COMPOSITION AND PROCESS FOR ENHANCING FUNCTIONAL PROPERTIES OF POLYLACTIC ACID FOR 3D PRINTING

摘要

The invention relates to a material based on polylactic acid with enhanced functional properties, meant for 3D printing, and to a process for preparing the same. According to the invention, the material consists of 100 parts of levo isomer of polylactic acid with a stereoisomer content of 96...99% and/or 2...55 parts of dextro isomer of the polylactic acid with a stereoisomer content of 5...10% and/or 25...35 parts of impact modifier and/or 1...3 parts of sterically hindered phenols and/or 0.05...3 parts of low molecular mass colour concentrates, the parts being expressed by weight. The process, as claimed by the invention, consists, in a first stage, in drying the polylactic acid up to a regain of 0.01...0.02%, after which, in a second stage, which is a compounding-homogenizing stage, the impact modifier is dispersed into the melted matrix of the levo polylactic acid, followed by extrusion in a double-screw extruder, at temperatures of 160...230°C, at a screw rotation speed of 55...250 rpm, drying of the so formed granules, screening by size and packaging or filament processing for 3D printing.