Method and apparatus for continuously caused by enveloping of a fully - or hollow profiles, particularly pipes, with an extruded foamed material made of thermoplastic synthetic material, as well as products prepared in this way

摘要

A process and an apparatus for continuously sheathing solid or hollow profiles (1), especially tubes, with an extruded foam jacket (3) of thermoplastic synthetic resin is provided. To this end a foam jacket is extruded, slit open, and into the slit foam jacket (3) the solid or hollow profile (1) to be sheathed is continuously coaxially introduced at synchronous speed. The slit foam jacket is closed by welding after the introduction. The process steps of slitting the foam jacket, introducing the profile to be sheathed into the foam jacket, and closing the foam jacket (3) by welding are to be carried out at temperatures of the foam jacket above the glass transition temperature of the synthetic resin material of the foam jacket. After the slit in the foam jacket (3) has been closed by welding, the jacket cools down and snugly shrinks onto the profile to be sheathed. According to a further embodiment said foam jacket (3) can be additionally provided with a protective film skin (5) extruded thereon in order to thus increase the impact resistance, the scratch resistance, and the water vapor impermeability of the foam jacket (3).