▎ 摘　　要

NOVELTY - Filament comprises poly lactic acid (PLA) (101) matrix defining the appearance of the filament; and 0.5-4 wt.% multiple graphene particles (102) dispersed in the PLA matrix, and having average thickness of 2-5 nm, two-dimensional surfaces of neighboring particles of multiple graphene particles aligned in parallel in the longitudinal direction of the filament, and dispersed graphene particles contact each other to achieve conductivity. USE - The filament is useful for three dimensional printing (claimed). ADVANTAGE - The filament has high conductivity, high reliability by enhancing mechanical properties and improving durability, and can be aligned in parallel in the longitudinal direction of the filaments and connected to each other to enhance mechanical properties. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for producing filament, comprising (a) providing liquid graphene and PLA solution; (b) mixing liquid graphene and PLA solution in a non-melting solvent mixing method to form a mixed solution in which multiple graphene particles uniformly dispersed in a solvent; (c) removing a part of the solvent from the mixed solution to form a gel-like product; (d) extruding the gel-like product through a nozzle to form a continuous filament, dispersing graphene particles uniformly in the PLA matrix defining the outer shape of the filament, aligning two-dimensional surfaces of multiple graphene particles in parallel to each other in the longitudinal direction of the filament, allowing the graphene particles to be connected to each other; and (e) removing the residual solvent from the extrudate . DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of a filament. Composite (100) Poly lactic acid matrix (101) Multiple graphene particles (102)