inglés al español Otros Manufactura Packing materials

The context is contamination factors in food plants. There is a section involving packing materials, and it reads: "packing materials include: trays, back boards, pan liners, press boards and bags. My knowledge on these terms allows me to translate trays as "bandejas" and "bags" as sacos o bolsas. But I get stuck with "back boards, pan liners and press boards". Can anyone help me with this?
Many thanks in advance!