Paperboard is a thick

paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distrib ...

-based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker (usually over 0.30 mm, 0.012 in, or 12 points) than

and has certain superior attributes such as foldability and rigidity. According to

ISO ISO is the most common abbreviation for the International Organization for Standardization. ISO or Iso may also refer to: Business and finance * Iso (supermarket), a chain of Danish supermarkets incorporated into the SuperBest chain in 2007 * Iso ...

standards, paperboard is a paper with a grammage above 250 g/m², but there are exceptions. Paperboard can be single- or multi-ply. Paperboard can be easily cut and formed, is lightweight, and because it is strong, is used in packaging. Another end-use is high quality graphic printing, such as book and magazine covers or postcards. Paperboard is also used in

fine art In European academic traditions, fine art is developed primarily for aesthetics or creative expression, distinguishing it from decorative art or applied art, which also has to serve some practical function, such as pottery or most metalwor ...

s for creating sculptures. Sometimes it is referred to as ''

cardboard Cardboard is a generic term for heavy paper-based products. The construction can range from a thick paper known as paperboard to corrugated fiberboard which is made of multiple plies of material. Natural cardboards can range from grey to light ...

'', which is a generic, lay term used to refer to any heavy

paper pulp Pulp is a Lignocellulosic biomass, lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibers from wood, fiber crops, Paper recycling, waste paper, or cotton paper, rags. Mixed with water and other chemica ...

–based board, however this usage is deprecated in the paper, printing and packaging industries as it does not adequately describe each product type.

History

In 1817, the first paperboard carton was produced in

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

Folding carton The folding carton created the packaging industry as it is known today, beginning in the late 19th century. The process involves folding carton made of paperboard that is printed, laminated, cut, then folded and glued. The cartons are shipped fla ...

s first emerged around the 1860s and were shipped flat to save space, ready to be set up by customers when they were required. The mechanical die cutting and creasing of blanks was developed in 1879. In 1911 the first kraft sulphate mill was built in

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

. In 1915 the gable top milk carton was patented and in 1935 the first dairy plant was observed using them. Ovenable paperboard was introduced in 1974.

Terminology and classification

Terminology and classifications of paperboard are not always uniform. Differences occur depending on specific industry, locale, and personal choice. In general, the following are often used: * Boxboard or cartonboard: paperboard for

folding carton The folding carton created the packaging industry as it is known today, beginning in the late 19th century. The process involves folding carton made of paperboard that is printed, laminated, cut, then folded and glued. The cartons are shipped fla ...

s and rigid set-up boxes **

Folding boxboard Folding boxboard, also referred to as FBB or by the DIN Standard 19303 codes of GC or UC, is a paperboard grade made up of multiple layers of chemical and mechanical pulp. This grade is made up of mechanical pulp in between two layers of chemical p ...

(FBB): a bending grade capable of being scored and bending without fracture ** Chipboard: a recycled, low quality board ***

White lined chipboard White-lined chipboard (also referred to as WLC, GD, GT or UD) is a grade of paperboard typically made from layers of waste paper or recycled fibers. Most often it comes with two to three layers of coating on the top and one layer on the reverse si ...

(WLC): a white, often clay-coated chipboard ** Kraft board: a strong virgin fiber board often used for beverage carriers. Often clay-coated for printing ** Laminated board: a lamination of paperboards and other materials, for example

liquid packaging board Liquid packaging board is a multi-ply paperboard with high stiffness, strong wet sizing and a high barrier coating, e.g. plastic. Only virgin paper fibers are used. The barrier coating must hold the liquid and prevent migration of air and flavo ...

Solid bleached board Solid bleached board (SBB) or solid bleached sulphate (SBS) is a virgin fibre grade of paperboard. This grade is made purely from bleached chemical pulp and usually has a mineral or synthetic pigment coated top surface in one or more layers (C1S ...

(SBB) or solid bleached sulphate (SBS): clean white board used for foods etc. Sulphate refers to the kraft process **

Solid unbleached board Solid unbleached board, also known as SUB, is a grade of paperboard typically made of unbleached chemical pulp. Most often it comes with two to three layers of mineral or synthetic pigment coating on the top and one layer on the reverse side. R ...

(SUB): board made from unbleached chemical pulp *

Containerboard Containerboard or corrugated case material (CCM) is a type of paperboard specially manufactured for the production of corrugated board. It includes both linerboard and corrugating medium (or fluting), the two types of paper that make up corruga ...

: a type of paperboard manufactured for the production of corrugated fiberboard ** Corrugated medium: the inner fluted portion of corrugated fiberboard ** Linerboard: a strong stiff board for one or both sides of corrugated boxes. It is the flat covering over the corrugating medium. * Other ** Binder's board: a paperboard used in bookbinding for making hardcovers.

Production

Fibrous material is turned into

pulp Pulp may refer to: * Pulp (fruit), the inner flesh of fruit Engineering * Dissolving pulp, highly purified cellulose used in fibre and film manufacture * Pulp (paper), the fibrous material used to make paper * Molded pulp, a packaging material ...

and bleached to create one or more layers of board, which can be optionally coated for a better surface and/or improved appearance. Pulp board is produced on pulping machines that can handle higher grammage and several plies.

