Leverkusen, Germany - A new filler incorporation method called Solid Injection by Air Stream (SIA) from Bayer MaterialScience transports the solids in a gas stream and only injects them into the mixing chamber during the blending phase.
BMS claims this method "opens up entirely new possibilities for the use of composite materials, regardless of whether they are hard or soft, or if the polyurethane is a solid or a foam."
One possible area of application, says the company, is adding flame retardants to polyurethane parts, which is required for a variety of applications.
This very versatile technology for the use of fillers in reactive polyurethane blends "is another example of how we use innovative developments to help polyurethane processors optimize their production processes," said Dr Stephan Schleiermacher, head of the project. The company will show the development at JEC 2011 in Paris, to be held 29-31 March.
In today's batch method, fillers are often added to the polyol component before it is blended with the isocyanate component in high-pressure mixing heads and reacted. This has two disadvantages: first, the system components must be adequately protected against wear caused by the solid, and second, large or mechanically sensitive filler particles limit the options.
"With the SIA technology, the components - polyol, isocyanate and filler - are added separately and not blended together until in the mixing head. This avoids the disadvantages of the batch method," said Roger Scholz, a polyurethane expert at Bayer MaterialScience.
The plant technology was developed in close cooperation with Hennecke GmbH, formerly a subsidiary of Bayer MaterialScience.
BMS says the method allows very light or heavy fillers and combinations of different types to be used, as well as reactive substances or particles with porous surfaces.
This significantly reduces the likelihood of changes to the fillers and cuts the wear of plant components due to abrasive or corrosive additives.
According to the developer, the technology also makes it possible to vary the filler content within a layer or between different layers, such as in a sandwich composite, for example.
Bayer MaterialScience is currently operating a pilot plant employing the method in Leverkusen.