Investigation of the Influencing Factors on the Extrudability of Rubber Compounds
The project aims to investigate fundamental relationships between the compound formulation of rubbers, compound production and the swelling behavior as well as the occurrence of surface defects in the extrusion process in order to enable clear conclusions to be drawn at an early stage about the influence of the interactions between the compound formulation and the mixing process on extrudability.
© IKVThe project aims to investigate fundamental relationships between the compound formulation of rubbers, compound production and the swelling behavior as well as the occurrence of surface defects in the extrusion process in order to enable clear conclusions to be drawn at an early stage about the influence of the interactions between the compound formulation and the mixing process on extrudability. For this purpose, the effects of all influencing variables on the viscoelastic properties, such as the relaxation time spectrum and the normal stress elasticity, must be quantified. Rubber compounds are produced by varying the polymer structure, filler type and filler quantity. In the mixing process, the polymer and filler dispersion and oil incorporation are varied in a targeted manner in order to additionally change the rheological compound properties.
In the Rubber Process Analyser, the relaxation time spectrum is determined at constant shear deformation with variation of temperature and strain. High-pressure capillary rheometry is used to investigate the first normal stress difference at stationary shear with variation of temperature, deformation rate and nozzle length. Furthermore, the true temperature of the extrudates is measured and the extent of flow instability and swelling tendency is evaluated. Extrusion tests of compounds with widely differing relaxation behavior and normal stress elasticity under varying melt temperature and throughput provide the data basis for assessing the actual processing behavior. A specially developed extrusion tool with different capillary lengths is used for this purpose.
Project data and thanks
We would like to thank the DFG for funding the project within the framework of HO 4776/96-1 and the project partners for their cooperation.
