What are virgin fibres? What is a bale? What is sludge? What is corrugated board? Use the list below to find out.

Absorbency

The ability of paper to absorb fluids such as water or printing ink

Acidification

Decrease in the pH of soil and water due to precipitation containing dissolved ammonium compounds, sulphur and nitrogen oxides; an indirect cause of forest damage

Activated sludge treatment

A biological method of cleaning up waste waters in three stages. Stage I involves (anaerobic) equilibration. In stage II activated sludge containing micro-organisms is led into an aeration basin to speed up oxidation of organic matter and ammonia. In stage III the sludge is allowed to settle and the treated waste water is run off. Some sludge is removed and a portion is returned to the aeration basin

Aerated lagoon

A biological waste water treatment method in which air (oxygen) fed into an aeration basin reduces the effluent load

Air drying

Method of drying the paper web on the paper machine by blowing air along the direction of the web

Air mail paper

Light weight, thin and mainly woodfree writing papers for air mail. Anaerobic treatment Process employing micro-organisms to reduce organic matter in waste water in the absence of oxygen

Annual ring

See Growth ring

AOX

Absorbable organic halogens. AOX is a sum parameter measuring total concentration of chlorine bound to organic compounds in waste water. AOX measures all chlorine compounds both harmful and harmless (a sum parameter)

Art paper

High quality and rather heavy two-side coated printing paper with smooth surface. The reproduction of fine screen single- and multicolour pictures ("art on paper") requires a paper that has an even, well closed surface and a uniform ink absorption

Artificial parchment

Woodfree paper that is produced by fine and extended grinding of certain chemical pulps and/or the admixture of special additives. As a result of the "smeary" grinding, the fibre structure closes homogeneously. It is used e.g. for wrapping meat and sausages or as corrugating medium for biscuit packaging

Artificial regeneration

Forest regeneration by sowing or planting, usually after final felling

Auxiliary chemical

A chemical added to a stage of paper-making aimed at improving the efficiency of a part of the process.

Back-pressure power

Generation of both heat and electricity from fuel; gives greater efficiency than condensing power

Bale

Solid, compressed stack of pulp or paper sheets

Banknote paper

Highly resistant, age-resistant, suitable for 4-colour printing, with watermark and other falsification safeguards such as embedded metal strip. Often containing cotton fibres (See "Rag paper")

Basis weight

See Grammage

Bast

Fibres located in the inner bark layer of trees and in outer portions of other fibrous, woody plants.

Bible paper

Woodfree, sometimes rag-containing speciality printing paper with a low grammage, mostly with a high filler content

Biodegradation

Breakdown of organic matter by micro-organisms into carbon dioxide and water or into less harmful compounds

Biological waste water treatment

A method of cleaning up waste water using living micro-organisms such as bacteria. See: Activated sludge treatment, Aerated lagoon, Anaerobic process

Biosludge

Sludge formed (in the aeration basin) during biological waste water treatment or other biological treatment process

Black liquor

Black liquor is a byproduct of the kraft process , one of the processes used by pulp mills during the production of paper pulp. Wood is decomposed into cellulose fibers (from which paper is made), lignin fragments and hemicellulose . Black liquor is an aqueous solution of lignin residues, hemicellulose, and the inorganic chemicals used in the process. The black liquor contains more than half of the energy content of the wood fed into the digester. The invention of the recovery boiler by G.H. Tomlinson in the early 1930s, was a milestone in the advancement of the kraft process. Most kraft pulp mills use recovery boilers to recover and burn much of the black liquor they produce, generating steam and recovering the "cooking chemicals" (sodium hydroxide and sodium sulfide used to separate lignin from the cellulose fibres needed for papermaking). This has helped paper mills reduce problems with water emissions, reduce their use of chemicals by recovery and reuse, and become nearly energy self-sufficient by producing, on average, 66 percent of their own electricity needs on-site.

Bleach plant

Department of a pulp mill where pulp is bleached

Bleached lined folding boxboard

Bleached lined folding boxboard is a multi-layer paperboard that has a bleached woodfree liner on one or both sides. Between two liners there are intermediate layers and middle layers of mechanical or waste paper pulp

Bleached pulp

Pulp whose natural brightness has been improved using chemicals

Bleaching

Removal or modification of coloured components in pulp to improve brightness. Bleaching is normally carried out in several consecutive stages

Blotting paper

Bulky, highly absorbent, filler-free paper which is mostly produced from pure cotton in the form of bleached linters and from chemical pulp

Blue stain

Discolouration of wood or sawn timber caused by blue stain fungus

Board

Generic term for stiff paper usually made in several layers with a substance normally varying from 160 to 500/g/m2, for certain grades even higher; widely used for packaging (e.g. folding cartons) and graphic applications

Book paper

Woodfree or mechanical paper used for printing book

Brightening

Addition of optical brighteners to the stock to make the pulp/paper appear whiter

Brightness

A measure of the whiteness of pulp and paper

Broke

Papermakers own waste paper created during papermaking process it is usually repulped

Brush glazing

Glazing of coated paper with the aid of brushes

Bulk product

A mass-produced product sold in large volumes without individual specifications, usually in compliance with a standard. For example, newsprint

Cable paper

See "Electrical insulating paper"

Calcium carbonate

Used in papermaking as a filler or coating pigment

Calender

Machine in which paper is given a glazed finish by passing it between two or more rolls, either on or off the paper machine

Calendered paper

Paper that has been smoothed and compacted between the rolls of a calender and is thus more or less glossy (sharp or matt calendered). The effect produced in the calender unit is the result of friction combined with temperature and pressure

Caliper

Thickness of paper, usually measured in nanometers

Cant

Log that has been roughly squared by either chipping or sawing. Ready for sawing into timber

Capacitor paper

See "Electrical insulating paper"

Capacity utilisation rate

Indicates the efficiency (%) at which a mill or machine is operating

Carbon cycle

After use and recycling wood-based products, such as paper, decompose releasing carbon into the atmosphere as carbon dioxide. New forests remove carbon dioxide from the atmosphere, and established forests retain the carbon dioxide

