Waterborne polyurethane dispersion with high solid content and preparation method thereof

The invention specifically relates to a waterborne polyurethane dispersion with a high solid content and a preparation method thereof, belonging to the field of high polymers. The waterborne polyurethane dispersion with high solid content comprises, by weight, 10 to 50% of fine grains and 50 to 90% of coarse grains, wherein the average particle size of the fine grains is in a range of 50 to 150 nm; the average particle size of the coarse grains is in a range of 200 to 700 nm; the solid content of the waterborne polyurethane dispersion is no less than 50%; and the viscosity of the waterborne polyurethane dispersion is in a range of 1 mPa.s to 1500 mPa.s. The waterborne polyurethane dispersion prepared in the invention is low in viscosity and applicable to fields like coating agents and adhesives for flexible substrates. 本发明属于高分子领域，具体的说是种粒径双重分布的高固含水性聚氨酯分散体及其制备方法。高固含水性聚氨酯分散体，按重量百分比计，含有10wt％～50wt％的细颗粒和50wt％-90 wt％的粗颗粒；细颗粒部分的平均粒径在50纳米至150纳米之间，粗颗粒部分的平均粒径在200纳米至700纳米之间，所述水性聚氨酯分散体固含量≥50％，粘度为1mPa.s～1500mPa.s。本发明制备的水性聚