How Bad Are Plastic 3-Ring Binders For Stamps?

Just returning to stamps after eons. Looking around I settled on the print the pages yourself option offered by stampalbums.com - they seem to have pages for every stamp in Scott's, but you just print out the pages you want as you go along. I was clever enough to think to buy acid-free card stock for the pages, but I'm wondering about the binders which will hold the pages. I had thought there would be acid-free binders available in the stamp world, but so far what I'm seeing are fancy plastic folders.

Currently I'm using some D-ring folders from Office Depot, but I wonder if the plastic is good for the stamps. On the other hand, some of my old stamps were on individual pages in a plastic sided binder that must be 30 years old and I'm seeing no problem.

Advice would be appreciated.