Nanjing Beyou Extrusion Machinery Co.,Ltd.
Nanjing Beyou Extrusion Machinery Co.,Ltd.
How to realize flame retardant modification of modified plas

How to realize flame retardant modification of modified plas

Time: 2019-12-20 Browse times:
油雾润滑系统提供十分细小的油颗粒悬浮在低速、低压的空气中。油颗粒通过各喷嘴和/或与高速运转的轴承部件撞击使轴承弯曲浸透油。


The application of modified plastics in home appliances, electronic appliances, automobiles and other fields often needs flame retardant,Flame retardant modification can be realized by adding flame retardant with bromine flame retardant and halogen-free flame retardant.
 
Flame retardants are also known as flame retardants, fire-proofing chemical or fire retardant, which give inflammable polymers the function of flame retardants. They are mostly compounds of the group A(phosphorus) A(bromine chloride) and A(antimony aluminum) in the periodic table.
 
Flame retardant principle of modified plastics
 
1.Endothermic effect
The amount of heat emitted by any combustion in a short period of time is limited. If a part of the heat emitted by the ignition source can be absorbed in a short period of time, the flame temperature will decrease, radiate to the combustion surface and act on the gasified gas. The heat of flammable molecules to be broken down to free radicals will be reduced, and the combustion reaction will be suppressed to a certain extent. Under high temperature conditions, the flame retardant has undergone a strong endothermic reaction, absorbing part of the heat released by combustion, reducing the surface temperature of combustible materials, effectively inhibiting the generation of combustible gases, and preventing the spread of combustion.
 
2.Covering effect
After adding flame retardants to combustible materials, the flame retardants can form glassy or stable foam covering layer at high temperature, isolate oxygen, and have the function of heat insulation, oxygen barrier, to prevent flammable gas from escaping outward, thus achieving the purpose of flame retardancy. For example, when the organic phosphorus resistant flame retardant is heated, it can produce a more stable cross-linked solid material or carbonized layer. On the one hand, the formation of carbonization layer can prevent the further pyrolysis of polymer, on the other hand, it can prevent the internal thermal decomposition of the polymer from entering the gas phase to participate in the combustion process.
 
3.Inhibition chain reaction
According to the chain reaction theory of combustion, free radicals are needed to maintain combustion.The flame retardant can act on the gas-phase combustion area to capture the free radicals in the combustion reaction, thus preventing the spread of the flame, reducing the flame density in the combustion area, and finally reducing the combustion reaction speed until the end.
 
4.Asphyxiation of non combustible gas
When the flame retardant is heated, it will decompose the non combustible gas and dilute the concentration of the combustible gas decomposed by the combustible to the lower limit of combustion.At the same time, it can also dilute the oxygen concentration in the combustion zone, prevent the combustion from continuing, and achieve the flame retardant effect.
 
Flame retardant grade of plastics
Flammability UL94--the most widely used standard for the flammability of plastic materials.It is used to evaluate the ability of materials to extinguish after being ignited. There are several methods to evaluate the droplet resistance according to the combustion rate, combustion time, and whether the droplet burns or not.
 
Flame retardant grade of plastics: HB, v-2, v-1, v-0,5VB increases gradually from HB, v-2, v-1, v-0,5VB to 5VA; HB: the lowest flame retardant grade in UL94 standard.
 
Flame retardants were developed together with flame retardants compounding technology. Flame retardant compounding technology refers to compounding between phosphorus, halogen, nitrogen and inorganic flame retardants, or within a certain type of flame retardant. In the practical application of flame retardants, a single flame retardant often has some defects, which is difficult to meet people's higher and higher requirements. Therefore, through the flame retardant compounding technology, the advantages of two or more flame retardants can be integrated, and the advantages and disadvantages can be drawn, so as to maximize the synergistic effect of flame retardants, so as to reduce the dosage and enhance the flame retardant effect.

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