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glossary of papermaking terms

A-FLUTE 
A-Flute is the highest flute size and when combined with an inner and outer facing, it is the thickest. Sometimes known as coarse flute.

ABRASIVE PAPERS 
Papers covered on one or both sides with abrasive powder, eg emery, sand paper etc.

ABSORBENCY
Ability of paper or board to take up or retain aqueous solutions; printing inks, varnishes and the like.

ABSORBENT PAPERS
Duplicator, blotting and filter papers are the best known; drying royal, matrix paper and towelling are other examples.

ACCEPTED STOCK
That part of the stock which is not rejected by cleaning and/or screening.

ACID FREE
A term describing paper and board that can be used with anything that may be tarnished or otherwise harmed by acid.

AIR DRY
Describing
(1) the moisture content of a substance when in equilibrium with the surrounding atmosphere;
(2) woodpulp contains approximately 10% of moisture, paper 8% of moisture.

ALUM
The term used in papermaking for aluminium sulphate. Its action on rosin size is to precipitate the size upon the fibres giving them a degree of water repellency.

B-FLUTE
The second flute size and has lower arch heights that A, and more flutes per metre. B-flute is used for high speed, automatic packing lines and for pads, dividers, partitions and other forms of inner packing.

BARYTES
Blanc fix of Barium Sulphate, high white loading. Used for coating photocopier base papers and lithos.

BEATING OR REFINING
The mechanical treatment of the fibres in water to increase surface area, flexibility and promote bonding when dried.

BIBLE PAPER
Thin printing paper, maximum of 5ogsm, opaque. It is intended specially for use in deluxe productions; eg bibles, dictionaries and high quality publicity productions. Bible paper indicates a paper containing at least 25% rag.

BIODEGRADABLE
A substance that will decompose as the result of action by bacteria and other living organisms.

BLOTTING PAPER
Very absorbent and bulky, woodfree, sometimes made from a pulp of cotton or wool fibres 1 20-300gsm.

BIODIVERSITY
Biological diversity in nature - influenced by man through construction, cultivation and raw material supply. Modern silviculture tries to preserve the biodiversity of nature.

BOARD
Papers of 220 gsm and over are generally called boards. They are most often of more than one ply.

BOD
Bio-chemical Oxygen Demand.

BOX COMPRESSION TEST (BCT)
Strength test. The maximum loading before collapse.

BOX MAKER'S CERTIFICATE (BMC)
Statement printed on a corrugated fibreboard box or solid fibreboard box testifying that all applicable container board requirements of the carriers have been observed. It identifies and locates the box maker.

BROKE
Paper or board that is discarded at any stage during its manufacture and is usually repulped. There are 2 kinds - wet broke, which Is accumulated at the wet end of the papermaking machine; dry broke which is accumulated at any stage on the dry end of the machine, trimmings from the reeling, slitting and cutting operations, as well as paper or board rejected during sorting.

BULK
The number obtained by dividing the thickness, In micrometers of paper or board, by its grammage. i.e. mass per unit volume.

C-FLUTE
C-Flute is thinner than A-Flute and thicker than B-Flute. It offers good cushioning, staking and printing properities. C-Flute is the most widely used.

CALENDER
A machine Intended to smooth or otherwise finish the paper and consisting essentially of a certain number of superimposed rolls of which only one is power driven.

CALIPER
The thickness of a sheet of paper measured under standard test conditions.

CARTON BOARD
A material of defined thickness and weight made from one or more layers of fibrous cellulose material to form a rigid or semi-rigid construction.

CARTRIDGE PAPER
Paper made from chemical woodpulp having good strength and a rough surface.

CENTRE OR CORE
A steel, wood or cardboard tube on which paper is reeled, or re-reeled.

CHEMICAL PULP
Pulp made by cooking the wood in the present of chemical agents (acids or alkali) which eliminates most of the non fibrous material.

CHINA CLAY
A mineral, obtained largely from Cornwall, used by papermakers to obtain finish and consistency; also for coating art and chromo paper. Also called Kaolin.

CHIP BOARD
A board made from waste paper used mainly in packaging, especially with a white liner and coating.

CLOSED SYSTEM
The system of operating a paper or board making machine whereby the water drained from the sheet during formation is collected and returned for re-use Instead of being discharged to waste.

CLOTHING
The felts, wires and fabrics used on a papermaking machine.

COATED PAPERS
Paper to which a coating has been applied on one or both sides, using a mix of clay or carbonates and latex to create a high quality printing surface.

