Preparation method for thermoplastic polyurethane micro air bag elastomer material

A method for preparing a thermoplastic polyurethane elastomer material with micro air holes, comprising following steps:

• (1) feeding liquid raw materials including diisocyanate molecules and a polyol, and solid additives into a double-screw reactor to trigger a polymerization type chain extension reaction so as to obtain a hot melt having a high molecular weight;
• (2) pushing the hot melt having a high molecular weight obtained in step (1) into a mixing extruder via an exit of the double-screw reactor, and allowing the reaction to continue to generate a macromolecular thermoplastic polyurethane melt with a molecular weight distribution in a narrow range;
• (3) continuously feeding the obtained macromolecular thermoplastic polyurethane melt into a foaming extruder, and at the same time, adding a nucleator and a foaming agent into the foaming extruder, well mixing and homogenizing all materials to obtain a mixture, delivering the mixture to a mold head by a melt booster pump under a controlled pressure and at a fixed amount, and extruding a high-pressure hot melt from the mold head into an under-water granulation chamber;
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• (4) granulating the high-pressure hot melt obtained in step (3) in the underwater granulation chamber, delivering granulated particles into a separator by process water via a multi-stage pressure-release expansion process water pipeline, separating the generated expanded particles from the process water at the separator, screening and drying the expanded particles to obtain the thermoplastic polyurethane elastomer material with micro air holes.