Valmet has set strict criteria for the bio-based raw material in the covers. Only renewable materials derived from non-food chain plants or plant parts are used, in order to prevent the effect to global food production. Cultivation and harvesting of plants must not endanger the growth of natural forests either.
Valmet is the first company in the world to offer roll covers based on biomaterials and recycled materials for board, paper, tissue and pulp making. These new composite covers for press, guide and calender rolls are now available for the first customer deliveries.
In new composite roll covers Valmet uses bio-based resin and hardener in the polymer matrix. The reinforcing fiber and filler are originating from recycled consumer plastic and glass. Depending on cover type, the content of recycled or bio-based raw materials is 75-96 percent. New materials are being tested continuously, and the target is to reach 100 percent as soon as possible.
“In best cases, bio-based materials can be produced from plant parts that would otherwise be waste. For example, lignin, carbon black made of lignin and nanocellulose can be utilized as reinforcing fillers in roll covers,” explains Jani Turunen, R&D Manager for Polymeric Roll Covers, Valmet. “Our customers do not have to compromise in product performance either, as the results have shown that in some applications the performance is even above the traditional offering.”
Roll covers used in paper, board, tissue and pulp making need periodical renewal and thus consume tons of materials. A major part of the raw materials of traditional roll covers has been manufactured from fossil-based materials, which has been refined and processed from crude oil.
Valmet is continuously investigating the possibilities to replace fossil-based materials with renewable or recyclable materials. For example, recycling and more sustainable use of ceramic and metallic roll covers is under active research.
“Our continuous investing in R&D of sustainable solutions for our customers helps us increase the occupational safety of our employees, replace fossil-based raw materials with renewable ones, re-use and recycle materials and save energy. This is our contribution to the global challenge we face regarding our planet’s future. And by doing this, we are helping our customers do their part as well,” says Jukka T Heikkinen, Senior Manager, Roll R&D, Valmet.
“In best cases, bio-based materials can be produced from plant parts that would otherwise be waste. For example, lignin, carbon black made of lignin and nano-cellulose can be utilized as reinforcing fillers in roll covers,” explains Jani Turunen, R&D Manager for Polymeric Roll Covers, Valmet (right) pictured with Pertti Hytönen, R&D Engineer, Valmet.