Patent ID: 8613184

Claim:
A core for a racket string, comprising: a thermoplastic matrix in which filaments are embedded, plural of these filaments being of natural origin, and the thermoplastic matrix being made of a thermoplastic material which, at a temperature lower than a threshold temperature, at which the filaments are not substantially damaged, has a viscosity suitable for an extrusion process, wherein the matrix comprises a plurality of strands that are helically twisted in a first direction, each of the strands comprising a plurality of the filaments of natural origin that are helically twisted in a second direction, which is or is not opposite the first direction, wherein at least one of the filaments of natural origin is a filament made of i) silk of plant or animal origin, processed or not processed, ii) extract from animal tissue or animal secretions, processed or not processed, or iii) plant fibers, and wherein each of the filaments is impregnated with the thermoplastic material.