WhatsAppHigh-Barrier Structures
Metallized PET and foil-laminate constructions reviewed against oxygen, moisture, light, and aroma exposure and the target shelf life.
Mylar bag packaging
Custom Printed Mylar Bags
Source custom printed mylar bags as engineered high-barrier packaging—not a generic commodity—by coordinating the product, barrier and shelf-life target, bag format, closure, print, and order plan.
Direct answer
A mylar bag is a flexible bag built on PET (polyester) film, usually metallized or laminated with aluminum foil, that provides high oxygen, moisture, and light barrier. The name comes from the Mylar® polyester film trademark but is used generically in packaging. Common formats include three-side-seal and stand-up bags; the exact structure, barrier level, and food-contact documentation are confirmed per project.
Formats & Closures
Three-side-seal, stand-up, and gusseted formats with zippers, tear notches, hang holes, and heat-seal closures reviewed as a complete bag.
Explore bag features →Custom Printing at Wholesale Quantities
Digital printing for lower quantities and multiple SKUs; flexographic or gravure routes for larger repeat orders.
Compare print routes →Food, Coffee & Supplement Applications
Long-shelf-life foods, coffee, snacks, powders, and supplements coordinated with barrier, sealing, and documentation needs.
See food packaging →What is a mylar bag?
Mylar is a trademarked name for biaxially oriented PET (polyester) film that has become a generic shorthand for high-barrier flexible bags. In practice, a packaging-grade mylar bag is a laminate: PET for strength and print, a metallized layer or aluminum foil for barrier, and a sealant layer for heat sealing. The metal layer blocks light and sharply reduces oxygen and moisture transmission, which is why the format is associated with long-term food storage and shelf-life-sensitive products.
- PET-based laminate with metallized or foil barrier layer
- High oxygen, moisture, and light protection relative to clear films
- Heat-sealable, with optional zipper reclosure
- Printable surfaces for brand artwork or plain stock formats
Metallized film vs. aluminum foil: choosing the barrier
Metallized PET deposits a thin aluminum layer on film and offers strong barrier at lower cost and weight, with better flex-crack tolerance in many constructions. Aluminum foil laminate provides the highest barrier and full opacity but can crack at flex points and costs more. The right choice depends on the product's sensitivity, target shelf life, distribution handling, and budget—confirmed with the exact structure rather than assumed from the bag's appearance.
Choose the bag format around use
Three-side-seal bags suit flat, dense, or vacuum-adjacent applications and efficient case packing. Stand-up formats add shelf stance and reclosure. Gusseted formats carry larger volumes. Zipper position, tear notches, hang holes, and gas flushing compatibility are specified with the format.
Confirm food contact, performance, and claims
Barrier level, food-contact suitability, seal performance, and any shelf-life or protective claim depend on the complete laminate, the product, filling and sealing conditions, and storage—not the word mylar. Products in regulated categories additionally require market-specific compliance review. Request structure documentation and validate with product-filled testing where shelf life matters.
- Structure specification and barrier documentation for the exact laminate
- Food-contact documentation as applicable to the application
- Seal, leak, and drop evaluation for the filled bag
- Shelf-life or accelerated testing where the claim requires evidence
Order custom printed mylar bags at wholesale quantities
Provide the product, bag format and dimensions or fill weight, barrier and shelf-life target, closure and features, print and finish, quantity for each size and artwork, sample needs, and target timing. Digital printing can support lower quantities and multi-SKU programs; flexographic and gravure routes are reviewed for larger repeat volumes.
Packaging Knowledge Center
Professional guides for this application
Use these practical articles to prepare specifications, identify project risks, and ask better questions before sampling or production.
Pouch Format Guide
How to Choose a Custom Pouch Format
Compare stand-up, flat-bottom, side-gusset, three-side seal, shaped, and spouted formats by product and process.Read the professional guide →Packaging Sourcing
Custom Packaging MOQ Guide
Understand how dimensions, materials, print route, and quantity per artwork shape minimum order quantities.Read the professional guide →Printing Guide
Digital, Flexographic, Gravure and Offset Packaging Printing
Compare printing routes by package, substrate, artwork count, order plan, finish, setup, and economics.Read the professional guide →Packaging Sourcing
How Much Does Custom Packaging Cost?
Understand the format, material, print, quantity, feature, setup, and freight factors behind a custom packaging quote.Read the professional guide →Frequently asked questions
Are mylar bags food safe?
Food-contact suitability depends on the complete laminate, the sealant layer, inks and adhesives, and the intended application—not on the mylar name. Request food-contact documentation for the exact structure and confirm suitability for the product, filling conditions, and storage.
What is the difference between mylar and foil bags?
Mylar refers to the PET film base; the barrier usually comes from a metallized layer or a laminated aluminum foil layer. Metallized PET offers strong barrier at lower cost and weight, while foil laminate provides the highest barrier and full opacity at higher cost and lower flex-crack tolerance. The exact structure should be specified rather than inferred from appearance.
Do mylar bags block odors?
High-barrier metallized and foil laminates substantially reduce aroma transmission compared with clear films, but odor performance depends on the complete structure, seals, closure, and the product itself. Applications with specific odor-control requirements should be validated with the exact bag and product.
What is the minimum order for custom printed mylar bags?
MOQ varies by bag dimensions, structure, print route, and quantity per artwork. Digital printing can reduce setup requirements for lower quantities and multi-SKU programs, while flexographic and gravure routes generally suit larger repeat orders. Quantities are confirmed at quotation.
Can mylar bags be resealed?
Yes, where the format supports it. Press-to-close zippers and slider concepts can be added to suitable formats, and plain heat-seal bags can be resealed with an impulse sealer. Closure choice, placement, and performance are confirmed with the complete bag specification.