This is a simple fix for those under_engineered and brittle plastic curtains, the folder contain two versions. The Shades_Fix_Simple Version is a simple plate with the a rectangular hole for the hook to hook into. On the other hand the Shades_Fix_complex version is more aesthetically pleasing and provides better grip due to its larger contact area with the curtain.
I would assume that those curtains usually fail from using the wrong plastic in making them, a more tough plastic should be used such that they can handle daily use.
Any type of semi_flex material can be used such as polypropylene or PETG. The important factor is for the material to be tough, i.e they can handle a lot of strain before failure.
I do not recommend using PLA or HIPS due to their rigidity and lack toughness.
Mark a 12 mm line from the edge of the damaged curtain and cut it along that line.
place some superglue inside the empty space of the _complex or on the lower edge of the _simple file (make sure to leave 1-2 mm gap between the hook opening and the plastic curtain).
Wait for the superglue to set for at least 5 minutes then replace the curtain in its place.
The standard mode of failure of the plastic curtain
Cutting out the damaged area
The slot which the plastic curtain fits in
The Final fix
View of the fixed Curtains