FLEXIBLE PACKAGE GLOSSARY

ACCUMULATOR
In automated packaging operations, a device, a table, or a type of conveyor designed to permit the gathering of packs or objects.

ACLAR
Trade name for a polychlorotrifluoroethylene (PCTFE) polymer. The polymer has outstanding moisture and excellent oxygen barrier properties, as well as being clear, rigid, and relatively easy to thermoform. Its main packaging application is for pharmaceutical blister packages.

ACRYLONITRILE
A monomer with the structure ( CH = CHCN). Its copolymers have good gas barrier and chemical resistance properties. Also known as trade name Barex.

ADHESIVE LAMINATION
A laminating process in which individual layers of multi-layer packaging materials are laminated to each other with an adhesive.

AEROBIC
A general term describing those micro-organisms that propagate only in the presence of oxygen

AEROSOL
In packaging, a gas-tight, pressure-resistant container, a valve, a product, and a propellant that forces the product from the container when the valve is opened.

AIR GAP
The distance from the die lips of a polymer-melt extruder and the chill roll.

ALUMINUM FOIL
A thin gauge (.285-1.0 mil) aluminum foil laminated to plastic films to provide oxygen, aroma and water vapor barrier properties.

ANAEROBIC
A general term describing those micro-organisms that will propagate in the absence of oxygen.

ANILOX ROLL
Engraved ink metering roll used in flexo presses to provide a controlled film of ink to the printing plates which print onto the substrate.

ASEPTIC PACKAGING
A pack and product system in which the product and pack are individually rendered aseptic(sterile) and then combined and sealed under aseptic conditions. In contrast, in a typical canning operation neither can nor food is sterile when they are brought together and sealed. Sterility is achieved by heat-treating the sealed can.

BAGGY, BAGGINESS
(a) In processing flexible packaging materials, slack areas in the web that should be flat. Usually caused by bands of unequal thickness (gauge bands) in the rollstock. (b) A roll in which the tension is not even across the width of the roll. A slack floppy area in the web is caused by the material being stretched and permanently elongated in the tighter areas. Rolls of film or laminate where one side of the material coming off the roll is loose or baggy while the opposite edge is tight is said to have a baggy edge.

BAR CODE
A machine-readable symbol.

BAREX
A trade name for acrylonitrile plastic.

BARRIER
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.

BARRIER MATERIAL
A flexible packaging material possessing properties that limit the transmission of various gases through the material. ( used to keep products dry, wet or extend shelf life and assure product freshness)

BARRIER PACKAGING
The utilization of engineered materials that possess properties capable of preventing the permeation of harmful substances through material, which would result in product damage.

BASE FILM
The original form in which a film exists before coating or laminating.

BIAXIAL ORIENTATION
Orientation of plastic films in both machine and cross machine directions by stretching. Biaxially stretched films are generally well balanced in both directions and much stronger in terms of tear strength.

BLEED
Image or color that extends beyond the trim edge of the finished printed piece.

BLISTER PACKAGING
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.

BLOWN FILMS
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.

BLOWN-FILM EXTRUSION
The manufacture of thin plastic films by extruding a bubble of plastic and then inflating the bubble. In film manufacturing the extrusion and inflation are a continuous process.

BON
Biaxially oriented nylon film, with excellent oxygen and aroma barrier properties, (see Nylon), but it is a poor water vapor barrier. BON is much stiffer than cast nylon film, but cannot be thermoformed.

BURST STRENGTH
A measure of the ability of a sheet to resist rupture when pressure is applied to one of its sides by a specified instrument under specified conditions.

BUTT
(a) To join with overlap or space between. (b) Butt register is where two or more colors meet with no significant overlap or space between.

CAN
Cast nylon film. Used mostly for thermoformable packaging applications.

CAPP OR CPP
Cast PP film, (see PP). Unlike OPP, it is heatsealable, but at much higher temperatures than LDPE, thus it is used as a heatseal layer in retortable packaging. It is, however, not as stiff as OPP film. (PP = polypropylene)

CAST 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. Film extruded through a flat die into a quench system.

CHEMICAL COMPATIBILITY TESTING
Any procedure that exposes a material to chemicals or mixtures of chemicals to determine whether such exposure has a negative effect on the material being evaluated.

CHEMICAL RESISTANCE
Ability of a material to retain utility and appearance following contact with chemical agents. Chemical resistance implies that there is no significant chemical activity between the contacting materials.

