Flame-retardant ABS is made from YISHION ABS resin as base material, adding 

high thermal stability flame retardant and so on. It is made by mixing, melting

 and plasticizing and granulating. The preparation methods of flame retardant

 ABS are usually divided into two types. One is copolymerization of monomers 

containing halogen elements in graft polymerization, and then the flame retardant

 ABS is prepared. This method is difficult to achieve satisfactory flame retardancy

 because of the limitation of the amount of fourth monomers when copolymerization

. The two is to blend the compounds or polymers containing halogen elements and

 other flame retardant additives and ABS resin to make blends of flame retardant ABS

, which has been widely used in industrial production. The flame retardant is easily 

decomposed, carbonized or yellowing at high temperature, so the forming temper

ature should be as low as possible. It is usually set below 190 C (the resin melt

 temperature is below 220 C). "Carbonization" is not bad, the flame retardancy 

principle can be divided into four mechanisms: (1) isolation of oxygen and promoting

polymer carbonization to reduce flammable gas production and flame retardancy; (2)

 produce non flammable gases to dilute oxygen concentration to slow combustion

 speed; (3) heat absorption and release of water gas before the combustion occurs, 

To reduce the temperature and achieve the effect of flame retardancy, (4) interfere

 with the formation of free radicals by chemical methods. According to the composition,

 the addition type flame retardants mainly include inorganic flame retardant, halogen

 flame retardant (organic chloride and organic bromide), phosphorus flame retardant

, and phosphorous compound is a promising combustible in the global halogen free

 combustible agent. Organic phosphate, such as BDP and RDP, is the main phosphorus

 burning refractory in China. The refractory carbonization layer (char) is formed on the

 plastic surface after the plastics are heated, and the carbonized layer obstruct the flow o