The remaining residues in plastic recycling facilities are incinerated or landfilled. In this study, hydro-char was prepared by hydrothermal carbonization of residue from plastics recycling facilities (RPRF) and the properties of hydro-char were analyzed. Additionally, the physical properties of the hydro-char/recycled polypropylene (PP) blends were studied to evaluate the possibility of physical recycling of the RPRF. The hydro-char thus prepared was regular shaped-fine powder with uniform size, and its bulk density increased compared to the raw material (i.e., RPRF), making it easier to handle. The mechanical strength of the hydro-char/recycled PP blend was much higher than expected value, slightly lower than the composition average of the hydro-char and recycled PP. When a small amount of the impact modifier was incorporated into the blend, the impact strength of the blends was significantly increased. Therefore, it was concluded that physical recycling of the RPRF is possible after the hydrothermal treatment.

폐플라스틱에서 유효 성분을 선별하고 남은 잔재물은 소각하거나 매립하여 처리하고 있다. 이 연구에서는 폐플라스틱 선별 후 잔재물을 수열 탄화 처리하여 hydro-char를 제조하였고 hydro-char의 특성을 분석하였다. 또한 hydro-char와 recycled polypropylene(PP) 블렌드의 물리적 성질을 연구하여 폐플라스틱 선별 잔재물의 물리적 재활용의 가능성을 조사하였다. 제조된 hydro-char는 크기가 균일한 입자 형태였고 겉보기 밀도가 원료 물질에 비하여 크게 증가하여 다루기가 쉽게 바뀌어 있었다. Hydro-char/recycled PP 블렌드의 기계적 강도는 hydro-char와 recycled PP의 조성 평균보다 약간 낮은 정도로 꽤 높은 값을 나타냈다. 블렌드에 PP에 사용되는 충격 보강제를 소량 혼합하면 충격강도가 크게 증가하였다. 따라서 폐플라스틱 선별 후 잔재물을 수열 처리하면 물리적 재활용이 가능하다는 것을 최초로 보고하였다.

Keywords: plastic waste, plastic recycle, hydro-thermal carbonization, recycled polypropylene.