Carbon dioxide (CO2)

Produced by burning coal and other carbon containing products. Burning fossil fuels or wood based products raises atmospheric carbon dioxide levels

Carbon paper

Carbon paper is a thin paper with a waxy coating, that is used to produce carbon copies on typewriters or other office equipment. Carbon base paper is made from chemical pulp

Carbonless copy paper

Paper that permits making multiple copies without intervening layers of carbon paper. The paper translates pressure into a dye reaction which transfers the image to the copy. Carbonless copy papers are mainly used for continuous form sets, for cov-ered pay slips, for vouchers to be dispatched by post and for payment forms. In the US and some other countries, carbonless copy paper is also called NCR paper (= Non Carbon Required)

Cast-coated paper

Cast-coated papers are coated papers that have obtained their high gloss by moulding on a highly polished, chromium plated drying cylinder

Causticizing

Process by which green liquor from sulphate pulping is converted to white liquor, thus allowing the cooking chemicals to be reused

Cellulose

Structural material giving strength to wood cells

Chemi-thermomechanical pulp (CTMP)

Chemi-mechanical pulp produced by treating wood chips with chemicals (usually sodium sulphite) and steam before mechanical defibration

Chemical oxygen demand (COD)

The amount of oxygen consumed in complete chemical oxidation of matter present in waste water; indicates the content of slowly degradable organic matter present.

Chemical pulp

Pulp in which wood fibres have been separated by chemical, rather than mechanical, means
Sulphite pulp: produced by cooking wood chips in a pressure vessel in the presence of bisulphite liquor. End-uses range from newsprint, printing and writing papers, tissue and sanitary papers. The sulphite can be either bleached or unbleached.
Sulphate (or kraft) pulp: pulp produced by cooking wood chips in pressure vessels in the presence of a sodium hydroxide (soda) liquor. The pulp may be unbleached or bleached. End-uses are widespread, with bleached pulp particularly used for graphic papers, tissue and carton board, wrappings, sack and bag papers, envelopes and other unbleached speciality papers.

Chemicals recovery

In chemical pulping, the recovery, treatment and regeneration of cooking chemicals

China clay

Mineral (kaolin) used in papermaking as both filler and coating pigment

Chipboard/Grey board

Paperboard made from waste paper pulp, rough or machine glazed, also lined on one or two sides or unlined

Chips

Wood chips produced by a chipper; used to produce pulp, fibreboard and particleboard, and also as fuel

Cigarette paper

This light weight, unsized paper (grammage 18 to 24g), converted to improve glowing. It normally has a filler content of approx. 30%

Clarification

Separation of a solid component from a solution

Clarifier

Basin where sludge is removed from treated effluent by settling; see Activated sludge treatment

Clear cutting

A harvesting method where almost all trees within a certain area are cut. Afterwards, this area is reforested by planting, sowing or through natural seeding from seed trees. (Also Final Felling)

Coated paper

The uniform application of a coating yields a more even and more closed surface of printing papers, which is suitable for the reproduction of fine screen artwork. The coating is applied in separate coaters or in the paper machine

Coating

Process by which paper or board is coated with an agent to improve its brightness and/or printing properties

Coating colour

Mixture used to coat paper and board: contains pigment, binder, special additives and water. Also coating slip

Coating colour kitchen

Department where coating colour is prepared and mixed

COD

See Chemical oxygen demand

Combined deinking

Deinking process combining flotation and washing; cf. flotation deinking, washing deinking

Condensing power

Power generation in which fuel is burned for electricity production only

Consistency

Dry solids content (%) of pulp present in a pulp slurry

Continuous cooking

A method used in chemical pulping in which raw material is fed continuously into the digester, while at the same time pulp and black liquor are removed (cf. batch cooking)

Converting

The operation of treating, modifying, or otherwise manipulating the finished paper and paperboard so that it can be made into end-user products

Cooking

A process for producing chemical pulp by treating wood with a cooking liquor at a certain temperature and pressure

Cooking liquor

Liquor made up of selected chemicals and used for cooking pulp

Copying paper

Copying paper is an uncoated paper in woodfree or mechanical grades, white or col-oured in A4 and A3.

Core

The tube, usually made of paperboard, on which a paper roll is wound

Corrugated board

Corrugated board is produced by guiding a paper web, the corrugating medium or fluting, through a slit between two corrugated rolls and pressing it into a waveform through a combination of pressure and heat. In the same machine, an even paper web (facing or liner) is then glued on to this corrugated paper on one or both sides. See "Kraftliner".

Corrugating medium

Papers used as fluting for the production of corrugated board.

Critical load

Highest pollutant load that, in the long term, does not damage essential characteristics in an ecosystem

CTMP

See chemi-thermomechanical pulp

Cutting

Cutting down trees and sorting the stems by species

Cutting site/area

Part of a marked stand of trees set aside for loggers or machines

Dandy roll

A cylinder on a paper machine used to improve formation; also wire roll

Decor paper

Woodfree, white or single-colour paper, often printed with various patterns, e.g. wood grains. The final product consists of laminated boards or directly coated particle boards used for furniture production.

Defibration

Separation of wood fibres by mechanical and/or chemical means

Defoliation

Premature loss of leaves or needles due to airborne pollution or other factors interfering with vital processes in trees. Used to refer to trees that have lost over 20% of their leaves or needles

Deinkability

Suitability of recovered paper for deinking; depends on paper grade, printing process used, age of paper, and other factors

Deinked pulp (DIP)

Paper pulp produced by deinking of recovered paper. Pulp made from recovered paper from which inks and other contaminants have been removed.

