Glossary

A laminating process in which individual layers of packaging materials are laminated to each other with an adhesive.

A thin gauge (6-12 microns) aluminium foil laminated to plastic films to provide maximum oxygen, aroma and water vapour barrier properties. Although it is by far the best barrier material, it is increasingly being replaced by metallised films, (see MET-PET, MET-OPP and VMPET) because of cost.

a system in which the product is sterilised before filling into pre-sterilised packs under aseptic conditions.

The ability to stop or retard the movement of one substance through another. In packaging, the term is most commonly used to describe the ability of a material to stop or retard the passage of atmospheric gases, water vapour, and volatile flavour and aroma ingredients.

A film that has been stretched under certain temperature conditions equally in both the machine and transverse directions. Biaxial stretched films are generally well balanced in both directions and much stronger in terms of tear strength.

A type of packaging in which the item is secured between a preformed (usually transparent plastic) dome or "bubble" and another surface or "carrier". Attachment may be by stapling, heat-sealing, gluing, or other means.

Plastic films produced from synthetic resins (such as polyethylene) by the blown process. In this process, the molten resin is extruded through a circular die into a tube. This tube is expanded (“blown”) by internal air pressure into a larger bubble with a much reduced wall thickness and cooled with external air quenching.

Bi-axially Oriented Nylon film, with excellent oxygen and aroma barrier properties, (see Nylon), but it is a poor water vapour barrier. BON is much stiffer than cast nylon film, but cannot be thermoformed.

Cast nylon film (see Nylon). Used mostly for thermo formable packaging applications.

Cast Polypropylene film. Unlike OPP, it is heat sealable, but at much higher temperatures than LDPE, thus it is used as a heat-seal layer in retort able packaging. It is, however, not as stiff as OPP film.

Plastic film produced from synthetic resins (such as polyethylene) by the cast process. In this process, the molten resin is extruded through a slot die onto an internally cooled chill roll.

Simultaneous extrusion of two or more different thermoplastic resins into a sandwich-like film with clearly distinguishable individual layers.

Coefficient of friction, a measurement of “slipperiness” of plastic films and laminates. Measurements are usually done film surface to film surface. Measurements can be done to other surfaces as well, but not recommended, because COF values can be distorted by variations in surface finishes and contamination on test surface.

A pressure relief valve added to coffee pouches to allow natural unwanted gasses to be vented whilst maintaining the freshness of the coffee. Also called an aroma valve as it allows you to smell the product through the valve.

A pressure sensitive adhesive coating on plastic films or laminates that will allow the packages to be sealed by application of pressure (with no heat or minimal heat).

A pouch that is formed with contour side seals that then passes through a die-punch to trim excess sealed material, leaving a contoured and shaped final pouch design. Can be accomplished with both stand up and pillow pouch types.

The jaws are heated to a preset temperature, these sealers are used for thicker material and foil based material.

A stand-up pouch that has seals on both sides and around the bottom gusset. In 1962, Louis Doyen invented and patented the first soft sack with an inflated bottom called Doy pack. Although this new packaging was not the immediate success hoped for, it is booming today since the patent has entered the public domain. Also spelt - Doypak, Doypac, Doy pak, Doy pac.

Ethylene acrylic acid copolymer. EAA is a copolymer of ethylene and acrylic acid. lts ionic nature allows for excellent adhesive bonding to metal foil and other polar surfaces. EAA's adhesive and toughness qualities are taken advantage of in high performance multi-layer laminates.

Ethylene-Ethyl Acrylate (EEA). The copolymerization of ethylene with ethyl acrylate produces an ethylene acid copolymer. The polymers are produced with varying percentages of acrylate content, most typically between 15 and 30%. EEA is compatible with all olefin polymers and often is blended with these to modify properties. EEA is used in hot-melt formulations.

Ethylene-Methyl Acrylate (EMAC). The copolymerization of ethylene with methyl acrylate produces an ethylene copolymer, one of the most thermally stable of the olefin copolymers. The polymers are produced with varying percentages of methyl acrylate content, most typically between 1 8 and 24% of the structure. Alone or in blends, it has found applications in film, extrusion coating, sheet, laminating, and co-extrusion.

Ethylene-Vinyl Acetate copolymer, Much softer and clearer than LDPE or LLDPE and has lower melt temperature. Its melt temperature goes down, while its softness increases with increasing vinyl acetate (VA) content. EVA resins with 2-18% VA content are used for cast and blown packaging films.

Ethylene-Vinyl Alcohol copolymer, used in co extruded plastic films to improve oxygen barrier properties. It is, however, a poor water vapour barrier. Even its otherwise excellent OTR, (oxygen transmission rate) is sensitive to high humidity, therefore, for packaging applications, it is usually the core layer of co extruded plastic films, where it is shielded from moisture by protective layers of polyethylene. Its OTR also depends on its VOH (vinyl alcohol) content.

