Packaging Glossary

Explore the intricacies of corrugated processing and bag sealing with our comprehensive glossary. From understanding different configurations like fanfold and single sheet to mastering terms such as "Adhesive" and "Wrap-Around Blank," this resource equips you with detailed explanations of terminology essential to both corrugated material production and effective bag sealing techniques. For practical insights, we also provide an overview of the most common corrugated box types used in shipping, helping you apply these concepts effectively in real-world packaging scenarios.

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a

Adhesive

Substance used to hold plies of solid fiberboard together; to hold linerboard to the tips of flutes of corrugated medium; or to hold overlapping flaps together to form the joint or to close a box.

b

Bale

A shaped unit of materials, enclosed in a fiberboard container or other wrapping, bound by strapping, rope, or wire.

Basis Weight

An attribute of containerboard, but the values may be determined from the combined corrugated board. When determining the basis weight from combined board, the take-up factor of the corrugated medium, which varies with flute size, and the weight of the adhesive must be considered.

Bending

Ability of containerboard or combined board to be folded along score lines without rupture of the surface fibers to the point of seriously weakening the structure.

Blank or Box Blank

A flat sheet of corrugated board that has been cut, scored, and slotted, but not yet glued together.

BOPP

BOPP is a type of polypropylene film that has been stretched in both the machine direction and across the machine direction. This biaxial orientation gives the film its superior strength, clarity, and barrier properties, making it an ideal material for packaging applications. BOPP films are widely used in the packaging industry for wrapping food products, labeling, and laminating purposes due to their excellent moisture resistance, transparency, and ability to be heat-sealed. They also provide a glossy finish, enhancing the visual appeal of packaged goods.

Box Manufacturer's Certificate (BMC)

In the United States, the Box Maker's Certificate is printed in a round or rectangular design on a corrugated box flap that certifies the box conforms to all applicable standards. This stamp identifies the material and certifies the results of the Mullen Bursting Test or the Edge Crush Test. Sometimes referred to as a class stamp or cert stamp.

Box Style

Distinctive configuration of a box design, without regard to size. A name or number identifies styles in common use.

Boxboard

Types of paperboard used to manufacture folding cartons and set up (rigid) boxes.

Built-Up

Multiple layers of corrugated board glued together to form a pad of desired thickness, normally used for interior packing.

Bulk

Unpackaged goods within a shipping container. Also, a large box used to contain a volume of product (e.g., "bulk box").

Bundle

Shipping unit of two or more boxes grouped together, usually with plastic banding.

Bursting Strength

Strength of material in pounds per square inch, as measured by the Mullen or Cady tester.

c

Caliper

Usually expressed in thousandths of an inch (mils) or sometimes referred to as "points." Caliper measurements are also used as an indirect measure of manufacturing quality.

Cardboard

Thin, stiff pasteboard used in the creation of playing cards, signs, etc. Term is often misused to refer to Boxboard (folding cartons) and Containerboard (corrugated boxes).

Carton

Folding box made from Boxboard, used for consumer quantities of product. A carton is not recognized as a shipping container.

Case

Corrugated or solid fiberboard box as used by the packaging industry.

Chipboard

Paperboard generally made from recycled paper stock. Uses include backing sheets for padded writing paper, partitions within boxes, and the center ply or plies of solid fiberboard.

Combined Board

Fabricated sheet assembled from several components, such as corrugated or solid fiberboard.

Compression Strength

Corrugated box's resistance to uniformly applied external forces. Top-to-bottom compression strength is related to the load a container may encounter when stacked. End-to-end or side-to-side compression may also be of interest for particular applications.

Containerboard

Paperboard components (linerboard, corrugating material and chipboard) used to manufacture corrugated and solid fiberboard. Raw materials used to make containerboard may be virgin cellulose fiber, recycled fiber or a combination of both.

Corrugated Board, Corrugated Fiberboard

Corrugated board is comprised of one or more layer of wavy corrugated medium (fluting) and one or more layer of flat corrugated linerboard. Corrugated cardboard is a fantastic choice when you are looking for sustainable packaging. Not only is it recyclable and biodegradable, but it is also strong and dependable.

Corrugated Paper Boards

Corrugated paper board is a versatile and strong material used extensively in packaging, known for its durability and protective qualities. It consists of a fluted corrugated sheet sandwiched between one or two flat linerboards. This structure provides excellent strength and rigidity, making it ideal for shipping boxes, protective packaging, and display stands. The corrugated design not only offers cushioning to protect items during transit but also allows the board to be lightweight yet capable of supporting substantial weight. Corrugated paper board is also eco-friendly, being recyclable and often made from recycled materials, making it a sustainable choice in the packaging industry.

Corrugator

Machine that unwinds two or more continuous sheets of containerboard from rolls, presses flutes into the sheet(s) of corrugating medium, applies adhesive to the tips of the flutes and affixes the sheet(s) of linerboard to form corrugated board. Continuous sheet of board may be slit to desired widths, cut off to desired lengths and scored in one direction.

d

Design Style

Style of fiberboard trays or caps having flaps scored, folded and secured at flange side walls forming the depth, as opposed to a slotted style having a set of major and minor closing flaps.

