Clariant talks about fire retardant coatings: how to prevent the spread of fire?

Fire-resistant coatings can save a lot of money, and more importantly: life.
But what is the current solution for developing this coating? How are they tested and what are the future trends? In our interview, Klaus Bender, Technical Marketing Director of Intumescent Coatings from Clariant, gave some answers.
When do we use which fire retardant paint? When do we use which fire retardant paint?Klaus Bender: There are so many different coatings, depending on the effect you want to achieve.
If fires are to be prevented, coatings that prevent inflammation of building materials should be used.
This is related to combustible ground, so wood is first; then ignition sources, such as short circuits or discarded cigarette butts, should be prevented.
Here, we have a relatively low level of demand, which involves the effect of temperature.
We found another situation is burning.
The spread of the fire house led to the burning of building materials, office materials and plastics.
This has become a big problem in our family because we find a lot of plastic here today.
The inflammation progresses relatively quickly and the smoke develops more intensely.
Such fires will spread through openings in other rooms.
We will soon have to deal with a large fire, such as the Grenfell Tower in London a few years ago.
If you want to protect the entire building from collapse in this situation, you need a more powerful weapon, and then use an intumescent coating for special protection of the steel structure.
The working principle of these coatings is to foam and form a protective foam in the event of a fire.
This foam has good thermal insulation properties and can withstand high temperatures.
What are the raw materials used by manufacturers of fire retardant coatings? What are the raw materials used by manufacturers of fire retardant coatings?   Klaus Bender: In the first case, when the paint is just to prevent fire, the raw material can be ammonium polyphosphate or aluminum trihydrate (ATH).
Hydrate forms water vapor, so it can reduce the temperature of the initial fire.
Ammonium polyphosphate will also form a carbon layer on the surface and react with the paint components, so that the building materials will not be affected by the oxygen supply and prevent the fire from spreading further.
     Intumescent fire retardant coatings are designed to provide passive fire protection.
Active fire protection is a sprinkler system, while passive fire protection simply exists and works without activation in the event of a fire.
Here, we also found that ammonium polyphosphate is the main ingredient to a large extent.
If more ingredients are needed to achieve the swelling effect, these ingredients must be accurately added to the color.

Halogenated flame retardants are still in use.
What is the current situation? Halogenated flame retardants are still in use.
What is the current situation?   Klaus Bender: Halogenated flame retardants, whether chlorinated or brominated flame retardants, still play a relatively important role, especially in plastics.
When a fire occurs, halogens will be separated out to act as free radical scavengers, that is, halogens will deactivate high-energy free radicals (such as hydroxyl radicals), thereby slowing down the chain reaction during fire.
  The disadvantage is that hydrogen halides, that is, toxic gases such as hydrochloric acid, are formed in the event of a fire.
Therefore, halogenated fire retardants have attracted more and more attention, and some of them have been banned.
This applies especially to PU substrates.
TCPP may no longer be used in the future, but there are some alternatives that can be used.
For example, the phosphorus flame retardant provided by Clariant has the same flame retardant effect.
What are the current testing methods for fire retardant coatings? What are the current testing methods for fire retardant coatings?   Klaus Bender: The tests developed to simulate fires are as varied as the fires themselves.
The first is a small flame with an attractant.
People try to ignite a small surface, but usually only get a simple result, and then it means pass or fail.
Modern methods also generate various physical test data, such as combustion energy or oxygen consumption.
The latter is measured with a cone calorimeter, we also use a cone calorimeter at Clariant, where the sample is relatively small, only 10 x 10 cm.
 
      The European SBI test (single combustion) also requires oxygen consumption, which is now the standard classification test for building materials throughout Europe.
But the old test standards and old test methods still exist.
For example, in Germany, this would be the "Brandschacht test", in the UK it would be the "radiant panel test", and in France it would be the "Epiradiateur".
They basically all want the same thing, that is, the evaluation of the burning ability of building materials.
These tests have actually been withdrawn from the market in order to obtain a unified test throughout Europe.

From the paint manufacturer's point of view, how are these tests performed? From the paint manufacturer's point of view, how are these tests performed?   Klaus Bender: Normally, a person uses a reference substrate, from the fire behavior that one person knows, such as particle board.
A varnish was applied to the particleboard, and the coated sample and the uncoated sample were compared.
Of course, the performance of the coated sample cannot be lower than that of the uncoated sample.
  It is very difficult to test the paint film yourself, because the paint film is too thick and the result is not real.
For example, testing of textiles and plastics.
Take plastic as an example.
Use a glowing wire and place it on the surface.
You can see if it starts to burn or if something falls and burns.
Therefore, the characteristics of the test are very different and adjusted for their respective applications.
  There are some standards that are universal and recognized globally, for example in the plastics or automotive industries.
But many are only used locally, such as in Russia, South Korea, and Japan.
What trends have been observed in the field of fire retardant coatings? What trends have been observed in the field of fire retardant coatings?   Klaus Bender: We see the general trend of water-based formulations.
Of course, we must also provide answers in the field of flame retardants.
For example, ammonium polyphosphate can also be used in aqueous systems, but it also has some special requirements, such as viscosity characteristics, which are different for aqueous formulations and solvent-based formulations.
  In the case that the aqueous system cannot be used, there is a tendency to favor the 2k system.
For example, it needs to have very good performance under severe conditions and must meet high requirements in terms of durability.