Cardboard glues are nearly always made of starch (corn/wheat/potato) not chemicals, as it is cheaper. Ref: 1 2
The weight of any laminate (if used) would weigh next to nothing. Assuming it were made of 100% oil, it would still weigh next to nothing and thus cost next to nothing as an ingredient.
Without referenced facts, instead of opinion, costs of cardboard contributing to Chops problem sounds to me like a load of old bollocks!
I've never heard of oil going into corrugated board making either, but at the very least it could be an indirect cost added to corrugated production (machine maintenance, transporting, etc.). That being said, oil prices have not doubled in 3 years time. So oil may be a factor, but it certainly doesn't explain a 200% price markup in 3 years time for mylar sheets, especially when the competition didn't have the same kind of markup.
I've already emailed Bags Unlimited asking them to produce their mylar sheets with the long side being the open side instead of the short side. It's hard enough as it is trying to wiggle a poster in via the long side. Otherwise, I'll won't be buying from them until they make that change.