Fibre Packaging Definitions

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Carton Dimensions - Dimensions refer to the interior of a carton, measured in millimetres of Length x Width x Height. Length (L) is the longer side of the opening and Width (W) is the shorter. Height (H) is the length between the openings on either end.
Cellulose - The main fibrous material in paper.
Corrugated Box Plant - An operation that has both corrugating capability and converting equipment. Most corrugated boxes throughout the world are produced in integrated box plants.
Corrugated Fiberboard - This material refers to the composite structure formed by gluing one or more sheets of fluted, corrugated material to one or more flat facings of linerboard.

Single-wall carton - This is a corrugated fiberboard carton made by gluing a sheet of fluted corrugated material between two flat sheets of linerboard.
Double-wall carton - This is a corrugated fiberboard carton made of three sheets of linerboard interleaved with two sheets of fluted corrugated material.
Flute, Corrugation - This refers to the wave shapes, or ridges, that are pressed into a sheet of material that has been softened by steam. This material is then sandwiched between flat sheets of material to form corrugated fiberboard. Flute serves as protective cushioning and helps strengthen a carton. Different widths and configurations offer distinctive performance advantages. Corrugated cartons feature either of the types below.
- A-Flute : Flute thickness of 4.7 mm
- B-Flute : Flute thickness of 2.5 mm
- C-Flute : Flute thickness of 3.6 mm - Depending upon the stacking strength, puncture resistance , crush strength required for the carton, one of the above three commonly corrugations are used in single-wall, general-purpose cartons. A-Flute has excellent stacking Strength, B-Flute has good puncture resistance and C-Flute has the optimum combination of both.
- E-Flute : Flute thickness of 1.5 mm - Is generally used for light applications such as Pizza Boxes, Mailers, Shoe boxes etc.
- BC Flute - This flute is a double-wall combination made from one B-flute, single-wall sheet and one C-flute, single-wall sheet. The result is a strong corrugation used when extra thickness or stacking strength is needed.
- AC Flute - This flute is a double-wall combination made from one A-flute, single-wall sheet and one C-flute, single-wall sheet. The result is a very strong corrugation used when extra strength is needed.

Die Cutting - The process of cutting a corrugated sheet into a shape which will convert to the required box size when assembled. A rotary die cutter uses a cylindrical die and is generally capable of higher speed than a flatbed die cutter, as the sheet flow basically continues. A flatbed die cutter uses a flat die and the corrugated sheet momentarily stops to enable the required cutting. This method provides both high accuracy and intricate shapes not available from the rotary process.
Double-facer - A double-facer, or double backer, is the part of a corrugator which bonds single-face board to another liner to produce a double-faced corrugated sheet.
Folding Cartons - Multi-layer paperboard cartons which are printed/coated and cut into carton blanks. The carton blanks also incorporate creases, which enable the carton to be formed for packaging the customer's product.
Functional Coatings - The lamination of polyethylene and/or plastic or foil films to paper substrates, providing a water or greaseproof barrier. Typically used in high humidity applications in both tropical and cold temperatures, for use with meat, seafood, pet food, fruit and produce.
Kraft - This term describes the natural, unbleached corrugated fiberboard used in making cartons
Linerboards - Linerboards form the inner and outer facings of corrugated fibre boxes and are chosen for their structural and/or decorative properties. They can be made from white or brown, kraft or recycled fibres, or a blend of both.
Pasting - Two, three or four plies of paper and paperboard are glued together to form a solid fiberboard with a thickness ranging between 0.8mm to 3mm. The boards are used for a variety of applications such as shoeboxes, screen-printing, display boxes, board games, book covers and ring binders.
Printing - Most printing of corrugated board is done by the flexographic method, which can be thought of as a sophisticated method of printing with rubber stamps. Flexo printing is used for both pre-print and post-print applications. Most printing on corrugated boxes is done in the conversion process after the corrugated sheet is produced, ie. post-printing. Pre-printing refers to the process of printing a design or pattern onto a roll of paper before it proceeds to the corrugating stage. This process is typically used for high volume jobs where quality printing is required.
Pulp - Primary raw material from which paper is made. A fibrous product produced by mechanical or chemical processes, or a combination of both.
RSC - This is the abbreviation for Regular Slotted Carton, the most commonly used style of carton. One side is glued, taped or stapled during manufacturing, making this carton well suited for easy set-up, filling, and closure.