CONSISTENCY
Bone dry concentration of fibre in grammes per 100 ml of suspension. Ratio for solid to liquid expressed as a percentage.

CONTRARIES
Materials unsuitable for papermaking, present in some raw materials and waste paper.

CONVERTING
A manufacturing plant which uses paper to make paper-based products, such as packaging or consumer products.

CORRUGATED or CONTAINER BOARD
Consists of one or more sheets of fluted paper stuck between fiat sheets of paper or board.

CORRUGATOR
The machine that actually makes the corrugated board from fluting and liner papers.

CORRUGATING MEDIUM
Paper used to form the fluted part of the corrugated board.

CHEMI-THERMO MECHANICAL PULP (CTMP)
Same as TMP only chips are also sprayed with chemicals.

CURL
Deformation of a sheet of paper or board over all its surface, which therefore tends to roll up into the form of a cylinder.

DCC
Die Cut Container.

DANDY ROLL
Hollow cylinder of wire gauze, which consolidates the wet web on the wire and may produce a watermark.

DECKLE
The untrimmed edge of the web of paper as it comes off the machine. (Also used to denote the width of the web).

DIE CUTTING
Cuts and scores formed on corrugated sheets with a stell rule die like a biscuit cutter.

DIMENSIONAL STABILITY
Paper or board changes in its dimension and flatness with variation in its moisture content and its termed dimensionally stable when such changes are of a low order.

DOCTOR
Thin blade of wood, metal or plastic, placed against rolls on the machine to keep them clean and smooth.

DOUBLE WALL BOARD
Board comprising liner, fluting, liner, fluting, liner.

DUPLEX BOARD

A multi ply construction of a board made predominately from mechanical pulp but with a bleached chemical pulp liner.

E-FLUTE
Has a very high number of flutes per metre which gives flat surface for high quality printing. It is one fourth the thickness of C-Flute. Sometimes known as extra fine flute.

ESPARTO
A coarse grass from Southern Spain and Northern Africa, employed principally by English and Scottish papermakers. Papers made from Esparto have a good writing and printing surface, are opaque and of good bulking properties. They are largely used for lithographic printing, for book production and as body papers for coating.

F-FLUTE
Fluting of height 0.75mm. Also known as N flute or micro flute.

FACINGS (OR LINERS)
Form of linerboard usd as the flat constituents of a corrugated fibreboard sheet.

FIBREBOARD BOX
A container made of either corrugated or solid fibreboard.

FIBRIL
Fine thread-like structure that fibres are composed of. They are often of more than one ply.

FIBRILLATION
Freeing of the fibrils from within the fibre during the beating/refining process.

FLAT CRUSH
Measure of the resistance of the flutes in corrugated board to a crushing force applied perpendicular to the surface of the board.

FLEXOGRAPHIC
A type of printing process where the machine may also slot, fold and glue to produce a finished case.

FLUTING MEDIUM (A, B, C & E)/FLUTE
One of the wave or arch shapes. These letters define the type of corrugated material in terms of the number of corrugations per unit length and height. Paper that has been formed into the flutes that make up the ridged part of the corrugated board between the liners.

FORMATION
The manner in which the fibres of a sheet of paper or board are distributed, disposed and intermixed to constitute the sheet.

FOURDRINIER
The terms applied to the standard type of paper machine which was produced by Fourdrinier about 1800.

FREENESS
The rate of water drainage from a fibre/water mixture. Decreased by beating to produce a wet’ stock, i.e. drainage is slow.

FURNISH
Mixture of fibre and additives used in a particular paper, I.e. ingredients and their proportions.

GLASSINE
A woodfree paper. Transparent, glazed and polished on both sides.

GREASEPROOF
Paper free of mechanical pulp, highly resistant to grease. Mainly used for the wrapping of greasy products.

GRAMMAGE
Mass per unit are in gsm

HANDMADE
The original manner in which all paper was made. So called from the fact that the sheet is formed by a workman dipping a mould into the pulp vat and taking up sufficient ‘stuff’ to form a sheet of paper of the required substances. A peculiar movement Is required to felt the fibres together, and this is the only acquired after long practice and experience.

HEADBOX
A tank supplying papermaking stock under a controlled pressure.

INTEGRATED MILLS
Mills which produce paper from pulp on site e.g. timber in one end, paper out at the other.

