In this study, we reports the first quantification details of the pencil hardness, eraser abrasion resistance and steel wool abrasion resistance of optically-transparent and biaxially-oriented poly(ethylene terephthalate) (PET) films in various thicknesses before and after hard coating (HC) and/or optically clear adhesive (OCA) coating. Surprisingly, the PET base films were determined to exhibit unrealistically very low hardness and abrasion resistances although their stress-strain behavior followed a ductile and tough plastic nature as a high performance engineering plastic: the pencil hardness was only ≤ 9B even at a low loading force, 0.100 kgf, and the onset loading force to cause scratches was far below 0.013 kgf in both eraser and steel wool abrasions. These collectively confirmed that, without surface protections, PET base films are not suitable for any advanced applications. Such the low hardness and poor abrasion resistances could be improved substantially by only thin HC coating of di(trimethylolpropane) tetraacrylate (HC-a, an ultraviolet curable acrylic resin). In addition, the OCA coating based on an acrylic copolymer adhesive provided adhesion function to the PET films, showing excellent adhesion strength onto chemically-toughened glass. However, the OCA layer causes cushioning effect because of its easy plastic deformation nature, making negative impact on the hardness and abrasion resistance performances of the PET film. Thus, the OCA coating should be thinned until retaining good adhesion to adherends. Overall, PET films coated with HC and/or OCA are suitable for advanced applications in various fields including smart phones, foldable phones, and flexible display devices.

在这项研究中，我们报告了各种厚度的光学透明和双轴取向聚对苯二甲酸乙二醇酯（PET）膜在硬涂（HC）之前和之后的铅笔硬度，橡皮擦耐磨性和钢丝棉耐磨性的第一个量化细节。 ）和/或光学透明粘合剂（OCA）涂层。出乎意料的是，尽管PET基膜的应力-应变行为遵循了作为高性能工程塑料的韧性和坚韧性，但它们的应力应变行为却表现出不切实际的非常低的硬度和耐磨性：即使在低加载力下，铅笔硬度也仅≤9B力为0.100 kgf，并且在橡皮擦和钢丝棉擦伤中，引起划痕的起始加载力均远低于0.013 kgf。这些共同证明，如果没有表面保护，PET基膜不适合任何高级应用。仅通过薄的二丙烯酸三（三羟甲基丙烷）四丙烯酸酯（HC-a，可紫外线固化的丙烯酸树脂）的薄HC涂层，就可以大大改善这种低硬度和差的耐磨性。另外，基于丙烯酸共聚物粘合剂的OCA涂层提供了对PET膜的粘合功能，在化学增韧玻璃上显示出优异的粘合强度。然而，OCA层由于其容易的塑性变形性质而引起缓冲作用，从而对PET膜的硬度和耐磨性产生负面影响。因此，OCA涂层应变薄，直到对被粘物保持良好的附着力为止。总体而言，涂有HC和/或OCA的PET膜适用于各种领域的高级应用，包括智能电话，可折叠电话，