Insulation / packing materials (North central)

I receive monthly shipments of medical supplies encased in these insulated packing materials. I’m told they’re compostable but I’m dubious.

It appears to be a composite of lightweight fiber materials encased in thin, flexible, waterproof plastic. The fiber composite is in about 2” thick sheets, squishy, lightweight, and flexible. Easy to cut to desired size, with no mess. The plastic casing should be recyclable with bags at Kroger, Meijer, etc.

I also have a few sturdy cardboard boxes these pieces fit in.