Packaging Materials Glossary: Paper, Board, Corrugated, Films and Coatings

How to use this packaging materials glossary

Each entry gives the term, its abbreviation and, where it helps, the German (DE), Dutch (NL) or US/UK variant, followed by a definition that stands on its own: what the material or property is, how it is made or measured, and why it matters on a specification. Typical values are labelled as such because mills, film producers and test methods vary; the binding values for any order come from the agreed specification and supplier data sheets, confirmed at quotation and technical review. Where another 9 Packaging guide covers a topic in depth, the entry links to it.

This page is one of five sub-glossaries under the packaging glossary, which keeps short definitions of the most common terms across all topics. Printing and prepress terms are in the printing and prepress glossary, machine and process terms in the converting and manufacturing glossary, test methods and defects in the testing and quality glossary, and legal, sustainability and trade terms in the regulation, sustainability and trade glossary.

The table shows how common specification lines decode using the terms below.

Fibre and pulp

How wood and recovered paper become the fibre in packaging, and the pulping and bleaching terms that appear in mill declarations. Grade-level comparisons are in packaging paper grades explained.

Bleached and unbleached pulp (DE: gebleicht / ungebleicht)

Unbleached pulp keeps the brown colour of lignin, the natural binder in wood that cooking does not fully remove, and is the base of brown kraft paper, kraftliner and kraft board. Bleached pulp has residual lignin removed or brightened in a multi-stage bleaching sequence, giving white fibre for print-critical or food-facing surfaces. Bleaching costs yield and some strength, which is why unbleached kraft is typically the strongest option for a given grammage.

Chemical pulp (DE: Zellstoff)

Chemical pulp is fibre separated from wood by cooking chips in chemicals that dissolve most of the lignin, leaving long, flexible, well-bonding fibres. Chemical pulping typically yields roughly 45-55 % of the wood as fibre, against 90 % or more for mechanical pulp, so it costs more per tonne but gives far higher strength per gram. The two chemical processes are kraft (sulphate) and sulphite; kraft dominates packaging grades.

CTMP (chemithermomechanical pulp)

CTMP is pulp made by impregnating wood chips with a mild chemical, typically sodium sulphite, steaming them and then refining them under pressure. It keeps the high yield of mechanical pulp (around 90 %) but gives cleaner, stiffer fibres that build a bulky sheet. CTMP is the usual middle ply of folding boxboard (FBB) and some liquid packaging boards, and it is the main reason FBB is stiffer per gram than solid bleached board.

See: FBB vs SBS vs WLC

Deinked pulp (DIP)

Deinked pulp is recycled fibre from which printing ink has been removed, usually by flotation and washing, to give a lighter, cleaner pulp. It is used in tissue, newsprint and the white top layers of some recycled boards and liners. Deinking removes much of the ink but not every residue, so food-contact use still depends on assessment of the finished material.

ECF and TCF bleaching (elemental chlorine free; totally chlorine free)

ECF (elemental chlorine free) bleaching uses chlorine dioxide instead of chlorine gas and is the dominant method for bleached chemical pulp worldwide. TCF (totally chlorine free) bleaching uses no chlorine compounds at all, relying on oxygen, ozone and hydrogen peroxide. Both are stated on mill declarations; some brand owners specify one or the other in sustainability policies.

Kraft pulp (sulphate pulp; DE: Sulfatzellstoff; US: sulfate)

Kraft pulp is chemical pulp made by cooking wood chips in a solution of sodium hydroxide and sodium sulphide, with the chemicals recovered and reused in the mill. The process preserves fibre strength, which gives kraft paper its name, from the German and Swedish word for strength. It is called sulphate pulp because sodium sulphate is used as the make-up chemical in the recovery cycle; "sulphate" and "kraft" mean the same process, as in solid bleached sulphate (SBS).

See: packaging paper grades explained

Mechanical pulp (groundwood, TMP; DE: Holzstoff)

Mechanical pulp is made by grinding logs against a stone (groundwood) or refining chips between discs (thermomechanical pulp, TMP), separating fibres by force rather than chemistry. Yield is typically 90 % or more and the pulp is bulky and opaque, but it keeps its lignin, so it is weaker than chemical pulp and yellows in light. In packaging it appears mainly in the middle plies of folding boxboard.

Non-wood fibre

Non-wood fibre is pulp from plants other than trees, such as sugarcane bagasse, bamboo, wheat straw, reed or cotton linters. It is widely used in moulded fibre tableware and some papers; fibre length, strength and cleanliness vary by plant and pulping process. A non-wood source does not by itself make a product compostable, PFAS-free or lower in impact; those depend on the additives, coatings and supply chain.

OCC (old corrugated containers)

OCC is used corrugated boxes collected for recycling, the largest single source of recycled fibre for testliner, recycled fluting and recycled kraft papers. Its long, kraft-derived fibres make it valuable, but quality varies with contamination, moisture and how many times the fibre has already been recycled. OCC prices move with demand and directly affect the cost of recycled containerboard.

Recovered paper grades (EN 643)

EN 643 is the European standard list of grades of paper and board for recycling, defining categories such as mixed papers, corrugated packaging, newspapers and high-grade white papers. Mills buy recovered paper against these grades, which set limits for prohibited materials and non-paper components. Packaging design affects which grade the used item falls into and whether mills accept it.

Recycled fibre (recovered fibre; DE: Recyclingfaser, Altpapierfaser)

Recycled fibre is pulp made from recovered paper and board by repulping, screening and cleaning, and sometimes deinking. It lowers material cost and environmental burden but gives less strength per gram and more shade variation, and it can carry residues such as mineral oil hydrocarbons from earlier printing, so direct food contact usually needs assessment or a functional barrier. Fibres shorten and stiffen each time they are recycled, which limits how many cycles they can make.

See: packaging paper grades explained; mineral oil barriers and food-safe cartons

Refining (beating; DE: Mahlung)

Refining, also called beating, is the mechanical treatment of pulp between bars on rotating discs, which roughens and frays the fibre surface so fibres bond more tightly in the sheet. More refining raises density, tensile strength and smoothness and lowers porosity and bulk; tear strength usually rises at first and then falls. The degree of refining is measured as drainage resistance in Schopper-Riegler degrees (ISO 5267-1) or Canadian Standard Freeness (ISO 5267-2); greaseproof paper and glassine get their fat resistance from very intensive refining.

Softwood and hardwood fibre (long fibre and short fibre; DE: Langfaser, Kurzfaser)

Softwood fibre from conifers such as pine and spruce is typically about 2-4 mm long, while hardwood fibre from species such as birch, eucalyptus or acacia is typically about 1 mm. Long fibre gives tear and tensile strength and is the backbone of sack kraft and kraftliner; short fibre gives smoothness, formation and opacity. Most papers and boards blend the two to balance strength against print surface.

Sulphite pulp (US: sulfite pulp; DE: Sulfitzellstoff)

Sulphite pulp is chemical pulp cooked with sulphurous acid and bisulphite salts rather than the alkaline kraft liquor. It is easier to bleach and refine than kraft pulp but gives weaker fibres, and its share of world pulp production is now small. It survives in speciality grades, including some greaseproof and glassine papers, and in dissolving pulp for cellulose products.

Virgin fibre (fresh fibre; DE: Frischfaser)

Virgin fibre is pulp made directly from wood or other plants rather than from recovered paper. It gives more strength per gram, a stable shade and a known history, which is why it is commonly specified for direct contact with fatty, moist or hot food. No EU, UK or US rule requires virgin fibre as such; it is one way of meeting food-contact obligations, alongside functional barriers.