Deinking

Removal of printing ink and impurities from recovered paper; to produce recycled fibre pulp with maximum whiteness and purity

Deinking loss

Unwanted loss of solid material from pulp during deinking (usually 10-40%)

Delignification

The removal of lignin, the material that binds wood fibres together, during the chemical pulping process

Deposit

Mass of airborne pollutants deposited on a unit area of land or water in a given time, e.g. grams per square metre per year (g/m2/a)

Deresination

Reducing the resin (pitch) content of wood prior to cooking either by storage or using bleaching chemicals to reduce the resin content in pulp

Digester house

That part of a chemical pulp mill where cooking takes place

Dip Sizing

The drying completed, the old papermakers dipped their paper into an animal size that had been made from the parings of hides, which they procured from the parchment-makers. It was necessary to size that paper so that it would be impervious to ink, but sizing was more needed in writing than in printing papers. Many books of the fifteenth century were printed upon paper that had not been sized, this extra treatment not being essential for a type impression. The sizing was accomplished by a worker holding a number of sheets by the aid of two wooden sticks, and dipping the paper into the warm gelatinous liquid. The sheets were then pressed to extract the superfluous gelatine. This crude method of sizing the paper was extremely wasteful as many sheets were torn and bruised beyond use. The sizing room of the early paper mills, was, for this reason, known as the ‘slaughter-house.

Direct cooking

Cooking in which heating is achieved by blowing steam into the cooking liquor

Dispersion

The separation of a substance into the smallest possible particles using another substance (the medium). Used in papermaking to homogenize pulp properties and remove impurities

Dissolving pulp

A chemical pulp grade used, for example, in the production of acetate and viscose fibres and cellulose films

Document paper

Document paper is paper with a high ageing resistance. It is woodfree but may also contain rags or be fully made from rags and is used for documents that have to be preserved for a longer period

Double coating

Coating of paper or board twice on one or both sides

Drainage

Formation of a paper or board web on the wire by removing water at the paper machine wet end

Drawing paper

The range of drawing papers includes woodfree and mechanical grades with proper-ties that are tailored for specific drawing techniques. They have a low opacity and are erasure proof and often also wash-fast

Dry coating

Coating method in which a binder is applied to the paper surface followed by dry coating pigment

Dry creping

Creping of a dry paper web

Dry end

Final part of the paper machine from the drying section onwards

Dry solids

Mass of dried sample as a percentage of mass of original sample

Dry strength

Mechanical strength of a dry paper sheet (includes tensile strength, tearing resistance and folding endurance)

Duplex board

Duplex board consists of two layers, mostly made from waste paper pulp. It is used for packaging purposes

Ecosystem

The plants, animals and microbes that live in a defined zone; e.g. the forest ecosystem

Elastic strength

The ability of paper or board to resist stress acting in the plane of the sample

Electrical insulating paper

Strong, pore-free paper, sometimes impregnated with synthetic resins, made from chemical pulp. Electrical insulating paper must neither contain fillers nor conductive contaminants (metals, coal, etc.) nor salts or acids. Cable papers, that are wound around line wires in a spiral-like fashion, are electrical insulating papers with a par-ticularly high strength in machine direction. Electrical insulating papers also include electrolytic papers and capacitor paper

Electrostatic precipitator

Used to clean up flue and process gases. Removes 99.5-99.8% of dust particles emitted from recovery boilers, lime kilns and bark-fired boilers

Emulsion coating

Coating of paper with an emulsion containing plastic or resin

Envelope paper

Envelope paper can be woodfree or wood-containing, machine glazed or calendered, white or in colour and is used for envelopes. It must be opaque, writable, and printable and must have a high folding strength

Enzyme bleaching

Bleaching technique in which cooked and oxygen-delignified chemical pulp is treated with enzymes prior to final bleaching. Allows pulp to be bleached without chlorine chemicals

Evaporation plant

Unit used at pulp mills to concentrate spent liquor to make it suitable for burning and chemicals recovery

Extended cooking

Method of cooking pulp to low lignin content, thereby reducing the need for bleaching chemicals

Fibre loss

Loss of fibre material in pulp and paper processing

Fibreboard

Board made from defibrated wood chips, used as a building board

Fibrillation

A structural change occurring in the walls of chemical pulp fibres during beating

Filler

Pigment, added to papermaking stock to improve properties such as opacity and smoothness, and often to reduce cost

Filler content

Percentage of filler in a paper

Filter paper

Unsized paper made from chemical pulp, in some cases also with an admixture of rags, sometimes with a wet strength finish. Filtration rate and selectivity, which are both dependent on the number and the size of the pores, can be controlled by specific grinding of the pulps and creping

Fine paper

High-quality printing, writing or copy paper produced from chemical pulp and usually containing less than 10% mechanical pulp

Fine paper

Quality term for a large number of woodfree printing papers, based on chemical pulp with usually less than 10 % mechanical pulp. Sometimes fine paper also is made with an admixture of rags or wholly from rag pulp

Flame resistant paper

Flame resistant paper may ignite but must extinguish immediately so that it chars. This property is imparted to the paper by impregnation with certain chemicals

Flong paper

A pulp-like, coated-type paper

Flotation deinking

Deinking process in which air is blown into a dilute fibre suspension. Ink particles adhere to the air bubbles and rise to the surface, where they are removed

Flue gas scrubber

Equipment for removing impurities from flue gases by dissolving them in aqueous solution

Fodder pulp

Protein produced from pulp mill spent liquors and sometimes mixed with animal feeds

Folding boxboard

Single or multilayer paperboard made from primary and/or secondary fibres, sometimes with a coated front, used to make consumer packaging (cartons)

Forest tree breeding

A method of improving certain racial characteristics of forest trees

Forwarder

Machine for carrying wood from the felling site to the transport route (usually a road)

Fourdrinier wire

Horizontally moving metal or plastic mesh belt (wire) on which the paper web is formed

Fraction

A component of a mixture that can be separated on the basis of some property or properties

Fully bleached pulp

Pulp that has been bleached to the highest brightness attainable (> 90 ISO)

Glassine paper

Paper made from finely ground chemical pulp that is largely greaseproof but does not have wet strength. Its high transparency is achieved by very intense calendering (smoothing between rolls). Used as chocolate wrapping, in photo albums, wrapping for fish preservatives, protective covers for leaflets, envelope windows etc.

