KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY (한국포장학회지)

Korea Society of Packaging Science and Technology (한국포장학회)
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Analysis of Compression and Cushioning Behavior for Specific Molded Pulp Cushion

  • Jongmin Park (Department of Bio-industrial Machinery Engineering, Pusan National University) ;
  • Gihyeong Im (Production Engineering Research Institute, LG Electronics) ;
  • Kyungseon Choi (Production Engineering Research Institute, LG Electronics) ;
  • Eunyoung Kim (Production Engineering Research Institute, LG Electronics) ;
  • Hyunmo Jung (Department of Logistic Packaging, Kyungbuk College of Science)
  • Published : 2024.04.30
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Abstract

Molded pulp products has become more attractive than traditional materials such as expanded polystyrene foam (EPS) owing to low-priced recycled paper, environmental benefits such as biodegradability, and low production cost. In this study, various design factors regarding compression and cushioning characteristics of the molded pulp cushion with truncated pyramid-shaped structural units were analyzed using a test specimen with multiple structural units. The adopted structural factors were the geometric shape, wall thickness, and depth of the structural unit. The relative humidity was set at two levels. We derived the cushion curve model of the target molded pulp cushion using the stress-energy methodology. The coefficient of determination was approximately 0.8, which was lower than that for EPS (0.98). The cushioning performance of the molded pulp cushion was affected more by the structural factors of the structural unit than by the material characteristics. Repeated impacts, higher static stress, and drop height decreased the cushioning performance. Its compression behavior was investigated in four stages: elastic, first buckling, sub-buckling, and densification. It had greater rigidity during initial deformation stages; then, during plastic deformation, the rigidity was greatly reduced. The compression behavior was influenced by structural factors such as the geometric shape and depth of the structural unit and environmental conditions, rather than material properties. The biggest difference in the compression and cushioning characteristics of molded pulp cushion compared to EPS is that it is greatly affected by structural factors, and in addition, strength and resilience are expected to decrease due to humidity and repetitive loads, so future research is needed.

Keywords

Acknowledgement

This paper was conducted with the support of LG Electronics' industry-academic research fund, and thank you for this.

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