Melamine cyanurate (MCA) is a salt synthesized from melamine and cyanuric acid. It is a nitrogen series flame retardant and is available in powder and granular forms. , odorless, melting point is about 350℃. MCA has good dispersion and lubricity, and has little impact on the processing properties and physical and mechanical properties of the polymer. It is understood that when the flame-retardant polyamide foam of this product is burned, the carbon foam layer formed protects the polymer and insulates heat and oxygen. With the addition of this product, the smoke density and toxic gases of the polymer can be greatly reduced without producing irritating hydrogen halide gas. It is widely used in flame retardant of rubber, nylon, polyurethane, phenolic resin, epoxy resin, polyethylene resin and acrylic, especially suitable for nylon 6 66 without fillers.
The production method and flame retardant mechanism of melamine cyanurate (MCA) are as follows:
1. Production method:
There are two methods for melamine cyanurate MCA flame retardant, one is the urea process and the other is the cyanuric acid process.
(1) Urea method: While urea is pyrolyzed to generate cyanuric acid, melamine is added for reaction, or urea and melamine are thermally melted together to produce crude MCA flame retardant in one step, and then MCA flame retardant is refined through acid boiling, washing, drying and other processes.
(2) Cyanuric acid method: Place equal moles of melamine and cyanuric acid in water to form a suspension, react at 90-95°C for several hours, and continue the reaction for a period of time after the slurry becomes obviously viscous. time, and then filtered, dried, and crushed to obtain the finished product. The mother liquor can be recycled and reused.
2. Flame retardant mechanism;
After reaching 350 degrees, the MCA flame retardant begins to decompose to form MA and CA. This process requires absorption and polymerization. A large amount of heat is absorbed from the object and the surface temperature of the substrate is reduced.
CA and MA further decompose to generate non-combustible gases, such as ammonia. These non-combustible gases can quickly dilute the combustibles and oxygen produced by the polymer and reduce the concentration of combustible gases.
Melamine cyanurate generally needs to be compounded with phosphorus or piperazine pyrophosphate, triazine char-forming agent, pentaerythritol, etc. It can foam and expand the covering generated by the decomposition of phosphorus-carbon flame retardant. Prevent the exchange of heat and outside oxygen.
