Investigation of the Effect of Internal Mold Release Agent and Filler on the Pulling Force in Pultrusion Process
Pulling force is one of the most important variables in pultrusion process which determines the capacity of the pultrusion machine. One of the characteristics of a desired pultrusion process is a low pulling force and a high line speed. Among the important factors affecting the pulling force are the internal mold release agent (IMR) and the content and particle size of the filler in resin formulation. In addition to facilitating the part separation from the die, IMR also affects the curing kinetics and in turn the pulling force. In this research, a commercial IMR has been used in a range 1-5 phr. DSC and DMTAAnalyses showed that the presence of IMR in concentrations above 3 phr reduces the heat of curing reaction and also the curing rate. This results in an increase in pulling force. Study of filler effect showed that the increase in filler content from 4 to 8 phr reduces the pulling force but beyond that it is increased. Also, decreasing the filler particle size in line speed lower than 30 cm/min reduces the pulling force but increases it at higher line speed.