Abstract: Ultra light-weight TPU particles were prepared by using supercritical fluid intermittent micro cellular foaming technology. The effect of four different kinds of foaming agents, water vapor, hot air, water, and glycerol, on the foaming behavior was studied by using scanning electron microscope and gravity meter. It showed that the optimal foaming time of high temperature vapor, hot air, glycerol, and water was 50, 180, 30, and 15 s, and the optimal foaming temperature of high temperature vapor, hot air, glycerol, and water was 120, 115, 75, 80 ℃. High temperature vapor foam particles was better than others for the appearance, particle uniformity, or the uniformity of bubble structure.

Key words: thermoplastic polyurethane, high temperature vapor foaming, oil foaming, water foaming, oven foaming