Department of Mechanical Engineering

Hamed Tsalloti Kashani

Principles of Chemistry, Paper Technology and Food

Technology

Report 2:

Paper Technology: Board and Cardboard Principles, Applications, and Manufacturing

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Abstract

LAPPENRANTA UNIVERSITY OF TECHNOLOGY

Hamed Tasalloti Kashani

Paper Technology: Board and Cardboard Principles, Applications, and Manufacturing

Principles of Chemistry, Paper Technology and Food

2011

19 pages, 5 figures

Keywords: Paper and board manufacturing, Board and cartonboard types and applications

The products made from pulp, paper, and paperboard have very important role in our

daily activities and our dependence on these products correspondingly and paper and

paperboard industry is obvious. Packaging has the largest usage of paper and paperboard

and this study provides basic necessary knowledge about the paper and board grades

which are available for packaging with focus on cartonboard grades. In this research the

requirements and applications of different cartonboard grades are discussed. The current

article also provides concise information about different steps of paper and board

manufacturing and the influences that those steps can have on the properties of the

product. This research can be used to get acquaintance to various ranges of packaging

paper, their characteristics, required characteristics, and the procedure of manufacturing

those papers.

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Table of Contents

Abstract ........................................................................................................................................... 2

Introduction ..................................................................................................................................... 4

1. Packaging paper .......................................................................................................................... 5

1.1. Board and Cardboard ........................................................................................................... 5

1.2. Cartonboard .......................................................................................................................... 6

1.2.1. Folding Boxboard (FBB) ............................................................................................... 6

1.3. White Lined Chipboard (WLC) ........................................................................................... 7

1.4. Solid Bleached Board (SBB) ................................................................................................ 7

1.5. Solid Unbleached board (SUB) ............................................................................................ 8

2. Paper and Board Manufacturing ................................................................................................. 9

2.1. Forming Section ................................................................................................................... 9

2.1.1 (Approach flow system) ................................................................................................. 9

2.1.2. Headbox ....................................................................................................................... 10

2.1.3. Wire Section ................................................................................................................ 10

2.2. Press Section ...................................................................................................................... 11

2.3. Dryer Section...................................................................................................................... 12

2.4. Surface Sizing .................................................................................................................... 12

2.5. On-line Coating .................................................................................................................. 13

2.5.1. Board ........................................................................................................................... 13

2.6. Calendaring ........................................................................................................................ 13

2.6.1. Board ........................................................................................................................... 14

2.7. Reeling ............................................................................................................................... 15

2.8. Paper and Board Machines ................................................................................................. 15

2.8.1. Cartonboard Machines ................................................................................................. 15

2.8.2. Coating of Paper and Board......................................................................................... 17

3. Finishing ................................................................................................................................... 18

4. Summary and conclusion .......................................................................................................... 18

Reference ...................................................................................................................................... 19

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Introduction

The paper and paperboard industry touch mankind practically every day and we are highly

dependent on the products made from pulp, paper, and paperboard. A wide range of paper and

board grades are available for packaging for various requirements and purposes. The grades

range of packaging paper from simple wrapping paper (WP, made from mixed recovered paper)

to kraft paper. Many different applications can be named for these grades including bags, beer

mats, carrier bags, gift wrapping paper. Different paper and board grades can be made from

various virgin pulps, recycled fibers or mixtures of chemical pulp and recycled fibers. Packaging

represents the largest usage of paper and paperboard and based on this fact this article’s focus is

on packaging paper especially cartonboard. It has been tried to all the main types of cartonboard,

and their basic properties and applications on which packaging made from these materials be

discussed.

Today, large papermaking machines operate continuously to prepare vast quantities of required

paper for versatile purposes. The second section of this report considers the raw materials and

manufacture of paper and paperboard. The aim of this research is to provide a preliminary yet

comprehensive knowledge about different cartonboard grades and also a proper understanding

about paper and board manufacturing process. For the latter case, the main steps of paper and

board manufacturing with the effect which each step can have on the web properties and final

result are investigated..

