Laminated textile composites – Problems with bonding layers and sewing

In this paper laminated composites with woven fabric on the front side, polyurethane foam (PU) in the middle and knitted fabric on the back side were analyzed. These materials are widely used in the automotive industry, medicine, protection activities and other groups of technical textiles Based on analyses and problems encountered in practice, the hypothesis was made that the speed of joining the components into a laminated composite influences the needle penetration force and finally the seam quality when sewing. Investigations were performed using three GB needle systems, two PU thicknesses (2 and 4 mm) and three joining speeds (30, 35 and 40 m/min). According to the results obtained, it can be concluded that higher joining speeds determine lower penetration forces. By systematic analysis of the sewing seam the deformation of laminated composites occur at stitch points, which is caused by hardened PU residues after the lamination of components to a composite. Heating the needle during sewing resulted in partial melting of PU and adhesion of needle to the material is penetrating through which means damage to the needle and seam. This negative occurrence is more pronounced at lower bonding speeds, for higher PU thickness and thicker needle. Based on the results obtained it can be claimed that bonding speed, polyurethane thickness (PU) as well as needle type affected the penetration forces of sewing and seam quality.