Fumed silica is one of the most commonly used flow additives in the powder coating industry. To investigate the influence of the properties of fumed silica on powder coatings, three different types of fumed silica, Aerosil R812, R972, and R8200, were selected and introduced to an ultra-high-gloss powder paint by the dry-blending method with preset mixing conditions and times. Their effect on the powder flowability, coating application related properties and film properties were carefully studied. The angle of repose (AOR) and bed expansion height data, which represent the semi-dynamic and dynamic flowability of powders respectively, show a strong flowability enhancement for the powders with additives, and R812 exhibits the best performance compared to 8200 and R972, mainly due to its high hydrophobicity and specific surface area. For the ultra-high-gloss powder paint, all the flow additives cause slight gloss reductions, surface roughness increase and a significant effect on the distinctness of image (DOI). The addition of R972 is beneficial to the transfer efficiency of powders compared with the other two, while the additives impose only a minor influence in the Faraday cage effect. The melting and curing dynamics, i.e., gel time, and inclined plate flow, are not affected by the flow additives.

中文翻译：

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气相法二氧化硅在聚酯粉末涂料中的流动性能研究

气相法二氧化硅是粉末涂料行业中最常用的流动添加剂之一。为了研究气相二氧化硅的性能对粉末涂料的影响，选择了三种不同类型的气相二氧化硅，即Aerosil R812，R972和R8200，并通过预先设定的干混方法将其引入超高光粉末涂料中。混合条件和时间。仔细研究了它们对粉末流动性，涂料应用相关性能和薄膜性能的影响。分别代表粉末的半动态和动态流动性的休止角（AOR）和床膨胀高度数据显示了具有添加剂的粉末的流动性增强，并且R812的性能优于8200和R972，主要是由于其高疏水性和比表面积。对于超高光泽度的粉末涂料，所有的流动助剂都会导致轻微的光泽降低，表面粗糙度增加以及对图像清晰度（DOI）的显着影响。与其他两种粉末相比，添加R972有利于粉末的转移效率，而添加剂对法拉第笼效应的影响很小。熔融和固化动力学，即胶凝时间和倾斜的板流不受流动添加剂的影响。