[Archive]

Posted By: Mark Anderson

My guess is that all major companies use polystyrene.

I should clarify, polystyrene is for the slabs, and polypropylene is for our inner sleeves. Neither polypro nor mylar, in my experience, can be used for the thicker plastics needed for the slabs.

I believe the little "sleeves" PSA uses on occasion are mylar. I'm not sure what SGC's black inserts are made of - perhaps Glyn will post.

Mark