Proprietary stream distributor and injector drastically shortens high-pressure recycling time reducing shear stress of expanded graphite flakes
Caronno Pertusella, (Varese), Italy, October 19, 2022
Cannon Afros, a company of Cannon Group, which specializes in mixing equipment and dosing systems for polyurethanes (PU) and urethane elastomers, has significantly upgraded its EG-AX multi-component mixing head system that now provides an easier, faster, and more economic processing of expandable graphite (EG) for discontinuous (molded foams) and continuous (sandwich and board panels) processes.
The EG-AX system consists of a Cannon AX mixing head with 4 streams – one for the polyol and expandable graphite slurry with an injection pressure of 120-160 bar, an isocyanate stream fed by a single pump and split into two by a flow divider and mainly used for discontinuous molded flexible foams, and a fourth stream as an optional input depending on the application – for example – for additives and blowing agents, such as water and hydrofluoroolefin (HFO), for integral skin foams for automotive engine covers. For sandwich and board panels requiring a continuous process, a generous proportion of the polyol is drawn from the slurry and injected via the fourth stream which allows injection pressures as low as 80-90 bar.
“Expandable graphite is probably one of the best inorganic and physical fire retardants for versatile molded flexible open cell PU foams used for seating, arm and headrests in public transport and automotives, where it is also used under-the-hood to provide protection from the heat and noise of the engine. It is considered as an eco-friendly, highly effective intumescent char-forming fire retardant with low smoke and toxicity however, it’s very sensitive to mechanical stress when incorporated into a PU formulation and therefore requires expertise when processed.”
Stefano Andreolli, Sales Manager, Automotive Applications
Expandable graphite has a mineral origin and is derived by treating flake graphite with reversible intercalation reagents such as nitric acid and sulphuric acid. Maintaining the integrity of flakes during processing is a critical step as normal high-pressure recycling times, of up to seven seconds, could disintegrate the flakes releasing sulphuric acid, thereby destroying the polyol catalyst, and may also corrode equipment.
The improved Cannon EG-AX mixing head system dramatically reduces the high-pressure recycling time to under one second before the shot. This considerably minimizes damage to the graphite flakes, thereby preserving the formulation intact for much longer processing times. Furthermore, the less the expandable graphite flakes are damaged, the less are needed in the foam application to successfully pass fire tests, which renders the cost performance ratio extremely advantageous.
To achieve these benefits, the upgraded Cannon EG-AX multi-stream mixing head system is composed of proprietary equipment which includes a hydraulically operated injector specially shaped to minimize damage to the graphite flakes; a sensitive gauge to detect build-up of pressure before pouring; a hydraulically operated stream distributor for very fast switching to high-pressure recycling; temperature sensors to keep the viscosity of the slurry at the mixing head under control; and two isocyanate injectors.
The Cannon EG-AX system is available with three different mixing heads, providing mass flow rates ranging from 100 g/s to 1100 g/s. Cannon also provides all upstream equipment to prepare and process expandable graphite in high pressure including batch slurry premixing, metering, and dosing machines.
To learn more, visit the Cannon Group at K2022, Düsseldorf, Germany (Oct. 19-26), in Hall 13 Booth B87.
About Cannon Afros
Cannon Afros, a company of the Cannon Group founded in the early 1960s, is the world’s leading supplier of dosing systems, mixing equipment and processing technologies for polyurethanes and multi-component resins. Today Cannon Afros offers an extensive range of processing technologies for molding, pouring, injection, spraying, pultrusion and manufacturing abilities dedicated to a comprehensive range of resins such as polyurethanes, silicones, elastomers, epoxy resins, phenolic foams, and bi-component adhesives. Cannon Afros design, manufactures and sells a vast range of equipment from single mixing heads and stand-alone units to complex turnkey and customizable production plants to serve the following main industrial applications: automotive interiors and exteriors, appliances and refrigerator insulation, rigid insulation for the cold chain industry and refrigerated transportation, building and construction insulation, sanitary ware, piping insulation for oil heating and district heating, technical components and medical equipment, flexible padding and seats for furniture and automotive industries, sealing and gluing for lighting and electrical enclosures, direct infusion and pultrusion for wind blades, and encapsulation and potting for electrical and electronic components.
About Cannon Group
Founded in 1962, Cannon Group comprises 30 companies, with a global presence in more than 40 countries and is recognized as a market leader in technologies, processing and molds for polyurethanes and urethane elastomers for the plastics and composites industries. The Group designs and manufactures high- and low-pressure dosing machines and mixing equipment, for continuous slab and discontinuous molded polyurethane foams. Dedication to continuous innovation now positions Cannon Group as a driving force offering the design, manufacture, servicing, and maintenance of equipment also in other key technology areas including: Energy – industrial boilers for standard and special applications, comprising steam boilers, hot water heaters, heat recovery boilers, and thermal oil heaters, with in-house engineering and fabrication services; Water & Wastewater Treatment – deareators, condensate treatment and recovery, effluent treatment plants, sanitary water treatment and sewage treatment, injection water treatment, demineralization, produced water; and Automation, where Cannon Group offers process digitization and condition monitoring, connect-IT and emissions monitoring. Cannon Group is committed to reducing the ecological footprint of all the Group’s technologies and industrial processes offered to the market through energy efficiency, resource consumption reduction and emissions reduction. Cannon Group delivered net sales of €230 million in 2021. To learn more, visit www.cannon.com
Head of Corporate Marketing Communications
+39 347 63 76 787
Cannon EG-AX system validates easy and economic processing of expandable graphite fire retardant filler for PU foams.
Photo: Cannon Group