Custom Printed Mylar Zip Lock Bags, Flat and Resealable

What is a mylar zip lock bag?

A mylar zip lock bag is a flat foil pouch sealed on three sides, with a zipper running across the inside just below the top. The black bag in our photo shows the layout: a tear notch on each side, the zipper band about 20 mm down, and the main panel below it. The kraft version is the same bag with a paper outer.

There is no bottom gusset, so the bag lies flat when empty and bulges gently when filled. It will not stand on a shelf on its own, but it stacks, hangs on a peg and posts in a padded envelope without creasing.

The gusseted bags with the same zipper are on our resealable zipper pouches that stand page, if you need a bag that sits upright.

Which businesses use flat zip lock foil bags?

Anyone who sells a product in small weights that the customer uses a pinch at a time. A spice blender in Leeds packs 40 g of smoked paprika in a 120 × 180 mm black bag. A tea seller sends three 20 g samples in a letterbox parcel. A supplement brand sends single-week trial packs of a powder.

Outside food, the same bags hold craft beads, screws and fixings, electronics parts that need a dry bag, and bath salts for a subscription box.

• Spice blends, dried herbs and rubs
• Tea and coffee samples by post
• Protein and supplement trial packs
• Seeds and dried flower petals for crafts
• Beads, fixings and small electronic parts
• Bath salts and foot soak sachets

How does the zipper behave when filling by hand?

The zipper on a flat bag is close to the top opening, which makes it easy to catch product in the channel. Powder in the zipper track stops it closing cleanly and leaves a gap for air. Use a funnel that reaches below the zipper, or fold the top of the bag outward while you fill.

Once the bag is filled, press the zipper shut from one side to the other with a thumb and finger, then heat seal the strip above the zipper. The heat seal is what the customer tears off at the notch; the zipper is what they use after that.

If your product is very fine, such as icing sugar or matcha, ask for a double zipper. The second track catches anything that slips past the first.

What size zip lock bag do I need?

Flat bags hold less than a gusseted bag of the same face size, because there is no depth. As a rule of thumb, a flat bag holds roughly half the weight a stand up pouch of the same width and height holds.

Measure the fill, allow 30 mm at the top for the zipper band and the heat seal, and add 10 mm on each side for the seals. A 50 g bag of dried herbs sits comfortably in 120 × 180 mm. Heavier products such as jerky or salt pack denser and can go in a smaller bag.

Send us the product and the weight per bag and we size it for you. The flat and three side seal pouch range lists the other flat styles if the zipper is not needed.

Laminates: black, kraft or printed foil

Matte black metallised PET / PE is the most ordered version. It hides the product, prints a logo in one or two colours and looks the same whether the bag is full or half used. Kraft / PET / PE gives a brown paper outer with a foil layer behind it, which suits herbs, teas and bath products.

Printed PET / foil / PE carries a full colour design and gives the best barrier for products that must stay dry for months. Clear PET / PE is available when the customer needs to see the contents, such as beads or seeds. Food-contact, high-barrier and compostable film options are available on request and confirmed on the quote.

Can a flat zip lock bag have a window or a hang hole?

Yes to both. A clear strip or a shaped window can be left in the front panel of a black or kraft bag, so a customer sees the colour of the spice or the tea leaves. Keep the window below the zipper and above the bottom seal.

A round hang hole or a euroslot goes in the top seal above the zipper, so the bag hangs on a hook in a shop. It does not affect the seal or the zipper. Both are available on request and shown on the proof.

Flat bags with a window are a close cousin of our mylar bags with a clear window, which have a gusset and stand up.

Print and artwork on a flat bag

A flat bag has two panels, front and back, and no gusset to print round. Keep the logo on the front panel between the zipper band and the bottom seal. The back takes the ingredients, the weight and the barcode.

One colour print on matte black or kraft is the most common order and the cheapest. White ink on black needs a solid white layer; white on kraft needs the same. Full colour digital print is used where the bag is a retail pack rather than a sample.

Spot gloss over matte lifts a logo off a matte black bag without adding colour. Our designers lay out the panel for free and send a proof. The artwork guide for printed pouches explains the seal margins to keep clear.

How do I seal a zip lock bag so it stays sealed?

A bench top impulse sealer is all most brands need for flat bags. Follow these steps for a seal that holds in the post.

1. Fill below the zipper using a funnel or a folded card chute.
2. Tap the bag so the product drops away from the zipper channel.
3. Press the zipper closed from one notch to the other.
4. Place the top edge in the sealer so the seal lands between the zipper and the notches.
5. Seal for the time the laminate needs, then hold the bag still for two seconds while the seal cools.
6. Pull gently on the sealed edge to confirm it holds, then stack the bag flat.

What mistakes do people make with flat zip bags?

Expecting the bag to stand. A flat bag lies down or hangs; if your product needs to sit upright on a shelf, order a gusseted pouch instead.

Overfilling. A flat bag filled to the zipper bulges, the zipper pops open in the post and the seal is put under load. Fill to two thirds of the panel height and leave the rest empty.

Choosing clear film for a product that light spoils. Spices and dried herbs fade in a window. Keep them in black or kraft and use a window only for products that do not mind light. For bags that need a vacuum rather than a zipper, see our vacuum seal pouches for long storage.

How do I order mylar zip lock bags?

Send the product, the weight per bag, the laminate you prefer and your logo or artwork. Quantities are quoted per order, from £0.25 per unit, with the final figure set out on your written quote.

A free design proof arrives before anything is printed. After you approve it, production takes 4–6 business days and your bags are delivered free with tracking to any UK address in 2–3 business days.

Misprints or damage reported within 10 days with photos are reprinted or refunded. Start with the quote request for flat zipper bags or message us on WhatsApp.