SULZER CHEMTECH
Process for continuous production of EPS from PS / Improved dispersion / Large-scale plant under construction
A further major producer appears to be set to join the European EPS market, providing competition to, for example, BASF (Ludwigshafen / Germany; www.basf.com) and Sunpor Kunststoff (St. Pölten / Austria; www.sunpor.at) with their new grey EPS products "Neopor" – see Plasteurope.com of 19.03.2009 – and "Lambdapor" – see Plasteurope.com of 06.02.2007 – respectively. Plant and machinery manufacturer Sulzer Chemtech (Winterthur / Switzerland; www.sulzer.com) has reported that it is currently building a production line for expandable polystyrene for an unspecified "major chemical company." The new plant will be based on a proprietary Sulzer process and is scheduled to go on stream at the end of 2009.
Like the BASF process, Sulzer’s technology is based on the introduction of the blowing agent into normal polystyrene using an extrusion process. However, unlike conventional EPS production, in which styrene monomer is suspension-polymerised in a stirred reactor in a batch process, the Sulzer process is continuous. Additives can be incorporated during the melting phase, even before the pentane gas is injected into the melt. Outstanding dispersion is claimed for the process, especially for pigments. Further additives, for example flame retardants, can also be added downstream of pentane injection. The resulting cooled mixture is pelletised in an underwater granulating system, which yields EPS micropellets that can be processed into slabstock and other foamed parts using standard processes.
Sulzer claims that EPS manufacturers have much better control of output thanks to the continuous process, which it says is a major benefit. One of the particular problems associated with EPS is its very limited storage stability of around three months due to its gas release behaviour. This is compounded by excess production from batch operation leading to ups and downs on the market. With the new process, it is very much easier to target production to demand, Sulzer says. Because it is freely scalable, smaller, decentralised production units could be built in the vicinity of the customer markets – a particular advantage in hot and humid regions.
The process offers other technological advantages. For example, the blowing agent and additives can be metered far more accurately, says Sulzer. Thanks to the high level of dispersion of pigments and additives, the process can lower the thermal conductivity coefficient by up to 20%, significantly reducing the amount of material used in the final application to obtain the same heat insulation. Colouring is claimed to be significantly better than with conventional EPS. Additionally, because the size distribution of the beads has a very much narrower window than conventional EPS, the material has improved filling behaviour in the mould during foaming. The fusing level of the expanded beads is also higher, resulting in improved mechanical properties.
Sulzer said that its capability to construct EPS production lines on a turnkey basis, including the process licence to which it holds rights, is available to customers. Additionally, customised EPS grades can be developed in a pilot plant at the company's headquarters in Winterthur, which is open to viewing by interested customers.
Like the BASF process, Sulzer’s technology is based on the introduction of the blowing agent into normal polystyrene using an extrusion process. However, unlike conventional EPS production, in which styrene monomer is suspension-polymerised in a stirred reactor in a batch process, the Sulzer process is continuous. Additives can be incorporated during the melting phase, even before the pentane gas is injected into the melt. Outstanding dispersion is claimed for the process, especially for pigments. Further additives, for example flame retardants, can also be added downstream of pentane injection. The resulting cooled mixture is pelletised in an underwater granulating system, which yields EPS micropellets that can be processed into slabstock and other foamed parts using standard processes.
Sulzer claims that EPS manufacturers have much better control of output thanks to the continuous process, which it says is a major benefit. One of the particular problems associated with EPS is its very limited storage stability of around three months due to its gas release behaviour. This is compounded by excess production from batch operation leading to ups and downs on the market. With the new process, it is very much easier to target production to demand, Sulzer says. Because it is freely scalable, smaller, decentralised production units could be built in the vicinity of the customer markets – a particular advantage in hot and humid regions.
The process offers other technological advantages. For example, the blowing agent and additives can be metered far more accurately, says Sulzer. Thanks to the high level of dispersion of pigments and additives, the process can lower the thermal conductivity coefficient by up to 20%, significantly reducing the amount of material used in the final application to obtain the same heat insulation. Colouring is claimed to be significantly better than with conventional EPS. Additionally, because the size distribution of the beads has a very much narrower window than conventional EPS, the material has improved filling behaviour in the mould during foaming. The fusing level of the expanded beads is also higher, resulting in improved mechanical properties.
Sulzer said that its capability to construct EPS production lines on a turnkey basis, including the process licence to which it holds rights, is available to customers. Additionally, customised EPS grades can be developed in a pilot plant at the company's headquarters in Winterthur, which is open to viewing by interested customers.
11.05.2009 Plasteurope.com [213298]
Published on 11.05.2009