Can't suggest a specific rope type (I used jute but failed to reach unconsciousness), but can suggest some things to think about. Note that these are things I've discovered from my own research, I am by no means an expert.
The rope should not be elastic since this will distribute the pressure put on your neck. It should not be too thin since it will dig into your skin (which hurts). And it should be sturdy enough to support your weight. Another thing to think about is friction, if the rope is rough the noose will not tighten as fast.