JUMBO REEL
First reel of paper produced after the papermaking process, before it is either slit into smaller reels or transferred for further processing.

KAPPA NUMBER
A value obtained by a laboratory test procedure for indirectly indicating the lignin content, relative hardness, or bleachability of higher lignin content pulps, usually with yields of 70 per cent or more. It is determined by the number of milliliters of tenth normal permanganate solution (0.1 KMn04) which is absorbed by 1 gram of oven dry pulp under specific conditions, and is then corrected to 50 percent consumption of permanganate.

KLS (KRAFT LINER SHAVINGS)
an important grade of recovered paper for making recycled corrugated cases

KRAFT PAPER
Solid pulp board produced by the sulphate process with or without bleaching.

KRAFT (IMITATION)
Made from different pulps, having the appearance of pure kraft and used for wrapping and packaging purposes.

LAID
Papers with a ribbed appearance produced by a mould or dandy roll which has wires parallel to each other and not woven.

LAMINATION
The combination of two or more materials using a bonding agent.

LETTERPRESS
A method of printing from type in relief, which is inked and applied to the paper.

LINED CHIPBOARD
Unlined chipboard that is modified by use of a thin layer of different pulp to provide a liner.

LIGNIN
A non cellulose material found in vegetable plants that may be considered as a binding agent or cement between the fibres of the plant.

LOADING OR FILLER
Fine white pigment in the form of powder or slurry used to improve smoothness, opacity, brightness and dimensional stability of paper and board.

MACHINE DIRECTION
The direction of a sheet or web of paper corresponding with the direction of the flow of ‘stuff’ on the papermachine.

MACHINE COATED
Paper or board, which is pigment coated at the end of the paper or board-making machine.

MACHINE GLAZED (MG)
Paper which is dried on the papermaklng machine by a very large cylinder with a polished surface. The paper has a smooth and rough side. MG papers are used for wrapping papers and posters.

MACHINE STACK
A set of steel rollers at the end of a paper machine between which the paper is passed to give it a smooth surface.

MANUFACTURER'S JOINT
Where the boxmaker joins the box together by taping, gluing or stitching.

MECHANICAL PULP
Pulp made by the grinding of steamed or boiled groundwood (without the addition of chemical agents).

MICROMETER
An instrument for measuring small distances accurately, e.g. the thickness of paper.

MIDDLES
Furnish layer of a board situated between the two external furnish layers or between an underliner and the back furnish layer.

MOTTLED
A variegated effect produced by the mixture of differently dyed fibres or a drip of colour on the wet pulp. When deliberately produced can also be known as ‘granite' or ‘silurian’ effect.

MOULD
The Implement with which hand made paper is made.

NCR PAPERS (NO CARBON REQUIRED)
Specially coated papers which will react to pressure to produce duplicate copies without the use of carbon.

NIP PRESSURE
The load on the web passing between two rolls which run together to press the sheet.

NBHK
Northern Bleached Hardwood Kraft

NBSK
Northern Bleached Softwood Kraft

OCC (OLD CORRUGATED CONTAINERS)
an important grade of recovered paper for making recycled corrugated cases

OCR (OPTICAL CHARACTER RECOGNITION)
Paper which is specially made for reading machines, having a tight specification on brightness, opacity and smoothness.

OFFCUT
Paper of usable size obtained as a by-product when larger sheets or reels are cut down to the size of the order.

PAMS
A grade of waste paper, mostly used or unused magazines.

PAPER
A compressed matted vegetable substance in thin flexible sheet form, being the precipitate of a fibrous pulp in water.

PAPER GRADES
Paper is classified into different grades according to the end use, the pulp used and the treatment of the paper.

pH VALUE
A measure of the active acidity or alkalinity of a solution. A value of 7.0 is neutral.

PHOTO GRAVURE
A method of printing by an engraving process.

PRINTINGS
A term applied comprehensively to the many varieties of papers used for printing purposes.

PROFILE
A graph showing the variations in grammage moisture content or other property from point to point on paper web, either across or along the machine direction.

QUIRED
A ream of paper in which the sheets are folded in half, rather than flat.

RAG
The two main rag fibres used in paper making are cotton and linen, rag paper consists of 25-60% rag fibre and the rest is chemical wood pulp.

REAM
A term denoting a number of sheets of paper ranging from 480 to 516, most commonly 500.

RELATIVE HUMIDITY
The mass of water vapour actually contained in a given volume of air expressed as a percentage of the maximum mass of water vapour that could be contained in that same volume at the same temperature.

