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Flame retardant is a functional additive that endows flammable polymers with flame retardancy. Adding flame retardant to rubber products can prevent the ignition of rubber products or delay the spread of flame. What are the flame retardancy effects of flame retardants in rubber products, and what are the common flame retardants?

1. The flame retardancy of flame retardant is reflected in the following aspects:

When the rubber surface reaches sufficient temperature and oxygen concentration, combustible gas will spontaneously burn and further promote the burning of rubber products. The burning of rubber requires combustibles, sufficient temperature and oxygen. When the above conditions cannot be met, the combustion will not be carried out or stopped, and the flame retardancy of the flame retardant will prevent the above conditions from being met at the same time, thus playing the role of flame retardancy.

Flame retardant can dilute the concentration of oxygen and the concentration of combustibles generated during combustion.

Non combustible gas or foam layer is generated during combustion, or a liquid or solid covering layer is formed to isolate the flame from oxygen.

Absorb the heat released by the burning of rubber products to reduce the temperature of rubber, so as to prevent the rubber molecules from continuing to degrade or crack, thus interrupting the source of volatile combustible gas.

The intermediate products produced in the chain reaction in the combustion process are eliminated through passivation, so that the chain reaction in the combustion process is interrupted.

2. Flame retardant type

Antimony trioxide is a white powder crystal, which has excellent flame retardancy when used with halogen flame retardants. The amount of chlorine containing polymer material is about 4 phr, which can suppress the combustion. For the polymer without chlorine, the same amount of chlorinated paraffin, chlorinated biphenyl or other chlorides should be added. In the compound containing carbon black, chlorinated paraffins and antimony trioxide are commonly used as flame retardants to obtain better flame resistance.

Aluminum hydroxide is an inorganic environment-friendly flame retardant. Its flame retardancy is that the crystal water released after being heated can absorb heat and play a cooling role. At the same time, the produced water vapor can also dilute combustible gases. Aluminum hydroxide and other flame retardants have better effect.

Chlorinated paraffin HY20S10J2LWFM with 70% chlorine content is a white powder, which is generally used together with equivalent antimony oxide. At the curing temperature, a small amount of decomposition will occur, and hydrogen chloride and chlorine will be released, which will hinder the vulcanization. Therefore, it cannot be used for hot vulcanized products, and the amount used in rubber can generally reach about 40 phr.

Chlorinated paraffin with chlorine content of 72% is a transparent yellowish liquid with high viscosity, which can well reduce the combustibility of natural rubber, synthetic rubber and reclaimed rubber vulcanizates, and has better effect when used with antimony oxide. The mechanical properties of the compound can also be improved in nitrile rubber and reclaimed butadiene nitrile rubber.

Trimethylphenyl phosphate is a colorless and tasteless liquid, which is used in rubber and has synergistic effect with a small amount of antimony oxide. Trimethylphenyl phosphate can also be used as a plasticizer, which has good compatibility with rubber, can also improve the compatibility of other additives, and improve the wear resistance, weather resistance, aging resistance, etc. of rubber.

In order to better prevent fire or spread of fire in rubber products, flame retardants are generally used in combination. Flame retardants are reasonably selected according to product performance.