Film Definitions

Polyethylene (PE) - First produced after World War II, polyethylene is the largest selling transparent packaging material in use today. More than 50% of all film used in packaging is in fact polyethylene. On a yield basis, it is the lowest cost alternative of any of the packaging grade films. It is very common to find polyethylene used in industrial and food environments. Polyethylene is found in three basic configurations or densities. Low density is used in manufacturing of bags. Medium density is used in machine over-wrapping applications where quick heat sealing qualities are desirable. High density polyethylene, on the other hand, is used in specialized applications. It is very stiff and heat resistant. All polyethylene films are virtually chemically inert, resistant to acids, alkalis, and other caustic compounds.

Cellophane - Cellophane is the oldest of the generally used packaging films. Cellophane has been a major food packaging film for many years. Its usage is on a down slide due to its particular cost and yield factor. The majority of the cellophane applications are now being converted to other types of films.

Vinyl Films (PVC) - Polyvinylchloride films rank as the third most popular used film. Because they are compounded with a wide choice of plasticizers and are produced by a variety of techniques, they have a uniquely wide range of properties. They can be soft, tacky, hard, or slippery. Shrink packaging in vinyl is widely used for canned goods and toys. Probably the largest single use for vinyl is in-store packaging of fresh meat and produce. Its appearance, strength, and high oxygen transmission all make it ideal for these applications. Grades meeting the requirements of the FDA for these specific purposes are utilized in this packaging. Both hand and machine stretch and shrink wrap methods are employed by food stores.

Polypropylene (PPP) - The first commercial use of polypropylene was in 1961. Since then it has become one of the most widely used films in its two forms, cast and oriented. It is the lowest density commercial film. The optical characteristics of both types of polypropylene films are outstanding. Some of the characteristics of the oriented polypropylene films are the high impact strength, strength retention at low temperatures and it has higher barrier properties and greater stiffness than the cast product. It is normally used in thicknesses of one mil or less. Most of the polypropylene products will be found used in the food industries wherein polyproylene has a tendency to duplicate the properties of cellophane and is found to replace cellophane in many applications.

Polyester Films - Polyester film has the highest tensile and impact strength of all plastic films. It retains good physical and mechanical properties over a wide temperature range, from minus 70°C to 205°C. Resistant to moisture, resistant to solvent and chemical attack and is nontoxic. In most cases it complies with the FDA requirements. Polyester film is therefore found to be used in many food applications. A new concept in packaging is metallization of polyester for esthetic considerations and improved barrier properties. Institutional coffee pouches, for instance, are one application of metallized polyester. Polyester film is used in many laminations to improve barrier properties, moisture transmission rates and other necessary requirements of a particular application.

Tape Definitions

Masking Tape - Masking Tape is designed for superior performance in a variety of applications such as paint masking, holding, light-duty, splicing, bundling, packaging and many more.

Flatback Tape - Flatback Tape is designed for a variety of packaging, splicing and tabbing applications, providing a quick, positive seal under a wide range of temperature and humidity conditions. Products take on demanding applications such as splicing floor coverings, heavy wallcoverings and abrasives during their manufacturing. Additionally used for leasing/beaming of fibers in textile manufacturing.

Double-Coated Tape - Double-Coated Tape features an extremely aggressive tack. Ideal for many industrial uses such as mounting, adhering, and bonding applications. Double-Coated Foam products bring exceptional performance in applications where long term bonding is needed. Ideal for mounting, cushioning, sound-dampening, and vibration. The conformable foam construction performs well when filling gaps on both uniform and irregular surfaces.

Duct Tape - A very strong, wide, adhesive tape, typically silver in color, used especially in making temporary repairs to pipes.

Filament MOPP Strapping Tape - Fiberglass reinforced filament tape delivers superior adhesion for a variety of light to medium load applications. Intertape Brand MOPP Strapping Tape utilizes mono-oriented tensilized polypropylene for light duty strapping, palletizing, and bundling.

Electrical tape - A type of pressure-sensitive tape used to insulate electrical wires and other material that conduct electricity. It can be made of many plastics, it stretches well and gives an effective and long lasting insulation.