See: packaging paper grades explained

Paper grades

Named paper grades that appear on packaging quotations. Food-wrap grades are compared in greaseproof vs parchment vs wax paper.

Airlaid (airlaid nonwoven)

Airlaid is a soft, cloth-like nonwoven made from cellulose fluff pulp that is formed into a web with air instead of water and then bonded, typically with a latex binder or thermoplastic fibres. It is thicker, more absorbent and more textile-like than tissue, and it is used for premium napkins, absorbent pads and table covers. Binder type affects whether the product behaves as paper in recycling.

See: 1-ply, 2-ply, 3-ply and airlaid napkins

Baking paper (US: parchment paper; DE: Backpapier; NL: bakpapier)

Baking paper is a greaseproof or vegetable parchment base coated on one or both sides with silicone, giving a non-stick surface that typically tolerates oven temperatures up to around 220-230 °C, depending on grade. In the US it is usually sold as parchment paper, which causes confusion with uncoated vegetable parchment. It is a release paper rather than a takeaway wrap and does not heat seal.

See: greaseproof vs parchment vs wax paper

Coated paper (C1S, C2S; DE: gestrichenes Papier)

Coated paper carries a pigment coating of fine minerals such as kaolin clay or calcium carbonate held in a binder, applied on one side (C1S) or both sides (C2S). The coating fills the fibre surface, giving higher smoothness, gloss and print sharpness than uncoated paper. In packaging it is used for labels, premium wraps and bag papers; a pigment coating improves print, not grease or water resistance, which need a barrier.

Extensible kraft (extensible sack kraft)

Extensible kraft is kraft paper compacted in the machine direction on the paper machine, a micro-creping process often known by the Clupak trade name, so it can stretch several percent before breaking. That extra stretch raises tensile energy absorption, letting a lighter paper survive drops and shocks that would split conventional kraft. It is the standard for multiwall sacks and is sometimes used for heavy-duty carrier bags.

See: packaging paper grades explained

Glassine (DE: Pergamin)

Glassine is greaseproof paper that has been supercalendered, pressed between polished rolls, until it is smooth, dense and translucent, typically at about 40-90 gsm. It resists grease and air through its density and is used for bakery bags, interleaving, confectionery and, when silicone-coated, as a release liner for labels. It can turn brittle in cold, dry conditions.

See: packaging paper grades explained

Greaseproof paper (DE: Pergamentersatz, fettdichtes Papier; NL: vetvrij papier)

Greaseproof paper is paper whose fibres are refined so intensively that the sheet becomes dense with very few pores, so it resists fat through its structure rather than through a coating. It is typically 30-60 gsm, rated for grease resistance by the KIT test, and properly made it needs no fluorochemicals. It is not waterproof and does not heat seal, and its EPR treatment varies by scheme, so it should be specified by grammage, KIT level and fluorine-free status rather than by name alone.

See: custom printed greaseproof paper; greaseproof vs parchment vs wax paper

Grease-resistant paper

Grease-resistant paper is an ordinary base paper, often MG kraft, given resistance to fat by a coating or surface treatment rather than by fibre refining. Its performance depends on the coating staying intact, so fold lines and creases can become weak points. Specifications should state the coating type, KIT level and confirmation that no fluorochemicals are intentionally added.

See: grease-resistant food bags compared

Kraft paper (DE: Kraftpapier; NL: kraftpapier)

Kraft paper is paper made from chemical pulp produced by the kraft (sulphate) process, which keeps fibres long and strong. It is supplied unbleached (brown), bleached (white) or with recycled content, as MF, MG or sack kraft grades, typically from about 25 gsm for light food bags to 150 gsm or more for heavy carrier bags. The word on its own says nothing about grammage, fibre source or surface, so a kraft specification needs all three.

See: packaging paper grades explained; brown vs white vs recycled kraft for bags

MF kraft (machine finished kraft)

MF kraft is kraft paper with the same matt texture on both sides, finished by light calendering on the paper machine. It is the standard material for handled carrier bags and SOS bags, typically from around 50-80 gsm for SOS and light takeaway bags up to 120-150 gsm for heavier retail bags. Its open surface gives a natural look but absorbs ink, so fine screens and small reversed text are harder to hold.

See: paper bag GSM guide

MG paper (machine glazed paper; MG kraft)

MG paper is paper dried against a large, polished, steam-heated Yankee cylinder, which leaves one side smooth and glossy and the other rough. It is usually around 25-60 gsm and is the standard base for counter, sandwich and bakery bags and many food wraps. The glazed side prints sharper and holds out grease slightly better than MF kraft, but on its own MG paper is not greaseproof.

See: packaging paper grades explained

Recycled kraft (recycled brown paper)

Recycled kraft is a trade name for brown packaging paper made wholly or largely from recovered fibre, usually OCC and used kraft papers, rather than fresh kraft pulp. It has lower strength per gram and more shade and speck variation than virgin kraft, so bags often need a heavier grammage for the same load. Some US jurisdictions set minimum post-consumer recycled content for paper carryout bags, which makes the recycled-content percentage part of the specification there.

See: brown vs white vs recycled kraft for bags; paper bag regulations by market

Sack kraft (DE: Sackkraftpapier)

Sack kraft is strong, porous kraft paper made from long virgin softwood fibre for multiwall sacks, typically 70-120 gsm. It is designed for high tensile energy absorption (TEA), so a filled sack survives drops, and for high air permeability, so cement or flour sacks de-aerate during filling. It is available in standard and extensible grades and sets the benchmark for what "strong kraft" means, though printed retail packaging rarely needs it.

See: packaging paper grades explained

Tissue (DE: Tissue, Hygienepapier)

Tissue is very light, soft and absorbent paper, usually well under 30 gsm per ply, dried on a Yankee cylinder and scraped off with a creping blade that gives it bulk and stretch. It is used for napkins, hand towels and wrapping tissue, and plies are combined and embossed for thickness and softness. Wet-strength additives are used in some grades so napkins hold together when damp.

See: 1-ply, 2-ply, 3-ply and airlaid napkins

Vegetable parchment (DE: Pergament, Pergamentpapier)

Vegetable parchment is paper passed briefly through a sulphuric acid bath that gelatinises and fuses the surface fibres, then washed and dried. It has high wet strength, very good grease resistance and tolerance for boiling and baking, and it is what the German word Pergament properly describes. It usually costs more than greaseproof paper and is used where wet strength or heat resistance is needed without a coating.

See: greaseproof vs parchment vs wax paper

Wax paper (US also deli paper)

Wax paper is a light paper treated with paraffin or another wax, giving good water and moisture resistance but little heat tolerance, because wax softens and melts. In the US, deli paper is a trade name for light food-safe counter sheets that are usually dry wax paper but sometimes greaseproof, so the material should be stated. Heavily waxed paper repulps poorly.

See: greaseproof vs parchment vs wax paper

White kraft (bleached kraft)

White kraft is kraft paper made from bleached kraft pulp, giving a clean white base for bright print and a fresh look on food bags. It is typically somewhat weaker than unbleached kraft of the same grammage and costs more. Colours print brighter and closer to target on white kraft than on brown, where the base shade dulls and shifts colour.

See: brown vs white vs recycled kraft for bags

Paper properties and units

The measurements on a paper or board data sheet. Strength and barrier test methods are defined in the testing and quality glossary.

Basis weight (US; lb per ream)

Basis weight is the US way of stating paper weight: the weight in pounds of a ream of a defined size. For bag paper the ream is 3,000 square feet, so 1 lb is about 1.63 gsm and a 50 lb bag paper is roughly 81 gsm; paperboard is often quoted per 1,000 square feet, where 1 lb is about 4.88 gsm. Other sectors use other ream sizes, so confirm the basis before converting.