Die-Cut

Cut made with special steel rule dies. The act of making a part or container which is cut and scored to shape by such tools. Also, a box that is stamped out from a steel rule die, as opposed to being produced on a flexo folder gluer. Die-cut boxes provide greater design options and tighter size tolerances.

Dimensions

For regular slotted containers (RSC), box dimensions are expressed as length x width x height, always using inside dimensions.

Double Wall

Corrugated board construction where two layers of medium are glued between three layers of flat linerboard facing.

e

Edge Crush Test (ECT)

The Edge Crush Test is a standard industry measure of the stacking strength, the amount of force in pounds per inch needed to cause compressive failure of an on-edge specimen of corrugated board. This measured force is a primary factor in predicting the compression strength of the completed box. When using certain specifications in the carrier classifications, minimum edge crush values must be certified.

f

Facings

Sheets of linerboard used as the flat outer members of combined corrugated board. Sometimes called inside and outside liners.

Fanfold

Continuous sheet of paperboard or paper.

Fiberboard

General term describing combined paperboard (corrugated or solid) used to manufacture containers.

Fixed Sheets

Readily available, highly flexible and cost-effective corrugated material.

Flaps

Extension of the side wall panels that, when sealed, close the remaining openings of a box. Usually defined by one score line and three edges.

Flexographic Printing

Flexographic printing is one of the most common methods of printing for packaging.

Flex Folder Gluer

Machine, usually capable or running at high speed that prints, folds, cuts, and glues sheets of corrugated board, converting them into shipping boxes.

Flute

The wavy layer of corrugated medium that is glued between the flat inner and outer sheets of linerboard to create corrugated board. Fluting generally runs parallel to the height of a shipping box. Flute sizes come in A, B, C, D, E, F and Z.

j

Joint

The opposite edges of the blank glued, stapled, wire stitched, or taped together to form a box.

k

Kraft

German word meaning "strength", designating pulp, paper, or paperboard produced from wood fibers.

Kraft Board

Kraft board is a thick, durable material made from Kraft pulp, known for its high strength and resilience. It is commonly used in the packaging industry for applications requiring sturdy and protective packaging solutions, such as boxes, cartons, and protective inserts. The board's strength comes from the Kraft process, which produces long, strong wood fibers. Kraft board is often chosen for its environmental benefits, including being recyclable and biodegradable. Its natural brown color is often associated with eco-friendly and sustainable packaging, though it can also be bleached or coated for enhanced aesthetics and branding.

Kraft Paper Bags

A Kraft paper bag is a type of packaging made from Kraft paper, known for its high strength, durability, and eco-friendly properties. Kraft paper is produced using the Kraft process, which involves the chemical conversion of wood into wood pulp, resulting in a sturdy, tear-resistant material. These bags are widely used in various industries for packaging products such as food items, retail goods, and industrial supplies. Kraft paper bags are valued for their recyclability, biodegradability, and ability to hold heavy or bulky items without easily tearing. They are also customizable, allowing for printing and branding, making them a popular choice for both functional and marketing purposes.

l

Liner

Creased fiberboard sheet inserted as a sleeve in a container and covering all side walls. Used to provide extra stacking strength or cushioning.

Linerboard

Flat sheets of paper that comprise the outer surfaces of a sheet of corrugated board.

m

Medium

Paperboard used to make the fluted layer of corrugated board.

Mullen (or Burst) Test

The Mullen Test is a standard industry measure of the bursting strength of corrugated board to withstand external or internal forces, and to contain the contents during handling. This test certifies that the box can withstand the stated pressure (lbs. per sq. in.) as applied by a Mullen Tester.

o

Overlap

Design feature wherein the top and/or bottom flaps of a box do not butt, but extend one over the other. The amount of overlap is measured from flap edge to flap edge.

p

Pad

Corrugated or solid fiberboard sheet, or sheet of other authorized material, used for extra protection or for separating tiers or layers of articles when packed for shipment.

Palletizing

Securing and loading containers on pallets for shipment as a single unit load, typically for handling by mechanical equipment.

Panel

A "face" or "side" of a box.

Paperboard

One of the two major product categories of the paper industry, Containerboard and Boxboard. Includes the broad classification of materials made of cellulose fibers, primarily wood pulp and recycled paper stock, on board machines. (The other major product group of the paper industry is paper, including printing and writing papers, packaging papers, newsprint and tissue.)

Partition

Set of corrugated, solid fiberboard or chipboard pieces that interlock when assembled to form a number of cells into which articles may be placed for shipment.

Pinch Bottom

A pinch bottom is a type of bag closure commonly used in the packaging industry, especially for products requiring a strong, secure seal. This closure style involves folding and gluing the bottom flap of a bag, typically made from materials like paper or plastic, to create a flat and stable base. The pinch bottom design is often used for bags that need to stand upright on shelves, providing an effective barrier against moisture, air, and contaminants. It is particularly popular in packaging dry goods, such as pet food, seeds, and grains, ensuring that the contents remain fresh and protected during storage and transport.

