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Effect of Talc Size on Surface Roughness and Glossiness of Polypropylene Injection Molding Application to Automotive Plastics
Author(s) -
Kuroda Shinichi,
Mizutani Atsushi,
Ito Hiroshi
Publication year - 2020
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.25266
Subject(s) - talc , materials science , gloss (optics) , polypropylene , composite material , shrinkage , microstructure , molding (decorative) , particle size , chemical engineering , coating , engineering
Talc‐containing polypropylene (PP) resin is extensively employed in automobiles. Herein, considering the microstructure transfer process in injection molding, the effect of the talc's dispersibility and particle size on this process and its impact on the gloss level of the product were investigated. Results show that a fine unevenness of about several micrometers was self‐formed by the shrinkage of PP in nontransferred areas due to the blending of talc. Additionally, the amount of self‐formed unevenness tended with an increase in the average particle size of talc. Furthermore, due to PP shrinkage and different densities of talc, it was observed that a fine tiger‐stripe pattern was self‐formed using special molds with modified microstructure. This self‐formed fine unevenness changes the gloss level owing to the diffused light reflection effect. This study proposes controlling this change by controlling the average particle size of talc and structure of the mold. POLYM. ENG. SCI., 60:132–139, 2020. © 2019 Society of Plastics Engineers