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Cannon EG-AX system for optimum processing of expandable graphite filler in flexible PU foam. (Source: Cannon Group)

18. November 2021

Cannon: Optimum processing of expandable graphite filler in flexible PU foams

The EG-AX system from Cannon Afros includes a high-pressure foaming machine and patented multicomponent mixing head which allows the speedy processing of expandable graphite filler while maintaining the integrity of the flakes.

“Our Cannon EG-AX system features a patented multicomponent mixing head available in different sizes equipped with special stream distributor and injector that shortens the high-pressure recycling time down to about one second, thereby greatly reducing the shear stress on the expandable graphite flakes in the polyol formulation,” said Stefano Andreolli, Sales Manager, Automotive Applications. “This system preserves the formulation in the foaming machine up to 3 times longer than conventional foaming machines.”

Flexible PU foams are intrinsically flammable and require high performing flame retardants and expandable graphite (EG) filler is considered one of the most effective to combat fire propagation EG is an inorganic flame retardant which has a mineral origin and is derived by treating flake graphite with reversible intercalation reagents such as nitric acid and sulphuric acid. When exposed to heat it will expand or exfoliate and create an intumescent layer on a material’s surface and is especially effective in flexible PU foams. However EG filler is sensitive to mechanical stress when incorporated into the PU formulation during processing and requires careful handling. In fact, it increases the release of sulfuric acid, which damages the catalyst in the polyol.

Cannon has introduced this new system at Utech Europe.


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