RETENTION
The percentage of the amount of a loading or additive added to the stock that is retained in the final sheet of paper.

RSC
Regular Slotted Container - or FEFCO 0201 - or ordinary box.

SALLE
The department of the paper mill, sometimes called the Finishing House, where paper is sorted and counted.

SCORE
A crease in corrugated board to allow folding.

SEAM
Where 2 flaps meet.

SECONDARY FIBRE
Fibre that has been used before, e.g. recovered paper.

SECURITY PAPER
Generally rag paper, always woodfree, watermarked and chemically impregnated. Very reactive and strong. Security papers also carry identification marks which help to prevent counterfeiting. Used for making bank notes, cheques etc.

SINGLE FACE
One piece of corrugated fluting glued to one liner.

SINGLE WALL
One corrugated flute glued between two liners.

SIZE
Non-fibrous materials used in papermaking to control the absorbency of paper. Rosin, Alum, starch and gelatine are the most commonly used.

SIZING
Addition of size and chemicals during manufacturing process or by coating to control absorbency.

SOLID WHITE BOARD
Board made of one or more plies of bleached chemical pulp.

STOCK, STUFF, PORRIDGE
Terms used to describe the papermaking material in all stages, but usually referring to the wet pulp before it is fed onto the paper machine.

SUCTION BOXES
Devices situated under a part of the wire which withdraw water and air from the rapidly consolidating web, also used in felt cleaning etc.

SUGAR PAPER
A quality wrapping paper, blue or purple, principally from waste paper and formerly used for sugar bags.

SUPERCALENDER
Machine for giving paper a very smooth surface by passing it through a series of alternate metal and composition rolls, revolving with high speed and pressure.

TEST-LINER BOARD
Used as the outer layer of a corrugated construction, the material being made partly from chemical pulp and partly from waste paper.

THERMO-MECHANICAL PULP (TMP)
Involves the grinding of chips under pressure and at a high temperature.

TISSUE PAPER
Absorbent paper used for a variety of hygienic purposes.

UNBLEACHED
Any type of paper made from pulp that was not treated in any bleaching process.

UNFINISHED PAPER
Paper which comes directly from the paper machine and goes through no additional surface treatment before it is used.

VEGETABLE PARCHMENT
Paper made from pure bleached chemical pulp, which goes through a treatment of sulphuric acid giving it a lasting resistance to grease penetration. This paper is used for wrapping of moist or greasy foodstuffs.

VIRGIN PULP
Pulp manufactured and used for the first time.

WATERMARK
Designs impressed into paper while in course of manufacture by means of a projecting wire, on the mould, or in the case of machine made qualities on the dandy roll. Watermarks were employed as early as 1282. They served to identify the product of each paper mill and the designs chosen (many of them extremely complicated) also expressed emblematically the tenets of the manufacturers, which were handed down traditionally from father to son. It was customary, and the custom has survived until the present day, for paper mills to use similar designs in common. These standard designs were triflingly modified by each individual maker; they have in many cases been the origin of modem terminology, such as Foolscap, Pott, Post and so forth.

WARP
The curve of a non-flat board.

WET STRENGTH
Papers to which this term applies retain an appreciable percentage of their mechanical strength after soaking in water, and are made by the addition of a resin to the stock during paper manufacture. This resin cements the fibres together and the bond tends to improve with age. The advantages of printing maps on, or making certain wrappings from, wet strength paper are obvious.

WHITE LINED BOARD
A multi ply construction made predominantly from selected waste paper.

WOODFREE OR FINE PAPER
Papers and boards containing no fibres other than those derived from chemical wood pulping processes i.e. contains no lignin.

WOODPULP
Wood reduced to a pulp for subsequent papermaking processes; can be either mechanical, chemical or combination; TMP and CTMP.

WRAP AROUND BLANK
A scored and slotted sheet that is machine assembled around a product to make a finished box.

XYLEM
Part of a tree between the bark and the pith which forms the mechanical structure that constitutes the wood from which the fibre is obtained for use in pulp and papermaking.

YIELD
Ratio of total amount of raw material entering a pulp and papermaking operation to the equivalent product output. 

Z-DIRECTIONAL STRENGTH
The strength of paper and board as related to the force and measured by means of tension applied to the surfaces of the test sample.

 
 

 
......© Confederation of Paper Industries, 1 Rivenhall Road, Swindon, Wiltshire SN5 7BD