Glazing

First calendering, in which paper is passed through a roll nip to give it a smoother surface

Grammage

Weight in grams of one square metre of paper or board; also basis weight

Gravure paper

Mostly mechanical, highly calendered (smoothed) paper with a high ash content, which is produced as coated or uncoated grade (See "Coated paper"). It must ensure uniform ink trapping at high printing speeds. In order to accept the ink from the deep etched or engraved ink cells of the gravure cylinders, gravure paper must have a certain degree of softness and suppleness. Applications: magazines and reviews, mail-order and travel catalogues, brochures and inserts with high print runs

Greaseproof paper

Greaseproofness is either achieved by grinding of the pulp and pore-free web formation or by special additives

Greyboard

Greyboard is produced from 100% recycled fibre and offer a smooth surface and high bulk to weight ratio.
Suitable for screen printing, letterpress, high frequency welding, paper over board lamination, and used for ring binders, files, slip cases, wallets, bookbinding, picture mounting and jigsaws.

Grinder

A machine in which logs are defibrated against a revolving grindstone

Groundwood mill

An installation for producing mechanical pulp by grinding

Groundwood pulp

A fibrous slurry produced by mechanically abrading the fibres from barked logs through forced contact with the surface of a revolving grindstone. It is used extensively in the manufacture of newsprint and publication papers

Growing stock

Volume of stemwood in a given area of forest, usually measured in solid cubic metres (with bark)

Growth ring

A tree increases in girth by one growth ring each year. Also known as annual ring

Gumming

Paper with a coating of an adhesive which becomes sticky when wet

Hard pulp

A commonly used term to describe chemical pulp with a high lignin content

Hardwood

Wood from deciduous trees

Hardwood chemical pulp

Chemical pulp made from hardwood

Harvester

A machine that fells, delimbs, cross-cuts and measures the logs

Harvester measurement

Timber measurements made by the harvester's measuring device during felling

Harvesting

Timber felling and haulage to roadside stockpiles

Headbox

Chamber at the beginning of a paper machine that dispenses pulp stock evenly onto a moving wire

Heartwood

Wood located in the centre of the trunk and often darker in colour than the surrounding wood

Hemicellulose

A carbohydrate component of the cell walls of wood

Hood

A hood covering the paper machine drying section and designed for moist air removal

Hot screening

Pulp cleaning at elevated temperature using pressure screens

Hot-ground wood pulp

Mechanical pulp produced by grinding logs that have been pre-treated with steam

Humus

Dead organic material derived from decomposition of plant and microbial wastes

Immission

The level of a particular pollutant in the environment. Widely used for air emissions and noise

Impregnation

The absorption of an impregnating agent into paper; in pulping, wood chips are impregnated with cooking liquor; timber is impregnated with preservative

Impressed watermark

Semi-genuine watermark made in the paper machine press section using engraved rolls while the web is still wet

Index board

Woodfree and mechanical board for office and administration purposes

Integrated Mill

Mill where timber is pulped and then made into paper

Integrated Pulp

Integrated pulp is pulp that is produced for use as a raw material in the production of paper at the same mill, or is for shipment by a producing mill to other mills, which it owns, controls or with which it is affiliated within the same country.

ISO brightness

The brightness of paper and board measured at a wavelength of 457 nanometres under standard conditions.

Jumbo roll

Large roll of paper coming off the paper machine before cutting; a large customer roll.

Kappa number

Measure of the amount of lignin remaining in pulp after cooking

Kitchen wipes

Kitchen wipes consist of creped paper made from chemical or waste paper pulp. They are used in private households or in trade and industry.

Knotter pulp

Pulp made from the rejects from chemical pulp screening

Kraft paper

High-strength paper made almost entirely of unbleached kraft pulp. Kraft paper is suitable for the production of paper sacks and paper bags

Kraft pulp

Chemical wood pulp produced by digesting wood by the sulphate process (q.v.).Originally a strong, unbleached coniferous pulp for packaging papers, kraft pulp has now spread into the realms of bleached pulps from both coniferous and deciduous woods for printing papers

Kraftliner

Paperboard of grammages of 120g and more, generally made from bleached or unbleached sulphate pulp and used as an outer ply in corrugated board

Label papers

Mostly one-side coated papers which must be printable in 4-colour offset and gravure printing. These papers are usually suitable for varnishing, bronzing and punching and sometimes also feature wet strength and alkali resistance (See "Wet strength and alkali resistant paper") in order to en-sure the removal of the labels e.g. in the bottle rinsing machines of breweries

Lacquering

Application of lacquer to give paper greater gloss and stiffness (brochures and some magazine covers)

Laminate

Material used to bond together two or more layers of paper, board, etc.; also a laminated product.

Lamination

Laminating paper or board with foil, plastics etc

Light-weight printing paper

Light-weight paper has a low grammage and is made from rags and bleached kraft pulp and is used e. g. for advertising material (catalogues, leaflets, mailings etc.), commercial and/or jobbing work (magazines, brochures, instruction leaflets, forms etc.)

Lightweight coating

Coating applied at 7-10 g/m2 on one or both sides of the paper

Lignin

Natural "adhesive" which binds wood fibres together in the tree and imparts rigidity. Pulp brightness depends on the amount of lignin remaining in the pulp. Paper containing high content will "yellow" in sunlight

Lime kiln

Used to reburn lime sludge (CaCO3) to form calcium oxide (CaO), which can be reused

Lime sludge

Sludge of calcium carbonate (CaCO3) formed during preparation of white liquor in the chemical pulping process

Linen finish

Imitation linen texture impressed onto the paper surface

Logging residue

Crowns, branches and tops of trees, and other parts of the stem remaining in the forest after felling

Long-length log

Stem of a felled tree that has been delimbed but not cross-cut

LWC

Lightweight coated. See Lightweight Coated Printing paper

LWC paper

Light weight, two-side coated mechanical reel printing paper with a grammage of less than 72g. It is used for magazines, mail-order catalogues etc. that are mostly produced in gravure or web offset printing (See "Coated paper")

Lye

caustic soda (ash)

Machine creping

Creping of paper on the paper machine using a large drying cylinder known as a Yankee

Machine roll

See Jumbo roll

Machine stack

Used for first calendering (glazing) of paper on the paper machine

Machine width

Width of the paper web in the paper machine

Magazine paper

The selection of the magazine printing paper is mainly dependent on the print run and the demands on the print quality (image reproduction, outer appearance, advertising appeal). High runs are mostly produced in rotogravure, rotary offset printing or rotary letterpress printing on uncoated or coated reel printing papers (mainly SC and LWC. See "SC" and "LWC"). Magazines with medium or smaller circulation are generally produced in sheet-fed offset or sheet-fed letterpress printing.

