The continuous phenolic board production line(foam sandwich wall insulation board) is a special equipment that produces phenolic insulation boards that the upper and lower layers are soft surface layers and the middle interlayer is flame retardant polyurethane, polyisocyanurate. The product is mainly used for exterior wall insulation. Its working principle is: The rigid foam plastic liquid is mixed into the mixing head by a metering pump of a filling machine and uniformly poured on the bottom surface of the sandwich panel. And it is fed into the laminating conveyor together with the upper layer material, and is foamed and solidified between the upper and lower chain plates of the laminating conveyor. Cured and formed sandwich panels are cut into a certain length of product as needed by automatic tracking machine after trimming on both sides on the production line.
When the phenolic board is used as the external thermal insulation of the external wall, improving system structure can fundamentally solve the safety hazard and avoid accidents. We can consider the following aspects:
Setting thermal stress blocking layer
The thermal conductivity of the phenolic board is relatively small, and the thermal conductivity of the crack resistant protective layer material is relatively large. The difference between the phenolic board and the crack resistant protective layer material is relatively large, so there will be a large difference in thermal stress between the two. The performance requirements of crack resistant protective layer material are relatively high. Only when crack resistant protective layer material can withstand these thermal stress differences, there will be no empty drums, cracks, falling off, etc. However, in practical external thermal insulation engineering applications, this is difficult to achieve. This problem can be solved relatively easily if a transition layer is added between the phenolic board and the crack resistant protective layer.
Wipe polystyrene particle slurry transition layer on phenolic board and when the external surface temperature of the wall is 70 ° C, the outer surface of the phenolic board reaches a maximum temperature of 61.5 ° C after 1.15 h. When polystyrene particle slurry having a thickness of 20 mm was applied, the surface temperature was greatly lowered, and the temperature stress was also drastically lowered. And it delays the high temperature occurrence time by 1.15h, which can alleviate the sharp change of the thermal stress of the phenolic board and provide better weather resistance for the external wall insulation.
Setting water dispersion structure layer
In the process of system design, each layer of material should have a certain degree of water vapor permeability to allow gaseous water to discharge from the building and balance the moisture content of the building wall.
A layer of water dispersion structure is set in the external insulation system to absorb a small amount of water vapor condensate produced by poor permeability of the insulation board. There is no flowing liquid water in the system. For example, polystyrene particle slurry is set as a water dispersion layer on the side of the phenolic plate that is easy to dew. Water vapor inside the system is discharged to the outside. When the outside temperature is low and the inside of the crack resistant layer is condensed, the polystyrene particle slurry layer having the moisture absorption, humidity control and moisture transmission performance can absorb a small amount of condensed water generated and disperse in the structural layer to avoid the three-phase change destructive force generated by the accumulation of liquid water. This improves the system's bonding performance and respiratory efficiency, thus it ensures long-term safety and reliability and long-term stability of the apparent quality of the exterior insulation project.
Setting waterproof and vapour permeable layer
Set a polymeric and flexible priming coat in the construction of the external insulation system and place it on top of the crack resistant protective layer. Under the premise of keeping the water vapor permeability coefficient basically unchanged, the surface water absorption coefficient of the surface layer material is greatly reduced. This avoids damage to the outer surface of the building caused by the frost heave force generated when it is frozen in winter after water seeps into the outer surface of the building. At the same time, the vapor permeability of the surface layer material is ensured. It avoids the wall surface being blocked by the water-impermeable material, thereby hindering the wall from being wetted, causing the water vapor to be diffused and the expansion stress is caused to damage the external thermal insulation system. Through reasonable external insulation structure and material selection, the system has the function of waterproof and steam permeable, thereby improving the freeze-thaw resistance, weathering.