The flame retardant principle of pressure sensitive adhesive varies

It is not an easy task to assume the role of safety guard against fire. Flame retardants must have excellent skills.

Combustion requires three main elements — combustibles, combustibles (oxygen), and ignition sources.

The process of combustion is divided into heating, decomposition, fire, combustion, and spread. If any of these elements are removed, or if the burning process is controlled to the initial stage of heating and decomposition, the fire can be effectively avoided.

Different types of flame retardants have their own tricks for stopping the flame from burning.

Some prevent combustible materials from producing combustible gases by absorbing heat; Some form a dense covering layer on the surface of fuel to isolate the contact between fuel and oxygen; Some capture the free radicals involved in the combustion reaction, so as to inhibit the free radical chain reaction. Others dilute oxygen by producing a non-flammable gas, thus slowing the rate of combustion.

Inorganic flame retardant Al(OH)3

Inorganic flame retardant Al(OH)3 will decompose when it is heated to 200℃ and give off crystalline water, which evaporates into water vapor when heated. This series of processes absorbs a large amount of heat, reducing the temperature of the material surface and the flame zone, and slowing down the thermal cracking reaction. In addition, the water vapor produced by the crystallizing water also reduces the oxygen concentration, further inhibiting the spread of the fire.

Phosphorous flame retardant

When heated, phosphorous flame retardants turn into a more stable cross-linked solid material or carbonized layer, which acts like a solid armor to wrap the fuel, preventing both further pyrolysis of the material and the escape of the decomposed flammable gas inside the material to continue burning.

Bromine flame retardant

The evaporation temperature of bromine flame retardants is the same or similar to the decomposition temperature of polymer materials. When the polymer materials are decomposed by heat, bromine flame retardants will also volatilize and enter the gas phase combustion zone at the same time as the thermal decomposition products. Flame retardants can quickly capture free radicals in the gas phase combustion zone, inhibit free radical chain reaction, prevent flame propagation, and finally slow down the combustion reaction until termination.

In short, each flame retardant has its own secret.