Physical and mechanical characterizations of recyclable insole product based on new 3D textile structure developed by the use of a patented vertical-lapping process

This paper deals with physical properties and compression behavior of new insole structure. This insole is developed based on a new 3D fibrous structure made of recycled polyester nonwoven (110 g/cm ² ) laminated with different textile materials by the use of a patented vertical-lapping process (VERTILAP®). To characterize physical and mechanical properties of the 3D structures, a methodology has been set up and new testing methods have been developed. The results of this study have shown interesting properties in terms of comfort and compression behavior (under static and dynamic loading). It has been observed that the 3D structure laminated with hemp woven fabric has the highest water absorbency, the highest thermal conductivity and the coolest touch effect compared to nonwoven made of a blend of polyester and viscose fibers. The compression behavior of the insole has been influenced by the physical properties of the 3D structure. The insoles developed in this work have a viscoelastic behavior with cushioning properties and can resist up to 218 kPa at 50% of deformation under static compression conditions and dissipate sufficient energy (higher than 180 N.mm) which allows the relieve of the foot pressure and distributes loads more evenly on the soft parts of the feet in use case.