Wall Panels
Experience Unmatched Insulation and Durability
Polyurethane sandwich panels deliver outstanding thermal insulation and impressive durability, making them perfect for wall cladding solutions.
Polyurethane sandwich panels are a type of building material commonly used for insulation and structural purposes in construction. They consist of three main layers: two external layers (often made of metal) called facings, and a middle layer of polyurethane foam, which acts as insulation.
Here's a simple breakdown of how polyurethane sandwich panels are made and their main components:
1. Facings:
These are the outer layers of the panel that provide strength and protection. They are usually made from materials like steel, gypsum, and aluminum, which can resist weather and mechanical stresses.
2. Polyurethane Foam Core:
The middle layer of the panel is made of polyurethane foam. Polyurethane is a type of plastic that can be created by mixing two main components: a polyol and an isocyanate. When these two components are combined, they react and expand to form a foam with good thermal insulation properties.
The process involves:
a. Mixing: The polyol and isocyanate are mixed together with other additives such as blowing agents and catalysts. Blowing agents generate gas bubbles in the mixture, causing it to expand and form a foam.
b. Foaming: The mixture is poured between the two facings in a mold. As it expands and solidifies, it bonds to the facings, creating a strong and insulated sandwich structure.
Polyurethane (PUR)
Polyurethane is the rigid foam formed by mixture of main components ‘polyol and isocyanate’ with catalyst materials under high pressure and special production conditions. Ensuring superior thermal insulation by its closed cell structure, polyurethane has high dimensional stability, and does not absorb water. It does not create bacteria. Its mechanical performance is very high thanks to its high compressive strength.
Polyurethane (PIR)
A new macromolecular structure called polyisocyanurate is formed when the main components of the polyurethane foam chemically react at different mixture quantities. Polyisocyanurate rigid foam is the version of polyurethane with higher, enhanced fire resistance performance due to the difference in its structure. In case of a fire, the formation of smoke is very low when compared to polyurethane.
3. Bonding and Curing:
Once the polyurethane foam is poured between the facings, it needs time to cure and harden. This curing process can take several hours to complete, depending on factors like temperature and humidity.
Polyurethane sandwich panel benefits:
· Insulation: The foam core provides excellent thermal insulation, helping to maintain a comfortable temperature inside buildings.
· Strength and Rigidity: The facings and foam together create a rigid and sturdy structure that can support loads.
· Lightweight: Despite its strength, the panel is relatively lightweight compared to solid construction materials.
· Ease of Installation: Panels can be manufactured off-site and easily transported and assembled on-site, saving time and labor during construction.
· Weather Resistance: The metal facings protect the foam core from environmental factors like rain, wind, and UV radiation.
Polyurethane sandwich panels are commonly used in the construction of walls, roofs, and floors for various types of buildings, such as warehouses, cold storage facilities, industrial buildings, and even residential homes.
U-Value (W/m²K):
The U-value represents the overall heat transfer coefficient. It is calculated using the formula:
U = 1 / R_total
Where R_total is the sum of the thermal resistances of all layers in the panel, including the foam core and facings.
R_total = R_core + R_facing1 + R_facing2 + ...
To calculate the R-values of individual layers, you can use the formula:
R = d / λ
Where d is the thickness of the layer and λ is the thermal conductivity of the material.
R-Value (m²K/W):
The R-value represents the thermal resistance of a material. It is calculated using the formula mentioned above:
R = d / λ
Where d is the thickness of the material and λ is the thermal conductivity.
Air Permeability:
Air permeability measures how easily air can pass through a material. It's often quantified in terms of air leakage rate. However, calculating air permeability for a sandwich panel involves complex airflow modeling and is typically determined through testing in accordance with relevant standards, such as ASTM E283 or EN 14509.
Blowing Rain Resistance:
Blowing rain resistance is typically not represented by a single calculated value, but rather evaluated through laboratory tests such as ASTM E331 or EN 14509. These tests involve exposing the panel to simulated driving rain conditions and measuring water penetration under different pressures. The result is reported as a pass/fail or a classification based on the panel's performance.
Keep in mind that specific standards and test methods may vary depending on the region and industry.
Guidelines for Sandwich Panel Coating and Color Selection
When considering the coating and color selection for sandwich panels, careful assessment of the environmental conditions your building will face is essential. Each aspect of the inner and outer sheet features should align with specific requirements to ensure long-term durability and aesthetic appeal.
Outer Sheet Considerations
The outer sheet of sandwich panels must withstand a range of environmental stressors such as temperature fluctuations, atmospheric pollution, UV exposure, and chemical exposure. It is crucial to select materials that can endure these factors and maintain their integrity over time.
Inner Sheet Analysis
Unlike the outer sheet, the inner sheet benefits from the insulating core of the sandwich panel and operates at a lower temperature. This makes it less susceptible to atmospheric conditions and UV rays. However, indoor environmental conditions may introduce different challenges such as condensation and exposure to chemical gases. Careful material selection is necessary to address these concerns effectively.
Metal Surface Alternatives
Several options are available for the metal substratum of sandwich panels, including preprinted galvanized or galvalume sheets, natural or preprinted aluminum, stainless steel, as well as gypsum and cement board sheets.
Preprinted Galvanized Steel Coating Layers
Preprinted galvanized steel undergoes a zinc coating process, typically with a thickness ranging from 60 gr/m² to 275 gr/m², using the hot dipping method. This process takes place on advanced, automated continuous lines known as coil coating lines.Coating Colors: For preprinted galvanized sheets, the RAL color chart serves as a reference for determining the colors during the production process.
Coating Types and Specifications
QPanel provides a variety of coating alternatives designed to match your building's location and requirements:
- Polyester Coatings: Polyester coatings offer extensive color and gloss choices, making them an economical and versatile solution. Their remarkable resistance to flexibility, abrasion, corrosion, humidity, and impact broadens their range of applications.
- PVDF Coatings: Notably resilient, PVDF coatings exhibit high resistance to color fading, gloss loss, chalking, and various chemicals. While excelling in impact resistance and flexibility, they may exhibit fewer color and gloss options compared to polyester coatings.
- Polyurethane Coatings: Reinforced with polyamide, polyurethane coatings achieve exceptional scratch and friction resistance. These coatings are applicable in both flat and patterned forms, offering corrosion resistance, vivid color, and gloss retention, as well as remarkable malleability.
- PVC Films: Primarily used for indoor or outdoor applications, PVC films are laminated onto aluminum or galvanized steel surfaces. Their exceptional corrosion and humidity resistance makes them a favored choice, particularly in cold storage applications.Make your coating selection based on the specific needs of your building and its intended function, keeping in mind factors such as durability, aesthetics, and the environment in which the panels will be utilized.
