Prediction of interfacial strength of HDPE overmolded with EPDM

Abstract

Multicomponent injection molding often combines a stiff thermoplastic material with a thermoplastic elastomer or thermoplastic vulcanite. Recently, for high‐demanding applications, a novel process has been developed to replace these thermoplastic elastomers or vulcanite with a thermoset rubber, for example, NBR or EPDM. One of the most important properties of a two component product is an adequate adhesion between both components. This paper describes a method, which combines experiments and numerical simulations to predict the adhesion strength between a thermoplastic, semicrystalline HDPE, and an EPDM thermoset rubber. This method uses numerical simulations of the interfacial temperature and the local degree of cure. The local interface temperature is combined with the results of DSC measurements to predict the degree of melting, subsequently linked to the ability to develop adhesive strength. The degree of cure is used to determine the local rubber strength. The combination of the given data will be used to predict interfacial strength. The results obtained by proposed numerical strategy have been successfully validated with experimental data on a simple plate product. POLYM. ENG. SCI., 59:1489–1498 2019. © 2019 Society of Plastics Engineers

Recent developments on the overmolding process for the fabrication of thermoset and thermoplastic composites by the integration of nano/micron-scale reinforcements

“…Six et al [12] developed a healing model towards the quantification of the interfacial strength using to define the strength between layers of thermoplastic composites (semi-crystalline high-density polyethylene (HDPE) and thermoset ethylene propylene diene monomer (EPDM)) by the investigation of the parameters of curing and interface temperatures. Experimental results were supported with numerical modeling, and successful plate production was achieved in this study.…”

Experimental and simulative investigation of a multistage 2K injection molding process of PA6 and EPDM

“…Simulations can be helpful in describing conditions in the interface during processing. A very interesting approach to the simulative description of adhesion and its dependence on general conditions is shown by Six et al 11 By considering the relationships between material strength, degree of crosslinking and interdiffusivity of the hard component (derived from DSC measurements), a model is described which can be used to estimate the bond strength between PE and HDPE with respect to process conditions.…”

Reactive wetting of polyethylene on ethylene-propylene-diene terpolymer

“…Similarly, Fuentes et al [13] observed a reduction in static contact angles with increasing maleic anhydride (MA) content in molten maleic anhydride-grafted polypropylene (MAPP)/polypropylene (PP) blends which was explained by covalent bonding between the MA groups and the glass substrate. For the combination of a thermoset rubber solid and thermoplastic melt, literature on reactive wetting is currently, to the best of our knowledge, lacking despite its importance for twocomponent (2K) injection molding of thermoset rubber with thermoplastics [21][22][23].…”