Flexible Packaging Glossary

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Barrier Film: A film structure designed to resist the transmission of oxygen, moisture, light, or other elements that degrade product quality. Barrier layers commonly include EVOH, PVDC, aluminum foil, or metallized films.; See also: EVOH, Metallized Film
Biaxially Oriented Polypropylene (BOPP): A polypropylene film that has been stretched in two directions (machine and transverse) to improve tensile strength, clarity, and barrier properties. Widely used as a print substrate and outer layer in laminations.; See also: Lamination, Polypropylene
Blown Film: Film produced by extruding molten plastic through an annular die, then inflating it into a bubble shape that is cooled, collapsed, and wound into rolls. The most common film manufacturing method for flexible packaging.; See also: Cast Film, Film Extrusion

Cast Film: Film produced by extruding molten plastic through a flat die onto a chilled roll. Cast film offers better gauge uniformity, higher clarity, and tighter tolerances compared to blown film.; See also: Blown Film, Film Extrusion
Coextrusion: The simultaneous extrusion of two or more polymer layers through a single die to create a multi-layer film structure in one pass. Eliminates the need for separate lamination by building barrier and structural layers together.; See also: Lamination, Barrier Film
Co-Packing: Contract packaging service where a third-party facility fills, seals, and packages products using their own equipment on behalf of a brand. Also called contract packaging.; See also: Co-Packer
Converting: The process of transforming rolls of film into finished packaging formats such as pouches, bags, or wraps. Converting operations include printing, laminating, slitting, and pouch forming.; See also: Pouch Making, Lamination

Delamination: Separation of bonded film layers in a laminated structure. Can occur due to insufficient adhesion, incompatible materials, contamination during lamination, or excessive stress during converting or use.; See also: Lamination, Adhesive Lamination

EVOH: Ethylene vinyl alcohol copolymer. A high-barrier resin used as an oxygen barrier layer within coextruded or laminated film structures. Highly effective oxygen barrier but sensitive to moisture.; See also: Barrier Film, Coextrusion

Film Extrusion: The process of melting plastic resin and pushing it through a die to form continuous film. The two primary methods are blown film extrusion and cast film extrusion.; See also: Blown Film, Cast Film, Coextrusion
Flexographic Printing: A relief printing process using flexible photopolymer plates to apply ink to a substrate. The dominant printing method for flexible packaging due to its speed, cost-effectiveness, and compatibility with a wide range of substrates.; See also: Gravure Printing, Anilox Roll

Gauge: The thickness of a film, measured in mils (thousandths of an inch) or microns. Gauge consistency across the web and reel is a critical quality parameter in film extrusion.; See also: Blown Film, Cast Film
Gravure Printing: An intaglio printing process that uses engraved cylinders to transfer ink to a substrate. Produces higher print quality than flexo at very high volumes but requires expensive cylinder costs that favor long production runs.; See also: Flexographic Printing

Heat Seal: A bond between two film surfaces created by applying heat and pressure. The quality of the heat seal determines pouch integrity and product shelf life.; See also: Sealant Layer, Seal Strength
HFFS: Horizontal Form Fill Seal. A packaging machine that forms pouches from rollstock film, fills them horizontally, and seals them. Commonly used for stand-up pouches and pillow pouches.; See also: VFFS, Form Fill Seal

Lamination: The process of bonding two or more film or foil substrates together using adhesive or heat to create a multi-layer structure with combined properties. Laminations can add barrier, strength, printability, or sealing capability.; See also: Adhesive Lamination, Extrusion Lamination, Coextrusion

Metallized Film: A film that has been coated with a thin layer of aluminum vapor in a vacuum chamber. Provides barrier properties similar to foil at a lower cost and weight, with some sacrifice in absolute barrier performance.; See also: Barrier Film, Aluminum Foil
Minimum Order Quantity (MOQ): The smallest production run a manufacturer will accept for a given product. In flexible packaging, MOQs vary widely by substrate, print complexity, format, and supplier capabilities.
Mono-Material Structure: A flexible packaging structure made entirely from a single polymer type, designed to improve recyclability. Common examples include all-PE pouches and all-PP structures that can be processed by standard recycling streams.; See also: Recyclability, Barrier Film

OTR (Oxygen Transmission Rate): A measurement of how much oxygen passes through a film or structure per unit area per unit time. A critical specification for packaging products sensitive to oxidation. Lower OTR indicates better oxygen barrier.; See also: Barrier Film, EVOH

PE (Polyethylene): A family of thermoplastic polymers produced from ethylene. The most widely used resin in flexible packaging. Key types include LDPE, LLDPE, HDPE, and mLLDPE, each with different stiffness, clarity, and seal properties.; See also: PET, LLDPE, Blown Film
PET (Polyethylene Terephthalate): A strong, clear thermoplastic polyester used as the outer structural layer in flexible packaging laminates. Biaxially oriented PET (BOPET or Mylar) is the most common form in packaging applications.; See also: PE, Lamination, Barrier Film
Pouch: A flexible packaging container sealed on multiple sides, formed from flat film. Pouches come in many formats including stand-up (SUP), flat, retort, spouted, zipper, and quad-seal styles.; See also: Stand-Up Pouch, Converting

Recyclability: The ability of a flexible packaging structure to be processed through existing recycling infrastructure. Determined by material type, structure compatibility, contamination levels, and recovery system availability.; See also: Mono-Material Structure, Sustainability
Retort Packaging: Flexible packaging designed to withstand high-temperature sterilization (retorting) after sealing. Must maintain seal integrity, barrier performance, and structural integrity through the thermal process.; See also: Pouch, Heat Seal
Rollstock: Film wound into a roll, supplied to a brand or co-packer to be run on their own form-fill-seal equipment. The brand purchases rollstock and handles forming, filling, and sealing in-house.; See also: VFFS, HFFS

Sealant Layer: The innermost layer of a flexible packaging laminate that comes into contact with the product and provides the heat-sealing surface. Typically a polyolefin such as LDPE, LLDPE, or cast PP.; See also: Heat Seal, Lamination
Stand-Up Pouch (SUP): A pouch with a bottom gusset that allows it to stand upright on a retail shelf. The most common flexible packaging format for food, beverage, and consumer products. Available with or without zippers and spouts.; See also: Pouch, Converting

VFFS: Vertical Form Fill Seal. A packaging machine that forms bags from rollstock film by pulling it downward over a forming tube, filling vertically, and sealing. Common for snacks, powders, and granular products.; See also: HFFS, Rollstock

WVTR (Water Vapor Transmission Rate): A measurement of how much moisture vapor passes through a film or structure per unit area per unit time. Critical for moisture-sensitive products. Lower WVTR indicates better moisture barrier.; See also: OTR, Barrier Film