See: paper bag GSM guide

Brightness (ISO brightness; DE: ISO-Weißgrad)

Brightness is the percentage of blue light (around 457 nm) that paper reflects, measured as ISO brightness under ISO 2470-1 or, in North America, often as TAPPI directional (GE) brightness. Fully bleached chemical pulp boards typically reach high brightness, while unbleached kraft and recycled grades are much lower. Optical brightening agents raise measured brightness; food-contact specifications commonly require that they do not migrate.

Bulk (specific volume; DE: spezifisches Volumen)

Bulk is caliper divided by grammage, expressed in cm³/g, and describes how thick a sheet is for its weight. Typical values are about 1.4-1.7 cm³/g for folding boxboard, 1.2-1.35 for solid bleached board and 1.3-1.5 for white lined chipboard. Because stiffness rises steeply with thickness, a high-bulk board can reach the same stiffness at a lower grammage, which cuts material weight.

See: FBB vs SBS vs WLC

Caliper (thickness; DE: Dicke; NL: dikte; US: points, pt)

Caliper is the thickness of a paper or board, usually stated in micrometres (µm) and measured to ISO 534; US converters quote board in points, where 1 pt = 0.001 inch = 25.4 µm. Bending stiffness rises roughly with the cube of thickness, so two boards of the same gsm can perform very differently. A lower price on a lower-caliper board is therefore not a like-for-like offer.

See: packaging paper grades explained

Calendering and supercalendering

Calendering passes paper or board through nips between rolls to smooth the surface and even out thickness, at the cost of some bulk. Supercalendering uses a stack of alternating hard and soft rolls under high pressure and is what turns greaseproof paper into dense, translucent glassine. Heavier calendering gives better print and grease hold-out but a thinner, less stiff sheet for the same grammage.

Density (apparent density)

Density is grammage divided by caliper, expressed in g/cm³, and is the inverse of bulk. Bulky boards and open kraft papers sit well below 1 g/cm³, while heavily refined and calendered papers such as glassine approach or exceed it. Higher density usually means better print sharpness and grease hold-out but less stiffness per gram.

Dry strength (dry-strength additives)

Dry strength is the strength of paper in normal, conditioned use, mainly tensile, burst and compression. Mills raise it with refining and with dry-strength additives such as cationic starch, carboxymethyl cellulose or synthetic polymers, which improve fibre bonding. These additives let a mill reach a strength target with less fibre or more recycled content.

Grain direction (machine direction and cross direction, MD/CD; DE: Laufrichtung; NL: looprichting)

Grain direction is the direction in which paper travelled through the paper machine (machine direction, MD), along which most fibres align; cross direction (CD) is at right angles to it. Tensile strength and stiffness are higher in MD, while tear resistance and moisture expansion are usually higher in CD, so data sheets quote both values. Converters set the grain on the dieline or bag tube so that creases, handles and stiff panels run the right way.

See: packaging paper grades explained

Grammage (gsm, g/m²; DE: Grammatur, Flächengewicht; NL: grammatuur)

Grammage is the mass of one square metre of paper or board, stated in grams per square metre (gsm or g/m²) and measured to ISO 536. It is the value paper is traded on, the main driver of material cost and the basis for packaging-weight reporting under EPR schemes. Grammage does not describe thickness; that is caliper.

See: packaging paper grades explained; paper bag GSM guide

Moisture content (DE: Feuchtegehalt)

Moisture content is the share of water in paper or board by weight, measured by oven drying under ISO 287 and typically about 5-9 % at delivery, depending on grade and climate. Paper absorbs and releases moisture with the surrounding air, which changes its dimensions, stiffness and compression strength. Too dry and boards crack at the crease; too damp and they curl, cockle or lose stacking strength.

Opacity (DE: Opazität)

Opacity is the ability of paper to hide what is behind it, measured as a percentage under ISO 2471 by comparing reflectance over a black backing with reflectance over a stack of the same paper. High opacity stops print showing through and hides contents such as greasy food; translucent grades such as glassine are low-opacity by design. Fillers, mechanical pulp and coating raise opacity, while refining and calendering lower it.

Porosity (air permeability; DE: Luftdurchlässigkeit)

Porosity describes how easily air passes through paper and is reported as air permeability, for example in Gurley seconds per 100 ml (ISO 5636-5) or Bendtsen ml/min (ISO 5636-3). Sack kraft is made porous so sacks vent during filling, while greaseproof and glassine are made almost closed so fat cannot penetrate. Porosity also affects how a sheet feeds on vacuum-fed machines and how much coating or ink it absorbs.

Sizing (internal and surface sizing; DE: Leimung)

Sizing is treatment that makes paper resist water penetration. Internal sizing adds agents such as AKD, ASA or rosin to the pulp so the fibres themselves repel water, which is what stops liquid wicking into the cut edges of cupstock; surface sizing applies starch or similar on a size press to strengthen the surface and control ink and coating absorption. Sizing slows water uptake, measured by the Cobb test, but does not make paper waterproof.

Smoothness (DE: Glätte)

Smoothness is how flat the paper surface is at the scale that matters for printing, usually measured by air leakage methods such as Bendtsen (ISO 8791-2) or Parker Print-Surf (ISO 8791-4), where lower values mean smoother paper. Smooth surfaces print finer screens and sharper type with less ink. Coating and calendering raise smoothness; MF kraft and recycled grades are rougher.

Standard climate (conditioning; ISO 187)

Standard climate is the atmosphere in which paper and board are conditioned and tested: 23 °C and 50 % relative humidity under ISO 187, with 27 °C and 65 % RH as the tropical alternative. Because moisture changes strength and dimensions, results are only comparable when samples have been conditioned to the same climate. Data sheets that omit the climate should be queried.

Wet strength (DE: Nassfestigkeit; NL: natsterkte)

Wet strength is the strength paper keeps when fully soaked, usually expressed as wet tensile strength as a percentage of dry tensile strength. Untreated paper keeps only a small fraction, while wet-strength grades made with resins such as polyamidoamine-epichlorohydrin (PAE) keep considerably more. Wet strength helps napkins, carrier bags in rain and labels, but it makes paper harder to repulp.

Whiteness (CIE whiteness)

Whiteness describes how white paper looks to the eye across the visible spectrum, usually reported as CIE whiteness (for example under ISO 11475), and can be tinted bluish or yellowish at the same brightness. It is the more meaningful value for matching board shades between suppliers. Two boards with similar brightness can look noticeably different in whiteness and shade, which shows on large solid-white areas.

Paperboard and carton board

Board classes and construction for cartons, cups and food boxes. Board choice for cartons is covered in FBB vs SBS vs WLC.

CKB (coated unbleached kraft board; also CUK, SUS)

CKB, also called CUK (coated unbleached kraft) or SUS (solid unbleached sulphate), is virgin unbleached kraft board, often with a white coated top layer that prints full colour while the inside stays brown. It is strong and tear-resistant for its weight and holds up well in moist conditions. It is used for takeaway boxes, beverage carriers and multipacks where strength and a natural kraft look are wanted.

See: kraft vs white board takeaway boxes

Clay coating (pigment coating; DE: Strich)

Clay coating, more accurately pigment coating, is a layer of fine mineral pigments such as kaolin clay and calcium carbonate held in a latex or starch binder and applied to the print side of board. Boards may be single, double or triple coated, with total coat weights commonly in the region of 10-30 g/m², to give a smooth, white, ink-receptive surface. It improves print but is not a grease or water barrier.