Raw materials

The above-mentioned fibrous material can either come from fresh (virgin) sources (e.g. wood) or from recycled waste paper. Around 90% of virgin paper is made from

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...

pulp. Today paperboard packaging in general, and especially products from certified sustainable sources, are receiving new attention, as manufacturers dealing with environmental, health, and regulatory issues look to

renewable resources A renewable resource, also known as a flow resource, is a natural resource which will replenish to replace the portion depleted by usage and consumption, either through natural reproduction or other recurring processes in a finite amount of ti ...

to meet increasing demand. It is now mandatory in many countries for paper-based packaging to be manufactured wholly or partially from recycled material. Raw materials include: * Hardwood: C. in length e.g.

Birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech- oak family Fagaceae. The genus ''Betula'' contains ...

which has short fibres. It is generally more difficult to work with; however, it does provide higher tensile strength, but lower tear and other strength properties. Although its fibres are not as long and strong as those in softwood, they make for a stiffer product defined by some stiffness tests. Hardwood fibres fill the sheet better and therefore make a smoother paper that is more opaque and better for printing. Hardwood makes an excellent corrugating medium. * Softwood: C. in length e.g.

Pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts ...

and spruce which have typically long fibres and make superior paperboard in services where strength is important. Softwood makes excellent linerboard. * Recycled: Used paper is collected and sorted and usually mixed with virgin fibres in order to make new material. This is necessary as the recycled fibre often loses strength when reused; the added virgin fibres enhance strength. Mixed waste paper is not usually deinked (skipping the deinking stage) for paperboard manufacture and hence the

may contain traces of inks, adhesives, and other residues which together give it a grey colour. Products made of recycled board usually have a less predictable composition and poorer functional properties than virgin fibre-based boards. Health risks have been associated with using recycled material in direct food contact. Swiss studies have shown that recycled material can contain significant portions of mineral oil, which may migrate into packed foods. Mineral oil levels of up to 19.4 mg/kg were found in rice packed in recycled board. * Others: It is also possible to use the fibres of Sugarcane Bagasse, Straw, Hemp,

Cotton Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor pe ...

, Flax,

Kenaf Kenaf tymology: Persian ''Hibiscus cannabinus'', is a plant in the family Malvaceae also called Deccan hemp and Java jute. ''Hibiscus cannabinus'' is in the genus '' Hibiscus'' and is native to Africa, though its exact origin is unknown. The name ...

, Abaca and other plant products

Pulping

Two principal methods for extracting fibres from their sources are: *

Chemical pulp Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibers from wood, fiber crops, waste paper, or rags. Mixed with water and other chemical or plant-based additives, pulp is the major raw ma ...

ing uses chemical solutions to convert wood into pulp, yielding around 30% less than mechanical pulping; however, pulp made by the kraft process has superior strength *

Thermo mechanical pulp Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibers from wood, fiber crops, waste paper, or rags. Mixed with water and other chemical or plant-based additives, pulp is the major raw mat ...

is a two-stage process which results in a very high yield of wood fibres at the expense of strength.

Bleaching

Pulp used in the manufacture of paperboard can be bleached to decrease colour and increase purity. Virgin fibre pulp is naturally brown in colour, because of the presence of lignin. Recycled paperboard may contain traces of

ink Ink is a gel, sol, or solution that contains at least one colorant, such as a dye or pigment, and is used to color a surface to produce an image, text, or design. Ink is used for drawing or writing with a pen, brush, reed pen, or quill. Thicker ...

s, bonding agents and other residue which colors it grey. Although

bleaching Bleach is the generic name for any chemical product that is used industrially or domestically to remove color (whitening) from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically, to ...

is not necessary for all end-uses, it is vital for many graphical and packaging purposes. There are various methods of

, which are used according to a number of factors for example, the degree of colour change required, chemicals chosen and method of treatment. There are three categories of bleaching methods: * Bleaching by delignification using

chlorine gas Chlorine is a chemical element with the Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate betwee ...

, which is a method that has been largely replaced by procedures which are gentler to the environment such as the use of oxygen as a replacement for the chlorine gas. * Bleaching by

oxidation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a ...

using chemicals such as

chlorine dioxide Chlorine dioxide is a chemical compound with the formula ClO2 that exists as yellowish-green gas above 11 °C, a reddish-brown liquid between 11 °C and −59 °C, and as bright orange crystals below −59 °C. It is usually ...

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%� ...

sodium hypochlorite Sodium hypochlorite (commonly known in a dilute solution as bleach) is an inorganic chemical compound with the formula NaOCl (or NaClO), comprising a sodium cation () and a hypochlorite anion (or ). It may also be viewed as the sodium s ...

. * Bleaching by reduction using chemicals such as sodium bisulphite.

Plies

Multi-ply paperboard generally has higher creasing and folding performance than single-ply as a result of layering different types of pulp into a single product. In cases where the same kind of pulp is being used in several layers, each separate layer is treated and shaped individually in order to create the highest possible quality.

