Do you know these differences in polyurethane and polystyrene insulation boards?
Release Time:
2019-01-31
When building a cold storage, how to choose polyurethane insulation board and polystyrene insulation board?
When building a cold storage, how to choose polyurethane insulation board and polystyrene insulation board? Do you understand the difference between them? I believe that after reading this article, this will no longer bother you!
1
Different foaming mechanism
Hard foam polyurethane is a two-component liquid (commonly known as black and white material), which is mixed thoroughly to produce rapid chemical reaction curing (tens of seconds to several minutes). It is foamed by additives such as foaming agent, catalyst and foam stabilizer. A lightweight foam with a high closed cell ratio of >90% and a network structure, which is a thermosetting foam.
Polystyrene foam (EPS, XPS) is a foam that is swollen by heating of pellets or powders, vaporized and expanded by a foaming agent, and formed by a die or extrusion machine. It has a granular structure and belongs to a thermoplastic foam. Higher sensitivity, the potential for secondary foaming.
2
The physical properties of the foam are different
1 Thermal insulation performance
Polystyrene foam has good thermal insulation, but the lambda value is relatively large compared with rigid foam polyurethane, such as EPS plate λ≈0.04w/k·m, XPS plate λ≈0.031 w/k·m, and PUR plate. λ ≈ 0.022 w/k·m. Under the premise of the same energy-saving index, the thickness of the insulation board can be reduced, and the quality stability of the insulation system can be improved.
2 Thermal stability
The thermal stability of the rigid polyurethane can be as high as 120 ° C, while the benzene board is only 70 ° C. The outer surface temperature of the outer wall of summer in China is generally above 70 ° C or above 70 ° C. Such a temperature is very likely to cause secondary foaming of the benzene board, resulting in cracking of the joint.
3 surface binding energy
Polyurethane molecular chain has a certain -OH bond, that is, a hydrophilic gene, which is easy to bond with cement-based slurry, while polystyrene has no -OH bond, which is a hydrophobic material, and its surface is difficult to be mixed with cement-based slurry. The fusion of inorganic materials is one of the main reasons for the cracking, hollowing and falling off of the benzene board external thermal insulation system.
4 Combustion
The rigid foam polyurethane is a thermosetting material, which forms a carbonized layer after being burned by heat, which blocks the further intrusion of heat and oxygen, hinders further combustion of the foam, and is less prone to fire spread accidents. Polystyrene foam is a thermoplastic material that undergoes shrinkage and melting after being heated, and then drops and burns. It does not produce a carbonization barrier layer, which is prone to flame spread and flashover accidents.
5 corrosion resistance
Polyurethane is water, oil and solvent resistant. Polystyrene is water-resistant but not solvent-resistant. It is extremely sensitive to benzene and ester solvents and is prone to rapid corrosion.
3
Different application methods
Polystyrene foam can only enter the molding and extrusion foam molding in the factory state, while the rigid foam polyurethane can be sprayed, cast and factory foamed, so the application and application fields are more diverse and convenient than polystyrene foam.
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