Involves the pasteurization of a product and the transfer to a package in controlled atmosphere filler.

A material that is capable of being stretched under normal processing conditions.

A laminating process in which individual layers of multi-layer packaging materials are laminated to each other by extruding a thin layer of molten synthetic resin (such as polyethylene) between the layers. Used to fabricate high barrier or exceptionally durable film structures.

A pack or container made of flexible or easily yielding materials that, when filled and closed, can be readily changed in shape.

A method of printing using flexible rubber or photopolymer printing plates in which the image to be printed stands out in relief. Fluid ink metered by an engraved roll is applied to the raised portions of the printing plate and then transferred to the substrate.

A thin gauge (0.2285-0.325 mils) aluminium foil laminated to plastic films to provide maximum oxygen, aroma and water vapour barrier properties. Although it is the best barrier material, it is increasingly being replaced by metalized films because of cost. Sometimes the multi-layer film containing a foil barrier layer is generically referred to as “the foil film.”

A pouch that is formed from roll-stock, filled, and sealed all on a single, multi stage machine.

(Rotogravure). With gravure printing an image is etched on the surface of a metal plate, the etched area is filled with ink, then the plate is rotated on a cylinder that transfers the image to the film or other material. Gravure is abbreviated from Rotogravure.

The fold in the side or bottom of the pouch, allowing it to expand when contents are inserted

High density, (0.95-0.965) polyethylene. This part has much higher stiffness, higher temperature resistance and much better water vapour barrier properties than LDPE, although it is considerably hazier.

A heat-sealable layer in plastic packaging films and laminates. Can be either adhesive laminated or extrusion coated onto a non-sealable film (or foil). This is also typically the product contact layer and often predominantly made from LLDE.

Strength of heat seal measured after the seal is cooled.

Strength of heat seal measured before the seal is cooled, which is very important for high-speed packaging operations.

(a) noun - A product made by bonding together two or more layers of material. (b) verb - To unite layers of material to produce a multilayer material.

An adhered combination of two or more films or sheets made to improve overall characteristics, also known as multilayer film.

A seal made with two layers of film overlapping one another. Because lap seals require less material than fin seals, packagers are converting to lap seals in the name of sustainability, lean operations and economics.

Use of high-energy narrow light beam to partially cut through a material in a straight line or shaped patterns. This process is used to provide an easy-opening feature to various types of flexible packaging materials.

Low density, (0.92-0.934) polyethylene. Used mainly for heat-seal ability and bulk in packaging.

The ability of material to withstand exposure to light (usually sunlight or the ultraviolet part of the light spectrum) without change of color or loss of physical and/or chemical properties.

Linear low density polyethylene. Tougher than LDPE and has better heat-seal strength, but has higher haze.

Medium density, (0.934-0.95) polyethylene. Has higher stiffness, higher melting point and better water vapour barrier properties.

Metallised OPP film. It has all the good properties of OPP film, plus much improved oxygen and water vapour barrier properties, (but not as good as MET-PET).

Metallised PET film. It has all the good properties of PET film, plus much improved oxygen and water vapour barrier properties. However, it is not transparent. see also VMPET.

Moisture vapour transmission rate, usually measured at 100% relative humidity, expressed in grams/100 square inches/24 hours, (or grams/square meter/24 Hrs.) See WVTR.

Mylar is a registered trademark of the Dupont-Teijin Corporation. Is the industrial brand name for that corporation’s polyester (PET) film. Polyester film is a staple of multi-layer packaging for a wide variety of applications.

Polyamide resins, with very high melting points, excellent clarity and stiffness. Two types are used for films - nylon-6 and nylon-66. The latter has much higher melt temperature, thus better temperature resistance, but the former is easier to process, and it is cheaper. Both have good oxygen and aroma barrier properties, but they are poor barriers to water vapour.

Hiding power of pigmented (mostly white) plastic films. It is beneficial for packing materials sensitive to light (visible or ultraviolet).

A stiff, high clarity film, but not heat sealable. Usually combined with other films, (such as LDPE) for heat sealability. Can be coated with PVDC (polyvinylidene chloride), or metallised for much improved barrier properties.

Very common alternative to PVC shrink films in Asia and Europe, but not readily available in the USA. Slightly higher priced than PVC films but more recyclable and has a greater shrink percentage.

OTR of plastic materials varies considerably with humidity; therefore it needs to be specified. Standard conditions of testing are 0, 60 or 100% relative humidity. Units are cc./100 square inches/24 hours, (or cc/square meter/24 Hrs.) (cc = cubic centimetres)

depending on its density, it may be low density (see LDPE). medium density (see MDPE). or high density, (see HDPE).