Coated and uncoated board (DE: gestrichen / ungestrichen)

Coated board carries a pigment coating on the print side, and sometimes on the reverse, while uncoated board shows the bare fibre surface. Coated board gives sharper, brighter print and better varnish and foil results; uncoated board has a natural, matt feel and absorbs more ink. In DIN 19303 codes, G marks a coated surface and U an uncoated one.

Cupstock (cupboard; DE: Becherkarton)

Cupstock is paperboard made specifically for forming cups and round containers, typically 170-350 gsm, made from virgin fibre and internally sized so liquid does not wick into the cut edges. It is coated on the inside, and on both sides for cold cups, with PE or an aqueous dispersion barrier, and must withstand side-seam sealing, bottom curling and rim rolling. Folding carton boards look similar but are not designed for those forming steps.

See: packaging paper grades explained; paper cup linings

DIN 19303 (paperboard classification)

DIN 19303 is the German standard, widely used across Europe, that classifies paperboard with a letter-number code; the current edition dates from April 2026 and keeps the same code structure. The first letter gives the surface (G coated, U uncoated), the second the main furnish (Z solid bleached chemical pulp, C virgin board with a mechanical pulp middle, T recycled with a white or cream back, D recycled with a grey back), and the number a sub-class, such as reverse colour for GC1 (white) and GC2 (cream) or bulk for the recycled GD and GT classes. Mills sell branded products within each class, so the code identifies the class and the mill data sheet gives the specification.

See: FBB vs SBS vs WLC

FBB (folding boxboard; GC1/GC2; DE: Faltschachtelkarton)

FBB is multi-ply virgin-fibre carton board with bleached chemical pulp outer plies and a bulky mechanical or CTMP pulp middle, classed GC1 (white reverse) or GC2 (cream reverse) under DIN 19303. Its high bulk gives more stiffness per gram than SBS, so it is widely used for food and consumer cartons. Typical bulk is about 1.4-1.7 cm³/g.

See: FBB vs SBS vs WLC

Greyboard (chipboard; DE: Graukarton, Graupappe)

Greyboard is board made entirely from recycled fibre, grey throughout and usually uncoated, used for rigid set-up boxes wrapped in printed paper, book covers, backing boards and dividers. It is dense and stiff but has no print surface of its own. In the US, chipboard usually means this kind of grey board, whereas in UK and European specifications white lined chipboard (WLC) is a coated carton board, so the term should be confirmed.

Liquid packaging board (LPB; DE: Flüssigkeitskarton)

Liquid packaging board is multi-ply virgin-fibre board made for beverage and liquid food cartons, laminated in converting with polyethylene on both sides and, for ambient long-life products, a thin aluminium foil layer. It needs high stiffness, clean taste and odour, and strong edge-wicking resistance. Fibre typically makes up roughly three quarters of a carton's weight, with the polymer and foil layers separated during recycling.

Paperboard (board; DE: Karton; NL: karton)

Paperboard is a heavier, stiffer grade of paper used for cartons, cups and boxes. There is no single universal cut-off, but material above roughly 200-250 gsm is generally called board; carton boards are classified by fibre and construction, for example as FBB, SBS, WLC or CKB. In German, Karton usually means carton board, while Pappe refers to heavier solid boards.

See: FBB vs SBS vs WLC

Ply (multi-ply board)

A ply is one of the fibre layers formed separately on the board machine and joined while wet into a single sheet. Multi-ply construction lets a mill put clean, bleached fibre on the outside and cheaper or bulkier fibre in the middle, as in the typical three-ply structure of FBB and WLC. Ply bond strength matters for creasing, gluing and resistance to delamination.

SBS (solid bleached sulphate; SBB; GZ)

SBS, also called SBB (solid bleached board) and classed GZ under DIN 19303, is carton board made of bleached chemical pulp in all plies. It is white throughout and dense, typically with a bulk of about 1.2-1.35 cm³/g, and takes deep embossing, fine foil and crisp die-cutting. It is the traditional choice for premium cosmetics, pharmaceuticals and confectionery; in the US, SBS is the default term for high-quality virgin carton board.

See: FBB vs SBS vs WLC

WLC (white lined chipboard; GD2/GT; US: CRB; DE: Chromoersatzkarton)

WLC is recycled-fibre carton board with a white top liner, classed GD (grey back) or GT (white or cream back) under DIN 19303; GD2 is the standard grade usually meant by WLC. In the US it is called coated recycled board (CRB). It is the economy choice for non-food retail cartons and is used for food only behind a suitable functional barrier or with a separately packed product.

See: FBB vs SBS vs WLC; mineral oil barriers and food-safe cartons

Corrugated board

Containerboard papers, flute profiles and board construction. Flute calipers below are typical; exact values depend on the corrugator and papers. Board grades for boxes are covered in corrugated board grades for mailer boxes and E-flute vs B-flute pizza boxes.

A-flute

A-flute is the tallest common corrugated flute, typically about 4.5-5 mm thick with roughly 105-125 flutes per metre. It gives the most cushioning and top-to-bottom compression for a single-wall board but has a coarse print surface. It is less common in Europe today than C-flute and appears mainly in heavy-duty and double or triple wall combinations.

B-flute

B-flute is a medium-fine corrugated flute, coarser than E and finer than C, typically about 2.5-3.2 mm thick with about 150-185 flutes per metre, giving more stiffness, cushioning and crush resistance than E-flute. It is widely used for large pizza boxes, US delivery boxes, heavier mailers and retail displays. Flute tips can show through solid print as washboarding.

See: E-flute vs B-flute pizza boxes

Board grade notation (for example 125K/125T)

Corrugated board grades are often written as a short code listing the papers from outside to inside, with grammage and a letter for paper type: K for kraftliner and T for testliner are widespread, and suppliers add their own letters for white-top, mottled, semi-chemical or recycled fluting. A "125K/125T B flute" therefore means a 125 gsm kraftliner outside, a 125 gsm testliner inside and B-flute between, with the fluting paper sometimes stated separately or implied by the supplier's standard. Conventions differ between companies and countries, so a quotation comparison should spell out every paper, grammage and flute rather than rely on the code.

See: corrugated board grades for mailer boxes

C-flute

C-flute is a medium-height corrugated flute, typically about 3.5-4.5 mm thick with roughly 120-145 flutes per metre. It is the standard flute for single-wall shipping cases because it balances stacking strength, cushioning and board weight. Its coarse surface suits post-print flexo rather than fine graphics.

Containerboard (DE: Wellpappenrohpapier)

Containerboard is the collective term for the papers used to make corrugated board: linerboards (kraftliner, testliner and white-top grades) and fluting papers. It is traded by grammage and strength class, and its price drives most of the material cost of a corrugated box. Containerboard mills and corrugator plants are often separate businesses.

Corrugated board (DE: Wellpappe; NL: golfkarton; US: corrugated cardboard)

Corrugated board is a sandwich of flat liners glued to one or more fluted (wavy) layers of paper called fluting or corrugating medium. Single wall has one flute between two liners; double wall, for example EB, has two flutes and three liners. The liners carry print and most of the burst strength, while the fluting provides thickness and compression resistance.

See: corrugated board grades for mailer boxes

Double wall (EB, BC; DE: zweiwellige Wellpappe)

Double wall board has two fluted layers and three liners, combining two flute profiles such as E with B (EB, typically about 4-5 mm) or B with C (BC, typically about 6-7 mm). It gives much higher stacking strength and puncture resistance than single wall and is used for heavy contents, export cartons and long or rough transit. The finer flute is normally placed outside for a better print surface.

