Calcined Kaolin in Plastic Applications
The Imerys portfolio of calcined kaolin includes fully calcined clays as well as Metakaolin, produced at a lower temperature which results in the Metakaolin having chemical activity which can be used beneficially in certain applications.
PoleStar 501 (metakaolin) is used in PVC cable compounds to improve the electrical performance in low and medium voltage formulations. It is normally used at a loading of 10-15 phr and in combination with calcium carbonate at much higher loadings. The chemical activity of the PoleStar 501 immobilises the free radicals within the PVC compound, contributing improved electrical resistance.
Fully calcined kaolin, PoleStar 200R, can also be used in PVC cables but does not contribute to the electrical performance.
Amino Silane treatment enhances the performance of the calcined kaolin. Polarite 102A is widely used in polyamide compounds as it gives better overall properties than minerals such as wollastonite, talc and fine coated calcium carbonates. Important properties which can be improved using Polarite 102A are tensile strength, flexural strength and elongation at break. Because of the random particle shape of calcined kaolin warpage is low, important when larger items such as wheel trims or engine covers are moulded.
Product Related Literature
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