I had an experience when trying to stick pneumatic cloth (the nylon
type, not the purple type) with hot glue and it didn't stick well to
hot glue.  I know that the recommendation is to use PVC glue for nylon
cloth, but I wanted to use hot glue.

To solve the problem, Craig Brougher recommended that I wash the cloth
with lacquer thinner and try it again.  After that it stuck and held
strong.

You might try that with the purple cloth before giving up.

Eliyahu Shahar