A process for introducing a plurality of perforations into a laminate , wherein said process comprises at least the following steps: i. providing a laminate , said laminate comprising at least one substrate layer , said substrate layer being in contact with at least one layer comprising a silicone gel ; said laminate further comprising, in contact with said layer comprising silicone gel , at least one deformable layer ; ii. providing an ultrasonic welding device comprising an array of perforating elements suitable for introducing perforations into at least said substrate and said layer comprising silicone gel; iii. bringing said array of perforating elements in contact with said laminate, in particular with said deformable layer; iv. applying ultrasonic energy to said laminate in order to simultaneously introduce a plurality of perforations into at least said substrate and said layer comprising silicone gel , while introducing deformed portions in said deformable layer , wherein said deformed portions essentially correspond to the shape of the perforating elements, further wherein said deformed portions at least partly penetrate into the perforations so created characterised by v. after having introduced said plurality of perforations into said laminate , i.e. after step (iv), keeping said deformable layer in contact with said layer comprising silicone gel , such that said deformed portions remain penetrating into said plurality of perforations , for at least 12 hours, preferably at least 24 hours, further preferably at least 36 hours, further preferably at least 48 hours; vi. optionally, after the time period indicated in step (v), removing said deformable layer from said layer comprising silicone gel . i. providing a laminate , said laminate comprising at least one substrate layer , said substrate layer being in contact with at least one layer comprising a silicone gel ; said laminate further comprising, in contact with said layer comprising silicone gel , at least one deformable layer ; ii. providing an ultrasonic welding device comprising an array of perforating elements suitable for introducing perforations into at least said substrate and said layer comprising silicone gel; iii. bringing said array of perforating elements in contact with said laminate, in particular with said deformable layer; iv. applying ultrasonic energy to said laminate in order to simultaneously introduce a plurality of perforations into at least said substrate and said layer comprising silicone gel , while introducing deformed portions in said deformable layer , wherein said deformed portions essentially correspond to the shape of the perforating elements, further wherein said deformed portions at least partly penetrate into the perforations so created characterised by v. after having introduced said plurality of perforations into said laminate , i.e. after step (iv), keeping said deformable layer in contact with said layer comprising silicone gel , such that said deformed portions remain penetrating into said plurality of perforations , for at least 12 hours, preferably at least 24 hours, further preferably at least 36 hours, further preferably at least 48 hours; vi. optionally, after the time period indicated in step (v), removing said deformable layer from said layer comprising silicone gel . <EOS>