Reduced density article

A reduced density article of manufacture comprising a mixture of thermoplastic polycarbonate composition and at least 50 ppm of a triaryl phosphate having a weight average molecular weight (Mw) of at least 300, the reduced density article of manufacture having (1) a density as measured by ASTM D792-00 of 80% to 95% by weight of a similar standard injection molded article having no voids;

• (2) having a micro structure as measured by optical microscopy containing from 1% to 20% by volume of voids wherein at least 80% of the voids are high aspect voids have an aspect ratio from 2:1 to 100:1 with a major length of less than 5 mm and less than 20% of the voids are spherical voids with a diameter of 10 to 100 microns;
• wherein the polycarbonate thermoplastic composition comprises at least 50 mole % bisphenol A having a weight-average molecular weight (Mw) of 10,000 to 50,000, a glass transition temperature (Tg) from 130 to 180 degrees C., a phenolic OH end group content of less than 50 ppm, a halide group content below 100 ppm, and a diaryl carbonate content below 1% by weight, a tensile strength at yield of greater than 5,000 psi, and a flex modulus at 100° C. greater than 1,000 psi;
• and wherein the reduced density article of manufacture is made by an monofilament additive manufacturing technique using a monofilament having a diameter from 0.01 to 5.0 mm.

A process for making a reduced density article of manufacture comprising (1) depositing a multitude of thermoplastic monofilament strands having a diameter from 0.1 to 20.0 mm using a fused deposition modeling apparatus in a crossing pattern and (2) fusing the multitude of strands together to make a reduced density article of manufacture having voids therein;

• wherein the a reduced density article of manufacture comprises a thermoplastic polycarbonate composition, the reduced density article of manufacture having (a) a density as measured by ASTM D792-01 of 80% to 99% by weight of a similar standard injection molded article having no voids and (b) a micro structure as measured by optical microscopy containing from 1% to 20% by volume of voids wherein at least 80% of the voids are high aspect voids and less than 20% of the voids are spherical voids with a diameter of 10 to 100 microns;
• wherein the polycarbonate thermoplastic composition comprises at least 50 mole % bisphenol A having a weight-average molecular weight (Mw) of 10,000 to 50,000, a glass transition temperature (Tg) from 130 to 180 degrees C., a phenolic OH end group content of less than 50 ppm, a halide group content below 100 ppm, and a diaryl carbonate content below 1% by weight.