覆盖膜打印字符结合力提升研究

Research on the improvement of the binding force of the printing legend on the cover lay

电子产品的轻薄化和多功能化趋势要求上游的印制电路板技术不断向高密度化、高精度化、微小化发展，使得部分刚挠板刚性区域空间受限而不足以容下字符标识，故刚挠板挠性区域上的字符打印不可避免，而覆盖膜上打印字符一直存在抗剥离强度不佳的问题。文章较系统分析了影响覆盖膜与打印字符油墨间结合力的各因素，并从覆盖膜表面改性和优化打印字符固化参数两方面着手来提升挠性区域上打印字符结合力。其中覆盖膜表面改性采用等离子处理法和碱处理活化法。最终得到的相关研究结论转化应用到生产，结果表明覆盖膜上打印字符附着力测试合格率相比改善研究以前得到显著提高，且达到了简化刚挠板打印字符流程的目的。

The trend of electronic products of light-weight and multifunction requires upstream of the printed circuit board technology continuous to high density, high precision, small progress. This trend also makes part of rigid-flex PCB rigid regions where space is limited and cannot contain legend identification, so the legend priming on the flexible area of rigid-flex PCB is inevitable, but the priming legend on the cover lay always have the problem of poor peel strength. This paper systematically analyzs various factors affecting the binding force between the film and the printing legend ink, and in combination with the practical determination of the two aspects of the surface modification of cover lay and the optimization of the curing parameters of the printing legend. In this paper, the surface modification by plasma treatment and alkali activation are introduced. Finally, the relevant research conclusions are applied to production, and the results show that the qualified rate of the printing legend adhesion test on the cover lay is significantly improved compared with the previous research, and the purpose of simplifying the process of the printing legend is achieved.