Marbling

Addition of strongly stained fibres to the stock to give the paper a marbled appearance

Market pulp

Pulp produced for sale on the market or for the producer's units abroad rather than for own use
Market pulp is pulp that is sold in open competition with that of other producers. All pulp exported from the producing country is considered to be market pulp.

Matt finish

A dull finish given to the surface of paper and board

Mechanical paper

This paper contains mechanical pulp, thermomechanical pulp (TMP) or chemithermo-mechanical pulp (CTMP) and also chemical pulp. The shares of chemical and mechanical pulp vary depending on the application. Highly mechanical papers such as newsprint tend to yellow more rapidly if exposed to light and oxygen than woodfree papers so that they are mainly used for short-lived products. In printing papers the mechanical pulp improves opacity

Mechanical pulp

Pulp consisting of fibres separated entirely by mechanical rather than chemical means
Stone Groundwood pulp: by grinding wood into relatively short fibres. This pulp is used mainly in newsprint and wood-containing papers, like lightweight coated (LWC) and super-calendered (SC) papers.
Thermo-mechanical pulp (TMP): produced in a thermo-mechanical process where wood particles are softened by steam before entering a pressurised refiner. TMP has mainly the same end-uses as stone groundwood pulp. Variants of the above two processes are pressurised stone groundwood pulp and refiner mechanical pulp.

Mechanical wood-processing industry

Industrial production of sawn timber, plywood, particleboard, fibreboard, wooden house components and joinery products

MF

Machine finished. Smooth paper calendered on the paper machine

MG

Machine glazed. Paper with a glossy finish on one side produced on the paper machine by a Yankee cylinder.

Micro-creping

A way of improving the extensibility of paper by pressing a wet mesh against the paper web

Mineral fillers

Materials such as chalk and china clay that are added to paper in order to change its density or improve its surface and optical properties

Mortality

Natural loss of trees through ageing, disease or other natural phenomena

Mould

Made from rows of metal wires or bamboo

Multi-layer web forming

Usually applied to a board machine on which several webs are combined into one

Multi-stage cooking

Chemical pulping process in which the alkalinity of the cooking liquor is varied by charging the alkali in several stages

Natural regeneration

Forest regeneration by seed trees or other standing trees (cf. artificial regeneration).

NCR paper

See "Carbonless copy paper"

Newsprint

Newsprint is a highly mechanical, machine-finished or calendered rotary printing paper (40 - 56g) mainly made from mechanical and increasingly waste paper pulps. In line with its intended use as a short-lived information medium, the demands on newsprint in terms of optical properties or printability are lower than those on other, e.g. coated printing papers. Newsprint must have a very good runnability: today's state-of-the-art printing techniques require a paper with a good tear strength so that the uninterrupted production on high-speed rotary presses is ensured. Newsprint is used for dailies, weeklies and free journals produced in letterpress or offset printing

Nitrogen emission

Emission of nitrogen compounds which, as nutrients, cause eutrophication and acidification in water systems

Non-Wood Pulp

Pulp made from materials other than wood, for example straw, grasses, bagasse etc

Nutrients

Generally refers to nitrogen and phosphorus compounds, which act as fertilisers in water systems

Off-machine coating

Coating of paper on a separate coating machine

Offset paper

Collective term for printing papers with special properties for offset printing. For in-stance, the paper must not emit dust during processing and must be pick resistant. Offset paper may be woodfree or mechanical, coated (matt, glossy, embossed) or uncoated and is processed in sheets as well as in reels

On-machine coating

Coating of paper on the paper machine

Optical characteristics

Characteristics of the appearance of paper or board. Most important are colour, brightness, opacity and gloss

Outturn

Total volume of wood recovered from felling

Oxygen bleaching

A process in which pulp is initially treated with oxygen followed by 4-5 bleaching stages

Ozone bleaching

Pulp can be treated with ozone at the start of the bleaching sequence to lower its lignin content. Ozone allows bleaching to high brightness without chlorine chemicals

Packaging paper

Collective term for papers of different pulp composition and properties, sharing only the application. Selection and mixture of the pulps depend on the demands made on the paper. Important are tear strength, bursting strength, creaseproofness, abrasion resistance as well as elasticity and stiffness. Often also good printability is demanded (packaging as advertising medium). For special purposes packaging paper can be imparted wet strength or water repellent properties or made impermeable for aromas or water vapour. For these purposes either special additives are admixed to the pulp or the paper is coated, impregnated or combined with plastic and/or metal film

Paperboard

Monolayer paperboard is basically thicker paper, frequently used in multilayers

Parchment paper

See "Vegetable parchment"

Particulates

Airborne solid impurities such as those present in gaseous emissions (sodium sulphate, lime, calcium carbonate, soot)

Patch scarifying (scarification)

In forest regeneration, removal of top vegetation to expose mineral soil beneath

PCC

PCC stands for Precipitated Calcium Carbonate-also known as purified, refined or synthetic calcium carbonate. It has the same chemical formula as other types of calcium carbonate, such as limestone, marble and chalk: CaCO3. The calcium, carbon and oxygen atoms can arrange themselves in three different ways, to form three different calcium carbonate minerals. The most common arrangement for both precipitated and ground calcium carbonates is the hexagonal form known as calcite. A number of different calcite crystal forms are possible: scalenohedral, rhombohedral and prismatic. Less common is aragonite, which has a discrete or clustered needle orthorhombic crystal structure. Rare and generally unstable is the vaterite calcium carbonate mineral

Peroxide bleaching

Method of bleaching pulp with hydrogen peroxide (H2O2) to remove lignin; reduces or avoids the need for chlorine dioxide in final bleaching

