Continuous PU Sandwich Panel Line

The Continuous PU Sandwich Panel Line is an efficient and automated production equipment specifically designed for the continuous production of polyurethane sandwich panels.

sandwich panel line

The Continuous PU Sandwich Panel Line can produce various specifications of polyurethane sandwich panels, such as cold storage panels, wall panels, roof panels, and soft faced coil composite panels. These sandwich panels have excellent insulation, heat insulation, fire resistance, and sound insulation properties, and are widely used in fields such as construction, cold chain, and transportation.

The working principle of Continuous PU Sandwich Panel Line is mainly based on the foaming and curing process of rigid foam polyurethane. The two-component raw materials of hard foam are sent to the mixing head by the metering pump of the high-pressure foaming machine in a certain proportion for mixing, and then evenly distributed on the bottom surface material of the sandwich board. Subsequently, both the upper and lower surface materials are simultaneously fed into the double track laminating conveyor. The rigid foam is foamed and solidified between the upper and lower conveying chain plates of the double crawler laminated conveyor. The cured sandwich panel is cut into finished products of a certain length by a cutting machine on the production line according to production needs.

The main equipment of the Continuous PU Sandwich Panel Line includes unwinding system, steel plate feeding system, steel plate automatic docking system, reinforcement unit, forming machine system, high-strength bonding system between steel plate and polyurethane, corona system, steel plate preheating device, double track machine and heating system, cutting saw, etc. In addition, auxiliary equipment such as laminating equipment, cooling equipment, automatic palletizing machines, packaging systems, and environmental protection equipment may also be equipped.

Characteristic

• Highly automated: The entire Continuous PU Sandwich Panel Line adopts advanced automation control system, realizing the full process automation production from raw material transportation, mixing, foaming, curing to cutting, greatly improving production efficiency.

• Product diversification: By adjusting the configuration and process parameters of the Continuous PU Sandwich Panel Line, sandwich panels of different specifications and core materials (such as rock wool and polyurethane) can be produced to meet the diverse needs of customers.

• Energy saving and environmental protection: The Continuous PU Sandwich Panel Line adopts energy-saving and environmental protection design, such as using efficient and energy-saving foaming equipment, recycling waste gas, etc., which reduces production costs and reduces environmental pollution.

• Stable Quality: The Continuous PU Sandwich Panel Line adopts advanced production processes and quality control measures to ensure the stability and reliability of product quality.

The products produced by the Continuous PU Sandwich Panel Line are widely used in fields such as construction, cold chain, and transportation. In the field of architecture, sandwich panels can be used for thermal insulation of walls, roofs, partitions, and other parts; In the field of cold chain, sandwich panels can be used for insulation and heat preservation of refrigeration facilities such as cold storage and refrigerated trucks; In the field of transportation, sandwich panels can be used for thermal insulation and sound insulation of vehicles, ships and other transportation vehicles.

The Continuous PU Sandwich Panel Line is an efficient, automated, and diversified production equipment with broad application prospects and market potential.

Continuous PU sandwich panel lines are advanced automated production systems designed to manufacture composite panels with a polyurethane (PU) foam core bonded between two facing materials, enabling high-efficiency, consistent, and large-scale production. These lines integrate multiple mechanical, chemical, and electrical processes to ensure the seamless formation of panels that balance structural strength, thermal insulation, and versatility, making them indispensable in various industrial, commercial, and residential fields. Unlike traditional discontinuous production methods, continuous lines eliminate the need for manual mold handling and batch processing, significantly improving production efficiency while maintaining uniform product quality across each panel. The core advantage of such lines lies in their ability to adapt to diverse material combinations and customization requirements, catering to the evolving needs of modern construction and manufacturing industries.