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1. Packaging paper

1.1. Board and Cardboard

Paperboard grades can be categorized into three groups: cartonboards, containerboards, and

specialty boards. This classification is demonstrated in Fig.1. Paper and board grades have a

basis weight less than 100g.m–2

and recently even lower than 80g.m–2

. Products with weights

over 600g.m–2

are usually called cardboards. Paperboards are commonly used for packaging

however, there are exceptions like plasterboard. Considering their function in the packages,

strength properties are generally very important for paperboards. Cartonboards are principally

used for consumer product packaging such as food, cigarettes, milk, and pharmaceuticals.

Containerboards (corrugated boxes) are used in various packaging applications ranging from

simple transportation containers to multicolor printed display containers for stores.

Figure 1. Classification of paperboard grades

Semichemical

Recycled

Cartonboards

Folding Boxboard

White Lined

Chipboard

Solid bleached

board

Solid unbleached

board

Unbleached

Bleached

Liquid Packaging

Board

Paperboard

Grades

Containerboards Special Boards

Linerbord

Brown

Kraftliner

Recycled

White Top

Coated White

Top

Mottled

Corrugated

medium

Core Board

Wallpaper Base

Plaster Board

Bookbinding Board

Woodpulp Board

Others

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1.2. Cartonboard

Cartonboard is pigment coated for clear printing, with dense, stiff outer layers and a bulky

middle thickness. Cartonboard usually consists of a multilayer material with three or more layers

of cellulose fiber (pulp) obtained from wood. The top layer generally has a white pigmented

coating. The opposite side may also be coated or may be white, brown, cream or grey depending

on the type of used fiber. The weight and thickness for most folding cartons are in the range of

200-600 g.m2 and 350-800 µm respectively.

Cartonboard is stiff, rigid with good toughness which provides compression strength to protect

products in distribution and use. It can be cut, creased, folded and glued, giving the structural

designer feasibility to produce functional and creative packaging. The surface is usually white

and smooth and provides the possibility to be printed by all the main printing processes.

Cartonboard can be embossed and hot foil stamped. It can be laminated to other materials, like

aluminum foil, extrusion coated with plastics, like PE, PP and PET, for improving its appearance

and performance.

1.2.1. Folding Boxboard (FBB)

As it is shown in Fig.2 FBB is composed of middle layers of mechanical pulp placed between layers of

bleached chemical pulp. The layer on top or liner is normally white pigment coated in 2 or 3 layers. The

back side is cream as the back layer of chemical pulp is translucent enabling the colour of the middle

layers to appear through. The back layer of chemical pulp is possible to be thicker and/or be white

pigment coated. In this case the board is known as White Backed Folding Box Board (WBFBB). FBB

also may be plastic extrusion coated, laminated with materials such as aluminium foil and greaseproof

paper (GRFBB), and other functional treatments.

Figure 2. Folding paperboard (FBB) appearance and construction

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FBB has a wide diversity of applications including cosmetics, chocolate and confectionery, dry

foods, frozen and chilled foods, medical and healthcare, toiletries, baked goods, tea and coffee,

biscuits, clothing, toys, games and photographic products.

1.3. White Lined Chipboard (WLC)

As it is shown in Fig.3 WLC comprises middle layers of recycled pulp made from mixed

recovered papers or carton waste. The top layer has either pulp made from selected recovered

papers or bleached chemical pulp. Recovered paper pulp is used for the back layer as well. The

overall content of recycled pulp differs from around 80% to 100%. The top surface generally has

two or three layers of white pigment coating and it is recently common to have a layer of

pigment coating on the back. WLC may be made with a white (WBWLC), grey or, sometimes,

brown reverse.WLC is used in an extensive range of applications including shoe boxes and

shoes, toys and non-food products.

