Except for a few synthetic rubber products, most synthetic rubber products, like natural rubber, are flammable or combustible materials. At present, the main methods used to improve flame retardancy are to add flame retardants or flame retardant fillers, and to blend and modify with flame retardant materials. There are several types of flame retardant technologies for rubber:
1. Hydrocarbon rubber
Hydrocarbon rubber includes NR, SBR, BR, etc. Hydrocarbon rubber generally has poor heat resistance and flame retardancy, and most of the decomposition products during combustion are combustible gases. Adding flame retardants is an important way to improve the flame retardancy of hydrocarbon rubber, and the synergistic effect of flame retardants is utilized to further improve the flame retardancy effect. However, attention should be paid to the adverse effect of the amount of flame retardant on the mechanical properties of rubber.
Add flame retardant inorganic fillers such as calcium carbonate, clay, talcum powder, white carbon black, Aluminium hydroxide, etc. to minimize the proportion of combustible organic substances. Calcium carbonate and nitrogen alumina have an endothermic effect when decomposed. This method will reduce certain physical and mechanical properties of the rubber material, and the filling amount should not be too large.
In addition, increasing the crosslinking density of rubber can increase its oxygen index. Therefore, it can improve the flame retardancy of rubber. This may be due to an increase in the thermal decomposition temperature of the rubber material. This method has been applied in Ethylene propylene rubber
2. Halogenated rubber
Halogenated rubber contains halogen elements, with an oxygen index generally between 28 and 45, and the oxygen index of FPM even exceeds 65. The higher the halogen content in halogenated rubber, the higher its oxygen index. This type of rubber itself has high flame retardancy and self extinguishing upon ignition. Therefore, its flame retardant treatment is easier than hydrocarbon rubber. To further improve the flame retardancy of halogenated rubber, the method of adding flame retardants is usually adopted.
3. Heterochain rubber
The most representative type of rubber in this category is dimethyl silicone rubber, with an oxygen index of around 25. The actual flame retardant methods used are to increase its thermal decomposition temperature, increase the residue during thermal decomposition, and slow down the production rate of combustible gases.
Post time: Jul-27-2023
