Reference
Flexible Packaging Glossary
Plain-language definitions of the formats, materials, and methods behind flexible packaging — so you can speak the language and spec with confidence.
- Barrier film
- Film engineered to block moisture, oxygen, light, or aroma — protecting product freshness and extending shelf life.
- BOPP
- Biaxially oriented polypropylene — a clear, stiff, moisture-resistant film widely used for snack and dry-goods packaging.
- Box-bottom bag
- Also called flat-bottom or block-bottom — a premium bag with a structured flat base and crisp panels, giving it a rigid, box-like stand.
- Degassing valve
- A one-way valve on coffee bags that lets carbon-dioxide off-gas from freshly roasted beans while keeping oxygen out.
- Digital printing
- Plateless printing ideal for shorter runs, many SKUs, fast turnarounds, and variable data.
- Flat pouch
- A lay-flat, three-side-seal pouch with no gusset — economical and good for samples, single servings, and thin products.
- Flexible packaging
- Packaging made from pliable materials (films, foils, papers, and laminates) that can change shape when filled — pouches, bags, rollstock, sachets, and sleeves, as opposed to rigid bottles or boxes.
- Flexographic printing (flexo)
- A plate-based print method efficient for long runs and spot colors; common in flexible packaging.
- Foil
- A thin aluminum layer that provides a near-total barrier to oxygen, moisture, and light — used where maximum protection is needed.
- Gusset
- A fold of material on the bottom or sides of a bag that expands to add capacity and let the package stand or square off.
- Hermetic seal
- An airtight seal that prevents the passage of gases and moisture, protecting the product inside.
- Lamination
- Bonding two or more film layers (and sometimes foil or paper) into one structure to combine printability, barrier, and sealability.
- Metallized film
- Film with a thin vaporized-metal coating that adds barrier and a shiny look at lower cost and weight than foil.
- Micron (gauge)
- A metric unit of film thickness (one-millionth of a meter) used to specify how thick a film or layer is.
- Mil
- A unit of film thickness equal to one-thousandth of an inch (0.001 in). Often used alongside microns (1 mil ≈ 25.4 microns).
- Mono-material
- A package made predominantly from one polymer family (e.g., all-PE) so it's easier to recycle in existing streams; a recycle-ready approach.
- MOQ
- Minimum order quantity — the smallest run a supplier will produce for a given format and print method.
- OTR / WVTR
- Oxygen Transmission Rate and Water Vapor Transmission Rate — lab measures of how much oxygen or moisture passes through a film; lower means a stronger barrier.
- PCR
- Post-consumer recycled content — recycled material incorporated into new packaging to reduce virgin plastic use.
- PET / BOPET
- Polyester film (polyethylene terephthalate) prized for strength, clarity, heat resistance, and a good printing surface.
- Polyethylene (PE)
- A flexible polyolefin used mainly as a sealant layer (e.g., LLDPE) for strong, reliable heat seals.
- Quad-seal bag
- A bag with four vertical corner seals that create flat side panels (a boxy shape) for strong shelf presence and stacking — popular for coffee.
- Rollstock
- Printed, laminated film supplied on a roll that runs through a form-fill-seal machine to make and fill packages inline. Efficient at higher volumes.
- Rotogravure
- An engraved-cylinder print method delivering high quality and consistency on very long runs.
- Sachet
- A small, flat, four-side-seal package for single-serve liquids, powders, or samples.
- Sealant layer
- The innermost film layer that melts and bonds to itself under heat to form the package's seals.
- Shrink sleeve
- A printed film sleeve that shrinks tightly around a container (bottle or jar) with heat, giving 360-degree decoration.
- Soft-touch finish
- A matte coating with a velvety, tactile feel that signals a premium product.
- Spouted pouch
- A flexible pouch with a molded spout and cap (fitment) for pouring or drinking — used for liquids, sauces, purees, and beverages.
- Stand-up pouch
- A flexible pouch with a bottom gusset that lets it stand upright on a shelf. Common for coffee, snacks, supplements, and pet food.
- Stick pack
- A narrow, single-serve tube package for powders or granules — drink mixes, supplements, and sweeteners.
- Tear notch
- A small cut at a seal edge that gives a clean, easy starting point to tear the package open.