Figure 3. White lined chipboard (WLC) appearance and construction

1.4. Solid Bleached Board (SBB)

Solid Bleached Board is made exclusively from bleached chemical pulp. It regularly has two or

three layers of a white pigment coated top surface and some grades are also coated on the reverse

(see Fig.4). SBB possesses outstanding printing, structural design and embossing properties

which make it ideal for luxury products and for products that preservation of flavour, aroma, and

also hygiene are critical. SBB is used for perfumes, cosmetics, chocolates, pharmaceuticals,

frozen foods and cigarettes packages (Fig.5).

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Figure4. Solid Bleached Board construction

Figure5. Application examples of Solid Bleached Board (SBB)

1.5. Solid Unbleached board (SUB)

Where very high strength (puncture, tear, etc.) or good wet strength properties are required SUB

can be used. SUB is used as carrier board and in addition to folding cartons it is used for

multipack applications in canning and bottling. The principal end use of this SUB is for

packaging of frozen or chilled food, cereals, toys, beverage carriers, detergent, shoes, etc. Solid

unbleached board is commonly composed of entirely unbleached chemical pulp and has brown

colour. The printing surface for many carton applications has a white pigment coating or a top

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layer of bleached chemical pulp plus coating. It is also known as SUS (Solid Unbleached

Sulphate).

2. Paper and Board Manufacturing

2.1. Forming Section

The purpose of the forming section is to produce a continuous wet paper web of a specific basis

weight and of the required uniform quality parameters in both cross machine (CD) and machine

directions (MD). This is completed by

feeding a continual volume rate of suspension of constant uniformity and furnish ratio to

the headbox (approach flow system)

Distributing the suspension in the cross direction of the paper machine equally,

accelerating it and transferring a suspension jet of high constancy to the formation section

(headbox)

Dewatering the suspension and hence forming an endless web (wire section)

2.1.1 (Approach flow system)

The approach flow system can be defined as the connection between stock preparation and

the headbox of the paper machine and following operation is done by it:

1. Metering and mixing the various stock components,

2. Diluting and mixing them with other components such as fillers, chemicals and

additives

3. Cleaning, deaeration and screening,

4. Feeding the components to the headbox.

The above mentioned operations control a continual flow rate of the suspension at steady

pressure, constant consistency and compound to achieve a uniform basis weight distribution

in the paper. Final cleaning and screening of the suspension are implemented in many

occasions to prevent wear or damages in the paper machine, for example rolls, clothings,

foils. In addition it is applied to improve the final paper quality in terms of cleanliness.

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2.1.2. Headbox

The objective of the headbox is to spread evenly the suspension in the cross direction of the

paper machine and to provide a suspension jet of high uniformity and about machine speed to the

wire section. Dewatering of the suspension occurs in this section and headbox is a critical

element in the paper machine defining various important quality parameters of the finished

paper. Crucial requirements for proper sheet formation are the breaking of fibre flocs that have

already formed, and the prevention of flocculation, at least for a short time until the suspension is

transferred to the wire.

It can be presumed that the fibres in the suspension jet are randomly orientated in the three

dimensions, the suspension flow on the wire is parallel to the machine direction and the wire

itself has no velocity difference, thus, the fibres remain randomly oriented on the wire. When a

certain velocity difference is applied between the suspension and the wire, the amount of fibers

laid down in the machine direction throughout web formation is larger than in the cross machine

direction. The fibres tend to align chiefly in the direction of the velocity difference between the

suspension and the wire which can cause alteration in the web characteristics, such as tensile

strength or stiffness. Additionally it can influence the shrinking and expansion behaviour of the

web during drying and when the finished paper sheet is exposed to heat or moisture.

2.1.3. Wire Section

Wire section, forms a fibre web form the suspension provided by the headbox. The quality of the

paper web formed is significantly dependant on the kind and quality of suspension delivery from

the headbox to the wire. The main goals of the wire section are:

1. Comprehensive separation of fibres from water (drainage)

2. Orderly deposition of the fibers on the wire (oriented shear)

3. Hindrance of excessive fibre flocculation (turbulence).

The separation of the fibers from water is integrated with filtration and thickening process.

