Artificial turf at sports facilities has been quietly polluting the oceans. Two Japanese companies have teamed up to answer this often-overlooked environmental problem. Re Green Grass 9, co-developed by Mizuno and Kaneka, is the world's first biodegradable artificial turf that breaks down naturally even in seawater. It was introduced at the home of the Chunichi Dragons from the 2026 season.

A World First for Eco-Friendly Artificial Turf at Vantelin Dome

In February 2026, an unprecedented material for a sports facility was laid at Vantelin Dome Nagoya (Higashi Ward, Nagoya), home of the Chunichi Dragons: Re Green Grass 9, a biodegradable artificial turf co-developed by sporting goods giant Mizuno and chemical maker Kaneka.

It was installed in the warning zone in front of the new "Home Run Wing" seats added during the 2025-26 off-season. The warning zone is the strip in front of the outfield fence where a different material from the main field is used, so fielders can feel through their feet that they are nearing the fence.

It is the first time biodegradable artificial turf has been adopted at a professional sports facility anywhere in the world, and it has drawn attention as a new step for sport and the environment.

Artificial Turf and the Microplastics Problem

Why does artificial turf need to be able to break down? Behind it lies microplastic pollution, a growing problem worldwide.

Conventional artificial turf is made from petroleum-based plastics and gradually wears down through play and weather. The tiny worn fragments become microplastics that flow with rainwater through drains into rivers and the sea. The European Chemicals Agency (ECHA) estimates that about 16,000 tons of rubber granules escape from artificial turf into the environment every year in the EU alone.

Some studies suggest that microplastics from artificial turf account for 12 to 50% of global microplastic pollution, and the European Union has decided to phase out the sale of synthetic polymer infill by 2031. Against this international backdrop, the idea of "turf that breaks down" answered a real need of the times.

Green Planet, a Material Born from Microbes

The core technology of Re Green Grass 9 is Green Planet, a biodegradable biopolymer developed by Kaneka.

Green Planet is a 100% plant-derived polymer produced through microbial fermentation from biomass such as vegetable oils. It is broken down by microorganisms found in soil and seawater, ultimately leaving only CO2 and water. Many biodegradable plastics break down only in soil, but Green Planet has been confirmed to biodegrade even in seawater, considered the hardest environment, and has earned TÜV AUSTRIA's "OK Biodegradable MARINE" certification. This strict standard requires at least 90% degradation within six months in seawater at 30°C.

Kaneka began researching the material in the early 1990s, when marine microplastics were not yet recognized as a global problem. The starting point was researchers' conviction that they wanted to create an environmentally friendly material that did not rely on oil. With the chance discovery of a Green Planet-producing microbe in the soil at Kaneka's Takasago plant, the material reached practical use after about 30 years of R&D.

Green Planet is already making its way into daily life, in straws at 7-Eleven and Starbucks, JAL Group in-flight items and FamilyMart cutlery.

Mizuno's Turf Technology and Environmental Work

Mizuno, for its part, is a sporting goods maker that has been working on environmental conservation for more than 30 years, since 1991. It has more than 50 years of experience installing artificial turf and holds the top share of artificial turf at Japan's professional baseball stadiums.

In recent years Mizuno developed "Mizuno Spiral Technology," a special crimping process for turf blades that reduces tearing and thus cuts the scattering and runoff of infill. It has also actively rolled out eco-friendly turf products, such as infill made from recycled tea leaves.

But however much runoff is reduced, as long as turf is made of petroleum-based plastic, fragments that reach the sea will remain there without breaking down. To solve this fundamental problem, Mizuno turned to Kaneka's biopolymer technology and entered into joint development.

A Technical Breakthrough Combining Eco Performance and Pro Specs

"Eco-friendly materials perform worse." Overturning that image is Re Green Grass 9's biggest feature.

The biggest challenge in making sports turf from a biodegradable polymer was producing monofilament (single fibers). Ordinary turf blades are made by processing petroleum-based resin into monofilament, but doing so with biodegradable material was considered technically extremely difficult. By designing a special resin formulation and production conditions, Mizuno and Kaneka succeeded in producing the previously impossible monofilament, and by optimizing its cross-section achieved a feel comparable to ordinary artificial turf.

The turf blades of Re Green Grass 9 use more than 90% biomass-derived resin, greatly reducing CO2 emissions compared with petroleum-based turf. Every step, from blade production to turf manufacturing, takes place in Japan.

At a press conference, Hidehisa Manou, senior managing director of Nagoya Dome, said: "Its biggest feature is its high environmental performance. Playing safety, durability and cushioning are on a par with conventional artificial turf. We hope it can show a new way forward for the environment." It was also revealed that professional players under contract with Mizuno have rated it highly.

Gold Prize at the Ministry of the Environment's "Plasma Award 2026"

The initiative has also been recognized officially. In the Ministry of the Environment's "Plastics Smart" campaign against marine plastic waste, Mizuno's biodegradable artificial turf won the gold prize in the "Use and Reduce" category of the "Plasma Award 2026," recognized as an outstanding effort that combines environmental performance and practicality.

Sports Facilities in a Global Trend

Starting with the EU's 2031 infill rules, regulation of artificial turf's environmental impact is expected to keep tightening worldwide. In the United States, about 19,000 artificial turf fields are in use, and debate over turf safety has intensified, compounded by the detection of PFAS ("forever chemicals").

Against this backdrop, Japan's "turf that breaks down even in the sea" could go beyond regulatory compliance and signal a fundamental paradigm shift for the artificial turf industry. Mizuno and Kaneka say they will promote it at sports and commercial facilities across Japan while also developing marine-biodegradable turf for outdoor use.

Kaneka plans to expand Green Planet production capacity from about 20,000 tons a year to 100,000 to 200,000 tons as part of its "net zero by 2050" goals, and Mizuno continues to pursue its corporate vision of "protecting a rich global environment where sport can be enjoyed and passing it on to the next generation."

The warning zone at Vantelin Dome is only a tiny part of the whole field. But the challenge of "turf that returns to the soil" that began in this small area may be a step toward changing the future of sports infrastructure worldwide.

What environmental measures are sports facilities in your country taking?

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