Patent ID: 8426007

Claim:
A laminate, comprising: metal layers ( 1 - 3 , 9 ); plastic bonding layers ( 4 - 6 ) situated between the metal layers ( 1 - 3 , 9 ), two external metal layers ( 1 , 3 ) extending substantially continuously; and at least one internal metal layer ( 2 , 9 ), wherein, at least one of the internal metal layers ( 9 ) has at least one opening ( 10 ), at a position of the opening ( 10 ) the other metal layers ( 1 - 3 ) and the plastic bonding layers ( 4 - 6 ) are bonded together to form a packet of lower thickness, at least one of the openings ( 10 ) is peripherally closed, the metal layer provided with the peripherally closed opening ( 10 ) is situated between the plastic bonding layers ( 5 , 6 ) and is bonded on either side to the plastic bonding layers ( 5 , 6 ), the plastic bonding layers ( 5 , 6 ) continue without interruption at a position of the peripherally closed opening ( 10 ) and are bonded together at that point, and at a location of the packet of lower thickness, an external layer ( 3 ) which extends continuously at said location has a stepwise recessed area ( 12 ) a step height of which is equal to a thickness of a single metal layer provided with the peripherally closed opening ( 10 ), and each internal metal layer ( 9 ) with a peripherally closed opening ( 10 ) being free from steps.