CLARITY
Degree of transparency

CLOSURE
Any device used to close a bottle, jar, can, pouch or any type of pack to retain the contents. Commonly closures are held in place by a screw thread.

COATING
Any fluid material applied as a thick layer to a substrate material or object.

CO-EXTRUDED FILM
Flexible packaging material consisting of two or more different materials that are layered within a single ply during the extrusion process.

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

COF (COEFFICIENT OF FRICTION)
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.

COLD SEAL
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).

COLOR MANAGEMENT
The process of translating specific color information from the computer screen image, through prepress, plate-making, printing presses and finally to a substrate in such a manner that color accuracy is maintained at acceptable levels throughout.

COLOR VALUE
The lightness or darkness of a color. A color may be classified as equivalent to some member of a series of shades ranging from black to white. The other two fundamental characterizers of color are hue and saturation.

CO-MONOMER
A monomer that is mixed with one or more other monomers for a polymerization reaction, to make a copolymer.

COMPATIBILITY
The ability of a container or material to resist chemical degradation or physical change caused by the product, or to chemically change or physically degrade the product contained.

CONFORMABILITY
The ability of a material to be bent or shaped around a form without being damaged or marred in any way.

CONVERTER
A manufacturer that takes raw materials and converts them into a usable pack or pack component. Most commonly used in reference to manufacturers of flexible packaging materials. For example, a converter may print a polypropylene film, combine it with foil and polyethylene, and slit it to the widths required by a user.

CORE
A paper tube used as a base for forming a roll of film

CORONA TREATMENT
A treatment to alter the surface of plastic and other materials to make them more receptive to adhesives or printing inks. An electrical discharge creates ozone, which in turn oxidizes the substrate surface and creates polar sites that contribute to strong bond formation.

CPP
Cast PP film, (see PP). Unlike OPP, it is heat sealable, at much higher temperatures than LDPE, thus it is used as a heat seal layer in retortable packaging. It is, however, not as stiff as OPP film.

CROSS DIRECTION (CD)
The direction at right angles to a material’s flow through a machine. Flow direction through a machine may impart directional properties to a material.

CROSS-LINKING
A film conversion technique in which polymer chains are bound into a web or network to increase the web’s heat stability and strength.

CURL
The tendency of a paper sheet to curl as humidity conditions change due to the hygroexpansive nature of paper. A paper sheet that is identical in construction on each side will expand and contract as humidity changes with little tendency to curl. However if the sheet is printed, varnished, or laminated to a plastic film or a foil, then the two sides will have different expansion and contraction rates and the paper will curl as the humidity changes from the conditions when the printing, varnishing or laminating were done. The greater the humidity difference, the greater the curl.

CURTAIN COATING
A method of applying wax or other coating to a material where the material is passed through a free-falling curtain or film of the fluid coating.

CUT EDGE
The uncovered edge of a laminated product. For example a high-barrier paper/foil laminate made into a hermetically-sealed carton using lap seals would have an exposed cut edge of paperboard through which oxygen could still permeate into the product. Such edges are often skived and folded back on themselves to seal the cut edge.

CUTOFF
ln web-fed processing, the cut or print length corresponding to the circumference of the plate cylinder.

DECK
A term used mostly in flexographic printing to describe a single print station with plate, impression cylinders, and inking rolls.

DEGRADATION
A change or break-down in a material’s chemical structure.

DELAMINATION
Separation or splitting of laminate layers caused by lack of or inadequate adhesion, or by mechanical disruption such as peeling or shearing forces.

DENSITY
The weight of a given volume of a material. In metric units density is given in kilograms per cubic metre, although in packaging, grams per cubic centimetre is more common. Relative density or specific gravity is the ration of the density of the observed object to that of water.

DIE-CUT
Any operation in which a form that incorporates sharp cutting edges is pressed into a substrate to cut out a designed shape.

DIRECTIONALITY
The tendency for certain materials to have properties imparted by the flow direction through a machine.

DOT GAIN
A physical and/or optical measurement and theoretical calculation of the apparent increase in dot area from one medium to another. Normally expressed as the difference between a midtone (nominal 50%) dot area on a film negative and the printed dot area; for example, a 50% film dot area which prints as a 78% dot has 28% dot gain. Dot gain (and loss) are normal and must be controlled throughout the press and printing process.

