The present invention discloses a methylated amino resin and its synthesis method, belonging to the technical field of amino resin preparation, and comprising the following steps: adding
methanol to the hydroxymethylated
intermediate product, adjusting the pH to 3 - 4.2 with acid, controlling the temperature at 60 - 65 °C, carrying out a heat preservation reaction for 3 - 4 h, then adjusting the pH to 8.8 - 9 with alkali, raising the temperature to 110 - 115 °C for distilling off water, cooling to 45 - 50 °C and adding auxiliary components, then raising the temperature to 85 °C for a constant temperature reaction for 3 - 4 h, after cooling to
room temperature, standing for 4 - 6 h and then filtering, heating the filtrate under normal pressure for
distillation for 1 - 2 h, then starting the vacuum
system, with a vacuum degree of -0.085 MPa, carrying out heat preservation treatment at 70 °C for 3.5 - 4 h, pumping the product into the finished product kettle, adding
isobutanol, and stirring evenly to obtain the methylated amino resin. Compared with the existing methylated amino resin, the content of free
formaldehyde is lower, and the paint film formed after crosslinking has good
toughness and good
water resistance.