See: corrugated board grades for mailer boxes

E-flute (microflute)

E-flute is a fine single-wall corrugated flute, typically about 1.1-1.8 mm thick with about 290-330 flutes per metre, giving a smooth print surface and good stiffness for its thickness. It is the default for most mailer boxes and common for small and medium pizza boxes in continental Europe. It takes direct print well and is often used for litho-laminated retail packs.

See: E-flute vs B-flute pizza boxes

F-flute

F-flute is a very fine corrugated flute, typically about 0.8-1.0 mm thick with 400 or more flutes per metre, close in feel to a thick carton board. It is used for small premium boxes, letterbox packs and retail cartons where a carton board would be too weak or a coarser flute too bulky. Its flat surface suits litho-lamination and fine print.

Flute (flute profile)

A flute is the wave formed in the corrugating medium, and the flute letter describes its height and pitch. Typical single-wall thicknesses are about 0.5-0.6 mm for N-flute, 0.8-1.0 mm for F, 1.1-1.8 mm for E, 2.5-3.2 mm for B, 3.5-4.5 mm for C and 4.5-5 mm for A. The letters were assigned historically rather than in size order, and exact caliper depends on the corrugator and the papers used.

See: corrugated board grades for mailer boxes

Fluting (corrugating medium; DE: Wellenstoff)

Fluting is the paper that is heated, steamed and formed into flutes on the corrugator, then glued between liners. It is typically about 90-180 gsm and comes as semi-chemical fluting or recycled fluting. Fluting is rarely seen or printed, but its compression strength decides much of a box's stacking performance and how flat the printed surface stays.

See: packaging paper grades explained

Kraftliner

Kraftliner is a containerboard liner made mainly from virgin kraft fibre, typically 115-440 gsm, with higher burst, tensile and compression strength per gram than testliner and better strength retention in humidity. It is supplied brown or with a white bleached top. It is often specified for pizza boxes, heavy shipping boxes and export packs.

See: packaging paper grades explained

Mottled liner (mottled white liner)

A mottled liner is a white-top liner whose bleached top layer is thin enough for the brown base to show through as an uneven, cloudy pattern. It is cheaper than a fully white liner and gives a lighter background than brown kraft. The uneven base makes colour and large solid areas less consistent, so it suits simple graphics better than photographic print.

N-flute and G-flute (microflutes)

N-flute and G-flute are the finest corrugated profiles, typically about 0.5-0.6 mm thick, made to compete with folding carton board in retail packaging. They give a near carton-like print surface with the crush resistance and rigidity of corrugated at low weight. Designations and exact profiles vary between corrugator manufacturers, so confirm caliper rather than relying on the letter.

Recycled fluting (DE: Wellenstoff)

Recycled fluting is corrugating medium made from recovered paper, mainly OCC, and is the cost-driven alternative to semi-chemical fluting. It gives lower stiffness and compression strength per gram and is more sensitive to humidity. It is the most common fluting in European corrugated packaging; in German specifications, Wellenstoff often refers to this grade.

Semi-chemical fluting (NSSC fluting)

Semi-chemical fluting is corrugating medium made mainly from virgin hardwood pulp produced by a semi-chemical process such as neutral sulphite semi-chemical (NSSC) pulping. It gives stiffer flutes, higher flat crush and compression strength and better performance in humid conditions than recycled fluting. It is specified where stacking strength under moisture matters, for example for fruit and vegetable trays.

Single wall and single face (DE: einwellige Wellpappe)

Single wall board, also called double face, has one fluted layer glued between two liners and is the most common corrugated construction. Single face board has a fluted layer glued to only one liner, leaving the flutes exposed, and is flexible enough to wrap round products as cushioning. Most mailers, pizza boxes and shipping cases are single wall.

Take-up factor

The take-up factor is the length of fluting paper needed to make one unit length of corrugated board, which depends on flute height and pitch and typically ranges from about 1.2 for fine flutes to around 1.5 or more for A-flute. It is used to calculate board grammage and cost from the papers specified. Taller flutes use more medium per square metre, adding weight and material cost.

Testliner

Testliner is a containerboard liner made mainly from recycled fibre, typically 100-300 gsm and graded by strength class (often labelled TL1 to TL3). It is cheaper than kraftliner but needs more weight for the same strength and loses strength faster when damp. It is widely used for mailer boxes, transit cases and the inside liner of mixed-liner grades.

See: packaging paper grades explained

Triple wall

Triple wall board has three fluted layers and four liners, typically around 10-15 mm thick depending on flute combination. It is used for heavy-duty bulk bins, pallet boxes and some export packaging as an alternative to wooden crates. It is rarely printed beyond simple marks.

White-top liner (white-top testliner, white kraftliner)

A white-top liner has a bleached white fibre layer formed over a brown kraft or recycled base, giving a light print surface on corrugated board. White-top testliner is a common economical white print surface; white kraftliner and coated white liners give cleaner, brighter print at higher cost. The evenness of the white layer decides how consistent large colour areas look.

See: corrugated board grades for mailer boxes

Plastics and films

Polymers, films, deposited barriers and multilayer structures used in bags, pouches, windows and lids. Laminate structures are explained in pouch laminate structures and barrier properties; PE bag films in LDPE vs HDPE vs recycled PE bags.

AlOx (aluminium oxide coating)

AlOx is a transparent aluminium oxide layer, a few nanometres to tens of nanometres thick, vacuum-deposited on PET, BOPP or PE film to give a high oxygen and moisture barrier while keeping the film clear. Unlike foil or metallisation, it lets the product be seen and is generally compatible with microwaves and metal detectors. Thin ceramic layers can crack if the film is overstretched or sharply creased, so barrier data should be checked on converted packs.

See: pouch laminate structures and barrier properties

Aluminium foil (US: aluminum foil; DE: Aluminiumfolie; NL: aluminiumfolie)

Aluminium foil is rolled aluminium sheet, typically about 6-9 µm thick in flexible laminates and much heavier in semi-rigid trays and containers. When intact it is a near-absolute barrier to oxygen, moisture, light and aroma, but thin foils can contain pinholes and crack under flexing. Foil cannot be recycled in plastic or paper streams without separation, which counts against foil laminates in design-for-recycling assessments.

See: pouch laminate structures and barrier properties

Bio-based PE (sugarcane PE)

Bio-based polyethylene is polyethylene made from ethanol derived from sugarcane or other plant feedstocks instead of from fossil sources. It is chemically identical to conventional PE, so it performs, seals and recycles in the same way. It is not biodegradable or compostable, and claims about its bio-based content should state the share and the method used to measure it.

BOPP (biaxially oriented polypropylene)

BOPP is polypropylene film stretched in both machine and cross directions, which makes it stiff, clear and dimensionally stable, typically used at about 15-40 µm. It has a good moisture barrier but a poor oxygen barrier unless metallised or coated, and comes in clear, white, pearlised and matt versions. It is used as the print or outer layer in snack and confectionery packs, often with CPP as the sealant, and as the film in carton lamination.

See: pouch laminate structures and barrier properties

Co-extrusion (coex; tie layer)

Co-extrusion is the process of melting several polymers in separate extruders and combining them in one die to form a single multilayer film or coating, commonly 3, 5, 7 or more layers. Where layers do not bond naturally, such as PE and EVOH or PA, thin tie layers of adhesive resin join them. Coextrusion builds barrier and sealing performance into one film without adhesive lamination.