PGW

See Pressurised groundwood pulp

Photographic paper

The base paper used for the production of photographic papers is a dimensionally stable, chemically neutral chemical pulp paper with wet strength properties, that must be free from contaminants. Today papers are coated on both sides with a thin polyethylene film. The cooking prevents chemicals and water entering the paper during development. This also permits shorter rinsing and drying cycles

Pick-up

Roll which lifts the wet paper or board web off the wire before the drying section

Picking

Removal of particles from the paper surface during printing when ink tack is greater than surface strength

Picking resistance

Ability of a paper surface to resist picking by tacky printing inks

Pigmentizing

Coating of paper with a chemical agent (pigment) to reduce surface porosity and increase opacity

Plasticizer

Agent mixed into coating colour to give a more flexible coating

Porosity

A structural property of paper reflected by the size distribution of pores

Postcard board

Postcard board is either slightly mechanical or woodfree and calendered

Poster paper

Poster paper is a highly mechanical, highly filled, mostly coloured paper that has been made weather resistant by sizing.

Press nip

On a paper machine, a pair of rotating rolls between which the paper web passes

Pressurised groundwood pulp (PGW)

Mechanical pulp produced by treating logs with steam before defibration against a grindstone under externally applied pressure

Primary fibre

See Virgin fibre

Printability

Describes how smoothly paper runs in a printing press and the quality of the printed image

Printing paper

Printing paper is a collective term for all printable mechanical or woodfree papers that may serve as the medium for printed information. In addition to uniform and fast ink trapping and drying (printability) as well as dimensional stability, sufficient opacity (no show through of the back print) and smoothness, such papers require a certain degree of strength and stiffness, so that the paper may run through the printing machine fast and without any problems (runnability). Many printing papers are coated to improve printability (See "Coated paper")

Process flowchart

Layout showing process equipment and material flows

Pulp grades

Pulp grades are classified according to their production process.
They are classified by original species: softwood or hardwood and by the production process used: chemical or mechanical and bleached or unbleached

Pulper

Unit for defibrating (slushing) pulps and paper machine broke, usually at the wet end of the paper machine

Pulpwood

Wood suitable for making into pulp; not usually good enough for sawmilling

Puncture resistance

Force acting perpendicular to a paper or board surface needed to puncture the sheet

Rag paper

Today rag paper is mostly made from vegetable fibres consisting of cellulose, such as cotton, linen, hemp and ramie. Rags are the most precious raw material for the papermaker. Rag papers and rag-containing papers with admixtures of chemical pulp are used for banknotes, deeds, documents, books of account, maps and copperplate engravings and as elegant writing papers. They are also used for special technical applications.

Rag pulp

Papermaking pulp made from textile waste, cotton, hemp or flax

Ream

Unit consisting of 500 identical sheets of paper

Recovered paper

Paper recovered for recycling into new paper products. Recovered paper can be collected from industrial sources (scraps, transport packaging, unsold newspapers...) or from household collections (old newspapers and magazines, household packagings)

Recovered Paper Base

Solid, compressed stack of recovered paper, sorted by grades, intended to be recycled by some papermills, to produce paper and board

Recovered Paper Grades

Recovered paper sorted by types in order to be recycled by paper mills. Specific grades are used by paper mills, in order to produce different types of paper and boards

Recovery boiler

Boiler used to burn black liquor from chemical pulping for recovery of inorganic chemicals as well as for energy production

Recovery rate

Volume of paper recovered as a percentage of volume of paper consumed

Recycled fibre

Fibre obtained from recovered paper; also secondary fibre (cf. virgin fibre)

Recycled fibre pulp

Pulp produced from recovered paper to be used in papermaking

Recycling

Use of recovered waste paper and board by paper mills to produce paper and boards

Refiner

A machine containing rotating disks between which wood chips are broken down into fibres for pulp making

Refiner mechanical pulp (RMP)

Mechanical pulp produced by passing wood chips between the plates of a refiner

Refiner sawdust pulp

Mechanical pulp produced from sawmill dust

Reflectivity

Ability of paper or board to reflect light; a measure of gloss

Regeneration felling

Felling of old-generation trees to make way for natural or artificial regeneration. Artificial regeneration is by either sowing or planting, while natural regeneration results from seeding by trees on the same site

Reinforcement

Method for strengthening paper with an insert or surface layer of glass or other synthetic fibre or metal

Reinforcement pulp

Softwood chemical pulp added to give paper greater strength and to improve runnability on the paper machine or printing press

Reject

Material removed and discarded during the cleaning of pulp/stock

Relative density

Mass of a unit volume of a particular substance

Release paper

Release paper is used to prevent the sticking of glue, paste or other adhesive substances. Coating paper with silicone yields papers with a surface that prevents adhesion of most substances. Application: cover material for self-adhesive papers or films, e.g. in label production.

Retention

Proportion of fibre and filler retained on the paper machine wire

Roofing paper

Board that is impregnated with tar, bitumen and/or natural asphalt.

Roundwood

Unprocessed industrial wood raw material

Runnability

How smoothly paper runs through a paper machine or printing press (also how well cartons run on an automatic packaging line)

Sack paper

See "Kraft paper"

Safety paper

Papers with a special protection against abusive imitation. The safeguards used during the production of the paper - some of them chemical - are secret

Sanitary papers

The group of sanitary papers includes cellulose wadding, tissue and crepe paper, made from waste paper and/or chemical pulp - also with admixtures of mechanical pulp. As a consequence of the importance of tissue today, this name is now used internationally as a collective term for sanitary papers. These grades are used to make toilet paper and numerous other sanitary products such as handkerchiefs, kitchen wipes, towels and cosmetic tissues

Sanitary tissue paper

Tissue is a sanitary paper made from chemical or waste paper pulp, sometimes with the admixture of mechanical pulp. It has a closed structure and is only slightly creped. It is so thin that it is hardly used in a single layer. Depending on the requirements the number of layers is multiplied. Creping is made at a dryness content of more than 90 %. The dry creping (unlike with sanitary crepe papers) and the low grammage of a single tissue layer result in a high softness of the tissue products. For consumer products it is normally combined in two or more layers. The flexible and highly absorbent product [is mainly produced from chemical pulp and/or DIP - sometimes also with admixture of groundwood pulp] can also be provided with wet strength. Applications: facial tissues, paper handkerchiefs, napkins, kitchen rolls, paper towels, toilet paper

