Sunforger is not a brand of canvas it is the treatment that it is applied to it. It is usually marked on the selvage of the canvas. It is marked to differentiate it with the untreated canvas. I used to use Texas patching Teflon treated canvas. It was also marked Sunforger on the selvage. When Texas patching became unavailable. I tried the minuteman patching in .020 and .015. The weave of the two different brands was totally different in regards to tightness and pliability.
I have since stopped using Teflon patching. I have found that pocket drill, denim. and some untreated canvas works just as well with the proper lube.