CPP (cast polypropylene)

CPP is polypropylene film made by casting the melt onto a chilled roll without orientation, giving a clear, soft and heat-sealable film. It is the usual sealant layer in BOPP/CPP and some PET laminates and is available in grades that tolerate high-temperature sterilisation. It has higher heat resistance than PE sealants but a narrower sealing window.

EPS (expanded polystyrene)

EPS is polystyrene foamed into light, insulating beads moulded into cups, clamshells, trays and protective packaging. Under the EU Single-Use Plastics Directive, EPS food containers for immediate consumption and EPS beverage containers and cups have been banned from the EU market since 3 July 2021. England, Scotland and Wales also ban EPS food and drink containers for ready-to-consume food, which is why EPS has largely left European foodservice.

See: paper vs plastic bowls

EVOH (ethylene vinyl alcohol)

EVOH is a copolymer of ethylene and vinyl alcohol with an outstanding oxygen barrier, used as a thin internal layer in coextruded films, trays and bottles. Its barrier falls as humidity rises, so it is always buried between moisture-resistant layers such as PE or PP, joined by tie layers. Design-for-recycling guidelines typically accept EVOH in PE or PP packs up to a few percent of total weight, which is why it is the usual oxygen barrier in recyclable mono-material structures.

See: recyclable mono-material pouches

HDPE (high-density polyethylene)

HDPE is polyethylene with long, mostly linear chains that pack into crystalline regions, giving a typical density of about 0.941-0.965 g/cm³. HDPE film is stiff, strong for its thickness, milky and rustling, which suits vest (T-shirt) bags, thin produce bags and liners. It is less clear and less puncture-resistant than LDPE/LLDPE blends but allows thinner films for the same load.

See: LDPE vs HDPE vs recycled PE bags

Laminate (adhesive and extrusion lamination; DE: Verbund)

A laminate is a material built from two or more layers, such as PET/PE or PET/ALU/PE, bonded so that each layer contributes print surface, barrier, strength or sealability; structures are written from outside to inside. Adhesive lamination joins webs with a thin adhesive, usually polyurethane, which then needs curing time; extrusion lamination bonds them with a layer of molten polymer, typically PE. Laminates of different materials give high performance but are harder to recycle than mono-material structures.

See: pouch laminate structures and barrier properties

LDPE (low-density polyethylene)

LDPE is polyethylene made by high-pressure polymerisation, with many long side branches that keep chains apart, giving a softer, more transparent film with a typical density of about 0.910-0.940 g/cm³. It processes easily and seals well, which makes it the standard polymer for extrusion coating of paper and board and a common sealant and bag film. It is usually blended with LLDPE for strength.

See: LDPE vs HDPE vs recycled PE bags

LLDPE (linear low-density polyethylene)

LLDPE is polyethylene made by copolymerising ethylene with a small amount of butene, hexene or octene, giving linear chains with short branches. Compared with LDPE it has higher tensile, puncture and tear strength and better hot tack, so it allows thinner films for the same duty. An LDPE/LLDPE blend is the typical retail carrier bag and pouch sealant film.

See: LDPE vs HDPE vs recycled PE bags

MDO-PE and BOPE (oriented polyethylene films)

MDO-PE is polyethylene film stretched in the machine direction, and BOPE is polyethylene film stretched in both directions; orientation makes PE stiffer, clearer and more heat-resistant. These films replace PET or BOPP as the printed outer layer so that a whole laminate can be made from PE. They are central to recyclable mono-PE pouch designs, although they still have less heat resistance than PET in sealing.

See: recyclable mono-material pouches

Metallised film (metPET, metBOPP; US: metallized)

Metallised film is plastic film coated with an extremely thin layer of aluminium, a few tens of nanometres, by evaporation in a vacuum chamber. It greatly improves light, oxygen and moisture barrier compared with the base film, with metallised PET typically outperforming metallised BOPP; the metal layer is usually specified by optical density. Barrier drops if the metal layer cracks under flexing, and it blocks product visibility.

See: pouch laminate structures and barrier properties

Micron, gauge and mil (film thickness units)

A micron (µm) is one thousandth of a millimetre and is the metric unit for film thickness. A mil is one thousandth of an inch, equal to 25.4 µm, and is the usual US unit, while UK gauge is a polythene trade unit in which 100 gauge equals 25.4 µm, so micron × 4 gives approximately gauge. Bag thickness normally refers to a single film wall, and the unit should always be stated on a quotation.

See: plastic bag thickness: micron, gauge and mil

mLLDPE (metallocene linear low-density polyethylene)

mLLDPE is LLDPE made with metallocene (single-site) catalysts, which give a narrow molecular weight distribution and very even comonomer placement. The result is higher toughness, puncture and dart impact strength, better clarity and a lower seal initiation temperature than conventional LLDPE. It enables thinner, faster-sealing films at a higher resin price.

See: LDPE vs HDPE vs recycled PE bags

Mono-material

Mono-material packaging is made predominantly from one polymer family, for example an all-PE or all-PP pouch, so it can be recycled in that material's stream. Small proportions of barrier layers, coatings or tie layers may be included; acceptance depends on design-for-recycling guidelines and, in the EU, on the PPWR recyclability criteria still to be adopted. Mono-material does not mean single-layer.

See: recyclable mono-material pouches

Multilayer (multilayer film; multi-material)

Multilayer describes a film or structure with more than one layer, made by coextrusion, coating or lamination. A multilayer structure can still be mono-material, such as a five-layer all-PE coextrusion, or multi-material, such as PET/ALU/PE. For recycling the question is which materials the layers are made of, not how many layers there are.

OPA (oriented polyamide; BOPA; nylon)

OPA is biaxially oriented polyamide film, usually nylon 6, typically about 12-15 µm thick in laminates. It gives outstanding puncture and flex-crack resistance and a moderate oxygen barrier that weakens as it absorbs moisture. It is used in vacuum packs for meat and cheese, pet food and heavy or sharp products, and it complicates recycling of PE-based laminates.

See: pouch laminate structures and barrier properties

PCR and PIR (post-consumer and post-industrial recycled content)

PCR is material recycled from products used by consumers, while PIR (post-industrial or pre-consumer recycled) is recycled production scrap. Recycled-content rules use their own definitions of which material counts: under the UK Plastic Packaging Tax, for example, pre-consumer plastic waste is no longer accepted as a source of recycled plastic from 1 April 2027. Confirm the applicable definition and the evidence required before specifying a percentage.

See: LDPE vs HDPE vs recycled PE bags

PET (polyethylene terephthalate; BOPET, rPET)

PET is a stiff, clear polyester; as biaxially oriented film (BOPET), typically about 12 µm, it is the outer print layer of many pouch laminates because it resists the heat of sealing jaws. It is also used for transparent lids, cups and trays, and rPET is PET with recycled content. Under the PPWR, contact-sensitive PET packaging other than single-use plastic beverage bottles (which have their own target) must contain at least 30 % recycled content from 1 January 2030, or three years after the implementing act on calculation and verification if that is later.

See: lids for paper food containers; pouch laminate structures and barrier properties

PHA (polyhydroxyalkanoates)

PHA is a family of polyesters produced by bacteria fermenting sugars or plant oils, used as a coating, film or moulded material. Some PHA grades are certified for industrial and home composting, and some for biodegradation in soil or marine conditions, but performance depends on the grade and on the whole construction. Buyers should not assume a PHA coating makes an item plastic-free in regulatory terms; the status should be confirmed for each market.

