Smoke Suppressant

Many plastics, such as PVC, PS, PU, etc., will produce a lot of smoke when they are burned. In a fire, smoke is the first and most likely cause of death and delays the timing of firefighting, so "smoke suppression" is on a par with "flame retardant".

Alfa Chemistry is committed to contributing to the research and development of flame retardant and smoke suppressant materials, providing a wide range of smoke suppressants, mainly including iron-based compounds, molybdenum-based compounds, and low-valent transition metal compounds.

Iron Compound

Molybdenum Compound

Transition Metal Compound

Other Smoke Suppressants

Composition of Smoke

During the combustion of the material, a large amount of black or white smoke will be produced. Among them, black smoke refers to the suspended solid particles and agglomerates in the combustion gas products. White smoke is mainly caused by water vapor generated when the material is burned, as well as tiny particles suspended in the air such as water vapor condensate, which reduce the light transmittance and increase the smoke density.

Smoke Generation Properties of Common Polymers

The maximum specific optical density (Dm), also known as the maximum smoke density, is generally used to measure the size of the smoke when the material is burned. The larger the Dm value of the polymer, the greater the fuming property, the thicker the black smoke when burning, and the greater the environmental pollution. The smoke generation properties of several common polymers are summarized in the table below.

Smoke Suppression Methods and Applications

There are two ways to reduce the amount of smoke. One is to use polymers with relatively low fumes (achieved through structural design and structural modification of polymers). Another is to use chemical methods or add smoke suppressants (or fillers) to the plastic. The diagram below lists various smoke suppression methods and application examples and possible mechanisms for reference only. [1]

Smokeless Flame Retardant Formula

When designing smokeless flame retardant formulations, low-smoke flame retardants should be selected as much as possible. The maximum specific optical density of various flame retardants is shown in the table below. Both the halogen/antimony flame retardant system and the coating of red phosphorus increase the amount of smoke and the diffusion of toxic gases, so when using a bromine flame retardant system, it is necessary to add a smoke suppressant at the same time.

Reference

1. Jianjun Li, et al. (2019). "7. The mechanism of smoke suppression". Theory of Flame Retardation of Polymeric Materials, pp. 195-210.