During pure filtration a filter cake is accumulated above the auxiliary filter layer while the

consistency of the suspension above the filter cake stays the same as before. Pure thickening

means that the consistency of the suspension is increased. For dewatering the fibre suspension

the driving forces can be hydrostatic, vacuum or mechanical.

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After the wire section the dry content generally is about 18–20%. The removed water within the

filtration process (white water) carries away fibres, fines and fillers. The solids percentage of the

suspension kept on the wire (retention) can be increased by adding retention aids. The white

water is reused in dilution of the thick stock in the stock approach flow system. The velocity

between the jet and the wire is determining for the controlled deposition of the fibers on the wire.

If the jet and the wire velocity are identical, the fibres will be deposited with random orientation

or according to a possible pre-orientation in the headbox nozzle. If the jet is slower or faster than

the wire, more fibres are aligned in the machine direction. The tensile strength of paper has its

highest value in the direction of the main fiber orientation. The relationship between the

properties in the longitudinal and cross directions is frequently important in the processing and

use of paper. Therefore, depending on the different paper grades, the difference in the range of

jet to wire velocity is about 15 to 70 m.min–1

. If the main fibre orientation is not in the machine

direction, it can be problematic and lead to diagonal sheet stress in certain types of paper (e.g.

copying paper). The properties of the wire, which performs as a filtering auxiliary layer,

influence the surface properties of the web (wire mark), fibre orientation, retention, dewatering

velocity, and machine operation.

2.2. Press Section

The target of the press section is to use compression in order to increase the dry content of the

paper web as much as possible. This is a mechanical dewatering procedure which reduces steam

consumption in the dryer segment and increases the web strength that helps to prevent web

breaks within production. The wet paper web is received from the wire section and then is

conveyed by felts through the press section which has one or more press nips to be passed. The

press nip is fulfilled between two opposing rolls pressed together.

Different kinds of felts are chosen for the top or bottom positions in the single nip as well as for

the various press nips, considering the press water flow and the target of sheet transfer. Suction

pipes are used for the dewatering of the felts. A conventional press section normally consists of

three to four consecutive press nips which can provide linear forces of 20–150 N.mm–1

and even

more than 300 N.mm–1

in some special designs. Since the fibre structure resistance at the

increases with higher dry content which the dewatering pressure must be elevated accordingly.

However, too high pressure may damage the paper web especially at higher moisture content.

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Nowadays, after press section the dry content reaches to about 50 to 55%, depending on the

product and the raw material used. Due to high dry contents, less thermal energy is needed in the

dryer section, and the resulting increased web strength results in less breaks. In modern paper

machines, particularly in the press section, the web is almost always supported by a felt, belt or

wire, or by the surface of a roll and is not conveyed freely.

2.3. Dryer Section

The function of the dryer section is to increase the content of dry paper web, commonly to 90–98

%, by evaporation. During drying, the fibres develop hydrogen bonds which provide the natural

strength of the paper. Drying is a joined process of heat and mass transfer in the way that heat

has to be transferred from a heat source to the paper and the evaporated water has to be removed.

During drying, the paper web which has been received from the press section has to be directed

safely all over the dryer section to the reel where it is wound up. Some dryer sections comprise a

size press for improving paper strength and/or breaker stack for pre-calendering.

2.4. Surface Sizing

Sizing process is applying a certain liquid media to the web surface such as a starch solution, a

sizing agent, or a mixturethereof and some paper machines contain this unit. The main purposes

of sizing are to increase the strength of the paper, and to modify the surface properties

concerning liquid uptake during writing, printing, or coating.

Sized papers considerably have higher strength that is important for some applications like, liner

and corrugated media, and other packaging papers as well as for graphic papers. For increasing

tensile strength, penetration of the size into the paper is required; however, when the main goal is

increasing surface strength, for instance for printing, the size should remain on the surface.

