低红外发射率水性聚氨酯/Al复合涂层的制备及性能表征

Preparation and property characterization of waterborne polyurethane/Al composite coating with low infrared emissivity

以自制WPU(水性聚氨酯)和片状Al粉为原料,采用简单的玻璃棒刮涂法制备得到了具有低发射率、低光泽特性和良好力学性能的绿色环保型WPU/Al复合涂层。系统研究了固化温度、Al粉添加量及交联剂对涂层性能的影响规律。研究结果表明:较高的固化温度和合适的Al粉添加量有利于实现涂层的低发射率和低光泽特性;当固化温度为120℃,w(Al)=40%时,涂层的发射率和光泽度可分别低至0.348和7.0。水性交联剂的使用可明显提高涂层的硬度,当w(交联剂)=5%时,涂层的硬度、附着力和耐冲击强度可分别保持在HB、1级和50 kg·cm,发射率和光泽度相比交联剂使用前有所增加,但仍具有较低的发射率(0.381)和光泽度(21.5)性能。

The green environmental friendly waterborne polyurethane(WPU)/Al composite coating with low infrared emissivity,low glossiness and good mechanical properties was prepared by simple blade coating method using self-made WPU and flaky Al powders as raw materials. The effects of curing temperature,Al content and cross-linking agent on coating’s properties were systematically studied. The results showed that the higher curing temperature and the appropriate Al content were beneficial to achieve low emissivity and low glossiness characteristics of the coating. When the curing temperature was 120 ℃ and the mass fraction of Al was 40% in coating,the emissivity and glossiness of the coating could be as low as 0.348 and 7.0,respectively. Using the aqueous cross-linking agent could significantly improve the hardness of the coating. When the cross-linking agent content was 5%,the hardness,adhesion strength and impact strength of the coating could be achieved at HB,1 grade and 50 kg·cm,respectively. The emissivity and glossiness were increased compared to before use of the cross-linking agent,but still had lower emissivity(0.381)and glossiness(21.5)properties.