PBT複合フィラー系を用いた射出成形品の変形挙動と配向評価

抄録

The addition of fillers, which come in various sizes and shapes, provides an effective means for improving various properties of plastics. In injection molding of fiber-filled plastics, warpage is often caused by anisotropic shrinkage due to filler orientation. Generally, to decrease warpage, particulate fillers are used in place of fibers, however, mechanical properties (modulus and strength) may suffer.
In the research reported in this paper, the warpage behavior using glass fibers and flakes and the anisotropic shrinkage at ribbed sections were examined. We have clarified the following: 1) Warpage decreases with decreasing fiber content. 2) The amount of warpage in fiber filled composites was unrelated to the rib-thickness. However, in glass flake-filled composites, rib-thickness depended strongly on the glass flake content. 3) The glass flakes, which were very small compared to the glass fibers, had a much smaller aspect ratio, and acted more like particulate fillers with minimal anisotropic shrinkage. 4) The relationship between the anisotropy and filler type and orientation was empirically determined.