水性近红外低反射与8～14μm低发射率兼容涂层的制备及性能表征

Preparation and Property Characterization of Waterborne Low Near-Infrared Reflection and 8-14 μm Low Emissivity Composite Coatings

为制备符合环保要求的低发射率、低近红外反射率兼容涂层,以自制水性聚氨酯(WPU)为黏合剂,片状Al粉和Sm2O3为功能颜料,采用简单的刮涂法制备得到了具有低发射率、低近红外反射率和良好力学性能的绿色环保型WPU/Al-Sm2O3复合涂层;系统研究了复合颜料添加量、固化温度及交联剂对涂层性能的影响规律。结果表明:复合颜料添加量和固化温度对涂层发射率影响明显,而对涂层的近红外反射率几乎没有影响。当复合颜料添加量为40%(质量分数),固化温度为120℃时,涂层的发射率和1.06μm近红外反射率可分别低至0.468和51.1%。水性交联剂的使用可明显提高涂层的硬度,当交联剂添加量为5%(质量分数)时,涂层的硬度可增大到H,附着力和耐冲击强度可分别保持在1级和500 N·cm,发射率和1.06μm近红外反射率相比交联剂使用前基本保持稳定,其值分别为0.473和50.9%。

The green environment-friendly waterborne polyurethane(WPU)/Al-Sm2O3 composite coating with low infrared emissivity,low near-infrared reflectivity and good mechanical properties was prepared by simple blade coating method using self-made WPU,flaky Al powders and Sm2O3 as adhesives and functional pigments,respectively.The effects of composite pigment content,curing temperature and cross-linking agent on coating’s properties were systematically studied.Results showed that the composite pigment content and the curing temperature had significant effects on the emissivity of the coating,but had little effect on the near-infrared reflectivity of the coating.When the composite pigment content was 40%(mass fraction)and the curing temperature was 120℃,the emissivity and the near-infrared reflectivity at 1.06μm of the coating could be as low as 0.468 and 51.1%,respectively.The use of the aqueous cross-linking agent could significantly improve the hardness of the coating.When the cross-linking agent content was 5%(mass fraction),the hardness of the coating increased to H,and the adhesion strength and impact strength were maintained at Grade 1 and 500 N·cm,respectively.The emissivity and the near-infrared reflectivity at 1.06μm remained stable,with values of 0.473 and 50.9%,respectively,compared with the coating without the cross-linking agent.