Flexible window stack structure and display device including the same

A flexible window stack structure, comprising:

• a substrate;
• a first hard coating layer formed on a surface of the substrate, the first hard coating layer comprising an acrylate compound different from a dendritic acrylate compound;
• and
• a second hard coating layer formed on an opposite surface of the substrate, the second hard coating layer comprising the dendritic acrylate compound,
• wherein the first hard coating layer has a curing contraction greater than that of the second hard coating layer, and the second hard coating layer is disposed at an opposite side of a folding direction or an elongated side when the flexible window stack structure is folded;
• and
• the flexible window stack structure has a normal curl in the folding direction such that a surface of the first hard coating layer faces each other, and a degree of the normal curl is in a range from 5 to 50 mm in a state including only the substrate, the first hard coating layer and the second hard coating layer,
• wherein the degree of normal curl is evaluated as an average of heights of four corners of a lower surface of the second hard coating layer spaced apart from a level where the lowermost surface of the second hard coating layer is positioned.