| abstract |
The present invention provides a method for producing a diphenylmethane-based polyamine. This methodn n n a) reacting aniline and formaldehyde in the presence of an acid catalyst at a temperature of 20 to 100 ° C. at a molar ratio of 1.5: 1 to 6: 1, wherein the water content of the acid reaction mixture is less than 20% by weight and the degree of protonation Is less than 15%) andn n n b) raising the reaction temperature to 110 to 250 ° C. when the weight content ratio of p-aminobenzylaniline to 4,4′-MDA in the acid reaction mixture drops to a value below 1.00.n n n Diphenylmethane Polyamine, Aniline, Formaldehyde, Acid Catalyst, Protonation Degree, Moisture Content, Diphenylmethane Polyisocyanate, Polyurethane |