Melamine has the advantages of bump resistance, corrosion resistance and high temperature resistance (the upper limit of high temperature is 120 degrees). Melamine tableware is formed by heating and pressing melamine resin powder. Melamine tableware belongs to high polymer, MF for short, and its monomers are formaldehyde and melamine. 37% formaldehyde aqueous solution was used in the reaction, and the molar ratio of formaldehyde to melamine was 2~3.
Extended data:
The results show that with the increase of formaldehyde dosage, the combined amount of formaldehyde also increases, and the reaction is easy to carry out. Melamine resins obtained from different hydroxymethyl melamine can be prepared by changing the amount of formaldehyde. When the pH of the reaction system is 8.5, there are fewer side reactions and the reaction is easy to control. High temperature, fast reaction speed, and little influence on formaldehyde binding capacity in the range of 54~80℃.
In the first step of the reaction, different numbers of N- hydroxymethyl substituents were synthesized, and then further condensed into linear resin. Generally speaking, the molecular weight of products varies with different reaction conditions, from water-soluble to water-insoluble, and even insoluble solids can be formed. Melamine resin does not cure at room temperature, and generally needs 130~ 150℃ thermal curing. The results show that adding a small amount of acid as catalyst can improve the curing speed. The cured melamine formaldehyde resin is colorless and transparent, stable in boiling water, and can even be used at the high temperature of 150℃, with self-extinguishing, arc resistance and good mechanical properties.