No.4（2001）19.Simple electrical evaluation method of the contamination degree on PET wastes

Katsumi YAMAMOTO, Yasuo TONOYA, Hirosi SHIGEMATSU and Masaru KIZAKI

In recycling plastic waste, it is indispensable to remove both of adgereing stuff and foreign substances. We discussed the relationship between contamination on plastic waste and its electrical characteristics. Therefore we adopted electrical resistance, dielectric constant and dielectric loss tangent as indexes for evaluating the degree of contamination on PET flakes. We measured the characteristics of various grade PET bottle flakes at a recycling plant to investigate the effect of contamination on them. The electrical resistance of low grade flakes is lower than that of virgin flakes. On the contrary, the dielectric loss tangent of low grade flakes is higher than that of virgin flakes. We found that both the values of the electrical resistance and the dielectric loss tangent are useful indexes of the degree of contamination, and we developed a simpe electrical evaluation method.

Keywords
Plastic waste, PET, Recycle, Contamination, Resistance, Dielectric loss tangent

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