Due to the production process of urea formaldehyde resin, the development of melamine industry has experienced a relatively rapid process. The research document first reported the synthesis of melamine resin in 1933. America Cyanamide Company began to produce and sell melamine powder laminates and coatings etc in 1939. In the 1950s and 1960s, Japan realized the full industrialization of melamine molding compound. In the 1960s, China began to introduce melamine production technology. After decades of development, the production capacity of melamine products is now the highest in the world, accounting for more than 80 9/6 of the global market share.
In order to know more about melamine powder, let’s have a look at the production process of melamine powder first.
The main raw material of melamine products is melamine molding compound, also known as melamine formaldehyde resin powder or melamine powder. The main raw material of melamine powder is melamine resin with high reactivity and crosslinkability. The melamine resin is a high-dandelion polymer synthesized by chemical reaction of melamine and aqueous formaldehyde solution under strict conditions. The reaction is usually carried out in a reactor equipped with a stirring, heating and condensing unit, generally in two steps.
1. The first step is the addition reaction. First, add 37% aqueous formaldehyde solution to the reaction vessel and adjust the pH to 7-9 to obtain a neutral or weakly alkaline medium. Then add an appropriate amount of melamine to make the moore formaldehyde and melamine between 2 and 3. The temperature of the reactor was adjusted so that it slowly heated to 60-85 ° C. At this time, formaldehyde and melamine were blocked by methylolation reaction, and a linear melamine oligomer containing 1 to 6 methylol groups was formed. The above reaction is an inexistible exothermic reaction. The higher the proportion of formaldehyde, the easier it is to form polymethylol melamine.
2. The second step is the condensation reaction. Under high temperature conditions, the highly reactive methylol melamine is further etherified or polycondensed to produces a crosslinked linear resin compound containing a methylene bond or a dimethylene ether bond. by intramolecular or molecular means in an acidic medium environment. When the amount of methylol group is small, a methylene bond is generally dominant; in a sorghum-based resin, a dimethylene ether bond is generally formed, and a methylene bond is formed. The greater the degree of condensation of the polycondensation reaction, the lower the water solubility of the melamine formaldehyde resin solution and the greater the viscosity.
In the above reaction process, the molecular weight of the final product is determined by the specific reaction conditions, and the water solubility of the product is also greatly changed. Product forms are widely available from resin solutions to poorly soluble and insoluble and infusible solids. The resin solution has poor stability and is not conducive to preservation. In actual production, it is often used as a substrate and also inorganic materials such as d-cellulose, wood pulp, silica, colorants are added. It is made into a powdery solid which is a so-called melamine powder by a spray drying ball mill.
Huafu Chemicals is such a factory producing melamine resin powder. If you are interested, please contact us Email : melamine@hfm-melamine.com
Post time: Sep-20-2019