If you've been researching fire retardant coatings, you've probably run into a wall of jargon — intumescent, halogenated, char formation, gas-phase inhibition. LDH fire retardant is one of the newer, safer options, and the good news is that the idea behind it is refreshingly simple. This guide explains what LDH is and how it stops fire, without the chemistry degree.
What does LDH stand for?
LDH stands for Layered Double Hydroxide. Picture a stack of thin mineral sheets, like pages in a book. Each sheet is made of metal and hydroxide (that's the "hydroxide" part). Between the sheets sit two things that matter enormously for fire safety: water molecules and carbonate ions.
That layered structure is the whole trick. LDH is essentially a mineral sponge that holds water and gas-forming compounds locked away until heat releases them.
How LDH fire retardant works
When fire meets an LDH-coated surface, three things happen almost at once:
- It absorbs heat. Breaking down the hydroxide layers is an endothermic reaction — it soaks up energy from the flame, cooling the surface and delaying ignition.
- It releases water vapour. The stored water escapes as steam, diluting the flammable gases and oxygen a fire needs to keep going.
- It leaves a mineral shield. What's left behind is a stable, non-combustible residue that insulates the material underneath from further heat.
Compare that to old-school halogenated retardants, which interfere with the fire's chemistry and can release toxic, corrosive smoke as they do it. LDH works physically — cool, dilute, shield — and gives off nothing worse than water vapour.
In lab testing, Aeon Core's LDH retained 82.36% of its mass even at 899°C — proof that most of the coating stays behind as a protective heat shield rather than burning away.
Why "halogen-free" is the headline
Many traditional flame retardants rely on bromine or chlorine (halogens). They work, but when they burn they can produce corrosive gases and dioxins — and several are now restricted worldwide. Because LDH contains no halogens, it sidesteps that entire problem. That's why it's increasingly the choice for indoor spaces, furniture, textiles and packaging. Read more in our guide to halogen-free fire retardants.
Where LDH coatings are used
Because LDH can be formulated as a thin, clear, water-based coating, it suits materials that thick intumescent paints would ruin: wood, plywood, MDF, paper, cardboard, fabric and bamboo. It's ideal for interiors where you want fire protection without changing how something looks.
How Aeon Core uses LDH
Aeon Core LDH Gel is India's first fire retardant coating built on this technology. It's a nano-scale LDH colloid (particles around 285 nm) that penetrates porous surfaces and dries clear. We've published the full XRD, TGA, FTIR and DLS test data so you can see the science for yourself.