Effect of areal density and fiber orientation on the deformation of thermomechanical bonds in a nonwoven fabric

Abstract

This study proposes a novel method to mechanically characterize the performance of individual bonds in low‐density, thermomechanically bonded nonwoven fabrics. Commercial bicomponent, polyethylene/polypropylene (PE/PP), nonwoven fabric was laser cut into bowtie‐shaped specimens for uniaxial tensile testing so that the central region of each specimen contained an individual bond. Three groups, each composed of 20 specimens, were tested with their longitudinal axes oriented along the machine direction (MD), the cross direction (CD), and at 45° between these two directions (DD). Prior to testing, the intrinsic variation in areal density and fiber orientation in the region surrounding the individual bond were quantified via orientation and relative basis weight parameters. During testing, images of the specimens were acquired to determine the occurrence of fiber breakage, bond deformation, and bond cohesive failure. Maximum force, stiffness, and orientation parameters were found to be significantly different among the three specimen groups (p < 0.01) but the relative basis weight was not (p > 0.01). The stiffness and maximum load were linearly correlated with both the areal density and fiber orientation. Pre‐existing voids or windows within the bond lowered the maximum force for specimens with the longitudinal axes aligned with the MD. These voids had no influence on the maximum force achieved by the specimens aligned with the CD and DD. The bonds in these specimens were observed to deform less than the bonds in the specimens with the longitudinal axes aligned with the MD. The results indicate the importance of the fiber structure surrounding the bond on the tensile properties, deformation and failure mode of individual bonds within the nonwoven fabric. POLYM. ENG. SCI., 59:311–322, 2019. © 2018 Society of Plastics Engineers

A brief review on the mechanical behavior of nonwoven fabrics

“…Effects of fiber orientation and areal density on the deformation mechanisms of the nonwoven fabrics were studied using a uniaxial tensile testing method and micrograph imaging in. 28 It was found that local fiber structure and fiber areal density were very important for the mechanical behavior of nonwovens.…”

Development of biaxial stretchable nonwoven paddings using novel polymeric fibers

“…However, there are very limited studies dealt with both elastic and thermal insulation behavior of nonwovens 13‐17 . Those studies revealed that the major disadvantages of such nonwoven padding are their lack of elasticity and conformability, bulkiness, and thermal insulation 18‐20 . Therefore, elastic fibers were opted as efficient choice to overcome the issues addressed above with existing nonwoven paddings.…”

Anisotropic mechanical behaviour of calendered nonwoven fabrics: Strain-rate dependency

“…6,7,[10][11][12][13][14][15][16] In addition, significant morphological changes occur at the bond periphery (interface region) during the bonding process, where typically damage initiates. 12,14,[17][18][19][20][21][22] Currently, only limited studies on the effect of anisotropy on the mechanical response of nonwoven materials are available. This is even rarer for calendered nonwovens.…”