DOYN-STYLE STAND-UP POUCH
A stand-up pouch that has seals on both sides and around the bottom gusset.

DRAW
ln flexible packaging laminates, the distance that a web travels between supporting rolls.

DRAWDOWN
A swatch of color or coating made by spreading a small amount of ink or varnish across a sheet of material. Made for visual comparison to a standard color swatch or chip.

ECONOMIC ORDER QUANTITY (EOQ)
Beyond the actual cost of manufacture, product cost is affected by the cost of setting up the production line and the cost of storing inventory beyond what can be immediately used. The longer the production run, the lower the setup cost per part. However, inventory costs increase as more products need to be stored beyond immediate needs. EOQ describes the point at which the two costs added together are at a minimum.

ELONGATION
The percentage a film will deform or stretch prior to breaking.

ETHYLENE ACRYLIC ACID (EAA)
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. lt also can be used alone or as a component of heat-sealable coatings where it offers improved toughness at low temperatures, excellent adhesion to nonpolar substrates, and a broad service temperature range. EEA is used as a tie layer between mating laminate films.

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 24o/o of the structure. Alone or in blends, it has found applications in film, extrusion coating, sheet, laminating, and co-extrusion.

ETHYLENE-VINYL ACETATE (EVA)
A polar copolymer of ethylene and vinyl acetate, retaining some of the properties of polyethylene but with increased flexibility, elongation, and impact resistance. EVA is frequently specified as the extrusion coating on polypropylene, aluminum foil and poly(ethylene terephthalate), to provide good heat-seals at high converting rates, or as the adhesion layer in some laminates. 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 (EVOH)
Can be regarded as a copolymer of polyethylene in which varying amounts of the -OH functional group have been incorporated. A typical packaging EVOH is about 20 to 35% ethylene. EVOH is one of the best polymeric oxygen barriers available to packagers. However, its susceptibiliÇ to water requires that for most applications it be laminated or co-extruded into a protective sandwich with materials that will keep the EVOH layer away from water.

EVOH
Ethylene-Vinyl Alcohol copolymer, used in coextruded plastic films to improve oxygen barrier properties. It is, however, a poor water vapor 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 coextruded plastic films, where it is shielded from moisture by protective layers of polyethylene. Its OTR also depends on its VOH (vinyl alcohol) content.

EXTENDED SHELF LIFE (ESL)
Involves the pasteurization of a product and the transfer to a package in a controlled atmosphere filler.

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

EXTRUDED FILM
The process in which the extrusion of molten resin occurs through a die, which then produces a film.

EXTRUSION
Technique for producing film. A mixture of resin and plasticizer is fed through a heated barrel where it is made plastic by heat and pressure by a continuously moving screw. The plastic mixture is forced out through a circular die, blown into a bubble, and then wound onto a roll at the end of the bubble.

EXTRUSION BONDING (LAMINATING)
A process wherein a film of molten polymeric material is extruded and immediately pressed between two substrate materials while still hot. The cooled polymer will bond the two materials together.

EXTRUSION COATING
A process wherein a film of molten polymeric material is extruded onto the surface of a substrate material and cooled to form a continuous coating.

EXTRUSION LAMINATION
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.

EYE-MARK
A machine-recognizable mark, printed on web-fed packaging materials. The eye-mark is the reference point from which the machine will register other operations such as further decoration, heat sealing, or pack cutoff.

FCL
Full container load

FILLING MACHINE
A packaging machine that measures a product from bulk by some predefined value, e.g. volume, mass, or level in a container

FILM
Generally used to describe a thin plastic material usually not more than 75 micrometres (0.003 inch) thick.

FILM YIELD
A yield measures the coverage of a film per unit weight. It can be expressed in square inches per pound or meters squared per kilogram (in US or metric units respectively)

FIN SEAL
A method of sealing plastic films where the two pieces to be sealed is “substrate-to-substrate” instead of overlapped as “surface-to-substrate”, then heated to form a seal and resulting a finlike protuberance.

FINISHING
Any final operation done to packaging before shipping.

FITMENT
A device attached to the container finish to provide a performance function’ For example, a pour-out fitment is plastic component for a glass, plastic or metal package, designed to improve the dispensing action of liquid products.

