Strength Optimization of Thermally Bonded Spunbond Nonwovens

Abstract

Recent research on all aspects of thermally point bonded nonwovens has led to considerable improvements in the understanding of material requirements for these nonwovens, the changes that occur during bonding and the resultant deterioration of the mechanical properties of the nonwoven materials. This paper addresses how one may use a bicomponent fiber technology to overcome the shortcomings of the thermal bonding and obtain high strength spunbond fabrics. In particular, we present the utility of islands-in-the-sea (I/S) bicomponent fibers for optimizing the strength of thermally bonded fabrics. To examine the role of various bonding temperatures on the fabric performance, preconsolidated webs were formed and subsequently, thermally bonded. Thus, any influence introduced by potential variations in the structure was minimized. Point-bonded bicomponent samples made up of nylon-6 (N6) as the islands and low density polyethylene (PE) as the sea showed great promise with respect to their mechanical properties, suggesting that the use of bicomponent fibers can be beneficial for strength optimization of thermally bonded spunbond nonwovens.

Durable Nonwoven Fabrics via Fracturing Bicomponent Islands-in-the-Sea Filaments

“…We do not see a justifiable reason why tensile properties would increase and then decrease with island count. Previously, we have shown that island fiber properties do not change at higher island counts [21,25]. Any significant changes therefore, may be due to structural variations, the degree of splitting and entanglement.…”

“…The typical crosssection of I/S fibers is shown in Figure 1. It was observed earlier [25] that a polymer ratio of 75/25, 25% being assigned to 'Sea' polymer or PE, had the best tear properties. In this study, nonwoven webs were produced with filaments that contain 75% of PA6 and 25% of PE, with different island counts.…”

“…We believe that the PE phase goes through stress relaxation since it does not solidify as rapidly and remains fairly un-oriented perhaps facilitating the fibrillation process. This was discussed fully by Fedorova and Pourdeyhimi in earlier publications [21,25]. Hydroentangling of all samples was performed on the Fleissner hydroentangling unit at the pilot facilities of the Nonwovens Cooperative Research Center (NCRC) [27] at a speed of 10 m/min using 5 manifolds with pressures ranging from 30 to 200 bar across the manifolds.…”

“…Fedorova and Pourdeyhimi [21,25] studied the feasibility of 'Islands-in-the-Sea' (I/S) cross-sections in the filaments in producing high-strength fabrics after bonding the spunbond webs using mechanical (hydroentangling) or thermal (calendering) techniques. During this study, it was observed that some of the islands in the sea fibers were fractured and the fibrillation of the sea led to Evolon ® -like fabrics with much improved tear strength.…”

Interconnected, microporous hollow fibers for tissue engineering: Commercially relevant, industry standard scale‐up manufacturing

“…). Typical island counts are 1 (sheath core), 7, 12, 19, 37, 108, 216, and 360 . Hills Inc. (West Melbourne, FL) has reported fabrication of filaments containing up to 1200 islands, with the potential of achieving over 4000.…”