Strong, Durable and Future-Proof Stadium Seats for Sparta Rotterdam

A Fresh Start for Het Kasteel

When Dutch football club Sparta Rotterdam decided to replace more than 7,500 stadium seats in the spring of 2021, the challenge was clear. The existing red, black and white seats at Het Kasteel had faded over time, losing both their appearance and performance. The new seats had to be strong, durable and future-proof, while remaining representative of the club for years to come.

With strict quality requirements and a tight project deadline, the seat manufacturer turned to De Monchy as a trusted partner to help select the right material solution.

The challenge: strength, durability and speed

Stadium seats are subject to extreme conditions. They are used intensively and must withstand high mechanical loads, while also being impact-resistant, fire-retardant, UV-resistant and color-retaining.
Initially, the customer tested a standard polypropylene with 30% glass fiber.

However, once a masterbatch was added, the material failed the mechanical test. It became clear that a mechanically stronger and more flexible solution was required. At the same time, the project timeline was extremely tight. Any solution had to be fully tested, reliable and available quickly.

The solution: combining compound and masterbatch

Drawing on its extensive material portfolio and supplier network, De Monchy quickly identified the right approach: a glass fiber reinforced polypropylene (PPH) combined with a dedicated masterbatch.

To ensure sufficient stiffness without brittleness, De Monchy partnered with Polykemi, selecting POLYfill PPH GF5030 HC, a polypropylene with 30% glass fiber reinforcement and high crystallinity. Johan Sonesson, Sales Representative at Polykemi, explains: “By choosing a highly crystalline material reinforced with fiberglass, we achieved the required hardness and stiffness. This ensures the seats can withstand the force of enthusiastic football fans.” Beyond performance, sustainability was also considered. The selected polypropylene is produced with relatively low CO₂ emissions and has a low density, making the seats lightweight and easier to transport and maintain.

For color, UV resistance, fire retardancy and long-term appearance, De Monchy worked with Gabriel-Chemie to develop a custom combination masterbatch in three club colors. This solution ensures compliance with the M3 fire standard, in line with local fire safety regulations.

The advantages: speed, flexibility and proven quality

By separating the base compound and masterbatch, De Monchy delivered several key advantages:
– Short lead times, essential given the tight project deadline
– Homologated material combinations, already tested together
– Simplified supply conditions
– Future flexibility, as only the color masterbatch needs to change for follow-up projects

Because the base material remains the same, no additional testing is required for future color variations. The entire project, including coordination between all parties, was completed in just six weeks.
The final stadium seats meet all functional requirements: high load resistance, long-term color retention, fire safety and UV stability. By inhibiting UV-related degradation, the seats maintain stiffness and quality for many years, ensuring long-lasting comfort for Sparta Rotterdam supporters.

A collaboration built on expertise and trust

The customer was highly satisfied with the material-masterbatch combination and looks forward to future projects with De Monchy. The result is a success story that perfectly reflects the collaboration between De Monchy, Polykemi and Gabriel-Chemie: combining technical expertise, speed and flexibility to deliver a robust, future-proof solution for a demanding application.