SC

See Supercalendered

SC paper

SC stands for supercalendered. This is a calendered, uncoated mechanical paper with fillers

Secondary fibre

See Recycled fibre

Security paper

Woodfree, sometimes rag-containing but always high quality paper with a genuine multistage watermark to avoid falsification

Seed tree

Healthy tree suitably sited and left standing after final felling for natural regeneration purposes; known also as mother tree

Selective felling

Felling of selected trees, usually the largest trunks meeting specified dimensions

Semi-alkaline pulp (SAP)

Sulphite pulp cooked at slightly alkaline pH (normal sulphite pulp is cooked at acid pH). SAP is superior in strength to normal sulphite pulp. Used mainly in printing papers

Semi-bleached

Pulp bleached to a brightness somewhere between that of unbleached and fully bleached pulp

Semi-chemical pulp

High yield pulp in which the fibres have been separated mechanically after a preliminary chemical treatment; e.g. NSSC pulp
Produced in a similar way to TMP (thermo-mechanical pulp), but the wood particles are chemically treated before entering the refiner. This pulp has properties suited to tissue manufacture. Some chemi-thermo mechanical pulp (CTMP) pulp is used in printing and writing grades. CTMP pulp is classified under semi-chemical pulps in the Harmonised System of the Customs Cooperation Council. In the Food and Agricultural Organisation (FAO) of the United Nations, as well as other industry statistics, such chemi-thermo mechanical pulps are grouped with mechanical pulp.

Settleable solids

Suspended solids that will settle out of an effluent during mechanical treatment.

Sheeter

Machine for cutting the paper web into sheets

Short fibre

Applies to paper or pulp containing a high proportion of short wood fibres

Single-grip harvester

A machine designed to fell, delimb, cross-cut and measure logs using a device mounted in the log loader

Sized paper

Sizing reduces the water absorbency of the paper and thus creates the condition for the writability with ink. Sized paper is also used for many other purposes (printing, coating, gluing, etc.), and the sizing agents must fulfil a wide range of tasks. For instance, they control the water absorbency and increase the ability to retain water and ink (pick resistance)

Sizing

Treatment of either stock or paper surface with size to improve strength and reduce absorbency of water

Sludge handling

Compaction and dewatering of sludge separated from treated effluent

Softboard

Softboards are soft, bulky boards with a felt-like character. They are used for protective covers, roofing papers, beer mat boards, packaging boards and flongs

Softwood

Woods obtained from coniferous trees

Soil preparation

Rendering the soil suitable for planting seedlings by scarifying, harrowing and mounding

Solid cubic metre

The volume of wood that displaces one cubic metre of water

Solid fibre board

Collective term for all solid board grades

Special pulps

Chemical pulps used for purposes other than ordinary papermaking (e.g. in textile production)

Speciality paper

The group of speciality papers comprises numerous paper grades, each characterised by particular properties. These properties often require special raw materials

Spent liquor

Waste liquids from pulping and washing (cf. black liquor)

Stand

Area of forest on a particular type of soil and with a uniform tree species distribution that is treated as a distinct entity

Steam calendering

See steam finishing

Steam finishing

A way of treating paper before calendering to improve its density and surface smoothness

Steaming

Wood chips are often treated with steam prior to pulping; used in thermomechanical pulping

Stem

Trunk of a tree after removal of branches and stump

Stock

Suspension in water (slurry) of fibres and other components for papermaking during the period between defibration and web formation

Strength

Ability of paper or board to withstand mechanical stress

Succession

In a forest, a natural gradual development towards a stable state (climax)

Suitcase board

Sized, high-density and strong board which generally is water repellent on both sides as a result of surface finishing. It may be pressed, folded, moulded, bent, riveted and sowed. Thickness 1 - 3 mm

Sulphate pulp

Chemical pulp produced by cooking wood in a liquor containing sodium hydroxide and sodium sulphide

Sulphite pulp

Chemical pulp produced by cooking wood in a liquor containing sodium, magnesium, ammonium or calcium bisulphite

Supercalendered (SC)

Paper treated in a supercalender, usually separate from the paper machine; uncoated magazine paper

Supercalendering

Treatment of paper on an off-machine supercalender to improve smoothness and gloss

Surface treatment

Treating the surface of paper or board with size or coating colour

Surface-sized paper

Paper that has been sized on the surface, generally using a size press inside the paper machine

Suspended solids

Bark, fibre and other wood-based material released into water during debarking and pulping; filler and coating colour residues from paper mills; solid impurities formed during waste water treatment. Solids can be removed from waste water by settling or filtration

Sustainable forest management

The Ministerial Conference on Protection of Forests in Europe (MCPFE) defines it as, "stewardship and use of forests and forest lands in a way, and at a rate, that maintains their biodiversity, productivity, regeneration capacity, vitality and their potential to fulfil, now and in the future, relevant ecological, economic and social functions, at local, national, and global levels, and that does not cause damage to other ecosystems".