Sizing can also reduce the penetration of liquids into the paper and it is beneficial for example, to

prevent the ink spread when writing or printing onto the paper. The same outcome is desired for

coating base papers, since sizing improves the coating resist in the succeeding coating process.

Sizing is generally performed in a size press or a film press. In a size press, the web is transferred

through a pond of the sizing agent, which is located above a roll nip consequently, due to both

capillary action in the pond and the hydraulic pressure in the roll nip, the paper web absorbs the

sizing liquor. The amount of size pick-up and its penetration degree depends to the pond height,

the concentration and viscosity of the size, and the absorption behaviour (porosity, temperature,

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moisture content, etc.) of the paper web, and the pressure length of the nip. Due to pond

turbulences, which become unacceptable, the speed of size press is restricted approximately up

to 1000 m.min–1

. There are limitations for size concentration and pick-up as well. The modern

film press overcomes these limitations. In a film press, a film of the application medium is

formed on the rolls and is then transferred to the paper web in the roll nip. To meter the applied

film, a profiled (or grooved) rod is usually used. The applied water in the size press increases the

moisture content of the paper web from about 2–4 % to 60–75 % and this water should be

evaporated in the after-dryer section.

2.5. On-line Coating

Papers of high surface quality receive a pigment coating. Traditionally, the application of this

coating for graphic papers was off-line and performed in a separate coating machine. The

advantage of on-line coating compared with off-line coating, is a considerable reduce of total

machine size since, a winder and an unwind station as well as a re-reeler can be omitted which

directly impacts on investment and personnel costs. In addition, paper losses through the extra

winding and unwinding process are avoided. These losses sometimes can reach up to 1% of the

entire production. However, if a web break occurs in an off-line coater, the paper machine can

continue production and the off-line coater will keep up with a higher machine speed while with

an on-line coater, the entire line has to terminate production because of the failure at a coater

station. Hence, it can be presumed the time efficiency of an on-line machine would be lower than

that of a paper machine with a separate off-line coater.

2.5.1. Board

Board as was discussed in pervious sections has high basis weight, a relatively high absolute

strength. Additionally board is produced at much lower speeds than packaging or graphic papers.

Therefore, it is less sensitive to web breakage and the coating of board is mostly done online.

2.6. Calendaring

Calendering is performed by pressing the paper web in one or more rolling nips formed by rolls

with special properties. The purpose of calendering is to modify the surface properties of paper

concerning its further use, such as printing. Depending on the individual grades, the focus is put

on different technological characteristics which chiefly are:

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• Gloss

• Brightness

• Blackening

• Opacity

• Smoothness/Roughness

• Density

The major prerequisites for a proper print quality are printed gloss and printing smoothness

which both are mostly dependent on the gloss of the paper, its smoothness/roughness, its

levelness, and compressibility. High printed gloss provides the printed product the required shiny

appearance, while high (printed) smoothness is determining for the evenness and density of print.

A series of explanations theoretical basis of calendering exist. Some scientists believe that

smoothness and gloss result from slipping of the paper in the nips. Some hold the view that

calendering is a flattening process where the smooth surface of the hard rolls is replicated on the

side of the web that contacts the hard roll. Others argue that it is the shearing action in the nip is

the source of gloss and smoothness by aligning the surface fragments of the web. All agree on

the influence of heat that softens the cellulose fibers (glass transition point) and thus enhances

the development of gloss and smoothness. Smoothing the surface and increasing gloss are

accompanied by decrease in calliper, brightness, strength properties and opacity to a certain

degree. The strength properties of the paper are crucial for the runnability of the web in the

printing machine. Brightness and opacity have a distinctive impact on the print quality.

Blackening occurs when parts of fibers have collapsed under pressure. Under transmitted light

the respective areas appear glassy, whereas under incident light they appear as darkened areas.

