The requirement for “Rope” when crafting shields is for a CNR provided Rope that looks like an ingredient icon (1×1 square). The rope from Iggy or Gloigan which looks like a coiled rope icon (2×2 square) is not the ingredient you are looking for.
I added the CNR rope to the random merchants general store to pull randomly. So it should show up with Gloigan, Iggy (now) and a few others that pull from that store group.
You can also craft the rope. Though I defer to the CNR masters and Recipe Guy (LT. Tyler) about how to go about it. If you undertake creating CNR Rope and something can’t be found, please post about it here.