Nowadays, with the explosive development of materials science and technology, plastics, rubber, textiles and paints as the main components of polymer materials have become indispensable elements of production. Electrical appliances, tablewares and vehicles made of polymer materials are our life belt To great convenience, but also brought a lot of security risks.
  Low oxygen index polymer materials, oxygen content of 21% of the air is sufficient to meet the burning conditions of most polymer materials. Moreover, the release of smoke and toxic gases during combustion not only endanger human health, but also cause environmental pollution. In order to reduce its flammability and prevent fire, environmental flame retardants came into being.
The application of flame retardants is seen as an effective way to prevent fires, but the harm of flame retardants to the environment and human beings can not be ignored. Some flame retardants will slowly release toxic chemicals into water and air. These toxic chemicals are absorbed by the body, can long-term accumulation in the human body, disrupting the bodys nervous, endocrine, immune system, particularly noteworthy that pregnant women if excessive exposure to these toxic substances, can lead to neonatal birth weight is too low, Mental retardation, impaired ability to act. In addition, some flame retardants generate large amounts of smoke and toxic, harmful and corrosive gases when burned, resulting in "secondary disasters".
  Therefore, the road to environmental protection is imperative!
  Magnesium hydroxide Mg (OH) 2 is a kind of additive fire retardant which develops rapidly. It is a green flame retardant with low smoke and non-toxicity. It can neutralize the acidic and corrosive gases in the combustion process. Its flame retardant mechanism is similar to that of AL (OH) 3. Compared with AL (OH) 3, the decomposition temperature of Mg (OH) 2 is 100-150C higher than that of AL (OH) 3, which can be used for the flame retardancy of engineering plastics with processing temperature higher than 250C, The role, but to achieve a certain flame retardant effect, the amount required to be more than 50%, a great impact on the performance of the material. In order to reduce the amount of Mg (OH) 2 added in the polymer, one method is to finer Mg (OH) 2 particles, and the other method is to modify the surface of Mg (OH) 2 by coating to improve Its compatibility with the polymer.
  Anhui Shanghai aluminum hydroxide AL (OH) 3 its amount accounted for more than 40% of the total use of flame retardants. Aluminum hydroxide itself has three functions: flame retardant, smoke elimination and filling. Because of its non-volatility and non-toxicity, aluminum hydroxide can also act as a synergistic flame-retardant agent with a variety of substances and is known as a pollution-free inorganic flame retardant. However, there is a large amount of aluminum hydroxide shortcomings, usually need to join more than 50% in order to have a good flame retardant effect. In order to overcome this shortcoming, the granulation technology can be adopted to develop the direction of ultrafine, the narrowing of the particle size distribution; the improvement of the wrapping technology to improve the dispersibility in the polymer; the method of treating with the macromolecular bond and the like .
  Expandable graphite is a new type of halogen-free flame retardant, which is made from natural graphite acidified by concentrated sulfuric acid, and then washed with water, filtered, dried, then puffed at 900-1000C system. Inflatable graphite expansion of the initial temperature of about 220C, usually 220C began to slightly expanded 230-280C rapid expansion, after the volume up to the original 100 times, or even 280 times. Expandable graphite mainly plays the following roles in the flame retardant process: (1) forming a tough charcoal layer on the surface of the polymer to separate the combustibles from the heat source; (2) absorbing a large amount of heat during the expansion and lowering the system Of the temperature; (3) in the expansion process of the release of acid ions in the interlayer to promote dehydration and carbonization, and combined with the combustion of free radicals to interrupt the chain reaction. Expandable graphite and phosphorus compounds, metal oxides used in combination, can produce a coordinating role, adding a small amount can achieve the purpose of flame retardant.