Magnesium hydroxide
Sustainable flame retardant for rubber and polymer
How can effective flame retardancy be combined with sustainability?
In the rubber and elastomer industry, there is a growing demand for high-performance, environmentally friendly additives. Especially in the field of flame retardancy, one substance is coming into focus due to its physical mode of action—completely free of toxic side effects: magnesium hydroxide (Mg(OH)₂).
This article explores the reasons for using magnesium hydroxide, its applications, and the benefits it offers compared to traditional flame retardants.
What makes magnesium hydroxide a sustainable alternative?
Magnesium hydroxide functions through a purely physical mechanism: upon heating, it decomposes to release water, which cools the material. As a result, it slows the spread of flames and reduces smoke generation – without leaving behind toxic or corrosive residues.
Our advantages at a glance:
Efficient flame protection by absorbing heat and reducing smoke
Free of toxic gases – halogen-free and eco-friendly
Enhanced heat resistance for rubber and elastomer products
Compatibility with international fire protection standards (e.g., UL 94, DIN EN 13501–1)
What standards does magnesium hydroxide comply with, and why does it matter?
Different flame retardant standards apply depending on the application. Magnesium hydroxide helps to reliably meet these requirements:
UL 94 standard
One of the most important global standards for assessing the flammability of plastics—particularly relevant for electronics and electrical engineering. Magnesium hydroxide enables classification into higher ratings such as V‑0 or V‑1, depending on the component and application.
DIN EN 13501–1 (Europe)
This standard assesses building materials based on flammability, smoke production (s1–s3), and flaming droplets/particles (d0–d2). The classification scale ranges from:
A1 / A2 – Non-flammable
B / C / D – Decreasing flame retardancy
E – Ignitable, yet with specified performance characteristic
F – Not tested or not classified
Magnesium hydroxide enables the targeted development of flame-retardant rubber items with reduced smoke generation—perfect for applications subject to building regulations.
FMVSS 302 (Automotive sector)
This American standard governs flame propagation within vehicle interiors, including materials like seat foams, gaskets, and wiring. Magnesium hydroxide enables compliance with stringent requirements without the use of halogenated compounds.
What are the typical uses of magnesium hydroxide?
Magnesium hydroxide is applied across various sectors that demand both fire safety and environmental sustainability:
Automotive industry: For flame-retardant cables, seals, and interior components.
Building sector: Used in fire-resistant floor coverings, sealants, and insulation.
Electrical and electronics industry: Used in heat-stable insulation, connectors, and enclosures.
Comparison to other flame retardants
| Property | Magnesium Hydroxide | Aluminium Hydroxide (ATH) | Halogenated Flame Retardants |
| Environmental Compatibility | Very high, no toxic gases | Medium, lower thermal stability | Poor, releases toxic gases |
| Temperature Resistance | High (up to 340 °C) | Medium (up to 220 °C) | Variable, often temperature stable |
| Cost | Moderate, good value | Cheaper, does not cover all classifications | High, with additional disposal costs |
Trends and Innovations
As requirements for sustainability and safety grow, businesses are looking for eco-friendly alternatives to conventional flame retardants in multiple fields:
Electric mobility: Enhanced fire protection demands for high-voltage wiring and battery casings.
Green building projects: Employing environmentally friendly additives to enhance fire safety standards in construction.
Recycling rubber materials: Magnesium hydroxide allows for simpler reuse of rubber waste without toxic byproducts.
What specific solutions does MAGNESIA offer?
Contact us now
Christian Block and the Technical Magnesia team supports you with technical know-how and finds tailor-made solutions for your product idea.
Also ask for detailed information about specifications, safety data sheets or material samples.
