The invention relates to a device for producing tubular structures for packaging tubes, comprising an elongate mandrel (3) extending axially, around which a substrate web can be subjected to a forming process to produce a tubular moulding (4), where, within the mandrel (3), there are a plurality of gas-outlet apertures (15) to which compressed gas can be applied to produce a gas cushion, in particular an air cushion, between the mandrel (3) and the tubular moulding (4), and where there are welding means for welding the tubular moulding, and where, with the aid of means (19) arranged radially adjacent to the mandrel (3) and capable of providing a combination of pressure-application and conveying, the tubular moulding (4) can be forced radially inwards in a direction towards a mandrel surface (16) which belongs to the mandrel (3) and which is convexly curved in a circumferential direction, and the tubular moulding (4) can be transported in a direction of the longitudinal direction of the mandrel (3) by virtue of a frictional effect between the means and the tubular moulding (4). The invention provides that the curved mandrel surface, at least sectionally, has been formed by the microporous and/or nanoporous material which has the gas-outlet apertures in the form of pores.