FLEXIBLE PACKAGING
A package or container made of flexible or easily yielding materials that, when filled and closed, can be readily changed in shape. A term normally applied to bags, pouches, or wraps made of materials ranging in thickness from 13 to 75 micrometres (0.0b0á to 0.003 inch) such as paper, plastic film, foil, or combinations of these.

FLEXO
Flexography Printing – Method of printing on a web press using rubber or plastic plates with raised images. Also called aniline printing because flexographic inks originally used aniline dyes. Abbreviated flexo.

FLEXOGRAPHIC PRINTING
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.

FLEXOGRAPHY
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.

FOGGING
A buildup of water droplets on the surface of a film.

FOIL (AL)
A thin gauge (6-12 microns) aluminum 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.

FOOD SERVICE
Practice or business of making, transporting and serving or dispensing prepared foods, as in a restaurant or commissary

FORM-FILL-SEAL MACHINES
A filling machine that is fed with a flexible packaging stock from a roll. The stock is folded to the desired pack shape and stabilised by heat sealing. The product is placed into the formed pack, and the remaining opening is sealed. Machines can be configured so that the product travels horizontally through the machine (horizontal form-fill-seal) or vertically through the machine (vertical form-fill-seal).

FOUR PROCESS COLORS
The four process colors (cyan, magenta, yellow and black) are also referred to as CMYK. However it is a myth that every image can be duplicated using the “four process colors.” Additional ‘spot’ colors are often required to generate the high resolution images that are most preferred in modern packaging.

FOUR-SIDE-SEAL POUCH
A pouch with seals along all four edges. Four-side-seal pouches can be made from a single stock or the front and back can be different stocks. The pouches are most commonly made on multilane pouch-forming machines where 16 or more pouches can be placed across the width of the web. gas chromatography An instrumental method of accurately determining the composition of volatile solvents and oils, and their residual presence in materials such as laminates or plastics.

GAS TRANSMISSION RATE (GTR)
The quantity of a given gas passing through a unit area of the parallel surfaces of a film, sheet, or laminate in a given time under the test conditions. Test conditions may vary and must always be stated.

GAUGE
Thickness. In North America, film thickness, measured in mils, is usually given in gauges. A 100 gauge shrink film is one mil, or 1/1000 of an inch, thick. In Europe, the film thickness metric is the micron. A quick equivalency equation is: 1 mil = 25.4 microns. Thickness of a plastic film(1/1000″=.001″=100 gauge)

GAUGE BAND
A thickness irregularity found in rolls of film. A thicker area in the machine direction at some location across the width of a flat film will produce a raised ring in a finished roll. Gauge bands can cause winding problems and when unwound, the material tends not to be perfectly flat.

GOOD MANUFACTURING PRACTICE (GMP)
Good manufacturing practice implies that the entire manufacturing procedure has been designed in such a way as to produce a quality product that presents a minimum risk to the consumer. GMP will vary from industry to industry depending on the nature of the product being packaged. Many GMPs have been formalized and are required by law for critical industries such as food and pharmaceutical packaging. Typically these GMPs describe the kind of equipment to be used, its validation, manufacturing procedures, inspection types and frequencies, record keeping, container types and approvals, and registration of company and product.

GRAVURE PRINTING
Gravure is abbreviated from the term rotogravure. During gravure printing an image is etched on the surface of a metal cylinder and chrome plated for hardness. The ink fills the cells and is transferred onto the printing substrate.

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

HAZE
The proportion of light which scatters in passing through a plastic film. Measured in percentage (the lower the percentage, the clearer the film), haze distorts colors and imparts a dusty, cloudy appearance to the film.

HDPE
High density, (0.95-0.965) polyethylene. Has much higher stiffness, higher temperature resistance and much better water vapor barrier properties than LDPE, but it is considerably hazier.

HEAT-SEAL COATING
An adhesive coating applied to a packaging material that is capable of being activated by heat and pressure to form a bond.

HEATSEAL LAYER
A heatsealable innermost layer in plastic packaging films and laminates. Can be either adhesive laminated or extrusion coated onto a non-sealable film (or foil).

HEATSEAL STRENGTH
Strength of heatseal measured after the seal is cooled, (not to be confused with “hot tack”, see next item).

HERMETIC SEAL
Airtight or impervious to gases or fluids under normal conditions of handling and storage.

HIGH BARRIER
Describes a material or package that has very low gas permeability characteristics; that is, it offers a great deal of resistance to the passage of a gas through its volume.

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

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