Acrylic offers these and other problems in flex and rigid/flex circuitry. It is,
after all "plastic" and relies on heat and pressure to effect lamination results
either acceptable or not. The heat during the lamination process almost does this
material "in."

For many years before the advent of other "adhesives" most of us sought alternatives.
We do still. Just the Tg alone is enough to want something much better
notwithstanding the aging problems - and those of polyimide film degradation with
heat and time.

Earl Moon