PLA (polylactic acid)

PLA is a bio-based polyester made from fermented plant sugars, used as a heat-sealable coating on paper cups and containers and as clear film for windows, lids and cold cups. PLA-coated paper can be certified industrially compostable when the whole construction is tested, but PLA is still a plastic in regulatory terms. Standard PLA softens from around 55-60 °C, so hot-fill suitability must be confirmed for the grade.

See: barrier coatings for paper packaging; paper cup linings

Polymer (resin; polyolefin)

A polymer is a material made of very long chain molecules built from repeating units; in packaging the raw polymer is supplied as resin pellets that are melted and formed into film, coatings or rigid parts. Polyolefins, mainly PE and PP, are the largest family in flexible packaging. EU law defines plastic as a polymer with possible additives that can function as a main structural component of packaging, excluding natural polymers that have not been chemically modified.

PP (polypropylene)

PP is a polyolefin with a typical density of about 0.90-0.91 g/cm³, the lowest of the common packaging polymers, and a higher melting point than PE (around 160 °C). It is used as oriented film (BOPP), cast film (CPP), and injection-moulded or thermoformed pots and microwaveable containers. All-PP structures are one of the two main routes to recyclable mono-material flexible packs.

PVDC (polyvinylidene chloride)

PVDC is a chlorinated polymer applied as a coating on BOPP, PET or paper, or used in coextrusions, giving a high barrier to both oxygen and moisture that is little affected by humidity. It is avoided in new designs because its chlorine content interferes with mechanical recycling of PE, PP and PET, degrading during reprocessing and contaminating the recyclate. Design-for-recycling guidelines and many brand and retailer policies exclude it, with EVOH, AlOx, SiOx or metallised layers as the usual replacements.

SiOx (silicon oxide coating)

SiOx is a transparent silicon oxide layer deposited on film in a vacuum, often by plasma-enhanced processes, giving a high oxygen and moisture barrier while keeping the film clear. It tolerates heat treatment well and is used for transparent high-barrier lids, pouches and microwaveable packs. Like AlOx it is very thin and can crack under severe flexing; some grades show a slight tint.

See: pouch laminate structures and barrier properties

Coatings and barriers

Layers applied to paper, board or film to hold back grease, water, oxygen or migrating substances, or to add sealability. Barrier options for paper are compared in barrier coatings for paper packaging.

Acrylic and styrene-based dispersions (styrene-acrylic, styrene-butadiene)

Acrylic and styrene-based dispersions are water-borne synthetic polymer coatings, such as polyacrylates, styrene-acrylic and styrene-butadiene latex, used as barrier layers on paper and board. Depending on formulation they give grease and water resistance, and some grades are heat-sealable or formulated not to stick together (block) in reels and stacks. Because these polymers are synthetic, coated items are generally treated as containing plastic under EU single-use plastics rules, so the regulatory position should be confirmed in writing with the coating supplier.

See: barrier coatings for paper packaging

Aqueous dispersion barrier (dispersion coating; DE: Dispersionsbeschichtung)

An aqueous dispersion barrier is a water-based polymer coating applied as a thin layer to paper or board on a coating line and dried. Depending on formulation it gives grease and water resistance, and some grades heat seal; its main advantage is lower polymer weight and better repulpability than PE, although performance varies widely between formulations. Test results on the actual coated paper matter more than the coating data sheet.

See: barrier coatings for paper packaging; paper cup linings

Bio-based dispersions

Bio-based dispersions are barrier coatings built wholly or partly from renewable materials such as starch, proteins, chitosan, alginates, plant waxes or PHA. Their grease and water resistance varies widely and often depends on humidity and coat weight. Whether a bio-based coating counts as plastic depends on whether its polymer is natural and not chemically modified, so modified starches and fermented polymers need checking.

See: barrier coatings for paper packaging

Coat weight (coating weight)

Coat weight is the dry mass of a coating applied per square metre, stated in g/m² per side. PE extrusion coatings on cupstock are typically in the region of 12-20 g/m² per coated side, while dispersion barriers are usually applied at lower weights, often in more than one pass. Coat weight drives barrier performance, cost, repulpability and the plastic share of the item, which the Commission's non-binding PPWR guidance of 5 June 2026 uses with a 5 % threshold for the Annex V restrictions.

See: barrier coatings for paper packaging

Dry wax and wet wax

Dry waxing drives wax into the paper with heated rolls so the surface feels dry and the sheet resists moisture through its body. Wet waxing leaves a continuous wax film on the surface, giving a glossy finish, a better moisture barrier and the ability to heat seal. Both melt at relatively low temperatures, and heavily waxed papers repulp poorly.

See: greaseproof vs parchment vs wax paper

Fluorochemicals (fluorochemical treatment; PFAS)

Fluorochemicals are fluorinated compounds, part of the PFAS group (per- and polyfluoroalkyl substances), historically used to make paper, board and moulded fibre resist grease and water. Under Article 5(5) of Regulation (EU) 2025/40 (PPWR), food-contact packaging placed on the EU market from 12 August 2026 must stay below 25 ppb for any single PFAS and 250 ppb for the sum of PFAS by targeted analysis, and below 50 ppm for all PFAS including polymeric PFAS, with total fluorine above 50 mg/kg triggering a duty to show whether it comes from PFAS. In the US, FDA announced in February 2024 that PFAS grease-proofing agents are no longer sold for food contact, and many states ban intentionally added PFAS in food packaging.

See: PFAS-free food packaging

Functional barrier

A functional barrier is a layer within a food-contact material that prevents substances in the layers behind it, such as mineral oil from recycled fibre, from migrating into food. It may be a film, a coating, an inner bag or a barrier ply in the board. Where compliance relies on a functional barrier, the Declaration of Compliance should say so.

See: food-contact packaging compliance

Heat-seal coating (HSC; DE: Heißsiegellack)

A heat-seal coating is a lacquer or thin coating, for example acrylic, EVA-based or polyester, that softens under heat and pressure to bond to itself or to another surface. It is applied by gravure, flexo or coating units to paper, aluminium foil or film for lidding, paper sachets and sealed paper bags. Seal strength depends on coat weight, temperature, dwell time and pressure, so the sealing conditions should be agreed with the filler.

Metallised paper (US: metallized paper)

Metallised paper carries an extremely thin vacuum-deposited aluminium layer, applied directly or by transfer from a carrier film, mainly for decoration, with a modest moisture and aroma barrier. It is used for labels, confectionery and decorative wraps. Paper mills generally handle it more easily than foil laminates, but acceptance varies.

See: barrier coatings for paper packaging

Mineral oil barrier

A mineral oil barrier is a layer, coating or inner bag that blocks the migration of mineral oil hydrocarbons (MOSH/MOAH) from recycled-fibre board or inks into food. Typical options include PET, PA, EVOH or metallised films, barrier coatings and adsorbent board layers. It is relevant mainly for dry foods with long shelf life packed in recycled board.

See: mineral oil barriers and food-safe cartons

OPV (overprint varnish)

An overprint varnish is a clear coating printed over ink to protect it from scuffing and rub, control gloss and, on food packaging, help limit set-off. Oil-based, water-based and UV-cured types exist, and low-migration grades are specified for food packaging. An OPV is a print finish, not a grease or water barrier.

See: carton finishes

PE extrusion coating (PE coating; PE-lined)

PE extrusion coating applies molten polyethylene, most often LDPE, as a thin continuous film onto paper or board. It gives excellent water resistance, good grease resistance and reliable heat sealing for cups, containers and wet-food trays, typically at about 12-20 g/m² per coated side. The coated item is treated as containing plastic under EU and UK single-use plastics rules, and the PE film is screened out as reject when the board is repulped.