Tough, temperature resistant polymer. Bi-axially oriented PET film is used in laminates for packaging, where it provides strength, stiffness and temperature resistance. It is usually combined with other films for heat sealability and improved barrier properties.

The most expensive shrink film for full body shrink sleeves, but clear, glossy, strong, and most recyclable. The highest shrink percentage available is about 75%, so this film is often required when the container has a narrow waist or neck.

a stand-up pouch that is made from one piece of film. The front, gusset, and back are continuous, so there is no seal at the gusset. Holds more weight than Doy-style pouches, so are commonly used for products weighing more than one pound.

The Pantone Matching System is the universally accepted color definition system. Colours can be blended or individually specified to match a specified Pantone reference colour exactly.

Has much higher melting point, thus better temperature resistance than PE. Two types of PP films are used for packaging: cast, (see CAPP) and oriented (see OPP).

A tough, stiff, very clear film. The oriented version is used mainly for shrink film applications.

Shrink percentages vary from about 40% for extruded PVC shrink tubing to over 60% for seamed material. The most cost-effective shrink film for full-body shrink sleeves.

A very good oxygen and water vapour barrier, but not extricable, therefore it is found primarily as a coating to improve barrier properties of other plastic films, (such as OPP and PET) for packaging. PVDC coated and ‘saran’ coated are the same.

A coating applied to the non-sealing side of cold-sealable packaging films and laminates supplied in a roll form that will allow the packer to unwind these films or laminates on packaging machines.

The thermal processing or cooking packaged food or other products in a pressurized vessel for purposes of sterilizing the contents to maintain freshness for extended storage times. Retort pouches are manufactured with materials suitable for the higher temperatures of the retort process, generally around 121° C.

Printing wrong-reading on the underside of transparent film. In this case, the outermost layer is printed on the backside and laminated to the rest of the multi-layer structure. While not mandatory in all industries, it is the preferred method for the food industry as it guarantees there will be no ink contact with the food product. The majority of all products are reverse printed.

Said of any flexible packaging material that is in a roll form.

With gravure printing an image is etched on the surface of a metal plate, the etched area is filled with ink, then the plate is rotated on a cylinder that transfers the image to the film or other material. Gravure is abbreviated from Rotogravure

Oriented films that are not heat-set after orientation. These films can shrink back close to their unstretched dimension at temperatures higher than the temperature of their orientation. See PVC Shrink Film, PET-G Shrink Film, and OPS Shrink Film.

A narrow flexible packaging pouch commonly used to package single-serve powder beverage mixes such as fruit drinks, instant coffee and tea and sugar and creamer products.

The process where by the ink is deposited directly onto the outermost surface of the packaging film or material. The process is most commonly used in short run printing. A UV (ultraviolet) coating may be added to provide a hard exterior finish that prevents the ink from flaking or chipping.

A special ionomer copolymer produced by Dupont. It has excellent heat sealability, maximum hot tack and it can be sealed through contaminants, and therefore it is used as a premium heatseal layer for packaging films, especially recommended for high speed packaging machines.

The ability of a packaging material to continue to easily tear once the tear has been initiated. Some plastics, such as polyethylene, have no tendency to continue to propagate an initiated tear.

The resistance of a material to tearing.

The amount of strength required to break a 1" wide strip of film (Results are in gram force/sq inch).

Another term for Reverse Printing (see Reverse Printing). Trap printing derives its name from the fact that the ink is trapped between the outer layer of material and the substrate.

The filling of containers with low-viscosity liquid product by drawing a vacuum on the sealed container. Vacuum filling requires the ability to form a good seal across the container finish and a container with sufficient rigidity that it will not collapse or distort under vacuum.

A method of packaging where the air is withdrawn from the primary pack. The usual objective of vacuum packaging is to remove atmospheric oxygen, which is implicated in most product degradation. Vacuum packaging when using flexible packaging materials also reduces volume to save transportation cost.

A form-fill-seal machine in which the roll-fed flexible packaging material is unwound and shaped while travelling vertically up and down through the machine's operating stations. A VFFS machine occupies less floor space than a horizontal form-fill-seal machine, but it has the disadvantage of having a single point through which filling or other open-package functions can be performed.

A method of moving product through a filling or transport system by inducing a vibration in a sloped tray at about the resonance frequency of the product. In effect, the product periodically becomes momentarily weightless, and in this state will descend the feed tray slope for a short distance.

It has all the good properties of PET film, plus much improved oxygen and water vapour barrier properties.

usually measured at 100% relative humidity, expressed in grams/100 square inches/24 hours, (or grams/square meter/24 Hrs.) See MVTR.

A recloseable or resealable pouch produced with a plastic track in which two plastic components interlock to provide a mechanism that allows for recloseablility in a flexible package.