The structure of a continuous PU sandwich panel line is a modular integration of functional units, each responsible for a specific stage of the production process, working in tandem to achieve continuous operation. The primary components include uncoiling and feeding systems, roll forming units, PU foam mixing and injection systems, cooling and curing sections, cutting mechanisms, and stacking or packaging modules. The uncoiling and feeding systems are designed to handle rolls of facing materials, typically steel, aluminum, fiberglass-reinforced thermoplastics (FRP), or continuous fiber-reinforced thermoplastics (CFRP), ensuring stable and precise feeding into the line. These systems often feature adjustable tension controls to prevent material deformation, as well as transverse positioning mechanisms to align the facing sheets accurately, laying the foundation for uniform bonding with the PU core. Following the feeding stage, the roll forming units process the facing materials through a series of tandem rolling stands, which progressively bend and shape the sheets into predefined profiles—such as corrugated, ribbed, or flat surfaces—based on application needs. The rolling process is guided by precision rollers and gears, ensuring consistent profile dimensions and surface smoothness, which are critical for the structural integrity and aesthetic appearance of the final panels.

The PU foam mixing and injection system is the core of the production line, as it determines the quality and performance of the panel’s insulation core. This system typically consists of high-pressure mixing equipment that combines polyol and isocyanate, the key components of PU foam, along with additives such as foaming agents, flame retardants, and stabilizers. The mixing process must be precise to ensure uniform chemical reaction and foam density, with modern lines featuring automated control systems to regulate material ratios, temperature, and pressure. Environmentally friendly foaming agents, such as pentane, are commonly used to replace traditional chlorofluorocarbons, aligning with global sustainability standards. The mixed liquid PU is then continuously injected between the two formed facing sheets, which are conveyed through a double-belt conveyor system that maintains uniform pressure and spacing, ensuring the foam fills the entire gap without voids or uneven distribution. The double-belt conveyor also plays a role in shaping the panel’s thickness, with adjustable gaps to accommodate different customization requirements.

After injection, the panels enter the cooling and curing section, where the PU foam undergoes a chemical reaction to expand and solidify. This section often uses heated air circulation ovens or water-cooled belts to control the temperature within an optimal range, accelerating the curing process while ensuring the foam bonds firmly with the facing materials. Proper curing is essential to prevent delamination, bulging, or structural weakness, with the cooling time adjusted based on the panel’s thickness and foam density. Once fully cured, the continuous panel is fed into the cutting mechanism, which uses automatic band saws or circular saws to cut the panel into fixed lengths as required. The cutting process is precise to ensure clean edges and consistent dimensions, with some lines integrating additional inline processes such as punching, embossing, or surface spraying to enhance the panel’s functionality or aesthetic appeal. Finally, the cut panels are automatically stacked and packaged, completing the production cycle with minimal manual intervention.

The performance of continuous PU sandwich panel lines is defined by their production efficiency, product consistency, and adaptability, as well as the performance characteristics of the panels they manufacture. In terms of production efficiency, these lines can achieve speeds ranging from 3 to 12 meters per minute, with an annual output of up to 1 million square meters, depending on the line configuration and panel specifications. The automated control system, often based on PLC (Programmable Logic Controller) technology, ensures stable operation and reduces human error, resulting in high product consistency—critical for applications that require uniform structural strength or insulation performance. The panels produced by these lines exhibit excellent comprehensive performance, including superior thermal insulation, sound insulation, and structural strength. The closed-cell structure of PU foam provides low thermal conductivity, typically between 0.018 and 0.024 W/(m·K), meaning a 5cm thick PU panel can achieve the same insulation effect as a 100cm thick concrete wall. This makes the panels highly energy-efficient, reducing heating and cooling costs in buildings and industrial facilities.

In addition to thermal insulation, the panels offer excellent sound insulation, effectively blocking airborne and impact noise, making them suitable for use in noisy environments such as factories, warehouses, or transportation hubs. The combination of rigid facing materials and high-density PU foam (usually 28 to 50 kg/m³) also provides strong structural strength, with compressive strength exceeding 180 kPa for some configurations, enabling the panels to withstand external loads and resist deformation. The panels are also lightweight, with a weight of 10 to 14 kg/m², reducing the overall load on building structures and simplifying installation. Other key performance characteristics include good weather resistance, with stable performance after more than six months of weathering tests, and temperature resistance, maintaining structural integrity between -110°C and 120°C without obvious volume or strength changes. Flame retardancy is another important performance feature, with additives integrated into the PU foam to achieve high fire ratings, meeting safety standards for various applications. The panels also exhibit excellent waterproof and moisture-proof properties, thanks to the closed-cell structure of the PU foam, which prevents water absorption and seepage, extending their service life.

