Brief introduction of flame retardant classification

Flame retardant is a kind of chemicals used to inhibit or delay the combustion of materials, widely used in plastics, textiles, wood and other fields. According to the chemical composition and action mechanism, flame retardant agents can be divided into the following categories:

1. Inorganic flame retardant

-Metal hydroxide: such as aluminum hydroxide (ATH), magnesium hydroxide (MH), decompose to release water vapor, dilute combustible gas and cool down.

-Borate: such as zinc borate, forming a glass protective layer at high temperature to isolate oxygen and heat.

-Phosphorus inorganic substances: such as red phosphorus, ammonium polyphosphate (APP), isolate oxygen and promote carbonization by generating phospic acid layer.

2. Organic flame retardants

-Halogen flame retardants: such as bromine (decbromodiphenyl ether) and chlorine (chlorparaffin), interrupt the combustion chain reaction through the release of halogen radicals, but may produce toxic gases.

-Phosphorus organic flame retardants: such as phosphate esters, which isolate oxygen and promote carbonization by generating a phosphoric acid layer.

-Nitrogen flame retardants: such as melamine, which dilute oxygen by decomposition to produce an inert gas and absorb heat.

3. Compound flame retardant

-Phosphorus-nitrogen system: combining the synergistic effect of phosphorus and nitrogen to improve the flame retardant effect.

-Silicon flame retardants: such as silicone, which isolate heat from oxygen by forming a silicon carbon layer.

4. Nanometer flame retardant

-Nanoclay: such as clay, which enhances the flame retardant and mechanical properties of the material by forming nanocomplexes.

-Carbon nanotubes: delaying combustion by forming a network structure.

5. Expansion-type flame retardant

-Acid source, carbon source, gas source: such as ammonium polyphosphate, pentaerythritol, melamine, heated expansion to form carbon layer, isolated heat and oxygen.

6. Reactive flame retardant

-Chemical bonding:such as bromo-epoxy resin, through chemical reaction and material combination,better for flame retardant effect lasting.

7. Add the type of flame retardant

-Physical mixing: for example, decambromide diphenyl oxide,DBDPO,ether is added to the material through physical mixing, which is easy to use but may affect the material properties.

Sum up

There are many kinds of flame retardants, so the material characteristics, flame retardant requirements and environmental protection factors should be considered when choosing. With the progress of technology, high efficiency and low toxicity of flame retardant has become trend.