Effect of Glass Fiber on Weld-line Protrusion Height and Impact Strength for FR-Polypropylene Composites

Abstract

In the injection molded parts of glass fiber reinforced PP (PPG), the increase of fiber content to improve the mechanical properties, results in protruding the surface at weld-line region, where melt flows unite in at injection mold, and deteriorates the surface appearance.In this study, the optimum material design were discussed to improve both surface appearance quality and mechanical property of PPG.The weld-line protrusion height as the surface appearance quality and izod impact strength as the mechanical property were measured for PPG's with various fiber contents. The influences of fiber content, short-fiber/long-fiber ratio and flowability of matrix PP were discussed. It can be found that the low-flowability PP with a proper quantity of long fiber is effective for solving the weld-line protrusion without reducing the impact strength.