Bree's link was directly to Aurifil in Italy (translated for English), not a retailer, and they don't list an 80 weight cotton. So perhaps what you have is old and no longer manufactured by them. If that is the case, it would explain why it isn't listed on their website and why it breaks so easily. I would use it for basting that you would rip out. That is what I do with my garbage thread.
I do know that Wonderfil makes an 80 wt poly called decobob that they market for bobbin use. I bought a sampler box at the AQS show and plan on trying it out for thread painting. I am currently using it for hand sewing binding and it sinks in beautifully. Can't see much difference between it and their 100 wt invisifil.