Coating

In order to improve whiteness, smoothness and gloss of paperboard, one or more layers of

coating A coating is a covering that is applied to the surface of an object, usually referred to as the substrate. The purpose of applying the coating may be decorative, functional, or both. Coatings may be applied as liquids, gases or solids e.g. Pow ...

is applied. Coated paper is usually made up of: * a

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compou ...

, which could be

china clay Kaolinite ( ) is a clay mineral, with the chemical composition Al2 Si2 O5( OH)4. It is an important industrial mineral. It is a layered silicate mineral, with one tetrahedral sheet of silica () linked through oxygen atoms to one octahedra ...

, calcium carbonate or

titanium dioxide Titanium dioxide, also known as titanium(IV) oxide or titania , is the inorganic compound with the chemical formula . When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. It is a white solid that is insolub ...

, usually a combination of two * an adhesive or binder as

styrene-butadiene Styrene-butadiene or styrene-butadiene rubber (SBR) describe families of synthetic rubbers derived from styrene and butadiene (the version developed by Goodyear is called Neolite). These materials have good abrasion resistance and good aging st ...

emulsions or starches and

water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...

. Additional components could be OBA ( optical brightening agents).

Grades

The DIN Standard 19303 "Paperboard - Terms and grades" (Publication date : 2005-09) defines different grades of paperboard based on the surface treatment (first letter), the main furnish (second letter) and the colour (non-D grade) or bulk (D grade only) (numbering). Example: GC1 would be a "pigment coated", "virgin mechanical pulp" board with a "white reverse side". Often the used paperboard type would be FBB, which was coated on both sides.

Common terms

Basis weight (US): Is the weight in of paperboard. Brightness: Brightness is a technical term that is defined as the amount of blue-white light that a paper reflects. This property is very subjective and individual to each buyer and end use, as skin colour and food are better reproduced on ‘warm’ (yellow) whites and not blue whites. Grammage: The grammage of the paperboard is assessed in accordance ISO 536. Grammage expresses mass per unit area and is measured in g/m². PH: Surface pH is measured on a water extract and is on a scale of 0–14. 0 is

acidic In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a ...

, 7 is neutral and 14 is alkaline. Stiffness: Stiffness is one of the most important properties of paperboard as it affects the ability of cartons to run smoothly through the machine that erects, fills and closes them. Stiffness also gives strength and reduces the propensity of a carton to bulge under the weight of settling flowable contents such as cereals. Although most paper strength properties increase with increasing sheet density, stiffness does not. A rule of thumb is that stiffness is proportional to the 1.6 power of sheet caliper. The species of fiber used has an effect on stiffness, other things being equal. Northern softwood species impart superior stiffness compared to southern softwoods. Other factors which affect board stiffness include coatings and moisture content. Smoothness: Smoothness is particularly important when being used for printing, the smoother the paperboard, the better the image quality, because of better ink coverage. Smoothness is measured using air leak methods – the greater the rate of air leakage, at a specific air pressure, from under a cylindrical knife placed on the surface, the rougher the surface. Caliper/thickness: In the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

caliper is usually expressed in thousandths of an inch (0.001”) or points, where a sheet of paperboard with a thickness of 0.024” would be 24 points. In

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

it is often sold in g/m², however the thickness of the board is measured in

micron The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Un ...

(μm). Paperboard also tends to be referred to with thickness rather than weight. Whiteness: It refers ideally to the equal presence of all colours, because a truly white sheet will reflect all

wavelengths In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tr ...

of visible light equally.

Paperboard industry

The paperboard sector is mainly looked at in conjunction with the paper industry. The Paper & Paperboard market size (2007) had a value of US$630.9 billion and a volume of 320.3 million metric tons. Of that market 40.1% is European. About 50% of all produced paper is used for packaging, followed by printing and writing. According to ProCarton, the consumption of paper and paperboard seem to correlate with economic trends (GDP). Sales of carton in Europe sum up to around 8 billion Euros worth. Over 1,100 printers produce 5.4 million tonnes of cartonboard yearly. Cartons make up one third of paper and board packaging and 15% of all packaging. A bit more than half (54%) of the European carton is produced using recovered fibre or waste paper. The paper and paperboard industry is quite energy and capital intensive. Just a coated board machine itself can cost around 90 - 120 million Euros (about 125 - US$166 million in 11/2011).

Economies of scale In microeconomics, economies of scale are the cost advantages that enterprises obtain due to their scale of operation, and are typically measured by the amount of output produced per unit of time. A decrease in cost per unit of output enables ...

apply, because of which a few large players often dominate the market place. E.g. in North America the top 5 producers have a market share of 85%.

References

External links

TAPPI
��Technical Association of the Pulp and Paper Industry {{Authority control Products introduced in 1817 Visual arts materials Coated paper English inventions Packaging materials Paper Pulp and paper industry es:Cartón fr:Papier cartonné it:Cartoncino ja:板紙 no:Massivpapp fi:Kartonki sv:Kartong