タルク充填ポリプロピレン射出成形物の融解再結晶化
Melt-Recrystallization of Talc-Filled Polypropylene Injection Moldings
藤山光美
Fujiyama, Mitsuyoshi
Talc-filled polypropylene injection moldings show a peculiar crystal orientation, in which the planes of the talc particle plates are aligned parallel to the molding surface, the c- and a*-axes of polypropylene crystals are bimodally oriented in the flow direction, and the b-axes are oriented to the thickness direction. If the samples are melt-recrystallized, although the orientation of talc and the b-axis orientation of the polypropylene crystals are restored, the c- and a*-axes become unoriented in a plane parallel to the molding surface. This peculiar crystal orientation cannot be explained by any effect of an epitaxy caused by lattice matching between the cleavage plane of the talc and the (040) plane of the polypropylene crystal, a crystallization nucleation effect, a concentration of stress or melt orientation, or their synergisms. From the facts that, even if talc-filled polypropylene injection moldings are melt-recrystallized, the b-axis orientation to the thickness direction is restored and that an injection molding of polypropylene filled with only 0.5wt% talc already shows the peculiar crystal orientation, it is assumed that talc has a remote influence on the crystalliza-tion of polypropylene.
Key words: Polypropylene / Talc / Injection molding / Melt-Recrystallization / Crystal orientation