Heat seal mylar bags are foil-laminated pouches that you close by melting the inner seal layer shut, which gives an airtight, tamper-evident closure that a zipper alone cannot match. TBPB prints them custom with no minimum order, and if you bring a written quote for the same specs we will beat it.
How the seal actually works
Mylar bags are laminated from several layers: an outer film that takes the print, usually a metallised or foil layer that blocks light and oxygen, and an inner heat-seal layer, commonly polyethylene. Put the open end between the jaws of an impulse sealer, or a heat sealer with a steady temperature, and the inner layers fuse. Once cooled, the only way into the bag is to tear or cut it, which is exactly why the buyer can see if someone has tampered with it.
Seal width matters. A bar that is too narrow or a seal that is slightly wrinkled is the usual reason for a slow leak. Leave about a quarter inch of clean bag above the product so the jaws have a flat area to work on, and keep the sealing area free of powder, oil or crumbs.
Heat seal only, or with a zipper
A plain heat seal bag is the right call when the product is sold once, shipped sealed and opened once. Coffee, freeze-dried food, loose-leaf tea, powders and bulk ingredients fit that pattern. If the customer needs to reopen it, a press-to-close zipper below the seal lets them do it, and our mylar ziplock bags suit that case. Stand-up bags with a gusset sit better on a shelf, and our stand-up pouches cover that shape; flat pillow-seal bags are best for single-serve and sample sizes.
Thickness, size and what goes in
Mylar thickness is quoted in mil. Thin bags in the 3 to 4 mil range are fine for light dry goods that sit on a shelf. Heavier bags, around 5 mil and above, stand up better and resist pinholes under sharp or coarse contents. Bigger is not always better: a bag 20 percent too large for the product wastes film and sags on the shelf. Measure the product volume, choose a width that fills the bag without straining the seal, and ask us for a sample in the size you plan to run.
If the contents are odour-heavy, ask whether you need the outer layer to be a barrier film; our smell proof mylar bags are built with that in mind. For the full list of bag types, see the mylar bags category.
Print and finish
Full-colour printing is standard, and you can choose matte, gloss or a mix of matte with a gloss logo. Foil shows through as a metallic look if you leave areas unprinted. Tear notches make the bag easy to open, and a clear window lets the buyer see the product, though a window lowers the light barrier.
- Formats: flat pouch, stand-up pouch, with or without a zipper
- Finish: matte, gloss, matte with spot gloss, unprinted foil areas
- Extras: tear notch, hang hole, clear window, round corners
- Print: full colour CMYK, Pantone match
- Quantity: no minimum order, one sample bag is fine
If the bag will hold food, supplements or any regulated product, labelling and contact-material rules are your responsibility. We print the artwork you supply, so confirm requirements with your own regulatory adviser first.
Next step
Send the bag size or the product volume, the quantity (even one) and whether you want a zipper. We draw the layout and quote it.
Frequently asked questions
What is the minimum order for heat seal mylar bags?
There is no minimum order. You can order one bag to check the seal and print, or thousands for a full run, with the same price-beat guarantee on any quantity.
What do I need to heat seal a mylar bag?
An impulse sealer is the usual tool. A flat iron can work for small jobs, but the seal is less consistent. Seal across clean film with no product in the seal area, and let it cool before handling.
Can I add a zipper to a heat seal mylar bag?
Yes. A press-to-close zipper sits below the heat seal line, so the buyer can tear off the seal and reseal the bag. It adds convenience but slightly lowers the barrier compared with a seal alone.
How thick should a mylar bag be?
Light dry goods do well in thinner film around 3 to 4 mil, while heavier or sharper contents suit 5 mil and up. Thicker film resists pinholes but costs more to ship and seal.
Are heat seal mylar bags airtight?
A correctly made heat seal on clean film is airtight and blocks light, which is why mylar suits coffee and dry foods. Wrinkled or contaminated seals can leak, so test a sample in your sealer first.
Can I customize the printing on heat seal bags?
Yes. We print full-colour artwork on the outer film, with matte or gloss finish, a window or tear notch on request. Send your artwork and bag size and we set up the layout.
More Mylar Bags
See the full Mylar Bags range, or explore related options with no minimum order and our best-price guarantee:
