TOPOLO’s production line for one-piece composite panels overcomes the limitations of traditional polyurethane sandwich panels—such as fixed dimensions and simple structural designs—enabling more flexible, customized manufacturing.
Unlike the conventional foam sandwich panels commonly available on the market, which are manufactured using the Continuous Injection Method, TOPOLO adopts a unique high-pressure molding process combined with large-tonnage vacuum lamination technology. First, high-quality closed-cell polyurethane (PU) foam is precisely cut into standardized dimensions. Then, using high-strength industrial structural adhesive, perfectly flat carbon steel sheets are seamlessly bonded with the PU core under controlled temperature and pressure, forming a highly integrated laminated composite panel with exceptional bonding strength and dimensional stability. By precisely controlling lamination pressure, adhesive application, curing time, and the production environment, a stable and reliable bond between the steel sheet and the PU core is ensured, effectively preventing issues such as delamination, warping, cracking, and dimensional deviations often associated with traditional processes.
Structural Diagram
Basic Specifications
| Skin Material | GI (Galvanized ) steel sheet GL (galvalume ) steel sheet PPGI (pre-painted galvanized) steel sheet PPGL (pre-painted galvalume) steel sheet |
| Total Thickness | 10-150mm. |
| Steel Sheet Thickness | 0.12-3.0mm. |
| Width | 600-1500 mm |
| Length | ≤12m |
| Steel grade | DX51D+Z, DX52D+Z, DC51D+Z, DC52D+Z, S350GD+Z, etc. |
| Surface Treatment | Regular spangle Minimized spangle Spangle-free PE (polyester) PVDF (fluorocarbon) |
| PU Foam Density | 40~85kg/m³. (Thermal conductivity: 0.017~0.022W/m·K) |
Advantages of Steel Skin PU Sandwich Panels
☑ High Structural Strength
Compared to lightweight materials such as aluminum sheets and FRP (fiber-reinforced plastic), steel offers superior mechanical strength and impact resistance. Steel skins can withstand heavier external loads and effectively resist collisions and impacts during transport, as well as mechanical damage during long-term use, providing reliable structural protection for the sandwich panel.
☑ Excellent Weather Resistance
TOPOLO steel panels utilize high-quality, corrosion-resistant steel, including galvanized steel (GI), Galvalume (GL), and pre-painted steel (PPGI/PPGL). Through protective plating, chemical passivation, and high-performance coating treatments, the steel substrate is effectively isolated from air and moisture, thereby enhancing corrosion resistance.
☑ Superior Thermal Insulation Performance
These sandwich panels feature high-quality closed-cell polyurethane (PU) foam as the core insulation material. With a closed-cell content exceeding 95% and extremely low thermal conductivity (approximately 0.020–0.025 W/m·K), the polyurethane foam effectively minimizes heat transfer, delivering outstanding thermal insulation and energy-saving performance.
☑ Cost-Effective Solution
Compared to aluminum or FRP sandwich panels, steel offers a superior cost-performance ratio and benefits from a more mature supply chain. While meeting all requirements for structural strength, protective performance, and service life, steel-faced foam sandwich panels effectively reduce material costs for projects.
Surface Material Options
TOPOLO selects premium substrates from top-tier steel mills, offering a variety of high-quality coated carbon steel sheets as facings for sandwich panels.
Galvanized Steel (GI) Sheet
Features a pure zinc coating formed on the steel surface via the hot-dip galvanizing process.
Galvalume Steel (GL) Sheet
Also produced via a hot-dip process, featuring a surface coating of aluminum-zinc alloy.
PPGI/PPGL) Steel Sheet
Features a colored coating system (primer and topcoat) applied over a galvanized or galvalume steel substrate.
01. Galvanized/Galvalume Steel Facing PU Foam Core Sandwich Panels
Sturdy and durable, with excellent cost-effectiveness.
02. PPGI/PPGL Steel Facing PU Foam Core Sandwich Panels
Features a high-performance coating, combining aesthetic appeal with dual-layer corrosion protection.
Application of Steel PU Sandwich Panels in Modular Structures
One of the most representative applications for steel-faced polyurethane sandwich panels is modular construction. Modular construction utilizes prefabricated sandwich panel components to significantly streamline on-site workflows, shorten installation times, and effectively reduce labor costs. Furthermore, modular structures offer the advantages of flexible disassembly, rapid relocation, and reassembly, allowing for adjustments and expansions based on specific usage requirements.
An increasing number of building projects—such as mobile homes, cold storage facilities, warehouses, industrial equipment enclosures, and modular building units—are adopting modular designs and utilizing polyurethane sandwich panels as the core material for their building envelopes.