Exhibition work is my main business and I have done lots of PopUps in my time.
I have tried many combinations and finally settled on Kentmere Opaljet 300 as the printed media overlaminated with an 80 micron matt laminate from Allprint (SR3).
I print these on a HP 5500 ps.
Depending on which make of frame you use, most graphics are attached by some form of hook at the top and mag tape down each side, the attachment of the hooks and tape is the secret to the finished graphics looking good on the frame, also the use of a quality mag tape is essential.
Regards
Russell.