With the aim of improving water absorption and controlled release performance of current controlled release fertilizers, a novel composite coating method for superabsorbent-polyurethane coated urea (SAPCU) was developed. Superabsorbent-polyurethane (SAPU) composite coating material was successfully formed through an insitu reaction, where castor oil polyurethane (COP) and superabsorbent polymer (SAP) were connected through urethane bonds with an optimal reaction ratio of SAP and PAPI as 2.5:1 (w w⁻¹). The ideal nitrogen release and water absorption characteristics of SAPCU were achieved by adjusting the amount of COP and SAPU. The SAPCU had a high total nitrogen content (40.23–42.14 %), large swelling ratios (120–160 g water/g SAPU), and long nitrogen release period (60–150 days).

为了提高目前控释肥料的吸水率和控释性能，开发了一种新型的超吸收剂-聚氨酯包膜尿素（SAPCU）复合包衣方法。通过原位反应成功地形成了超吸收性聚氨酯（SAPU）复合涂料，其中蓖麻油聚氨酯（COP）和超吸收性聚合物（SAP）通过氨基甲酸酯键连接，SAP和PAPI的最佳反应比为2.5：1（ww ^-1）。通过调节COP和SAPU的量可以达到SAPCU理想的氮释放和吸水特性。SAPCU的总氮含量高（40.23–42.14％），溶胀率大（120–160 g水/ g SAPU），氮释放期长（60–150天）。