PA/PE Vacuum Pouches Explained: What the Film Is Made Of

Every vacuum pouch we sell is described as PA/PE. Two polymers, made into one film. Knowing what each does explains most of how a pouch behaves: why it keeps meat fresh, why it seals at the temperature it does, why it goes hazy in a damp chiller and why thickness doesn't change shelf life.

PA: the barrier

PA is polyamide, the same family as nylon. It's the outer layer of the pouch and it's there for one property above all: it's very hard for oxygen to get through. Air is 21% oxygen, and oxygen is what the bacteria and moulds that spoil meat need. A polyamide layer a few hundredths of a millimetre thick cuts the oxygen reaching the product to a fraction of what an open tray sees, and that's the mechanism behind the longer shelf life.

Polyamide also gives the pouch its toughness. It resists punctures better than polyethylene at the same thickness, it doesn't stretch and go thin over a corner, and it stays flexible in a freezer. And it has a high melting point, well above 200°C, which is why the outside of the pouch doesn't stick to the seal bar.

PE: the seal

PE is polyethylene. It's the inner layer, the one that touches the food, and it's there because it welds to itself at a temperature a seal bar can reach. Press two polyethylene surfaces together at around 130 to 150°C for a second and they fuse into one. That's the seal along the top of the bag. It's also the reason the seal area has to be clean: a smear of fat between the two surfaces stops them touching, and no weld forms where it sits.

Polyethylene is also the layer that gives the pouch its slight softness and its cling to the product when the air comes back into the chamber.

Why co-extruded

There are two ways to put the layers together. You can make each film separately and glue them with an adhesive, which is a laminate. Or you can melt both polymers and push them through one die at the same time, so they come out already bonded as a single film. That's co-extrusion, and it's how our pouches are made.

Co-extrusion has no adhesive layer to fail, no solvent to migrate, and it keeps the film thinner for the same strength because nothing is wasted on glue. In practice there's usually a thin tie layer between the PA and PE that bonds the two, so a "PA/PE" film is often three to five layers. You'll never see them; the film looks like one clear sheet. The how our pouches are made guide follows the film from pellet to box.

What the structure means in practice

You notice	Why
Meat keeps two or three times longer	Polyamide oxygen barrier
Thicker pouch, same shelf life	Barrier comes from the PA layer, thickness only adds puncture resistance. See the gauge guide
A greasy seal leaks	Polyethylene has to touch polyethylene to weld
Fine in the freezer at -18°C	Both polymers stay flexible well below that
Fine in a sous vide bath to 85°C	PE seal holds; PA outer is nowhere near softening
Faint haze in a humid chiller	Polyamide absorbs a little water. Cosmetic.
Won't seal in a FoodSaver	Nothing to do with the polymers, it's the smooth surface. See the embossed vs smooth guide

Food contact

Both polymers are used in food packaging worldwide and the film complies with UK and EU food contact regulations. Neither needs plasticisers, so there's nothing to migrate into a fatty product. A declaration of compliance for the film is available for your records, and the site it's made on holds BRC Global Standard for Packaging at AA, covered in the BRC guide.

Recycling, honestly

A two-polymer film can't go in kerbside recycling, because household sorting can't separate polyamide from polyethylene. Some commercial flexible-plastics schemes will take it. Against that, the pouch is a few grams of plastic protecting a kilogram of meat, and the food it stops going in the bin has a far larger footprint than the film. That's the trade-off the whole industry works to, and it's worth being straight about it with customers who ask.