The thermal insulation performance of the core material in sandwich panels is a critical aspect that significantly influences the energy efficiency and comfort of buildings. The core material acts as the central component responsible for impeding the transfer of heat, thereby enhancing the thermal resistance of the entire sandwich panel structure. This thermal insulation performance is commonly measured by the material's thermal conductivity, expressed in units of Watts per meter-Kelvin (W/m·K). A lower thermal conductivity value indicates a higher capacity for thermal insulation.

Among the various core materials employed in sandwich panels, polyurethane (PU) foam stands out for its exceptional thermal insulation properties. PU foam typically exhibits a low thermal conductivity, contributing to its effectiveness as an insulator. This quality is crucial in mitigating heat transfer and maintaining stable indoor temperatures. Another closely related material is polyisocyanurate (PIR) foam, which shares similarities with polyurethane and offers high thermal resistance. PIR foam is often chosen for applications where improved fire resistance is a requirement, making it a versatile choice for construction projects.

Expanded Polystyrene (EPS) foam is a lightweight and cost-effective core material that provides good thermal insulation. While its thermal conductivity may be higher than that of PU or PIR, EPS remains a popular choice, especially in residential and commercial construction. Its affordability and suitability for various applications contribute to its widespread use in the industry.

Mineral wool, including rock wool and slag wool, is another core material recognized for its excellent thermal insulation properties. Notably, mineral wool is known for its ability to resist high temperatures, making it a preferred choice in applications where fire resistance is a priority. Its fibrous structure contributes to effective heat resistance and thermal insulation, enhancing the overall performance of sandwich panels.

Extruded Polystyrene (XPS) foam, characterized by its closed-cell structure, offers good thermal insulation with a relatively low thermal conductivity. XPS is resistant to moisture, adding an extra dimension to its suitability for specific applications where moisture resistance is essential, such as in below-grade insulation or roofing systems.

While the individual thermal conductivity values of these core materials provide insights into their insulation capabilities, it's crucial to consider the entire sandwich panel system. The overall thermal performance is influenced by factors such as panel thickness, facing materials, and panel configuration. The combination of a high-quality core material with appropriate facings is essential for achieving optimal thermal efficiency. Proper installation and sealing are equally critical to ensuring that the designed thermal insulation performance translates effectively into real-world applications.