Technological characterization of PE/EVA blends for foam injection molding

• Good products can be achieved by accurately controlling the blend formulation and mixing.
• The choice of the proper foaming agent has a great influence on the part quality.
• The use of DSC allows the evaluation of the material properties after processing.

Foam injection molding is one of the most important processes for producing lightweight plastic parts. The main feature of this process is the use of a foam blowing agent (physical or chemical) that decomposes during heating, generating gasses that are dispersed into the melt. Predicting the microstructure of the final part requires the investigation of the foam process which is a complex problem because it is necessary to combine transport phenomena of the multi-phase flow in non-isothermal conditions with foam kinetics and gas formation. The aim of this work is to evaluate the material-processing relationship in foam injection molding. The experimental measurements of PE/EVA blends, properly formulated, coupled to two types of ADC foaming agents were carried out using differential scanning calorimetry and rotational rheometry. The injection molding and direct measurements of foamed parts were then performed, based on previous measurements, to evaluate the process performance.

Figure optionsDownload as PowerPoint slide