| 摘要 |
PROBLEM TO BE SOLVED: To provide a new method accompanying a further wide improvement of color, although in the coloration of a mixture of formed diamine and polyamine and the coloration of a mixture of isocyanate and polyurethane produced therefrom, the improvement is achieved by changing each of process parameters e.g. the addition of components, concentration of acid catalyst, control of temperature or product composition in rearrangement. SOLUTION: The diphenylmethane-based diamine and polyamine are produced by the reaction of aniline with formaldehyde in the presence of an acid catalyst, wherein the used aniline contains <3 mass% diphenylmethane-based diamine and polyamine, advantageously by 0.001 to 3 mass%, especially advantageously by 0.01 to 1 mass% based on the mass of the used aniline. COPYRIGHT: (C)2007,JPO&INPIT
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