At Polyco, we’re always pushing the boundaries of innovation in asphalt modification. One of our biggest breakthroughs is SigmaBond—a high-performance asphalt binder that includes recycled tire rubber that is liquefied through our unique chemical process (Rapid Digestion Process™). Unlike traditional methods that simply blend crumb rubber with asphalt, RDP harnesses the power of pyrolysis to chemically transform tire rubber, enhancing asphalt performance and sustainability.

The Science Behind SigmaBond: More Than Just Blending

When our chemists first began developing SigmaBond with RDP, the process started with a simple lab setup—heating asphalt to extreme temperatures and adding tire rubber to see what would happen. What we discovered was remarkable: at around 600°F, the rubber particles were no longer visible when passed through a sieve. At this temperature, the tire rubber breaks down into its base components, allowing it to homogeneously blend with asphalt mixtures. 

This reaction, known as pyrolysis, is the key differentiator between SigmaBond and conventional rubberized asphalt. Instead of mixing rubber particles into asphalt (the “wet” or “dry” methods used by competitors), we use heat to break rubber’s long polymer chains into smaller molecules. This results in a stable, homogeneous blend of asphalt—a combination that enhances durability, elasticity, and overall pavement performance.

Why Pyrolysis Matters

Most rubberized asphalt technologies do not chemically alter the tire rubber; they merely suspend rubber particles in the asphalt, which can lead to separation, inconsistent performance, and processing challenges. With SigmaBond, the controlled pyrolysis process ensures a permanent chemical transformation, producing a smoother, longer-lasting asphalt blend.

Since tire rubber consists of several complex bonds—carbon-carbon, carbon-sulfur, and sulfur-sulfur—each requires different levels of energy to break. By carefully managing temperature and reaction time, RDP optimizes these chemical changes, ensuring the right balance of rubber integration without unwanted byproducts. This results in an asphalt modifier that retains the benefits of rubber without the downsides of high viscosity or poor mixability.

Performance & Sustainability Benefits

SigmaBond offers a range of advantages for pavement applications:

• Superior Durability: The enhanced elasticity and stability of SigmaBond-modified asphalt reduce cracking and extend pavement lifespan.
• Smoother, Darker Surfaces: The high carbon black content gives roads a deep black finish, which some customers have noted as a visual advantage.
• High Rubber Content: SigmaBond can incorporate up to 50% tire rubber by weight, making it one of the most sustainable asphalt solutions available.
• Better Workability: Despite its high rubber content, our proprietary process ensures that SigmaBond remains easy to transport, mix, and apply.

Setting a New Industry Standard

At Polyco, we’re not just modifying asphalt—we’re redefining how recycled materials can be used to build stronger, more sustainable roads. By introducing pyrolysis into the equation, SigmaBond represents a fundamental shift in asphalt technology, offering unmatched performance and environmental benefits.

As the industry moves toward more sustainable infrastructure solutions, SigmaBond stands at the forefront, proving that innovation and environmental responsibility can go hand in hand.