A modular spiral belt and method for molding belt modules for constructing a heat-resistant belt. The spiral belt is constructed of a series of hingedly interconnected belt modules. The modules have single hinge links at the outside of a turn and dual hinge links elsewhere. All the hinge links extend outward from opposite faces of a central transverse spine. The dual hinge links, which each have a pair of parallel legs joined at a distal end by a yoke, are separated by a transverse pitch greater than the transverse pitch of the single one-legged hinge links at the outside of a turn. When molded from a blend of a thermoplastic polymer and a nanoclay, belt modules are useful in heat-resistant applications without sacrificing beam stiffness.