Insulation & Facades

Method for the production of insulation material based on non-modified, starch-containing raw materials

An extruder was designed and manufactured which is suitable for the plastication of non-modified starch materials like corn grits due to its particular plastication unit. In order to adapt the foam properties to the demands of an insulation material, different additives have been evaluated.

Summary

The main objective of the research project was the development and the manufacturing of an extrusion line for the production of foamed sheets made of starch containing raw materials. The main application of the foamed sheets is the use as an insulation material.

The knowledge about the processing characteristics of this extruder type is very limited, hence a process analysis was done in order to investigate the connections between process parameters and melt and foam properties, respectively. Furthermore, the flow properties of the plasticated starch material have been investigated. For this investigation a special online-rheometer system was designed and manufactured.

Results:

The manufacturing of foamed sheets and profiles based on corn grits is possible.
A flame protection was obtained by the use of a halogen flame retardant and the water stability was improved by adding water resistant thermoplastics.
The heat conductivity of the foam can be compared to the heat conductivity of other insulation materials based on renewable raw materials.
The melt properties of starch permit a foaming effect even in case of the use of slit dies, but it is still problematic that wide sheets still have low product thicknesses due to the affinity of the melt to longitudinal expansion. A method was successfully developed to predict the foaming performance of different corn species.

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Source: German National Library of Science and Technology Hannover (TIB)