Ply

Any of the several layers of linerboard or solid fiberboard.

Point

Term used to describe the thickness or caliper of paperboard, where one-point equals one thousandth of an inch.

Puncture Resistance

Puncture resistance of combined board indicates the ability of the finished container to withstand external and internal point pressure forces and to protect the product during rough handling. This method is used on heavy double wall and triple wall as an alternative to burst.

r

Regular Slotted Container (RSC)

Box style created from a single sheet of corrugated board. The sheet is scored and slotted to permit folding. Flaps extending from the side and end panels form the top and bottom of the box. The two outer flaps are one-half the container's width in order to meet at the center of the box when folded. Flute direction may be perpendicular to the length of the sheet (usually for top-opening RSCs) or parallel to the length of the sheet (usually for end-opening RSCs).

Right Sized Packaging

Protected contents without excessive packing material allowing for a smaller box.

s

Score or Score line

Impression or crease in corrugated or solid fiberboard, made to position and facilitate folds.

Scored and Slotted Sheet

Sheet of corrugated fiberboard with one or more scorelines, slots or slits. May be further defined as a box blank, a box part, a tray or wrap, a partition piece, or an inner packing piece.

Seam

Junction created by any free edge of a container flap or panel where it abuts or rests on another portion of the container and to which it may be fastened by tape, stitches or adhesive in the process of closing the container.

Set-Up Boxes

Boxes that have been squared, with one set of end flaps sealed, ready to be filled with product. An article that is packed for shipment in a fully assembled or erected form.

Sheet

Rectangle of combined board, untrimmed or trimmed, and sometimes scored across the corrugations when that operation is done on the corrugator. Also, a rectangle of any of the component layers of containerboard, or of paper or a web of paperboard as it is being unwound from the roll.

Single Face Corrugated

is a standard packaging, cushioning and converting material that has been used in a wide range of industrial, retail and decorative applications. Think of sleeves for your coffee cup, to litho-laminated boxes for your smartphone to general pallet wrapping.

Slit

Cut made in a fiberboard sheet without removal of material.

Slit Score

Cut made in a fiberboard sheet through only a portion of the thickness in a box blank to allow its flaps and sides to be folded into a shipping box.

Slip Sheet

Flat sheet of material used as a base upon which goods and materials may be assembled, stored and transported.

Slot

Wide cut, or pair of closely spaced parallel cuts including removal of a narrow strip of material made in a fiberboard sheet, usually to form flaps and permit folding without bulges caused by the thickness of the material. Common widths are 1/4 in. (6 mm) and 3/8 in. (9 mm).

Stacker

Receiving and palletizing of corrugated material.

Stacking Strength

Maximum compressive load a container can bear over a given length of time, under given environmental/distribution conditions, without failing.

Stapling

A method of securing materials, typically by using metal staples to fasten together layers of paper, cardboard, or other packaging materials. It is commonly used in the production of boxes, cartons, and other types of packaging where durability and strength are required. Stapling provides a cost-effective and efficient way to seal packages, especially in heavy-duty applications such as corrugated boxes or industrial packaging. This method ensures that the packaging remains intact during transportation and handling, offering a secure closure that can withstand rough conditions.

Stitching

The process of using thread or wire to bind or secure packaging materials, typically for bags, cartons, or other containers. This technique is often used for heavy-duty packaging applications, such as in the sealing of multi-wall paper bags, corrugated boxes, or for reinforcement in industrial packaging. Stitching provides strong, durable closures that can withstand significant stress during shipping and handling. It is particularly common in sectors like agriculture, construction materials, and bulk goods packaging, where secure containment is essential to protect the contents.

t

Tensile Strength

Indicates the containerboard's resistance to breaking when it is pulled into or through equipment during the converting and printing processes.

Tube

Sheet of combined boards, scored and folded to a multi-sided form with open ends. May be an element of a box style or a unit of interior packing that provides protection and compression strength.

u

Unit

Large group of bundled or unbundled boxes, banded and/or stretch filmed together for shipment.

Unitized Load

Load of a number of articles or containers, bound together by means of tension strapping, plastic shrink or stretch films.

w

Web or Fanfold

Continuous sheet of paperboard or paper.

Wrap-Around Blank

A scored and slotted sheet of corrugated fiberboard that is formed into a box by folding it around its contents. The user makes both the flap and joint closures.

z

Z-Fold

A specific folding technique used in the packaging industry where a material is folded in a "Z" shape, creating three panels. This type of fold is commonly used in the design of brochures, cartons, or labels, where space efficiency is critical. In packaging applications, the Z-fold allows for compact storage and easy unfolding for consumers or operators. It is especially useful for creating multi-page information panels, compact product inserts, or flexible packaging designs that need to expand for additional surface area. The Z-fold's versatility makes it a popular choice for creating neat, organized packaging while optimizing material use.