| 摘要 |
<p>A process for preparing etherified melamine-formaldehyde condensates, in which a methylolation of melamine is first performed with a formaldehyde component in a molar ratio of 1:6 to 1:15, preferably at a pH of > 7. This is followed by an etherification of the resulting hydroxy-methylation intermediate in the presence of a C1-C20-alcohol, preferably of a C1-C6-alcohol, more preferably of a C1-C4-alcohol, at a pH of < 4.5, and subsequently by at least one distillation step in order to remove methanol in particular from the system, wherein a pH of > 9.5 is established before, during and/or after the distillation. According to the invention, this is followed by several hydroxymethylation, etherification and distillation steps, in order to achieve an etherified melamine-formaldehyde condensate which features a high degree of hydroxymethylation, a high solids content and a low viscosity.</p> |
