Now I often hear a lot of friends say: why can't the cold room built with polyurethane insulation board reach my ideal temperature? In fact, this problem is very simple. In addition to machine problems and frequent door opening, the more important reason is that their own polyurethane insulation board is not insulated. Therefore, in the selection and purchase of polyurethane insulation board, we must choose the polyurethane insulation board with good heat insulation effect and good air tightness.

How to choose polyurethane insulation board and polystyrene insulation board when building cold storage? Do you know the difference between them? I believe that after reading this article, this will no longer trouble you!

One,Different foaming mechanisms

Rigid foam polyurethane is a lightweight foam with a high porosity of 90% and a high net structure. It is completely mixed by two component liquids (commonly known as black and white) and is chemically solidified (tens of minutes to minutes). It is a lightweight foam with high sealing porosity and mesh structure under the use of additives such as blowing agent, catalyst and even blowing agent.

EPS (XPS) is a kind of foam formed by heating expansion and vaporization of foaming agent. It is formed by mould or extruder. It belongs to thermoplastic foam, has high sensitivity to temperature, and has the potential of two times foaming.

Two,the physical and chemical properties of foam are different.

1. Thermal insulation performance

The thermal insulation properties of polystyrene foam are better, but the lambda value is still larger than that of rigid foam polyurethane, such as polystyrene foam board lambda 0.04w/k? M, XP plate lambda =0.031 w/k m, lambda =0.022 W/k m, polystyrene foam has better thermal insulation performance, but the lambda value of PS plate is still relative to rigid polyurethane foam. Under the same energy saving index, the thickness of insulation board can be reduced, and the quality and stability of insulation system will be improved.

2. Thermal stability

The thermal stability of rigid polyurethane foam is as high as 120 C, and the thermal stability of benzene board is only 70 C. The exterior surface temperature of exterior wall in summer in China is generally 70 ℃ or above, which is easy to cause secondary foaming of benzene board and lead to joint cracking.

3. Surface binding energy

Polyurethane molecular chain has a certain - OH bond, that is hydrophilic gene, easy to combine with cement slurry, but polystyrene has non - OH bond, belongs to hydrophobic material, and its surface is difficult to integrate with inorganic materials such as cement slurry, which is one of the main reasons for cracking and hollowing off of external insulation system of benzene board.

4. Combustion theory

Rigid polyurethane foam is a thermosetting material, which forms carbide layer after thermal combustion, separating heat and oxygen from further entry, hindering the further combustion of foam, and is not easy to cause fire spread. Polystyrene foam belongs to thermoplastic material. After heating, it will shrink and melt, and then burn down. It will not produce carbide barrier. It will easily cause flame diffusion and flashover.

5. Corrosion resistance

Polyurethane water resistance, oil resistance, solvent resistance. Polystyrene is water-resistant, but not solvent resistant. It is very sensitive to benzene and ester solvents and easy to produce rapid corrosion.