Transient behaviors of dual-layered patches for Newtonian liquids were numerically investigated in dual-layer slot coating processes for the first time using step-changed inlet flows. To further tune the leading and trailing edges in a patch cycle, startup and end lag times between the top and bottom layers were proposed, considering the flow state of a bottom-layer liquid in a coating bead region. Carefully chosen lag times significantly reduced the defects in the leading and trailing edges of a dual-layered patch. It was also found that a greater coating layer viscosity results in a greater amount of residue left on the die lips, which affects the next patch cycle.

中文翻译：

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间歇式双层槽涂工艺的实际操作

牛顿液体双层贴片的瞬态行为首次在双层槽涂工艺中使用步进变化的入口流量进行了数值研究。为了进一步调整补丁循环中的前缘和后缘，考虑到涂层珠粒区域中底层液体的流动状态，提出了顶层和底层之间的启动和结束滞后时间。精心选择的滞后时间显着减少了双层贴片前缘和后缘的缺陷。还发现涂层粘度越大，模唇上残留的残留量就越多，这会影响下一个贴片周期。