Aluminum plastic panel bulging deformation? Innovative solution for regulating the thermal expansion coefficient of brucite powder

In the construction and decoration industry, aluminum-plastic panels, as a lightweight, beautiful, and easy to process composite material, are widely used in curtain walls, interior decoration, advertising signs, and other fields. However, in actual use, some aluminum-plastic panel products may experience "bulging" or "deformation", which seriously affects their appearance and service life. The reasons behind this problem are complex and diverse, but one of the core factors is the mismatch of thermal expansion coefficients between the components inside the material.

In order to solve this industry problem, a new regulatory method has gradually gained attention in recent years - by adding brucite powder to optimize the thermal expansion performance of aluminum-plastic panel core materials, effectively alleviating or even eliminating the problem of bulging deformation. We start from the structural principle of aluminum-plastic panels, analyze the causes of bulging deformation, and focus on introducing the mechanism and application prospects of brucite powder in it.

1、 Phenomenon and hazards of bulging deformation in aluminum-plastic panels

Aluminum plastic panel is composed of two layers of aluminum alloy thin plates and a middle layer of plastic core material, which has good wind pressure resistance, weather resistance, and decorative effect. But in environments with large temperature differences, especially in areas with large day night temperature differences or distinct seasons, aluminum-plastic panels often exhibit surface bulging, edge warping, and other phenomena, known as "bulging deformation".

This deformation not only affects the overall aesthetics of the building, but may also cause cracking and sealing failure at the joints of the panels, leading to safety hazards such as water seepage and detachment. Especially in high-rise buildings, the consequences of panel detachment are unimaginable.

2、 The fundamental reason for bulging deformation: difference in thermal expansion coefficient

The reason why aluminum-plastic panels bulge and deform is mainly due to the different degrees of thermal expansion between the metal aluminum layer and the plastic core material during temperature changes. The thermal expansion coefficient of aluminum metal is relatively low, while the thermal expansion coefficient of traditional plastic core materials (such as polyethylene) is relatively high. When the ambient temperature rises, the expansion rate of plastic core material is much faster than that of aluminum panel, resulting in internal stress imbalance, ultimately manifested as bulging or curling of the surface of the board.

In addition, if there are problems such as uneven composite technology and improper cooling control in the production process of aluminum-plastic panels, it will also exacerbate this deformation trend. Therefore, the key to solving bulging deformation lies in reducing the thermal expansion coefficient of the core material, making it closer to the expansion characteristics of the aluminum layer, and achieving coordinated and consistent thermal expansion of the overall material.

3、 Magnesite powder: a new approach to regulating thermal expansion

Brucite is a natural mineral with a chemical composition of magnesium hydroxide (Mg (OH) ₂), and its powder form exhibits excellent functionality in building materials. In recent years, researchers have found that adding an appropriate amount of brucite powder to the core material of aluminum-plastic panels can effectively regulate their thermal expansion behavior, thereby improving the dimensional stability of the panels.

1. Thermal expansion inhibition effect

Magnesite powder has a relatively low coefficient of thermal expansion, usually around 5 × 10 ⁻⁶/℃, much lower than the coefficient of thermal expansion of ordinary plastic matrices (about 150-200 × 10 ⁻⁶/℃). When added to the plastic core material, it can significantly reduce the thermal expansion rate of the entire core material, narrow the expansion difference with the outer aluminum plate, thereby reducing internal stress accumulation and preventing the occurrence of bulging phenomenon.

2. Enhance mechanical properties

In addition to regulating thermal expansion, brucite powder also has a certain enhancing effect. It can form tiny filling networks in the plastic matrix, improve the rigidity and compressive strength of the core material, and further enhance the overall mechanical properties of aluminum-plastic panels.

3. Flame retardant and environmental advantages

When brucite powder decomposes under heat, it releases crystalline water, which plays a role in heat absorption and flame retardancy, helping to improve the fire resistance of aluminum-plastic panels. Meanwhile, brucite is a non-toxic and harmless natural mineral material that meets the requirements of modern building materials for environmental protection and health.

4、 Application practice and effectiveness verification of brucite powder

At present, some enterprises have introduced brucite powder into the formula of aluminum-plastic panel core materials and conducted systematic experimental verification. Experimental data shows that:

Adding 5% to 10% brucite powder to the core material can reduce its thermal expansion coefficient by more than 40%;

In the simulated diurnal temperature difference cycle test, the aluminum-plastic panel modified with brucite powder did not show significant bulging, while the control group generally showed varying degrees of deformation;

The bending strength and impact resistance of the board have also been improved, showing better overall performance.

These results indicate that the application of brucite powder as a thermal expansion regulator in aluminum-plastic panels has broad prospects.

5、 Future Development Direction and Industry Suggestions

Although the application of brucite powder in the field of aluminum-plastic panels is still in its infancy, its potential for performance improvement has begun to emerge. The future development directions include:

Refined formula design: Adjust the particle size and addition ratio of brucite powder according to different application scenarios to achieve optimal thermal expansion matching;

Composite modification research: compounding brucite powder with other functional fillers (such as talc powder and calcium carbonate) to further improve the performance of the core material;

Production process optimization: Improve mixing, coating and other processes to ensure uniform dispersion of brucite powder in the substrate and maximize efficiency.

For industry practitioners, it is necessary to strengthen their attention to new materials and technologies, and actively promote the research and application of green and high-performance aluminum-plastic panel products. At the same time, relevant standard setting organizations should also consider using the coefficient of thermal expansion as one of the important indicators for evaluating the quality of aluminum-plastic panels, guiding the industry to develop to a higher level.

Although the problem of bulging deformation in aluminum-plastic panels is common, it is not insurmountable. By introducing brucite powder, a natural mineral material, not only can the thermal expansion coefficient of the core material be effectively controlled, but it can also bring multiple advantages such as flame retardancy and reinforcement. With the continuous maturity and promotion of technology, we believe that more high-quality and high stability aluminum-plastic panel products will enter the market in the future, injecting new vitality into the building decoration industry.