Thermosetting plastics lose mobility at high temperature due to the cross-linking reactions which form a 3D network between molecular chains. Whether it is EMC in IC packaging or AB glue in resin transfer molding, choosing the proper type of materials that can cure quickly at the end of filling is the primary consideration of thermosetting plastics molding.

The new DSC (Perkin Elmer Instrument DSC 8500) of Moldex3D Material Lab provides complete reaction curve of thermosetting plastics (shown in Fig. 1). The degree of cross-linking not only relates to the quantity of the heat generating from the reaction, but also directly affects the viscosity of the material (shown in Fig. 2). At low conversion, the viscosity of thermosetting plastics will decrease due to the elevated temperature, which is the same for thermoplastic materials. When the temperature reaches a certain point, the rapid increase in conversion and the cross-linking will cause a great increase in viscosity, which is characterized by the U-curve.

Moldex3D Material Lab provides accurate shear viscosity measurements of thermosetting plastics to help optimize the processing conditions to identify the flow front, the processing time and the temperature for optimum performance.

Moldex3D Material Lab also provides precise measurements of heat capacity and thermal conductivity (shown in Fig. 3) by means of DSC. This will help accurately predict the heat transfer and the temperature distribution between the mold temperature and the melt temperature to optimize the process cycle time and product quality.

Fig. 1  Kinetic curve of thermosetting plastics

Fig. 2  Shear viscosity of thermosetting plastics

Fig. 3  Heat capacity at different temperatures