Uses of melamine

Melamine appears as pure white monoclinic prismatic crystals, is tasteless, and has a density of 1.573 g/cm3 at 16°C. Normal pressure melting point: 354°C (decomposition) ； Rapid heating sublimation, with a sublimation temperature of 300°C. Soluble in hot water; water solubility is 3 G/L at 20 ºC. Slightly soluble in cold water, very slightly soluble in hot ethanol; insoluble in ether, benzene, and carbon tetrachloride. Soluble in methanol, formaldehyde, acetic acid, hot ethylene glycol, glycerol, pyridine, etc. Low toxicity. It is relatively stable under normal conditions, but may decompose to release cyanide at high temperatures. The molecular model of melamine is weakly basic (pKb=8), and it can form melamine salts with hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic acid, and others. Under neutral or slightly alkaline conditions, it condenses with formaldehyde to form various hydroxymethyl melamines; however, in slightly acidic conditions (pH 5.5–6.5), it undergoes polycondensation reactions with derivatives of hydroxymethyl groups to produce resin products. Upon hydrolysis in strong acid or strong base solutions, the amine groups are gradually replaced by hydroxyl groups, first yielding diamide cyanuric acid, which further hydrolyzes to yield monamide cyanuric acid, and finally cyanuric acid. Melamine is a widely used basic organic chemical intermediate, with its primary use being as a raw material for the production of melamine-formaldehyde resin (MF). Melamine can also be used as a flame retardant, water reducer, formaldehyde cleaner, and more. This resin has a higher hardness than urea-formaldehyde resin; it is non-flammable, resistant to water, heat, aging, arcs, and chemical corrosion. It possesses good insulating properties, gloss, and mechanical strength, and is widely used in industries such as wood processing, plastics, coatings, papermaking, textiles, leather, electrical engineering, and pharmaceuticals. Its main uses include the following: (1) Decorative panels: It can be used to create fire-resistant, earthquake-resistant, and heat-resistant laminates, as well as decorative panels with bright colors that are strong and heat-resistant. These panels can be used as cladding for airplanes, ships, and furniture, as well as as fire-resistant, earthquake-resistant, and heat-resistant materials for house decoration. (2) Coatings: After being etherified with butanol or methanol, it is used as a binder for high-performance thermosetting coatings and solid powder coatings, and can be used to produce metal coatings as well as high-quality amino resin decorative paints for vehicles and electrical equipment. (3) Molding powder: Through processes such as mixing and granulation, it can be turned into melamine plastic, which is dimensionally stable and resistant to stains; it maintains good electrical properties even in humid conditions. It can be used to manufacture white, impact-resistant household items, sanitary ware, porcelain-like tableware, as well as high-grade insulating materials for electrical equipment. (4) Paper: After being etherified with diethyl ether, it can be used as a treatment agent for paper to produce high-quality papers such as anti-wrinkle, anti-shrinking, and non-rotting banknotes and military maps. (5) When mixed with other raw materials, melamine-formaldehyde resin can also be used to produce fabric finishing agents, leather tanning agents, polishing agents and water-repellent agents, rubber adhesives, combustion promoters, high-efficiency cement water reducers, steel descaling agents, etc.

On September 13, 2008, the China **Food Quality Supervision and Inspection Center stated that melamine is a chemical raw material and is not allowed to be added to food; therefore, no residue limit standards similar to those for pesticides have been established yet. On October 8, the Ministry of Health, the Ministry of Industry and Information Technology, the Ministry of Agriculture, the **State Administration for Industry and Commerce, and the **General Administration of Quality Supervision, Inspection and Quarantine issued a joint announcement establishing temporary regulatory limits for melamine in milk and dairy products: the limit for melamine in infant formula milk powder is 1 mg/kg, and products with levels higher than 1 mg/kg are not allowed to be sold. The limit for melamine in liquid milk (including raw milk), milk powder, and other formula milk powders is 2.5 mg/kg; products with a level higher than 2.5 mg/kg are not allowed to be sold. For other foods containing more than 15% milk, the limit for melamine is 2.5 mg/kg; products with a level higher than 2.5 mg/kg are not allowed to be sold. Furthermore, the \"2008 Liaoning Province Feed Product Quality and Safety Monitoring Plan\" stipulates that the amount of melamine added to feeds must be below 2 mg/kg, as determined by the Liaoning Province Animal Health and Supervision Bureau. And **** passed emergency legislation on September 22, 2008, to ban levels of melamine in food that exceed specified limits. New regulations stipulate that foods for infants, young children, and pregnant women must not contain more than 1 milligram of melamine per kilogram, while foods in general must not contain more than 2.5 milligrams per kilogram. On the Taiwan side, on September 24, 2008, the Health Bureau of the Executive Yuan, taking into account international testing methods and **the latest legislative provisions, as well as consulting experts from the Bureau of Pharmaceutical and Food Testing and the Food Industry Research Institute, decided that since it was difficult to detect melamine levels below 2 ppm in a short period of time, 2.5 ppm (2,500 ppb) should be set as the standard for detecting melamine residues in food in order to speed up the testing process. Later, due to public concerns, it is no longer allowed for melamine to be detected in dairy products. Referencing the European Union’s acceptable daily intake standards (0.5 mg per kilogram of body weight per day; for a 20-kilogram child, this amounts to 20*0.5=10 mg, and for an 70-kilogram adult, it is 70*0.5=35 mg), the New Zealand Food Safety Authority has set provisional limits for melamine residues in food at 5.0 ppm (5,000 ppb) for general foods and 1.0 ppm for infant foods. If the levels in commercially available foods are below these values, no risk warnings are issued. However, if it is found that these levels could lead to consumers consuming more melamine than the acceptable daily intake, or if cases of adulteration are detected, these limits will be reviewed promptly. The United States, following the pet food contamination incident in 2007, banned the addition of melamine to feed. The U.S. Food and Drug Administration (FDA) has recently set standards for the level of melamine in food, stipulating that adults should consume no more than 2.5 ppm of contaminated food per day

From a practical perspective, it would be strange if no accidents occurred from the use of melamine in food.

Melamine is a triazine-based nitrogen-containing heterocyclic organic compound, and an important raw material in the field of nitrogen-containing heterocyclic organic chemistry. Abbreviated as triamine; commonly known as melamine or protein essence. It is also called 2,4,6-triamino-1,3,5-triazine, 1,3,5-triazine-2,4,6-triamine, 2,4,6-triaminourea, cyanuramide, or tricyanuramide. . It is a widely used basic organic chemical intermediate, with its primary use being as a raw material for the production of melamine-formaldehyde resin (MF). Melamine can also be used as a flame retardant, water reducer, formaldehyde cleaner, and more. This resin has a higher hardness than urea-formaldehyde resin; it is non-flammable, resistant to water, heat, aging, arcs, and chemical corrosion. It possesses good insulating properties, gloss, and mechanical strength, and is widely used in industries such as wood processing, plastics, coatings, papermaking, textiles, leather, electrical engineering, and pharmaceuticals.

Dear experts, a large amount of waste is generated during the production of melamine. How should this waste be handled? Is there the best way to handle this? Our company is currently piled up with them; there are already so many that it’s difficult to deal with. Thank you.