Preparation and Mechanical Property Evaluations of Puncture-Resistant Insoles Composites Reinforced by High-Modulus Filament and Thermal Bonding

High-modulus PET filaments and thermal bonding are used to reinforce the puncture resistance stability of the insole composite. This study aims to discuss the influences of the amount of low-melting-point polyester fibers (LMPET) and needle densities (ND) on tensile, bursting, and quasi-static puncture resistance properties. Besides, significance of LMPET amount and ND on puncture resistance against flat-head (A), spherical-head (B), and pointed-head (C) probes are in particular investigated to simulate the diversified application environments for insoles. Research result shows that, LMPET amount significantly affects the static puncture resistance against three probes; ND only significantly influences the puncture resistance against Probe A and C. Thermal bonding significantly improves the puncture strength against Probe B with various LMPET amounts of insoles, but evidently increases the puncture resistance against Probe A and C when being punched at various ND. The amount of LMPET fibers has a positive influence on the puncture strength of insoles, and 70 wt% of LMPET provide the average static puncture resistance up to 342.6 N. The high-modulus resultant insoles have advantages of flexibility, ease of process, and bendability with a higher and more stabilized puncture resistances.