Brucite powder flame retardant aluminum-plastic panel: a fire barrier with a decomposition temperature of 320°C

With the continuous upgrading of building decoration materials, fire safety has become one of the important indicators for measuring product performance. Especially in crowded places such as high-rise buildings, commercial complexes and transportation hubs, higher requirements are placed on the flame retardant properties of building materials. In this context, brucite powder, as a natural inorganic mineral flame retardant, has been increasingly used in aluminum-plastic composite panels due to its excellent thermal stability and environmental protection characteristics, and has become the core technical support for a new generation of high-performance fireproof building materials.

1. Basic characteristics and flame retardant mechanism of brucite powder

Brucite is a natural magnesium hydroxide mineral with a chemical composition of Mg(OH)₂. Its crystal structure is stable and has good thermal decomposition properties. When the temperature rises to about 320°C, brucite begins to undergo a dehydration decomposition reaction to generate highly active magnesium oxide and release a large amount of water vapor. This process not only effectively absorbs heat and reduces the temperature of the combustion area, but also dilutes the oxygen concentration through water vapor, thereby inhibiting the spread of flames.

Compared with traditional halogen flame retardants, brucite powder has significant advantages:

Halogen-free and environmentally friendly: It does not contain toxic halogen elements, and no harmful gases such as dioxins and hydrogen bromide are produced during combustion.

High smoke suppression: The released water vapor can greatly reduce the smoke density and improve the visibility of escape in fire.

Stable residual carbon: The formed magnesium oxide layer has good ceramic properties and can form a dense protective layer at high temperature to further isolate heat sources and oxygen.

These characteristics make brucite powder an ideal green alternative material in the flame retardant system of aluminum-plastic panels.

2. Application form and process optimization of brucite powder in aluminum-plastic panels

Aluminum-plastic composite panels are lightweight and high-strength decorative materials composed of two layers of aluminum alloy thin plates and an intermediate core material. They are widely used in curtain walls, indoor ceilings, billboards and other fields. In order to improve its fire resistance, a certain proportion of brucite powder is usually added to the core material to build an efficient flame retardant system.

1. Material selection and formula design

In actual production, the selection of brucite powder needs to consider the following factors:

Purity control: It is recommended to select products with high whiteness and few impurities to ensure that the appearance quality of the board is not affected;

Particle size matching: Generally, finely ground powder with D₅₀ between 1.5 and 3.0 μm is used to ensure dispersibility without destroying the mechanical properties of the substrate;

Morphology control: Flake or spherical particles are more conducive to improving filling uniformity and interface bonding.

In conventional formulas, the addition amount of brucite powder is controlled between 25% and 40%, and an appropriate amount of synergistic flame retardants such as zinc borate and aluminum hydroxide are added to enhance the overall flame retardant effect.

2. Process adaptation and key technical points

To ensure that brucite powder can play the best performance in aluminum-plastic panels, the processing technology needs to be finely adjusted:

Mixing uniformity: Use a high-speed mixer for premixing to ensure that the powder is evenly distributed in the resin matrix;

Extrusion molding control: Adjust the extrusion temperature curve to avoid premature dehydration of brucite due to local overheating;

Surface treatment technology: Use silane coupling agent to modify the surface of brucite powder to improve its compatibility with the polymer matrix;

Curing system optimization: Use a segmented heating method to achieve simultaneous release of internal stress and structural stability of the material.

Through the above process optimization, the flame retardant grade, mechanical strength and weather resistance of aluminum-plastic panels can be significantly improved.

3. Actual measurement and analysis of the fire resistance of brucite powder flame-retardant aluminum-plastic panels

In order to verify the actual application effect of brucite powder in aluminum-plastic panels, many authoritative testing institutions have conducted systematic tests on it, covering multiple dimensions such as vertical combustion, smoke density, and heat release rate.

1. Combustion performance

In accordance with the GB/T 2408 standard, the vertical combustion test was carried out. The aluminum-plastic plate samples containing brucite powder reached the UL94 V-0 flame retardant grade. The burning dripping did not ignite the cotton paper, showing good self-extinguishing properties.

2. Smoke suppression and toxicity control

In the cone calorimeter test, the smoke density peak of the brucite powder flame-retardant aluminum-plastic plate was only about half of that of the traditional material, and the content of toxic gases such as CO and HCN in the combustion products was significantly reduced, which greatly improved the living environment in the fire scene.

3. High temperature tolerance

Through the thermal shock experiment under simulated fire conditions, it was found that this type of aluminum-plastic plate can still maintain basic structural integrity under a high temperature environment of 600℃, and the temperature of the back-fire surface rises slowly, which meets the technical requirements of A2-level non-combustible materials.

IV. Market application prospects and development trends

With the continuous upgrading of the country's building fire protection regulations and the continuous enhancement of the public's awareness of fire safety, brucite powder flame-retardant aluminum-plastic plates are gradually becoming the mainstream choice in the high-end building market.

1. Clear policy drive

National standards such as the "Code for Fire Protection Design of Buildings" (GB 50016) and the "Code for Fire Protection Design of Building Interior Decoration" (GB 50222) impose strict restrictions on the combustion performance of building materials, which has promoted the widespread application of flame-retardant aluminum-plastic panels.

2. Outstanding performance advantages

Compared with ordinary aluminum-plastic panels, brucite powder flame-retardant products perform better in fire prevention, environmental protection, and durability, and are especially suitable for crowded areas such as airports, subway stations, hospitals, and schools.

3. Innovative technology support

In the future, with the development of technologies such as nano-modification, microcapsule encapsulation, and bio-based resin compounding, the flame retardant efficiency of brucite powder will be further improved, and it is expected to achieve a higher level of fire protection at a lower addition amount.

With its unique physical and chemical properties and excellent environmental performance, brucite powder is reshaping the fire protection technology landscape of aluminum-plastic composite panels. Its initial decomposition temperature of 320°C enables it to respond quickly at the beginning of a fire and build an effective thermal barrier defense line. For modern buildings that pursue both safety and aesthetics, brucite powder flame-retardant aluminum-plastic panels are undoubtedly an ideal choice. With the improvement of industry standards and the continuous advancement of technology, this type of green flame-retardant material will occupy a more important position in future building fire protection systems.