I stand corrected that it doesn't have polyester in it, however, I stand by my belief that you aren't going to get a great result with it. There's a big difference in having polyester in it and being good for sublimation.
50/50 t-shirts have 50% polyester in them, but it doesn't mean they make great t-shirts for sublimation.
Unless it's some special powder coating made for dye subbing, I stand by my belief that I don't think it's going to work well.
I've said from the beginning of this that without knowing the details we wouldn't be able to accurately answer the question. We have no more details now than before, and talking theory about what you could possibly do is pointless without knowing the details.
I can assure you that if normal, every day powder coating was good for dye sub,you'd see powder coated products listed in every dye sub supplier catalog. Ever seen 1 powder coated blank in any sub sub catalog? I haven't.