Decabromodiphenyl ether is an additive flame retardant. It is widely used in a variety of polymer synthetic materials, plastics, fibers, building materials, resins, coatings, etc. It is a general-purpose flame retardant at home and abroad. Agent. However, it is recognized that the quality of domestic decabromodiphenyl ether is worse than that of imports, but where is the difference and how to improve it can be described as diverse. This article briefly expounds the problems in the production of decabromodiphenyl ether in China.
Decabromodiphenyl ether is produced by the reaction of diphenyl ether and bromine in the presence of a catalyst. The process is divided into solvent method and excess bromine method. In the excess bromine method, bromine is used as a raw material and as a solvent, and diphenyl ether is directly added dropwise to the bromine for reaction. Compared with the solvent method, the method is easy to operate, has low requirements for equipment, high bromine content, good thermal stability, less "three wastes" in the production process, and is easy to govern, so it is commonly used at home and abroad.
However, in terms of technology, domestic products have a large gap compared with foreign countries. The main points are as follows:
Low raw material purity requirements: There are strict requirements on the purity and moisture content of diphenyl ether and bromine used as raw materials for decabromodiphenyl ether production. In order to meet the requirements, the raw materials purchased from the market must be purified to remove impurities and water, to ensure that there are few impurities in the raw materials; while the domestic requirements for diphenyl ether are relatively rough, and the raw materials are basically untreated. The brominated diphenyl ether has many impurities and poor thermal stability. It is also possible that the anhydrous aluminum trichloride is deactivated due to the excessive moisture in the raw material, resulting in failure of the reaction and scrapping of the material.
The reaction temperature is low: foreign countries have strict control over the temperature during the reaction, and the domestic dropping temperature and the continuous reaction temperature are lower than those in other countries. When the reaction temperature is too low, not only does the amount of frozen mass consume, but also the reaction time is long, which affects the production capacity of the device.
Post-treatment is too simple: After decabromodiphenyl ether is synthesized, it needs to undergo a series of post-purification post-treatment processes before it can be put into use. The post-processing process and equipment in foreign countries are all perfect; however, the post-processing of domestic products is basically limited to simple crushing and drying, and the quality of products cannot be compared with foreign countries at all.
In the course of many years of development, although many researchers have done related work, compared with foreign products, domestic products have large gaps in terms of appearance, melting point, particle size, free bromine, etc., and they still exist in production. More problems. China has a large number of manufacturing enterprises and a small scale. It is impossible to spend a lot of money on various technologies and equipment. Coupled with the low requirements for indicators, there is a clear gap between domestic products and imported products. The low quality of the products and the small market for sales have naturally led to low benefits, and many companies have ceased production in succession, creating a vicious cycle.
There is a gap between China's flame retardants and foreign products. While solving problems such as corrosion of equipment and poor labor environment, we must improve product quality in the first place, and take effective measures to improve the refining and refining process in order to truly improve product quality. Only to open the market of domestic decabromodiphenyl ether.