Double-sided tape - A variety of adhesive tape that is coated with adhesive on both sides. It is designed to stick two lightweight surfaces together.

Water activated tape - Gummed paper tape or gummed tape is starch or animal glue (gelatine) based adhesive on a paper backing. Gummed tape is used for closing and sealing boxes and casings. Before closing corrugated fiberboard boxes, the tape is wetted/remoistened to make the adhesive sticky again.

Shrink and Stretch Packaging

Both these types of packaging are used to group together individual packages, containers, or items of cargo on a pallet to form a cargo unit.

Shrink-packaging - Shrink-wrapping involves enclosing the package contents in shrink film (flat or tubular film), heat sealing any unsealed portions, and separating the package from the film web, or covering the package contents with a shrink cover. Depending upon the shape and weight of the package contents, the shrink material used should be PE or plasticized PVC film of a thickness of 0.01 to 0.2 mm, with PE films being particularly suitable for heavy items. The film is heated from the outside in a shrink oven or with hand-held heat gun, so releasing the "frozen in" tension in the film. Shrink films are produced in forms which are oriented either monoaxially (in a single direction) or biaxially (in two directions). As the film cools down, it shrinks around the package contents, applying a very slight pressure per unit area. The tear strength of shrink films to DIN 53371 is 1.8 to 3.2 Nm/mm² in machine direction and 1.6 to 2.5 Nm/mm² in transverse direction. If the shrink packaging is intended to secure loads in transit, compliance with VDI guideline 3968, sheet 4 must be ensured. There are no restrictions either with regard to the compressive strength of the packaged item or with regard to differing loading areas, heights and weights. Sharp-edged items should be shrink-wrapped either with film of an appropriate thickness or using edge protectors. When shrink-wrapping pallet loads, the film should be placed such that it extends over the lower edge of the pallet deck, so ensuring that the cargo cannot slip and may be described as a functional cargo unit. If the base area of the packaged item is smaller than the area of the pallet, care must be taken to ensure that the item is firmly attached to the pallet before it is shrink-wrapped. Shrink-wrapping provides protection from dust and moisture in indoor storage. Particularly hygroscopic goods must stand on a film on the pallet or be otherwise protected. Shrink packaging provides a psychological barrier to theft.

Stretch packaging - In stretch wrapping, one or more flat films are placed under mechanical tension and wound helically around the item to be packaged. Depending upon the shape and weight of the package contents, the stretch material used should be PE or plasticized PVC film of a thickness of 0.01 to 0.05 mm, with stretch packaging only being suitable for light weights and firmly consolidated items. The ends of the film web are heat sealed or coated. The cargo unit is held together by the tension of the film. If the stretch packaging is intended to secure loads in transit, compliance with VDI guideline 3968, sheet 5 must be ensured. Pre-tensioning of the film when stretch wrapping should not exceed the compressive strength of the item being packaged. However, if low levels of pre-tensioning are applied, securing of the cargo in transit is also reduced. Securing of the cargo in transit is also reduced by over- or under-stacking of the pallet base area. There are no restrictions with regard to differing loading areas, heights, and weights. Sharp-edged items should only be stretch wrapped using edge protectors, as the film may tear during the stretch wrapping operation. When stretch wrapping pallet loads, the film should be placed such that it extends over the lower edge of the pallet deck, so ensuring that the cargo cannot slip and may be described as a functional cargo unit. Stretch wrapping provides protection from dust and moisture in indoor storage only if an additional cargo cover sheet is used. Particularly hygroscopic goods also require an additional cargo cover sheet and must stand on a film on the pallet or be otherwise protected. Stretch packaging provides a psychological barrier to theft.