See: barrier coatings for paper packaging; paper cup linings

PLA coating

PLA coating is polylactic acid applied by extrusion to paper or board, like PE, to give a heat-sealable water and grease barrier. PLA-coated paper can be certified industrially compostable when the whole construction is tested, but PLA remains a plastic in regulatory terms and is a contaminant in conventional plastic recycling. Standard grades soften at lower temperatures than PE, so hot-fill performance must be checked.

See: paper cup linings

Primer

A primer is a thin layer applied to a substrate before printing, coating, extrusion or lamination to improve adhesion. Examples include primers that help PE bond to film or foil in extrusion coating and primers that help inks anchor on low-energy plastic films. Primers form part of the food-contact assessment of the finished structure.

Silicone coating

Silicone coating creates a release surface rather than a classic barrier, so food and labels do not stick. It is used on baking paper and oven liners, where it tolerates oven temperatures, and on release liners for self-adhesive labels. Silicone-coated paper does not heat seal and is often not accepted in standard paper recycling.

See: barrier coatings for paper packaging

Wax (paraffin wax, microcrystalline wax)

Wax for packaging is mainly refined paraffin wax from petroleum, often blended with microcrystalline wax for flexibility or with natural waxes such as beeswax, carnauba or soy wax. It gives water and moisture resistance at low cost and typically melts somewhere between about 45 and 70 °C, so it is unsuitable for hot fatty food held for long, ovens or microwaves. Food-contact wax grades are specified by purity.

See: greaseproof vs parchment vs wax paper

Adhesives

Adhesives join seams, laminate webs and close packs. Their type affects line speed, heat resistance, food-contact documentation and recyclability.

Cold seal (cold seal adhesive; DE: Kaltsiegel)

Cold seal is a coating, typically based on natural rubber latex, applied in a pattern to the inside of a wrapper so that it bonds to itself under pressure alone, without heat. It allows very high-speed packing of heat-sensitive products such as chocolate bars and ice cream, with a release lacquer printed on the outside so reels unwind. Cold seal has a limited shelf life before use, and natural rubber latex content may need to be declared for allergy reasons in some supply chains.

Hot-melt adhesive (hot melt; DE: Schmelzklebstoff)

Hot-melt adhesive is a solvent-free thermoplastic adhesive, commonly based on EVA or polyolefins, applied molten at typically about 120-180 °C and set by cooling within seconds. It is used for carton closing and case sealing, some carton side seams, handle attachment on paper bags and display assembly. Conventional hot melts can form sticky particles in paper recycling, so repulpable or dispersible grades are available.

Laminating adhesive (polyurethane laminating adhesive)

A laminating adhesive bonds two webs in flexible packaging and is most often a two-component polyurethane in solvent-based or solventless form, with water-based systems for some applications. After lamination it needs curing, often several days, before slitting and pouch making. Aromatic polyurethane systems must be fully cured so that primary aromatic amines do not migrate into food in detectable amounts under Regulation (EU) 10/2011.

See: pouch laminate structures and barrier properties

Pressure-sensitive adhesive (PSA)

A pressure-sensitive adhesive stays permanently tacky and bonds on light pressure, without heat, water or solvent. It is used on self-adhesive labels, tapes and resealable flaps, in acrylic, rubber-based and hot-melt types, with permanent, removable and wash-off variants. For paper packaging, the adhesive choice affects whether labels and tapes break down or leave stickies during repulping.

PVAc adhesive (polyvinyl acetate; white glue)

PVAc adhesive is a water-based dispersion of polyvinyl acetate that sets as water is absorbed into the paper and evaporates. It is widely used for carton side seams on folder-gluers, paper bag seams, paper tube winding and window patching on board. It is generally compatible with paper recycling and is available in food-contact compliant grades.

Starch adhesive (DE: Stärkekleber)

Starch adhesive is a water-based adhesive made from maize, wheat, potato or tapioca starch, cooked or chemically modified to control viscosity and tack. It is the standard glue for bonding liners to fluting on the corrugator and is widely used for paper bag tube and bottom seams. It is inexpensive and fully compatible with repulping, though it sets more slowly than hot-melt.

Moulded fibre

Pulp formed into three-dimensional shapes for trays, carriers, tableware and inserts. Formats are compared in moulded fibre vs board cup carriers.

Bagasse (sugarcane bagasse)

Bagasse is the fibrous residue left after juice is pressed from sugarcane, pulped and used mainly for moulded fibre plates, bowls, clamshells and cup lids. It is usually wet-pressed into smooth, rigid shapes, unbleached or bleached, with sizing or barrier additives for grease and water resistance. Fluorochemicals were historically used on such products; the EU PPWR PFAS limits apply to food-contact packaging from 12 August 2026, and Maine's PFAS ban for plant-fibre packaging types took effect on 25 May 2026.

See: PFAS-free food packaging

Dry-moulded fibre (dry forming)

Dry-moulded fibre is an emerging process that forms cellulose fibres into shapes from an air-laid web pressed in heated tools, using little or no water. It promises lower energy use and faster cycles than conventional moulding. It should not be confused with dry-pressed moulded fibre, which is formed from a water-based slurry.

Dry-pressed moulded fibre (conventional moulded fibre)

Dry-pressed moulded fibre is formed by drawing a pulp slurry onto a mesh-covered tool, transferring the wet shape and drying it, usually in an oven, sometimes with a light pressing afterwards. It typically has thicker walls, one smooth side and one rougher side, and is often made from recycled newsprint or OCC. It is used for cup carriers, egg cartons, fruit trays and protective inserts.

See: moulded fibre vs board cup carriers

Moulded fibre (moulded pulp; US: molded fiber; DE: Faserguss)

Moulded fibre is packaging made by forming a dilute pulp slurry on a shaped, mesh-covered tool, removing the water by suction and then drying or hot-pressing the shape. It can use recycled paper, virgin wood pulp or non-wood fibre such as bagasse, and its shape is fixed by the tool, so new shapes need new tooling. It is used for cup carriers, food trays and tableware, egg packs and protective inserts.

See: moulded fibre vs board cup carriers; custom printed cup sleeves and cup carriers

Wet-pressed moulded fibre (thermoformed fibre)

Wet-pressed moulded fibre is formed from slurry and then pressed and dried in heated, matched tools while still wet, giving a dense, thin-walled part that is smooth on both sides. It is the usual process for bagasse and virgin-fibre tableware, clamshells and premium inserts. Tooling and energy costs are higher than for dry-pressed moulding, but the finish and dimensional accuracy are better.

See: moulded fibre vs board cup carriers

Turning material terms into a specification

A material line that a converter can quote without guessing names the grade or structure, the weights and the functional requirement, not just a familiar word. Use the terms above to check that each line in your request covers:

• Paper and board: grade name or DIN 19303 class, grammage, caliper for boards, fibre (virgin, recycled or a stated recycled-content minimum) and colour of both sides.
• Corrugated: flute, each liner and fluting paper with its grammage, and the strength requirement the box must meet.
• Films and laminates: each layer from outside to inside with thickness in µm, recycled content and which layer touches the product.
• Coatings and barriers: barrier type, side, coat weight if known, the grease or water performance needed and any PFAS-free or plastic-free requirement.
• Adhesives: only where they matter, for example heat resistance, food-contact documentation or recyclability targets.

The rest of the request, including quantities, print and documents, is set out in the packaging RFQ guide. 9 Packaging is an Istanbul-based manufacturer and exporter of printed packaging for business customers, and material proposals are part of the technical review at quotation; send your product, contents and target markets through our contact page.

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