Cable-reinforcing element, especially for optical cables, has a core containing filaments embedded in thermoplastic adhesive and an outer skin of thermoplastic adhesive containing a water-absorbent swelling agent

摘要

A reinforcing element for cables, with a core comprising filaments embedded in thermoplastic adhesive. The core is also enveloped in a skin of thermoplastic adhesive containing a dispersed, water-absorbent swelling agent which causes the core to expand in contact with water. A reinforcing element, especially for use in cables, particularly in optical cables, consisting of many parallel, untwisted single filaments embedded in a thermoplastic adhesive matrix to form a long core with an essentially constant cross-section. The core is also enveloped in a skin (S) consisting of another thermoplastic adhesive containing an homogeneously dispersed, water-absorbent swelling agent, so that the core expands in contact with water. Independent claims are also included for : (1) cables with a core, e.g. a core with optical waveguides, surrounded by one or more reinforcing elements as described above, in which the reinforcing elements are enveloped in an outer cable sheath; (2) a method for the production of these reinforcing elements by coating the filaments with molten adhesive and passing them through a die to form the core and then applying the outer skin to the still-hot core directly after the die; (3) a method for the production of cables by laying several reinforcing elements parallel to or helically round the main core (containing the waveguides) and then applying an outer cable sheath of thermoplastic material (e.g. HDP) by passing the combination through a sheathing die.