Seam properties of ultrasonic welded multilayered textile materials

Abstract

This study examined the effects of ultrasonic welding parameters on bond strength, seam thickness and seam stiffness, as well as water permeability. For study purpose, two types of four-layered fabrics with same compositions and different areal densities suitable for inner part of sport shoes were used. Two different types of seams, lapped and superimposed, were applied for ultrasonic welding and also compared by traditional seam applied by shoe manufacturer. The morphology of different type of seams was also analyzed to observe the influence of welding parameters on the layers during the ultrasonic welding process. Bonding strength was found to depend on the seam type and composition of the joined fabric layers. It was confirmed by the shoe manufacturer that all the produced welded seams provided the requested minimum bond strength to be suitable for the use of the shoes. The traditional seams applied by the shoe manufacturer were thicker but had lower stiffness in comparison to all welded seams. It was also found out that ultrasonic welding damaged the membrane, which was confirmed by no water resistance of welded seams. Statistical analysis showed that ultrasonic welding parameters, such as welding frequency and velocity, influence the bond strength, thickness, and bending stiffness of welded seams, but the obtained results were statistically insignificant.

Experimental Investigation of Ultrasonic Welding on Thermoplastic Material – A Review

“…Simona Jesvnik and et.al [9] conducted an experiment on Polyurethene to Polyamide using process parameters Frequency, Velocity and Pressure to influence effect on Bonding Strength and Weld Quality and analyzed experimental reading through Student T-Test. Statistical analysis showed that ultrasonic welding parameters, such as Velocity and welding frequency has high impact on the bending stiffness, thickness and bond strength of welded seams, but the obtained results were statistically insignificant.…”

Applying Heat for Joining Textile Materials

“…The multilayer material with the integrated waterproof layer such as SympaTex ® or GoreTex ® are the most frequently used materials. The traditional joining technique used for joining the multilayer waterproof material for the inner socks of the shoes was carried out in two steps in order to keep the waterproofness [27]. The multilayered fabrics were sewn by zig-zag stitches with the predefined specifications.…”

“…The waterproof tape has to be welded exactly on the middle (±1 mm) of the seam and during welding puckering of the membrane should be avoided. Next, the hot air welding was carried out at the following processing conditions: temperature of hot air was 365-380°C, the speed of welding was 2.5 m/min., the pressure of welding was 0.7 bar, the pressure between welding wheels was 2.5 bar, and the pressure of hot air blowing was 0.6 bar [27]. Table 4 presents the characteristics and visual appearance of a joining seam of a multilayered material for shoes.…”

“…From the point of shoe manufacturer view, all produced seams would reach the desired minimum of bond strength, which is between 10 in 20 N/5 cm. But the traditionally joined materials can reach even the strength of 562.5 N/5 cm [27].…”

“…Moreover, the seam stiffness is also higher than the multilayered fabric, therefore the used seam construction is not enough functional during the shoe wearing because the friction problem can appear. To avoid the above-mentioned problems, the ultrasonic welding as the alternative technological process were proposed by Jevšnik et al [27][28][29]. The first results have shown that that the stiffness of the traditional seams applied by the shoe manufacturer was higher than those of ultrasonic welded seams.…”