Synthetic fibre paper

Papers made from synthetic fibres such as polyamide and polyester, from viscose staple fibre or sometimes also with fillers. The fibres are mainly held together by binders. The durable synthetic fibre papers are used for maps and highly important documents such as driving licences or vehicle registration books

Talc

Mineral used in papermaking as a filler and coating pigment

Tearing resistance

Force needed to tear a sheet of paper under specified conditions

Testliner

Mainly produced from waste paper used as even facing for corrugated board or as liner of solid board. They are often produced as duplex (two-layer) paper. The grammage is higher than 125 gsm

Thermal papers

One-side coated thermoreactive papers used for printing text and illustrations on telefax machines, thermoplotters (e.g. for technical drawings) and thermoprinters (e.g. for labels, tickets, sales slips and other vouchers)

Thinning

Selective felling designed to promote the growth of the remaining trees. Thinning normally provides merchantable wood

Three-layer paperboard

Paperboard consisting of three layers: front liner made from chemical pulp and/or waste paper pulp, middle made from waste paper pulp and back made from mechanical and/or chemical and/or waste paper pulp

Timber harvesting

Felling, delimbing and cross-cutting of trees in the forest followed by haulage to the transport route, usually a road

Timber procurement

See Wood procurement

Tissue paper

Collective term for papers of a grammage of less than 30 gsm that differ in applica-tion and composition but have the common feature of being thin. They are mainly used to wrap delicate items, as tissue for bottle wrapping, as fruit tissue wrappers for oranges or as wet strength flower tissue. They are also used as base paper for the carbon paper production, as lining tissue for envelopes and as lining paper (e.g. as a composite with aluminium foil in cigarette packaging). The extremely thin Japanese tissue papers are sometimes produced in grammages as small as 6 to 8g

Toilet papers

See "Sanitary tissue papers" and "Sanitary crepe papers"

Total drain

Volume of stemwood removed from a growing forest during a given time either by natural events or felling; sum of wood felled and natural mortality

Totally chlorine-free (TCF)

Pulp bleached entirely without chlorine chemicals

Totally Chlorine-free paper (TCF)

Abbreviated used for papers made from pulps that were not bleached with chlorine compounds. The paper itself is not bleached

Transparent paper

Extended and particularly careful grinding of high quality fibres (hard chemical pulps, rags) yields a raw material permitting the production of transparent paper

Trimmings

Paper or board left over from web or sheet cutting operations

Twin-wire machine

Paper or board machine in which the web is formed and partially dewatered between two wires

Typewriter paper

Typewriterpaper (bank paper) is often woodfree, usually sized, erasure resistant and in rare cases coloured. It can be both with and without watermark and can also be embossed. Typewriterpaper (bank paper) is often woodfree, usually sized, erasure resistant and in rare cases coloured. It can be both with and without watermark and can also be embossed

Unglazed (UG)

Uncalendered paper

Vegetable parchment

Vegetable parchment, often also called parchment paper, is a highly pure packaging material that is impermeable for grease and has a particularly high dry and wet strength. It is made from an absorbing, pure, bleached chemical pulp in a special process using concentrated sulphuric acid

Veining

Uneven colouring of pulp

Virgin fibre

Wood fibre never before used to make pulp, paper or board. Also primary fibre (cf. secondary fibre)

Virgin forest

Forest in its natural state, untouched by man

Viscose pulp

Dissolving pulp intended for the manufacture of viscose

Wall base paper

Collective term for papers that are suitable for wallpaper production. These papers may be monolayer or multilayer (simplex/duplex), woodfree or mechanical, uncoated or coated, and can also be laminated, pre-pasted or peelable

Washer room

Pulp mill department where pulp is washed free of cooking chemicals

Washing deinking

Deinking in which solid particles are separated on the basis of their size by washing

Waste paper

Paper after it has been used. Most can be recycled into new paper products. Known also as recovered paper and secondary fibre

Wastewood

Residual crowns, small trees etc. left after felling

Watercolour paper

Woodfree (See "Woodfree paper") drawing paper with a rough or structured surface, sometimes also rag-containing or pure rag paper. Sizing is adapted to ensure that the water colours are well accepted by the paper but do not strike through. The paper must be erasure resistant. If they are hand-made, water colour papers have the additional advantage that they expand evenly in all directions when they are moistened

Watermark

A localised modification of the formation and opacity of the sheet, so that a pattern or design can be seen

Waxed paper

Nearly woodfree papers that are impregnated with paraffin, wax or wax/paraffin/plastic mixtures. With the appropriate saturation agent and process the product may be tailored for specific applications, e.g. packaging of bread or sweets or wrapping razor blades

Waxing

Coating or impregnating of paper or board with paraffin or wax

Web

Continuous sheet of paper formed on the paper machine wire

Web glazing

Imparting a gloss to the paper web; calendering

Wet end

First part of the paper machine up to the drying section

Wet strength

Mechanical strength of paper when wet, measured under specific conditions

Wet strength and alkali resistant paper

Adding alkali resistant wet strength agents to the fibre suspension yields papers that have a remarkable strength even when wet

Wet tensile strength

Ability of wet paper to resist tension in the plane of its surface

White water system

Flow circuit for paper machine white water (includes pipes, storage tanks, cleaning equipment, water from forming section and return feed)

Winder

Machine for cutting the paper web longitudinally into narrower webs, which are then wound to reels; also slitter-winder

Winding

Operation whereby a web of paper or board is wound into one or more reels

Wire

Flat belt of metal or plastic mesh on which the paper or board web is dewatered

Wood cellulose

A polymeric carbohydrate that forms the main constituent of the wood cell wall

Wood Chips

Pieces of wood (approximately 1 inch square and 1/8 inch thick) resulting from the cutting of pulpwood logs in chippers in the wood preparation area of a pulp mill prior to conversion into pulp in the digester(s)

Wood containing

Paper containing a certain proportion of mechanical pulp

Wood fibre

Wood cells; the main raw material for papermaking

Wood procurement

Purchase, harvesting and transport of wood to the mill

Wood production

The growing of wood in a forest together with related activities

Wood pulp

Mechanical or chemical pulp made from wood (cf. Non-wood pulp)

Wood-based energy

Energy obtained by burning wood. Part of the natural cycle in which carbon dioxide is released and taken up again by new, growing trees via photosynthesis

Woodfree

Paper made using the chemical rather than the mechanical pulping process

Woodfree paper

Paper consisting of chemical pulp fibres. It does not contain any mechanical pulp beyond a permissible content of 5 % by mass

Woodroom

Part of a pulp mill where logs are debarked

Writing paper

Uncoated paper that is suitable for writing with ink on both sides. The writing must neither bleed nor strike through. Writing paper is always fully sized (See "Sized paper") and also suitable for printing. It can be woodfree or mechanical, depending on the intended purpose. The admixture of fillers makes it less translucent

Year Ring

See Growth Ring

» Back to top