Gobert Sven R L, Vancleef Arne, Clercx Seppe, Braeken Leen, Thomassen Leen C J
Department of Chemical Engineering, KU Leuven, Research Unit CIPT, Diepenbeek Campus, Agoralaan Gebouw B, B-3590 Diepenbeek, Belgium.
ACS Omega. 2021 Sep 28;6(40):25884-25891. doi: 10.1021/acsomega.1c01525. eCollection 2021 Oct 12.
UV-curable polyurethane dispersions (UV-PUDs) have applications in coatings for a variety of materials. Historically, the neutralization and dispersion steps of the UV-PUD production process have been performed in batch. However, continuous processing might reduce capital and operating costs, improve the dispersion characteristics, and facilitate scale-up. Static mixers and inline high-shear mixers are able to provide the necessary shear forces to obtain miniemulsions. The production of a UV-PUD is therefore studied in a continuous setup, whereby the neutralization step is performed in static mixers and the dispersion step is performed either in static mixers or in a high-shear mixer. The influence of the prepolymer temperature, mixing energy, and feed flow rate on the particle size and stability of the UV-PUD particles in water is explored. The results show that the neutralization step is mixing-sensitive, and the temperature of the neutralized prepolymer influences the particle size in the dispersion process. The amount of shear force applied during the dispersion step has a limited effect on the particle size. UV-PU dispersions with an average particle size below 80 nm and PDI below 0.1 are obtained with static mixers or in an inline rotor-stator mixer, at flow rates of 5.2 and 7.2 L/h, respectively. This research demonstrates that continuous processing using static mixers and high-shear mixing is a viable option for the neutralization and dispersion of UV-PUDs.
紫外光固化聚氨酯分散体（UV-PUDs）在多种材料的涂料中都有应用。从历史上看，UV-PUD生产过程中的中和及分散步骤一直是分批进行的。然而，连续加工可能会降低资本和运营成本，改善分散特性，并便于扩大规模。静态混合器和在线高剪切混合器能够提供获得细乳液所需的剪切力。因此，在连续装置中研究了UV-PUD的生产，其中中和步骤在静态混合器中进行，分散步骤在静态混合器或高剪切混合器中进行。探讨了预聚物温度、混合能量和进料流速对UV-PUD颗粒在水中的粒径和稳定性的影响。结果表明，中和步骤对混合敏感，中和后预聚物的温度在分散过程中会影响粒径。分散步骤中施加的剪切力大小对粒径的影响有限。分别在流速为5.2 L/h和7.2 L/h的情况下，使用静态混合器或在线转子-定子混合器可获得平均粒径低于80 nm且多分散指数（PDI）低于0.1的UV-PU分散体。这项研究表明，使用静态混合器和高剪切混合进行连续加工是UV-PUD中和及分散的一种可行选择。
