Polyurethane sandwich panel with polyurethane foam cores meet the strictest heat insulation requirements, while also complying with the required insulation properties and maintaining a good bearing capacity. PU Sandwich Panels are composed of 3 layers, the external and internal is two dyed Galvanized or Aluminum corrugated plates, and core rigid polyurethane foam. PU sandwich panel is the most effective acoustic materials and flame retardant foam used on construction. Panel production in small amounts is made by batch processes. In contrast, continuous processes have higher productivity, but the initial investment cost is higher. In addition, the change of process conditions is less flexible than with the batch process.
Polyurethane sandwich panel are applied as external walls and internal division walls, installed vertically or horizontally on single- or multi-span structure. Widely used in the steel structure factory building, activities room, roof, wall, air clean room ceiling and partition. Each of the insulating core materials used in a sandwich panel varies in terms of thermal conductivity, sound insulation, and strength to weight ratio. Many construction projects today use PIR and PUR panels due to their low thermal conductivity, good insulation, and versatility.
Maximum compressive strength in panels occurs parallel to the panel walls in vertical pours. The high vertical rise is the easiest to handle, as it may be poured through a single opening at the top of the mold. The foam properties of vertically filled panels are uniform from top to bottom. A low vertical rise may also be used where high panels cannot be conveniently handled. In this case, the foam may be poured through a single hole at one end if the mold is tilted to ensure adequate distribution. Otherwise, it may be necessary to traverse the length of the mold.
In some cases, it is desirable to achieve maximum strength perpendicular to the panel walls. In such cases, the panel can be foamed horizontally. In pouring horizontal panels, one of the panel skins is placed on the bottom of a mold. The mold skins are used to retain the foam as it rises to meet the other skin being held in place by the upper mold section. As with vertical panels, electromagnets and vacuum may be used to hold the top substrate to the upper mold section. The liquid mixture of foam components can be flowed in by a mixing head in a predetermined pattern, traversing the mold area. Skin materials used for insulated building panels include steel, aluminum, melamine laminates, plywood, sheet rock, and paper.
The most important application of polyurethanes panels in buildings is insulation. Polyurethanes are regarded as an affordable, durable and safe way of reducing carbon emissions that lead to global warming. Polyurethanes can dramatically reduce heat loss in homes and offices in cold weather. During the summer, they play an important role in keeping buildings cool, which means air conditioning is needed less.
Advantages and Disadvantages of Insulated Sandwich Panels
The use of sandwich panels has overrun the traditional way of creating buildings from masonry. That’s because insulated sandwich panels offer many construction advantages such as:
- Faster Construction Time
- Lower Costs for Materials, Shipping, And Labor
- Quick Assembly Using a Dry Process
- Good Thermal and Sound Insulation
- Resistant to Corrosion And Other Biological Effects
Now, the main disadvantage of sandwich panels is its inability to withstand additional construction loads. Cosmetic damage to the building is also more likely.
What is the difference between PIR and PUR panels?
When it comes to modern roof insulation, you often hear about PIR and PUR panels. PUR is a polyurethane that was used to make sandwich panels until recently. PIR is a polyisocyanurate that is slowly replacing it. Although the two materials are similar in many respects, they differ in one important feature. PIR and PUR have a similar chemical composition. Both are made of isocyanate, polyol and special stabilizers and activators. It is the large amount of isocyanate that makes a given foam a PIR foam.
PIR and PUR panels have different fire protection properties. In the case of PIR, the breakdown of the chemical chains takes place at a temperature of 300 ˚C. As for PUR, it is only 200 ˚C. This means that in the event of a fire, PIR plates give the user a little more time to react and fight fire, and in extreme cases – to evacuate. A charred coating forms on the PIR plate, which further delays the fire from spreading further. In the event of a fire, the PIR board retains its structural properties longer, so it is much safer, especially when used in the roof structure. PUR usually receives a fire resistance class equal to B2/B3 (DIN 4102), and PIR – B1/B2.
Although PIR and PUR panels are light and easy to install, both are highly resistant to mechanical damage. This makes them great protection against birds or martens, as well as against moisture, mold and bacteria. Due to the relatively low weight, they are also convenient to transport.