Multi-layer composite material

The multi-layer composite (10) comprising

• at least two layers (12, 14) made out of thermoplastics, wherein at least one first layer (12) is a nonwoven layer comprising thermoplastic fibers (20), wherein the layers (12, 14) are at least thermally bonded with each other in bonding zones (26), wherein the materials of the layers (12, 14) in the area of the bonding zones (26) are at least partially melted together, and wherein the bonding zones (26) impart a three-dimensional structure to the composite (10),
• the bonding zone (26) is formed by at least one bead (66, 68), which is edgeless and curved transverse to its progression, wherein the bead (66, 68) is formed by a floor area (70) comprising a bonding center (76), as well as by seamlessly adjacent lateral areas (72, 74);
• and
• wherein the immersion depth of the bonding center (36) into the second layer (14) measures 5-50% of the initial thickness of the second layer (14).

A process for manufacturing a multi-layer composite (10) comprising

• bonding at least two layers (12, 14) made out of thermoplastics, wherein at least one first layer (12) is a nonwoven layer comprising thermoplastic fibers (20), wherein the layers (12, 14) are at least thermally bonded with each other in bonding zones (26) by means of a roller arrangement (38), wherein the materials of the layers (12, 14) in the area of the bonding zones (26) are at least partially melted together, and wherein the bonding zones (26) impart a three-dimensional structure to the composite (10);
• wherein the bonding zone (26) is formed during thermal bonding in a roll pressure nip (48) of the roller arrangement (38) by rolling in an edgeless bonding stub (50) of at least one bonding roller (40) in both layers (12, 14) with continuous transmission of force via the longitudinal axes of the fibers (20) located in a sphere of influence of the bonding zone (26);
• and
• wherein the immersion depth of the bonding stubs (50) measures 5 to 80% of the initial thickness of the composite (10).