The aviation aluminum foil has a honeycomb-like structure and possesses strong corrosion resistance and aging resistance. It does not crack or blister. It performs exceptionally well in terms of fire retardancy, insulation, soundproofing and shock absorption. It is also non-toxic and harmless, making it extremely environmentally friendly. When pressed with the palm, if a slightly louder sound can be heard, it is very likely to be the aviation aluminum foil. However, its bonding process requires high standards. If the bonding is not good, there will be noise when opening and closing the door, and the price is relatively higher.
When using polyurethane foaming material for filling, first, the internal space is covered by arranging the keels horizontally and vertically or by using steel wire mesh. Then, the foaming machine injects the material into the gaps, causing the door to become heavier and stronger after expansion. This material has good sealing performance, excellent heat insulation and soundproofing effects, and can withstand temperatures up to over 200℃, significantly extending the service life of the door. However, its fire resistance is poor. It will catch fire easily at high temperatures and produce toxic gases.