| 摘要 |
A method of stabilizing an intermediate polymer containing unreacted isocyanate groups and derived from (1) an organic diisocyanate; (2) a material of molecular weight at least 750 which is a polyalkylene ether glycol or a hydroxy terminated polyester derived from a glycol and a dicarboxylic acid, and (3) a chainextending agent having a plurality of active hydrogen atoms, comprises incorporating with the intermediate polymer enough of a nitrogen base having a basic ionization constant of at least 1 X 10-12 at 25 DEG C. and containing one and only one nitrogen atom having hydrogen attached thereto and no other functional groups containing active hydrogen, to provide at least one such nitrogen atom for each unreacted isocyanate group in the polymer. The stabilized polymer may be subsequently converted to the final elastomeric product by incorporating 1-20 per cent of an organic polyisocyanate and subjecting the mixture to a temperature of 80-175 DEG C. The stabilizer is normally incorporated by mixing on a rubber mill. In examples: (1) a polymer derived by reacting polyethylene glycol and 2,4-tolylene diisocyanate in presence of benzene sulphonyl chloride and reacting the product with water in presence of pyridine, is stabilized with morpholine, ethyleneimine, cyclohexylamine, dicyclohexylamine, n - butylamine, di - n - butylamine, diisobutylamine, allylamine, benzylamine or ammonium carbonate (which decomposes at the temperature used); (2) a polymer derived from polypropylene glycol, 2,4-tolylene diisocyanate and water as in Example (1), is stabilized with piperidine; (3) and (4) a polymer derived by reacting poly-ethylene-propylene adipate with 2,4 - tolylene diisocyanate in presence of benzene sulphonyl chloride and reacting the product with water in presence of triethylamine is stabilized with allylamine, ammonium carbonate, aniline, benzylamine, n-butylamine, cyclohexylamine, di-n-butylamine, morphomorpholine, N-methylaniline or piperidine; (5)-(7) a polymer derived from polybutylene ether glycol, 2,4-tolylene diisocyanate and water, succinic acid, dithiooxamide, 1,3-propane disulphonamide, 1,2-ethanedithiol, 4-(beta - hydroxyethoxy) phenol, beta - hydroxymuconic acid or ethylene glycol is stabilized with piperidine; (8)-(11) a polymer derived from polybutylene ether glycol, hexamethylene diisocyanate or 2,4-tolylene diisocyanate, and water is stabilized with piperidine, dimethylamine, aniline or o-chloroaniline. Many of the stabilized polymers in the examples are cured by heating them with the dimer of 2,4-tolylene diisocyanate with, if desired, some magnesium oxide; di-(3-isocyanato-4-methylphenyl) urea may also be used. Chain-extending compounds specified, in addition to those exemplified are hydrogen sulphide, adipic acid, adipamide, hydroquinone, monoethanolamine, ethylenediamine and 4-hydroxybenzoic acid. Stabilizers specified in addition to those exemplified are mono- and di-ethylamine. Many other polyalkylene ether glycols, diisocyanates and polyester forming reactants are specified. Specifications 580,524, 580,526, 581,134, 581,143, 585,083, [all in Group IV], 731,071 and 791,852 are referred to.
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