This is still escalated by the printing process, i.e. the light full tone areas turn murky gray.

2.6.1. Board

2.6.1.1. Uncoated Board

Uncoated boards comprise a large diversity of sub-grades like test liner, white top liner, kraft

liner, liquid container board etc. Some of these grades do not need any calendaring. Where

calendering is demanded to achieve better surface properties, Yankee cylinders and soft

calenders have been used. As with coated grades, this traditional technology is about to be

replaced by extended nip calendering.

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2.6.1.2. Coated Board

Coated board grades range from one to five ply boards and can be composed of intact fibres

and/or recycled fibres. The most important properties are high bulk, smoothness and stiffness.

The board is usually one-side coated. In some cases, however, it can also be two-sided.

Traditionally, calendering has been performed with Yankee cylinders or soft calenders. In

consideration the bulk saving, this classical technology is increasingly being superseded by

extended nip calendering.

2.7. Reeling

The objective of reeling is to wind up the continuously produced paper web on reel spools

building up paper rolls of up to 4.5 m diameter. The paper rolls have to meet the requirements of

any subsequent process phases which principally concern the paper roll structure such as

hardness and overall shape. Reeling is a discontinuous process economic aspects concerning

broke due to roll change/turn-up are also important.

2.8. Paper and Board Machines

Traditionally papermaking fourdrinier and mould formers have been utilized for the production

of all kinds of paper and board. Since the last century the machines started to be more

customized to the special requirements of the each product grade, based on quality, operational

requirements and economy. According to the scope of this research cartonboard machine is

discussed here.

2.8.1. Cartonboard Machines

As was explained before cartonboard is a product with a wide range of basis weight from nearly

160 to more than 600g.m–2

. About 80 % of the total paperboard production is cartonboard which

is used for wide variety of production including carton boxes to pack food, cigarettes,

pharmaceuticals or cosmetics. In addition a diversity of specialty boards exists for instance art-

board, playing-card board, gypsum board, bookbinders board etc. As the requirements for these

board grades is considerably different, the furnish and the board machine design may differ

parallelly. Some of the basic required properties are:

• Mechanical properties like bending stiffness (bulk, Young’s modulus), to preserve the

packed goods against damage.

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• Flatness, plybond, creasability, punching, to guarantee good runnability in converting and

packaging lines.

• Resistance to moisture, gas and flavor, to protect the product from quality changes.

• Freeness from impurities such as micro-organisms, toxic or mutagenous substrates, taint

or odour, to preserve the goods against contamination.

• Brightness, gloss, printability of the surface, and roughness to ensure appealing

information, identification and promotion of the packed goods.

Paperboard generally has a multi-ply structure to meet the different product requirements in the

most economical and environmentally friendly way. The surface plies (top and back plies)

should have the proper strength properties (bending stiffness) and, together with the coating, the

required surface quality. With the inner plies (under-top and filler plies) the bulk is optimized

(affecting bending stiffness). Most cartonboards are on-machine coated and calendered to

acquire appealing surface characteristics.

Depending on the product and the geographic position of the board producer, virgin or recycled

fibres or both fibre types are used as raw material. In multi-ply production the individual plies

are shaped on separate forming units and couched together in wet condition. Two layers can also

be formed in one forming unit is also done. Different forming principles as described below have

been and are applied either uniquely or in combination with others. Cylinder formers in series

with suction chambers fabricate webs of about 25 to 100 g.m–2

each which are couched on a

transfer felt, thus making the baseboard. Inside the fourdriniers and hybrid formers each ply is

formed on a separate fourdrinier wire. Hybrid formers are used e.g. to make the filler ply with

the widest basis weight range and highest basis weights which require prolonged dewatering

capacity. The headbox and wire section have to be matched to the high yield ratio and to the high

surface quality requirements for coating and printing. The press components of modern machines

for cartonboard are designed for high dewatering capacity, high bulk, smoothness and good

runnability. The press unit commonly has three press nips, e.g. a first double-felted suction press

nip followed by a double felted shoe-press nip and finally an unfelted smoothing press or a single

felted roll press to increase surface smoothness. The dryer unit comprises of up to 100 drying

cylinders in the pre-dryer section and about 16 in the after-dryer section. For fine flatness of the

finished product the top and the bottom cylinder rows are heated individually to control curl

tendency. Starch or size can be applied by either a film press or a pond size press to improve

