a device for sealing plastics films , particularly in batch packages comprises a sealing jaw and a sealing surface thereon . in order to avoid the adhesion of residues of the film on the sealing jaw or its sealing surface during sealing of sealable plastics film in packaging technology , the sealing jaw or sealing surface is protected by a cover comprising a polytetrafluoroethylene strip . this teflon strip is so disposed and designed that it may be moved on from time to time relative to the sealing jaw or sealing surface , so that unused areas of the teflon strip pass into the sealing position to the required extent .