Preparation of a novel melamine formaldehyde resin with palmitoylated melamine involved and its functional coating

Generally, melamine-formaldehyde resin (MF) has some defects, including poor fluidity, high cross-linking density, high curing shrinkage rate, and a tendency to cause brittle fracture in cured films. These factors pose significant obstacles for the direct application of MF in coatings. In this study, a novel purified palmitoylated melamine (PM) intermediate was synthesized by acylation reaction between equal molar palmitoyl chloride (Pc) and melamine(M), and then mixed with M (with 10% mass substitution of M). The mixture was reacted with formaldehyde, butanol, and polyethylene glycol 400 (PEG400) to prepare palmitoylated melamineformaldehyde resin (PMF). The prepared PMF displays excellent direct coating ability on various hard substrate surfaces, with a cured coating film surface that is uniform and smooth. In addition, the coating exhibits excellent surface hydrophobic function (with a water contact angle is up to 100 degrees), high light transmittance (with a gloss of 135 degrees and a light transmittance of 95.8%), intrinsic flame retardancy (with a limiting oxygen index is 27.6% and a surface resistance to cigarette burning of 5 grade), self-cleaning properties (hydrophobicity, lipophobicity and lubrication) and other comprehensive properties. The adhesion of the coating (cross cut test) was 0 grade, the impact resistance is 80 mm, the pencil hardness was 8H, the wear resistance of the coating was only 0.02 mg per 100 revolutions (0.02 mg/100r), and the coating surface resistance to chemical contamination (tested with acetone, 10% citric acid solution, and 25% sodium hydroxide solution) was level 5. These advantages of great significance for the expansion of the application field of melamine-formaldehyde resin.