Plastic Film Terminology

Air Evacuation — A hole or series of holes placed in the film to allow the excess air in the bag to escape during shrinkage.
Antifog Film — A film containing a wetting agent which reduces the surface tension on the film to allow water to wet the surface rather than form water droplets, which causes a cloudy appearance.
Ballooning — The lifting action of the film away from the product caused by the pressurizing of the excess air in the bag during the shrink process.
Bead Seal — A heat seal formed when two pieces of plastic film are joined by melting the film with an electrically heated wire. The seal is bead-like in appearance and is made on an impulse “L-Sealer.” (See HEAT SEAL)
Biaxial Orientation — A film that has been stretched under certain temperature conditions equally in both the machine and transverse directions.
Blister Film — Used in blister packaging. The film is rigid, clear plastic that is preformed and often heat-sealed to a coated paperboard. Other blister styles include fold over, clam shell, and slide designs.
Blocking — A condition where a plastic film tends to stick to an adjacent surface, either film or some other substance.
Blown Film — Film produced by extruding resin into a tube which is expanded by air pressure.
Bubble — The inflated tube of film in the blown film extrusion process.
Burnthrough — A weakening of the film where the heat of the tunnel exceeded the heat resistance of film. Typically, it will appear as a hole or a very cloudy area.
Cast Film — Film extruded through a flat die into a quench system.
Centerfolded Film — Film folded in half in the machine direction and then wound into roll form.
Clarity — Degree of transparency.
Coefficient of Friction — In plastics films, indicates the ease with which a film surface is slid against like film or adjacent surface. A low value (near zero) indicates a slippery; a high value (7 or more) indicates a tacky film which will stick to itself. (See CLING, SLIP and TACKINESS)
Coextrusion — Two or more different materials simultaneously extruded into a composite film.
Copolymer — This is more than one gas polymerized together at the same time.
Core — A paper tube used as a base for forming a roll of film.
Dancer Roll — A mechanical device used to control the tension of the film between the film unwind and fhe film sealing area.
Density — Weight per unit volume. Films with a low density offer more coverage per weight of film.
Elmendorf Tear Resistance — A measure of the resistance to tear after the film has been cut.
Elongation — The percentage a film will deform or stretch prior to breaking.
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, then wound onto a roll at the end of the bubble.
Film — A general term for plastics having a thickness of 0.010 inches or less.
Fish Eye — An unrefined or unmelted mass in a transparent plastic film which has not blended completely into the surrounding material, giving somewhat the appearance of a fish eye. Also called gel.
Gas Transmission Rate (GTR) — A measure of the permeability of a packaging film to gases. Expressed in cc/100sq. in./24 hrs./mil.
Gauge — Thickness of a plastic film (1/1000”=.001”=100gauge) (See THICKNESS)
Gloss — The amount of light reflected from a film at a given angle in ratio to the total light striking the sample. The more light a film reflects, the higher the gloss of the film.
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.
Heat Sealing — Joining plastic films by controlled application of heat and pressure to the area to be sealed (See also LAP SEAL, BEAD SEAL, and IMPULSE SEALING)
Hole Burner — A device that uses a hot wire formed in a circular shape to burn a round hole in the film for air evacuation during shrinkage.
Hole Punch — A device to punch a round hole in the film for air evacuation during shrinkage.
Impact Resistance — The resistance to impact of a film.
Impulse Sealing — A heat sealing technique in which a pulse of intense thermal energy is applied to the sealing area for a very short time, followed immediately by cooling. (See HEAT SEALING)
Initial Tear Resistance — A measure of the force needed to begin a tear in a film.
Inverting Head — A mechanical device used to separate and invert centerfolded film as the film is ansferred into the sealing device of the wrapper.
Irradiation — A process that uses highenergy electrons to cross-link a film.
Lap Seal — A method of sealing, plastic films where the two pieces to be sealed are over-lapped, then heated to form a seal. (See HEAT SEALING)
L-Sealer (L-Bar Sealer) — A hot wire impulse sealing machine, mounted in an I-shape, used for sealing plastic films.
Low Temperature Flexibility — The lowest temperature at which film can withstand a flexing test without cracking.
Machine Direction (MD) — The direction parallel to that taken by the majority of molecules in a plastic film, or the direction of the film web as it moves through the filmmaking machine. Also called Longitudinal.
Migration — The transmission of a material from within a plastic film to its surface or to another contacting material. Also called Bleed or Exudation.
Mil — Measure of the thickness of a film. (.001”=1mil) (See THICKNESS)
Modulus — A measure of the film stiffness.
Moisture Vapor Transmission Rate (MVTR) — The rate moisture vapor will pass through film.
Monomer — A comparatively simple organic compound which can under certain conditions, react to form a polymer. (See POLYMER)
Orange Peel — A surface distortion of a plastic film which looks like the skin of an orange.
Orientation — Mechanical stretching of a plastic film to produce a parallel arrangement of its molecules. Films may be stretched unixially (in one direction, called preferential) or biaxially (in two directions).
Orientation Release Stress — The force exerted per square inch of film cross sectional area, when that film is shrunk by heat at a given temperature. Also called shrink force.
Plastic — A synthetic resin which (a) generally has a high molecular weight; (b) is made up of at least two atoms; (c) is sold in its unprocessed and processed states but in between, while it is being processed into finished items, is softened enough through the combined application heat, pressure, and mechanical working to be formed into various shapes.
Plasticizer — A substance blended into a plastic to improve flexibility or softness.
Polyethylene — A resin made from ethylene gas which produces tough transparent film.
Polymer — A chain-like compound of high molecular weight formed by the linking together of simple molecules under suitable conditions.When two or more monomers are involved, the product is called a copolymer. (See MONOMER)
Polypropylene — A resin made from propylene gas which produces lightweight, highly transparent, stiff film.
Pseudo Shrink — Material (such as polyethylene film) that expands upon heating and shrinks as it cools.
PVC — (POLYVINYL CHLORIDE) — A thermo plastic material composed of polymers of vinyl chloride; a colorless solid with outstanding resistance to water, alcohols, and concentrated acids and alkalis. Compounded with plasticizers, PVC yields a flexible film, widely used in the manufacture of clothing and packaging films.
Resin — A solid or semi-solid organic material which has an indefinite and often high molecular weight; it exhibits a tendency to flow when subjected to stress and usually has a distinct softening or melting temperature range.
Sealing Wire — A nichrome wire which is heated by its resistance to electrical current. It is used for stealing and cutting shrink film.
Sheet — A general term for plastic having a thickness of 0.010” or more.
Shrink Film — A plastic film which meets all of the following criteria:

