toluidines, anisidines, and p-phenetidine, o-phenylene-diamine, and a -naphthylamine, and heterocyclic, e.g. pyridine a - and b -picolines, N-methyl and N-ethyl morpholine, and pyrazole. After the decomposition, one or more layers appear, and each layer is distilled under reduced pressure, the polyol being obtained as the residue. The amine derivative is isolated by recrystallization of the distillate. In the examples, the preparation and decomposition of polyurethane foams is described together with tests to establish the identical nature of the products of decomposition and the reactants of the preparation. A mixture of 2,4- and 2,6-tolylenediisocyanates is used for the preparation of the polyurethane in Examples (1-8) and 2,4- and 2,6-diamino toluene are obtained from the ensuing decomposition. Similarly, 1,5-naphthylene-diamine in Example (9) and 4,41-diamino diphenylamine in Example (10) are also obtained from the decomposition. The polyols used are:-(1) the product of polymerization of propylene oxide with glycerol, (3) the product of polymerization of propylene oxide with sorbitol, (4) a polyester obtained from adipic acid and diethylene glycol, (8) polytetramethylene ether glycol, and (9) a polyester obtained from adipic acid and ethylene glycol.