Buffering sandwiches made of thermoplastic polyurethane honeycomb grids: Manufacturing technique and property evaluations

Abstract

Diverse products are delivered from the production place to different destinations, during which any impacts or shakes easily lead to the damage of products. Buffering packaging materials are thus used to absorb the energy caused by damage, thereby preserving the goods. Buffering packaging materials are commonly made of plastics and foams, which are the materials that have limited buffering effect and cannot be repetitively used. Therefore, this study proposes eco-friendly buffering sandwich-structured composites using thermoplastic polyurethane honeycomb grids and three-dimensional crimped, flame-resistant polyester nonwoven fabrics. Thermoplastic polyurethane honeycomb grids have advantages of a lightweight, a high strength, and high impact resistance. Thus, thermoplastic polyurethane honeycomb grids can be combined with flexible nonwoven fabrics that features ease of process to form environmentally friendly buffering packaging materials. Polyester nonwoven fabrics are made of differing basic weights. A total of one to three layers of polyester nonwoven fabrics serve as the cover sheets of the sandwiches, while a thermoplastic polyurethane grid serves as the interlayer in order to obtain different thicknesses. The buffering sandwiches are tested for bursting strength, air permeability, resilience rate, limited oxygen index, and drop-weight impact test, thereby characterizing their mechanical properties and buffering efficacy. The buffering sandwiches have an optimal residual impact stress of 4762 N when the polyester nonwoven fabrics have a basic weight of 150 g/m2. Moreover, the buffering sandwiches have an optimal resilient rate of 41.8% when they are composed of three-layered polyester cover sheets on both upper and lower sides, and are industrial product that qualified for use as buffering packaging.