Abstract: A conveyor belt, which has a high strength, tear resistance and flame retardancy, and which is particularly suitable for use in coal mines. It comprises a matrix of thermoplastic resinous material, e.g., PVC, reinforced with an armouring comprising a layer of primary tension elements extending substantially rectilinearly in the longitudinal direction of the belt and consisting of continuous filaments, and covering layers consisting of yarns or threads disposed on both sides of the primary tension elements so as to impart coherence in the transverse direction of the belt, the top and bottom covering layers being connected by tying yarns or threads. The primary tension elements are composed of cables or cords of aramid. Adjacent primary tension elements are separated by gaps having a width of 0.5 to 3 times, more particularly 2 times the outer diameter of the primary tension elements. The gaps are filled up with one or more elements such as, e.g., cotton cables or cords.

Abstract: Filte restproof conveyor belt, which has a high strength, and is particularly suitable for use in coal mines. It includes a matrix of, e.g. rubber having incorporated therein at least one layer of reinforcement fabric extending parallel to the supporting surface and the tread of the belt, the warp of the fabric extending in the longitudinal direction of the belt and including both polyamide and polyester filaments. Filtertestproof qualities are imparted to the belt by using aramid filaments as polyamide warp filaments, and by weaving the fabric in such a way that the yarn-in-fabric take-up of the aramid warp yarns, cords or cables is higher than that of the polyester warp yarns, cords or cables.

Abstract: A process for the improvement of the adhesion to rubber or a thermoplastic elastomer of synthetic yarns, cords or fabrics made therefrom by applying thereto an adhesive consisting of an aqueous solution or dispersion of a polyurethane with ionic groups, capped isocyanate groups and groups with a Zerewitinoff-active H atom, followed by drying the product thus treated. The polyurethane corresponds to the structure: ##STR1## wherein X has the meaning of an O or S atom or of an O-, S-, N- or P-containing group with a Zerewitinoff-active H atom or to which prior to reaction with an isocyanate group a Zerewitinoff-active H atom had been attached,R.sub.1 represents the remainder of a capping agent,R.sub.2 represents an at least divalent organic group which remains after removal of isocyanate groups from a polyisocyanate,R.sub.3 represents an at least divalent organic group which remains after removal of --XH groups from an organic compound having a molecular weight of 62 to 2000,R.sub.