Improvement on Adhesion Properties of Insert Injection Molding Composites: Effect of Inserted Parts, Adhesive Lengths and Injection Conditions

The focus of this project is on the insert injection molding process, developed for merging similar or different materials by molding injected melted polymer around an inserted part and injecting in the molded cavity of the conventional injection molding machine. This method is ideal for attaching automotive parts without having to use bolts or adhesives. Glass fiber-reinforced polypropylene (GF/PP) with various adhesive lengths of 0 and 5 mm was prepared as the inserted part and injected to the mold. The effects of the inserted parts, adhesive lengths, and injection conditions on the adhesive properties were investigated. The strength of the interfacial adhesive between the insert and the injected polymer was measured by using an Intron Universal Testing machine. The effects of the material in the inserted and injected parts were analyzed. It was found that by increasing the binding area of the adhesive interface, the barrel temperature, and the mold temperature, the interfacial adhesive strength of the insert injection molded-part was improved in all tested specimens.