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surface strength and bending stiffness in this case an after-dryer section is required for baseboard

drying. Before coating, the roughness of the baseboard has to be lessened by calendering. In

modern board machines this is accomplished by a heated hard-nip calender. As an alternative

soft-nip calenders can be implemented for reduced densification. The latest development is the

shoe-nip calender which integrates long dwell time, low specific pressure and high roll surface

temperature to obtain minimum roughness at lowest densification. Virgin-fibre based

cartonboard is chiefly double coated on the top side and uncoated or single coated on the back

side. White-lined chipboard made of recycled fibres is primarily triple-coated on the top side and

uncoated or single-coated on the reverse side, each layer with special tasks and coating

formulations. Coating is fulfilled by roll applicators or by free jet applicators for highest surface

requirements and machine speeds. Final cartonboard post-calendering is mainly performed with

soft-nip calenders.

2.8.2. Coating of Paper and Board

The main reason for coating is to increase the surface quality of paper or board. The demanded

improvement in surface quality can be optical properties such as brightness, gloss or opacity, or

tactile properties such as smoothness, but, most importantly the printability and print image

quality. The application of (commonly white) pigments to the base paper surface increases the

brightness of the paper. Moreover, the opacity increases due to the high light scattering of the

pigments. This improves the optical appearance, because the shine-through of the back side

printing is reduced. The coat layer also evens out the surface topography of the sheet, resulting in

an improved smoothness, which respectively gives a better gloss. The coat layer diminishes the

penetration of ink into the paper sheet and prevents the ink spreading which yields clear and

sharp. It also enhances the print density and the print gloss, thus, ink demand is reduced

compared to uncoated papers. The coat layer in specialty papers can have functional properties.

The thermo-sensitive layer of thermal papers or the capsule-containing coat layers of carbonless

papers are examples. Paper surface quality can be further increased by the application of a top

coat. Coating the paper with another 12 g.m–2

per side notably enhances the existing pre-coated

surface quality.

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3. Finishing

The term of finishing is a summarization of the process steps after the paper machine, i.e. reel

slitting and roll packaging, format cutting and packaging of the formatted sheets, also offline

calendering, and sometimes offline coating. Reel-slitting converts the large parent reels from the

paper machine into appropriate size rolls, to be delivered to the (external) customer after being

suitably packed, or for further in-house processes such as sheet cutting. The feed into the sheet

cutter is pre-cut reels of up to 2.5 m. The sheet cutter cuts the web into separate sheets. The

individual sheets are automatically piled and packed.

4. Summary and conclusion

In this research different paperboard grades were presented and form this category

cartonboard group including: folding boxboard (FBB), white lined chipboard (WLC), solid

bleached board (SBB), and solid unbleached board (SUB) were scrutinized with more details

and also the application of each type was discussed.

In the second section of current report main steps of manufacturing paper and board

comprising: forming section, press section, dryer section, surface sizing, coating, calendaring,

and reeling were investigated. It was also tried to the impact of each step on the product

characteristics be explaned and also the orientation of this research towards cartonboard be kept.

Finally paper and board machine and finishing step were briefly explaned.

From this article the vast different application of paper and board materials with their wide ranges

of grades can be conceived.

The versatile characteristics and mechanical properties of different paper and board gardes and

also the influence of each step of production procedure on these properties can be concluded.

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Reference

Herbert Holik, (2006) Handbook of Paper and Board, 6th edn, Wiley-VCH Verlag GmbH & Co.

KgaA, Wennheim, Germany