Cologne, Germany – Low-free prepolymer polyurethane is replacing rubber in a newly designed star-wheel from Lanxess. These wheels are used to separate different waste streams in recycling plants.
To be effective, they need good mechanical performance, water and heat moisture resistance, the German company claimed.
In use, several wheels are mounted on a rotating steel shafts which are combined into an array. As they rotate, they separate waste at up to 50 tonne/hour.
Sorting waste is a tough environment for the wheels, according to Michael Timm, global head of marketing and development at Lanxess’ urethane systems business unit.
He said that the polyurethane wheels are twice as durable as a component made of rubber. ‘The wheels can therefore be replaced less often,’ he claimed. ‘This saves material costs, and extends the plants maintenance intervals.’
Low-free TDI materials have less than 0.1% free TDI in the prepolymer, and the Adiprene grade used has low viscosity and a long pot life, Timm added. The wheels are also easy to remove from the moulds.
As well as the material for the wheels, Lanxess designed the wheel itself. ‘We have already signed contracts with processors in North America to ensure customers of star wheels benefit from the highest level of quality and performance,’ said Timm.
These wheels could also find homes in in agriculture, for example in harvesting systems or for handling mulch, peat, humus and compost, he added.