| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a new method leading to improvement of coloration of a produced diamine/polyamine mixture of diphenylmethane series or coloration of isocyanate and polyurethane produced from the mixture. <P>SOLUTION: In the method for producing diamines and polyamines of diphenylmethane series by reacting aniline with formaldehyde in the presence of an acid catalyst, the aniline to be used contains totally less than 0.5 wt.% of one or more compounds which contain at least one carbonyl group or one or more compounds that are formed by reaction of these compounds which contain at least one carbonyl group with aniline, based on the total weight of the aniline. <P>COPYRIGHT: (C)2010,JPO&INPIT |
