Process for producing insulated jacketed pipes by a continuous production process

Abstract

The present invention relates to a continuous process for producing insulated pipes comprising a conveying pipe, a jacketing pipe, a layer made of at least one polyurethane between conveying pipe and jacketing pipe, and a foil tube between the at least one polyurethane and the jacketing pipe, comprising at least the steps of (A) in a gripper-belt system, providing a foil tube formed continuously from a foil, and providing a conveying pipe, where the arrangement has the conveying pipe within the foil tube in such a way that an annular gap is formed between conveying pipe and foil tube, (B) charging a polyurethane system comprising at least one isocyanate component (a) and at least one polyol mixture (b) to the annular gap, (C) foaming the polyurethane system and allowing the same to harden, and (D) applying a layer made of at least one thermoplastic to the foil tube via extrusion, in order to form the jacketing pipe, which comprises using a multiple nozzle system having curvature corresponding to the radius of the annular gap to charge the material in step (B).