Continuous PU sandwich panel lines can produce a variety of panel types, classified primarily based on the facing materials, PU core type, and application-specific configurations. The most common type is metal-faced PU sandwich panels, which use galvanized steel, color-coated steel, or aluminum as facing materials. Metal-faced panels are widely used due to their high strength, durability, and aesthetic versatility, with color-coated steel offering a range of surface finishes to suit different architectural styles. Fiberglass-reinforced panels, including FRP and CFRP-faced panels, are another popular type, leveraging the lightweight, corrosion-resistant, and high-toughness properties of fiberglass materials. These panels are ideal for applications in harsh environments, such as coastal areas or chemical plants, where resistance to moisture and chemicals is critical. CFRP-faced panels, in particular, offer enhanced mechanical performance, making them suitable for high-load applications.

Another classification is based on the PU core type, with rigid PU foam and polyisocyanurate (PIR) foam being the two main variants. PIR foam is a modified form of PU foam with improved flame retardancy and thermal stability, making it suitable for applications with strict fire safety requirements, such as high-rise buildings or public facilities. Additionally, lines can produce customized panels with varying thicknesses (ranging from 30mm to 200mm, excluding corrugation height), widths (up to 1250mm), and lengths (from 2000mm to 16000mm), catering to diverse application needs. Some lines also integrate specialized processes to produce panels with hidden nail connections, which enhance the aesthetic appearance by eliminating external screws, or panels with embedded structural components (such as wood or metal profiles) to improve load-bearing capacity.

The versatility of continuous PU sandwich panel lines translates to a wide range of applications across multiple industries, driven by the excellent performance of the panels they produce. In the construction industry, these panels are extensively used for building envelopes, including external walls, roofs, and partitions, in industrial factories, warehouses, commercial complexes, and residential buildings. Their lightweight nature and easy installation reduce construction time and labor costs, while their thermal insulation properties improve energy efficiency, aligning with global efforts to reduce carbon emissions. For cold chain logistics, the panels are ideal for constructing refrigeration rooms, freezers, and insulated containers, as their low thermal conductivity helps maintain stable low temperatures, protecting perishable goods such as food and pharmaceuticals. The panels’ hygienic and easy-to-clean surfaces also make them suitable for cleanrooms in the pharmaceutical, electronics, and food processing industries, where contamination control is critical.

Prefabricated and modular buildings are another key application area, as the lightweight and durable panels enable quick assembly of portable cabins, on-site offices, and temporary structures, making them ideal for construction sites, disaster relief, and remote areas. In the agricultural sector, the panels are used to construct farm warehouses, livestock shelters, and crop storage facilities, protecting agricultural products and equipment from temperature fluctuations, moisture, and pests. The industrial sector relies on these panels for constructing warehouses, workshops, and logistics hubs, where their structural strength and sound insulation properties create a safe and comfortable working environment. Beyond construction, the panels are used in the transportation and maritime industries as lightweight, insulated structural components for vehicles, ships, and trains, reducing fuel consumption while improving passenger comfort. They also find applications in electrical insulation, leveraging the PU foam’s excellent insulating properties to protect electrical equipment.

The continuous development of continuous PU sandwich panel lines is driven by the growing demand for energy-efficient, sustainable, and high-performance building materials. Advances in automation technology have improved production efficiency and product quality, with the integration of smart control systems enabling real-time monitoring and adjustment of production parameters. Environmental considerations have also shaped the evolution of these lines, with the adoption of eco-friendly foaming agents and energy-saving processes reducing their carbon footprint. Additionally, the ability to produce customized panels for specialized applications—such as high-temperature environments, corrosive conditions, or high-load requirements—has expanded their market reach, making them a versatile solution for modern manufacturing and construction needs. As industries continue to prioritize sustainability and efficiency, continuous PU sandwich panel lines are expected to play an increasingly important role, offering a balance of performance, versatility, and environmental responsibility.