Abstract: This article introduced the preparation of ultra-light TPU granules through batch foaming by supercritical fluid. The effect of foaming temperature, saturation time, and saturation pressure on the density and performance of TPU granules was studied. It showed that the foaming temperature and pressure constituted the main factors influencing the particle cell structure distribution. When the saturation pressure and temperature were 11 MPa and 145 ℃, respectively，the foamed TPU granules possessed low density, big size，large and uniform porosity.

Key words: supercutical fluid, TPU, foaming temperature, saturation pressure, density