We all know that fire doors play a very important role around us. The national standard for fire doors mainly proposes two points. First, the material is required to meet the combustion performance A1 level specified in the national standard GB8624, and the fire resistance limit time after the fire door is required to be extended accordingly, up to 3 hours; second, the material is required to be environmentally friendly, It reaches the ZA2 level of smoke toxicity according to GB/T20285. The vermiculite fire door core board produced from the main raw material vermiculite can meet the standard requirements and achieve high quality. In terms of vermiculite, it is a high-quality inorganic heat-insulating raw material, non-combustible, heat-insulating, small in specific gravity, low in thermal conductivity, and high in refractory temperature. The vermiculite board produced is suitable for fire-resistant door core panels. However, in the production process, the key technical point is how to improve the heat insulation and deformation resistance of the fire door core board.
The thermal insulation of the fire door core board is an index to test the thermal insulation ability of the fire door, that is, the fire resistance limit, the longer the better. It is known in the experiment that the appropriate specific gravity can reduce the thermal conductivity of the fire door core board, which has a decisive influence on the thermal insulation of the door core board. When the specific gravity and porosity of the stone fire door core board are suitable, the sum of its thermal conductivity, convection heat transfer coefficient and radiation heat transfer coefficient will be small, and the temperature of the back fire surface will rise the slowest. Deformation resistance refers to the ability of the fire door to resist the stress caused by the temperature difference during the heating process of the one-way surface fire when a fire occurs, thereby bringing about deformation. Generally, the fire door is heated in one direction, and there will be a huge temperature difference between the two sides. The temperature on the fire side can reach 1000°C, while the temperature on the back side is as low as possible, and the highest temperature can only reach 180°C, so the expansion stress on the fire side is very If it is too large, it will cause the deformation of the board and cause the damage and failure of the fire door, so the smaller the deformation, the better. To increase the deformation resistance of the fire door core board, it is necessary to add an appropriate amount of materials that shrink after heating to reduce deformation and maintain the integrity and sealing of the fire door core board.