(a) A flexible film of gauge less than three mills.
(b) A film which can be redily sealed by the simple application of heat, pressure, and/or solvent.
(c) A film which will shrink (reduce a linear dimension) a minimum of 20% in at least one
direction when subjected to heat.
(d) A film which exerts a shrink tension of 100 psi or more.

Shrink Force - The force exerted on the product by the film during the shrink process.
Shrinkage/Percent Shrink — The decrease in dimension of a film when it is subjected to heat.
Single Wound Film — Flat film wound on a core.
Skin Film — Used in skin packaging, this is heated and vacuum-sealed to a coated board over the product to be packaged.
Slip — A low coefficient of friction. (See COEFFICIENT OF FRICTION)
Slip Agent (Slip Additive) — An internal lubricant added to the formulation of PVC film which increases the slip (decreases the coefficient of friction) on the surface of the film.
Static — An electric charge generated by film moving across itself (unwinding from the roll) or any other surface.
Stretch Film — Used in packaging and unitizing, this film can be applied by hand or by machine for product protection and stabilization. In shipping and storage applications, stretch film is used to wrap or bundle skids of boxes or other packages together to prevent slippage and damage during transportation.
Surlyn — A trademarked film product from DuPont® used in skin packaging. Used in conjunction with a oard stock, this film is used most often for retail packaging due to its high quality optics and excellent formability.
Tack — A high coefficient of friction. (See COEFFICIENT OF FRICTION)
Tear Strength — Elmendorf tear is a measure of the force required to continue a tear already started in the film sample. Results are reported in grams of force per mil thickness of film.
Tensile Strength — The force required to break a film.
Tension — A force exerted on the film from external sources.
Thermoplastic — A plastic which may be repeatedly softened by the application of heat.
Trim — The edges of film which are cut from a package formed on an L-sealer or side sealer when the seal is made.
Uniaxially Oriented Film (Preferential Shrink Film) — A film that will shink in only one direction.
Water Vapor Transmission Rate (WVTR) The penetration of water vapor through a packaging film or other barrier, expresses as grams/100square inches/24 hours at 100°F and 90% relative humidity. WVTR is preferred over MTVR although both terms are synonymous with the same units.
Yield (Area Factor) — Area of material per pound of with, expressed a square inches per pound of square yards per pound.