Aluminum foil insulation material is a functional material that combines the high reflectivity of aluminum foil with the support/buffering effect of the substrate to achieve heat barrier. It is widely used in fields such as construction, home appliances, transportation, aerospace, etc. Its core technological logic is to reduce the three main forms of heat transfer (radiation, conduction, convection), especially in terms of radiation insulation, which has significant advantages.

Heat transfer is mainly carried out through three methods: thermal radiation, thermal conduction, and thermal convection. The technical design of aluminum foil insulation materials is aimed at weakening these three types of transfer. The core function of aluminum foil is to block thermal radiation, while the substrate assists in suppressing conduction and convection. Aluminum foil has a smooth surface and high metal purity, with a reflectivity of up to 90% -98% for infrared radiation (much higher than non-metallic materials such as plastics and fabrics). It can reflect most of the radiated heat back to the heat source side, avoiding heat absorption or penetration by the substrate. Aluminum foil itself is a metal with a high thermal conductivity (about 237W/(m · K)), but it is usually combined with low thermal conductivity substrates (such as polyethylene, glass fiber, bubble wrap) to reduce the overall thermal conductivity of the material. Partial structures (such as bubble aluminum foil) further reduce conduction through an "air layer" - the thermal conductivity of air is only 0.026W/(m · K), and the air flow inside the bubble is restricted, reducing the conduction path. The density of aluminum foil can block air penetration and reduce convective channels. The base material in the composite structure (such as closed cell foam and bubble layer) can fix the air layer to avoid convection circulation caused by air flowing inside the material.

Aluminum foil insulation material is not a single aluminum foil, but a composite structure of "aluminum foil layer+substrate layer+(optional) functional coating", with clear functional division of labor at different levels, jointly determining the insulation performance, mechanical strength, and application adaptability of the material. With the increasing demand for thermal insulation efficiency, environmental friendliness, and multifunctionality, we will continue to develop high reflectivity aluminum foil and further improve its infrared reflectivity (target ≥ 99%) through "nano coating modification", while reducing the thickness of the aluminum foil (such as 4 μ m) and lowering material costs.