Flame retardant materials include organic flame retardant materials and inorganic flame retardant materials. Current flame retardant materials are materials that can achieve flame retardant effects after adding flame retardants. Generally speaking, there are various types of flame retardants, including organic flame retardants and inorganic flame retardants. Organic flame retardants have good flame retardant effects and relatively few additives. However, organic flame retardants have the disadvantages of large smoke production and release of toxic gases during combustion. Inorganic materials have the advantages of being non-toxic, smokeless, non-volatile and cheap, but they contain a large number of additives.

1. Current status of development at home and abroad

Flame retardants are propellants for polymer synthetic materials. They can be used to treat polymer materials to prevent them from burning and prevent the spread of fire, making the synthetic materials smoke-extinguishing, self-extinguishing and flame-retardant.

2. Analysis of the advantages and disadvantages of commonly used flame retardants

In recent years, with the increase in the output of plastic products and the improvement of safety standards, flame retardant materials have been more widely used. Generally speaking, flame retardant materials can be divided into organic flame retardant materials and inorganic flame retardant materials. Among them, organic flame retardant materials are mainly halogen additives, and inorganic materials not only have a certain flame retardant effect, but also produce hydrogen chloride and prevent smoke. In addition, inorganic flame retardant materials are non-toxic, non-corrosive and cheap. The consumption of inorganic flame retardant materials in the United States, Japan and other countries exceeds 60%, however, the consumption of inorganic flame retardant materials in my country is less than 10%.

2.1 Halogen flame retardant

Halogen flame retardants not only have the largest output, but also are the most widely used. Materials added with this flame retardant can release hydrogen halides during combustion and obtain free radicals, thereby preventing the transmission of the combustion chain and generating low-activity free radicals to slow down combustion. Halogen flame retardants are generally used in thermoplastic materials and thermosetting materials. They are not only compatible with polymer materials, but also easy to use. Therefore, they are popular in the market and widely used in the automotive, packaging, textile and other industries.

2.2 Phosphorus flame retardants

Inorganic phosphorus flame retardants mainly include phosphates, red phosphorus, etc. Red phosphorus is widely used and is a good flame retardant. However, in actual applications, red phosphorus flame retardant materials are easily oxidized and release harmful and highly toxic gases. The dust produced by combustion can easily lead to explosions. There are certain dangers in resin mixing and molding processing. Therefore, phosphorus flame retardant materials are subject to certain restrictions on use. The improved red phosphorus flame retardant is to add metal hydroxides to it, which solves the toxicity problem of polymer materials to a certain extent.

2.3 Nitrogen flame retardants

Common varieties include melamine, melamine cyanurate (MCA), etc., which often require the addition of synergists. Nitrogen/phosphorus is the most commonly used synergistic flame retardant system, mainly used in PA, PU, ??PO, PET, PS, PVC and other resins.

Melamine cyanurate is a nitrogen-containing, halogen-free, environmentally friendly flame retardant, particularly suitable for unfilled PA6 and PA66, available in powder and granular forms. When the polyamide foam flame-retarded by this product burns, the carbon foam layer formed protects the polymer and insulates heat and oxygen.

2.4 Metal oxide flame retardants

Metal oxide flame retardants mainly add inorganic elements with inherent flame retardancy in the form of simple substances or compounds to the flame-retardant substrate, fully mix them with polymers in a physically dispersed state, and play a flame retardant role through chemical or physical changes in the gas phase or condensed phase.

Aluminum hydroxide is the most sold inorganic hydroxide flame retardant, mainly used in artificial rubber, thermosetting resin and thermoplastic plastics with processing temperature below 200°C. Plastics flame-retarded by aluminum hydroxide have the outstanding advantage of low smoke generation in flames.

Magnesium hydroxide is an inorganic flame retardant with better thermal stability. It is still stable at over 300°C and is widely used in many artificial rubbers, resins, including engineering plastics and other resins processed at high temperatures. It plays a role in flame retardancy and smoke elimination in polymer systems. When used in combination with ATH, they complement each other and have better flame retardant effects than when used alone.

3. Future development trend of flame retardants

In the past 10 years, the growth rate of flame retardants in my country has remained at 15% to 20%. The current annual consumption is about 570,000 tons, and the consumption of flame retardants in my country will increase to about 840,000 tons in 2019. Although the total consumption of flame retardants in my country is higher than the world average, in terms of proportion, the application of flame retardant materials in my country is still far below the world average, and the gap with developed countries in Europe and the United States is even greater.