Investigation of the Performance of Fumed Silica as Flow Additive in Polyester Powder Coatings

Coatings

Junqing Xie¹  Haiping Zhang¹  Hui Zhang¹  Yuanyuan Shao¹  Jesse Zhu¹  Danni Bao² 

[1] Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China;Particle Technology Research Center, Department of Chemical & Biochemical Engineering, The University of Western Ontario, London, ON N6A 5B9, Canada;

关键词: fumed silica;    flowability;    flow additive;    powder coating;    property;   

DOI  :  10.3390/coatings10100977

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown