Paper and Packaging Industry Terminology

AKD (Alkyl Ketene Dimer)

A neutral/alkaline internal sizing agent that renders paper and board more hydrophobic by reacting with cellulose; widely used to reduce liquid penetration and improve holdout.

Examples: - Switching from rosin-alum to AKD improved water resistance and brightness at neutral pH. - We increased cure time to ensure the AKD fully reacted, reducing Cobb values. - The AKD dosage is 6 kg per ton with cationic starch and a microparticle program.

Anilox Roll

An engraved roll in flexographic printing that meters and transfers a precise volume of ink to the plate; characterized by cell volume (bcm or cm³/m²) and line screen (lpi or l/cm).

Examples: - A 3.5 bcm anilox with 400 lpi improved ink control on the linerboard. - We swapped the anilox to reduce dot gain on the kraft substrate. - Proper doctor blade setup prevents anilox plugging during long runs.

Basis Weight

The mass of paper per unit area. In North America, linerboard and medium are in lb per 1000 square feet (msf); printing papers often in lb per ream; globally, grammage (g/m²) is preferred.

Examples: - The spec calls for 42 lb/1000 ft² linerboard. - In metric, the same sheet is 205 g/m² grammage. - Pricing moved to basis-weight brackets for the new grade.

Barrier Coatings

Functional coatings applied to paper/board to resist water, oil/grease, moisture vapor, or gases; include dispersion, acrylic, PVOH, bio-based and nanoclay systems.

Examples: - A water-based dispersion barrier met the 30 g/m² MVTR target. - We replaced PE extrusion with a recyclable barrier coating for cups. - PVOH added oxygen barrier for the retort pouch paper layer.

Box Compression Test (BCT)

A measure of the compressive strength of a finished box, indicating stacking performance under load; reported in lbf or N.

Examples: - The RSC passed a BCT of 1,000 lbf under standard lab conditions. - We estimated BCT using the McKee formula from ECT and board caliper. - Palletization changes increased BCT safety factor by 15%.

Brightness (ISO/TAPPI)

Optical reflectance of blue light from paper, reported as ISO brightness (%) or TAPPI brightness; correlates with perceived whiteness and print contrast.

Examples: - Target ISO brightness is 88 for the SBS board. - Optical brightening agents bumped TAPPI brightness by 1.5 points. - The customer switched to higher brightness for improved shelf pop.

Caliper

The thickness of paper or board, commonly expressed in micrometers, mils, or points; measured under defined pressure and area.

Examples: - Board caliper increased from 18 to 20 pt to improve stiffness. - Tightening press loading reduced caliper variation CD. - Caliper is 0.5 mm measured under TAPPI T 411 pressure.

Chain of Custody (CoC)

A documented system that tracks certified fiber/materials from forest through manufacturing and distribution to ensure claims like FSC or PEFC are credible.

Examples: - The mill maintains FSC and PEFC CoC for mixing claims. - Our ERP links batches to CoC certificate numbers. - The carton was labeled FSC Mix via verified CoC trail.

Cobb Value (Cobb Test)

A standardized measure of water absorptiveness (g/m²) over a set time, indicating how much water a paper or board absorbs; lower values mean better water resistance.

Examples: - AKD reduced the 60-second Cobb from 40 to 25 g/m². - Spec requires Cobb 120 s below 30 for the folding carton. - Surface sizing variability showed up as Cobb scatter across the deckle.

Coated vs Uncoated

Coated papers/boards have mineral or polymer coatings for improved printability, smoothness, and barrier; uncoated rely on base sheet properties for ink receptivity and feel.

Examples: - The customer moved from uncoated kraft to C1S for better graphics. - C2S freesheet gave superior gloss and ink holdout. - Uncoated liner helped meet recyclability goals.

Corrugator

A production line that flutes medium and bonds it to linerboard(s) with starch adhesive to make corrugated board; key sections are single facer, glue machine, and double backer.

Examples: - The new single facer runs E- and B-flute at 1000 fpm. - Tweaking adhesive gel point stabilized the double backer bond. - Trim scheduling reduced offcuts on the corrugator by 2%.

CTMP (Chemi-ThermoMechanical Pulp)

A high-yield pulp made by mild chemical treatment followed by thermomechanical refining; delivers high bulk and opacity, commonly used in board middle plies.

Examples: - CTMP increased board bulk without sacrificing stiffness. - We blended 20% CTMP in the middle ply of FBB. - CTMP energy costs rose with lower chip moisture.

Die Cutting

A converting process using steel rule dies or rotary cylinders to cut, crease, and perforate sheets or web into packaging blanks.

Examples: - We switched from flatbed to rotary die cutting to boost throughput. - Nicks were adjusted to improve blank handling on the folder-gluer. - Score-to-cut distance was tightened to eliminate cracking.

Dieline (Die Line)

The 2D layout file that defines the cut, crease, perf, and bleed areas of a package; used by designers, prepress, and die makers to ensure fit and function.

Examples: - The brand approved the dieline with a 3 mm bleed and 2 mm safety. - CAD updated the dieline to add a tear strip. - Printer requested vector dielines with layer separation for scores.

Digital Printing (Packaging)

Non-contact printing methods such as inkjet or electrophotography used for short runs, versioning, and variable data on paper and corrugated substrates.

Examples: - We ran a 5,000-box promo on a single-pass digital corrugated press. - Variable data printing enabled personalized mailers. - Digital white ink improved opacity on kraft substrates.

Doctor Blade

A thin blade that meters ink on an anilox or removes excess coating from a cylinder to ensure consistent laydown in flexo and coating operations.

Examples: - Adjusting blade angle reduced anilox leakage and dirty print. - Composite blades extended life on abrasive recycled liners. - Poor blade seating caused streaks on the solid areas.

ECT (Edge Crush Test)

A measure of the edgewise compressive strength of corrugated board, reported in lb/in or kN/m; widely used to specify box performance for stacking.

Examples: - The 32 ECT board met the RSC requirement. - Increasing medium take-up improved ECT by 1.5 lb/in. - ECT correlated better than Mullen to stacking for this shipper.

EPR (Extended Producer Responsibility)

Policies that shift some end-of-life costs and responsibilities for packaging from municipalities to producers, often through fees, labeling, and design requirements.

Examples: - New EPR fees will vary by recyclability of the package. - We redesigned to mono-material board to reduce EPR assessments. - The roadmap plans for EPR compliance in four states by 2027.

Fiber Yield

The percentage of input biomass converted to usable pulp. Chemical pulps have lower yield and higher strength; mechanical and CTMP have higher yield with different property trade-offs.

Examples: - Kraft pulping yields around 50% from wood to usable pulp. - Mechanical pulping increases yield but raises energy demand. - Higher yield lowered cost per ton but impacted strength.

FSC (Forest Stewardship Council)

A leading forest certification system that sets standards for responsible forest management and chain of custody for wood and fiber products.

Examples: - The carton carries an FSC Mix label. - The brand requested FSC 100% for premium SKUs. - CoC audit confirmed FSC inputs matched outputs.

Grammage

The mass per unit area of paper, expressed in grams per square meter (g/m²); the global standard metric for paper and board weight.

Examples: - The spec is 300 g/m² SBS for the folding carton. - Grammage variation CD indicated headbox control issues. - Converters priced by grammage brackets to manage freight.

Heat Seal Strength

The bonded strength of two coated or laminated surfaces after heat, time, and pressure are applied; critical for paper-based pouches and lidding.

Examples: - At 150 C and 0.5 s, seal strength reached 8 N/15 mm. - Coating formulation B improves low-temperature seals. - We mapped the sealing window across dwell times.

Hot Tack

The immediate seal strength while the joint is still hot, important for high-speed form-fill-seal processes so seals hold before cooling.

Examples: - Higher hot tack prevented zipper seals from popping on the VFFS line. - The bio-based coating lacked hot tack at fast fill speeds. - We added an ionomer layer to boost hot tack performance.

Ink Mileage

The printable area covered per unit mass or volume of ink; influenced by substrate absorbency, anilox volume, viscosity, and print method.

Examples: - Switching anilox volume improved ink mileage by 10%. - Higher holdout on C1S reduced ink consumption. - Viscosity control stabilized ink mileage run to run.

ISO Standards (Paper Testing)

International test methods such as ISO 536 (grammage), 2470 (brightness), 534 (thickness), 5636 (air permeability), and 8791 (roughness) used to measure paper properties.

Examples: - Grammage measured per ISO 536. - ISO 2470 defines ISO brightness for this grade. - The lab moved porosity to ISO 5636 for global comparability.

Kraft Process

An alkaline chemical pulping process using sodium hydroxide and sodium sulfide to dissolve lignin, producing strong fibers; also called the sulfate process.

Examples: - Switching to hardwood in the kraft cook improved formation. - Black liquor recovery efficiency raised kraft mill uptime. - Unbleached kraft linerboard met burst targets at lower basis weight.

Lamination

Joining two or more layers of paper, film, or foil using adhesive or extrusion to combine properties like strength, barrier, and printability.

Examples: - We solventlessly laminated paper to aluminum for high OTR barrier. - A paper-paper lamination improved stiffness while staying recyclable. - Adhesive coat weight adjustments fixed curl post-lam.

LCA (Life Cycle Assessment)

A standardized method for quantifying environmental impacts of a product across its life cycle, often basis for EPDs and eco-design.

Examples: - The LCA showed lower GHG for recycled content at typical grid mixes. - We used ISO 14040/44 for the LCA boundaries and allocation. - LCA hotspots pointed to printing energy and transport.

Linerboard

The outer facing sheets of corrugated board; made from virgin kraft or recycled fibers and specified by basis weight and strength properties.

Examples: - Switching to kraft liner reduced warp versus testliner. - We trialed 35 lb liner to cut costs on light-duty RSCs. - Moisture balance between liner and medium minimized washboarding.

Machine Direction/Cross Direction (MD/CD)

Directions relative to paper making: MD is the flow direction on the machine; CD is across the web. Properties are anisotropic, affecting runnability and converting.

Examples: - CD crush caused cracking along the fold. - We aligned the carton grain direction with the main score. - MD tensile exceeded spec but CD tear was marginal.

Mullen Burst Test

A hydrostatic pressure test that measures resistance to rupture; historically used for linerboard and box strength, now often supplanted by ECT for stacking performance.

Examples: - The customer still specifies 200 psi Mullen for legacy reasons. - Higher Mullen correlated with fewer punctures in parcel networks. - We validated ECT substitution where Mullen was not critical.

MVTR (Moisture Vapor Transmission Rate)

The rate at which water vapor passes through a material; key for moisture-sensitive products. Lower MVTR indicates better moisture barrier.

Examples: - Target MVTR is below 10 g/m²/day at 38 C, 90% RH. - Adding a dispersion barrier halved MVTR without PE. - MVTR rose after scoring; we adjusted coating laydown.

OEE (Overall Equipment Effectiveness)

A composite metric for manufacturing performance: Availability × Performance × Quality, indicating how effectively equipment is utilized.

Examples: - OEE improved from 62% to 70% after reducing changeover time. - Scrap reductions lifted the quality component of OEE. - We visualize OEE by shift on the corrugator dashboard.

OTR (Oxygen Transmission Rate)

The rate of oxygen permeation through a material; vital for shelf life of oxygen-sensitive products. Lower OTR means better oxygen barrier.

Examples: - OTR dropped below 1 cc/m²/day with a PVOH barrier. - Pinholes from die cutting raised OTR in the test lot. - We specified OTR at 23 C, 0% RH for benchmarks.

PAE (Polyamide-Epichlorohydrin) Wet-Strength Resin

A cationic resin used to impart wet strength to paper and tissue so the sheet retains integrity when wet.

Examples: - Adding PAE raised wet tensile for kitchen towel. - Compliance review checked AOX and extractables from PAE use. - We balanced PAE with retention aids to avoid deposits.

PEFC (Programme for the Endorsement of Forest Certification)

An international umbrella system that endorses national forest certification schemes, promoting sustainable forest management and chain of custody.

Examples: - The mill holds dual FSC and PEFC certifications. - PEFC claims were added to the spec sheet for EU customers. - PEFC Chain of Custody audit passed without nonconformities.

Poly Extrusion Coating

A process where molten polymers (e.g., PE, PP) are extruded onto paper/board to add sealability, barrier, and stiffness.

Examples: - Single-sided LDPE extrusion converted cupstock to heat-sealable board. - Tie-layer was added for EVOH adhesion in the laminate. - Neck-in control reduced edge trim waste on the coater.

Porosity (Gurley/Bendtsen)

Air permeability of paper measured by methods such as Gurley (s/100 mL) or Bendtsen (mL/min); affects ink penetration, drying, and barrier coating holdout.

Examples: - Gurley increased after surface sizing, improving ink holdout. - Bendtsen roughness and air permeance were correlated for this grade. - We tuned refining to hit porosity without over-densifying.

Recycled Fiber Grades (OCC, DLK, ONP)

Common recovered paper categories: OCC (old corrugated containers), DLK (double-lined kraft cuttings), ONP (old newspapers), among others, each with quality specs.

Examples: - The furnish moved to 70% OCC with 10% DLK to improve strength. - ONP content was reduced due to stickies risk. - Bale specs for OCC tightened to limit moisture and prohibitives.

Regular Slotted Container (RSC)

The most common corrugated box style with flaps meeting in the middle; efficient to produce and suitable for many shipping applications.

Examples: - The FEFCO 0201 RSC is the default shipper style. - We added hand holes to the RSC without compromising ECT. - RSC size optimized to cube out pallets and trucks.

Sizing (Internal/Surface)

Treatments that control liquid penetration and printability. Internal sizing (e.g., AKD, ASA, rosin) added at the wet end; surface sizing (e.g., starch) applied at the size press.

Examples: - ASA internal sizing improved Cobb with faster cure than AKD. - Surface sizing with cationic starch boosted surface strength pre-coating. - Alum levels were lowered as we moved to neutral sizing.

SKU Rationalization

A process to reduce the number of product variants to optimize capacity, inventory, cost, and complexity across printing and converting.

Examples: - Cutting 20% of low-volume SKUs freed corrugator capacity. - We standardized board grades across SKUs to reduce trim. - Artwork consolidation reduced plate changes and waste.

Starch Adhesive (Corrugating)

The primary adhesive for corrugated board, typically cooked from corn or potato starch with caustic and borax; properties like viscosity and gel point are critical.

Examples: - Stein-Hall adhesive reached gel point at 150 F for stable bonding. - Potato starch provided better tack on high-moisture liner. - Borax adjustment fixed warp by balancing penetration.

TAPPI Standards

Test methods and technical standards from TAPPI (Technical Association of the Pulp and Paper Industry) widely used in North America for measuring paper properties.

Examples: - Burst measured per TAPPI T 807 for corrugated. - Cobb testing followed TAPPI T 441. - We benchmarked roughness via TAPPI T 538 to match legacy data.

Trim Loss

Material wasted due to width mismatches when cutting rolls or webs to size; managed via trim optimization, order mix, and deckle planning.

Examples: - A better order mix cut trim loss by 1.2%. - Wider deckle on the winder reduced trim on narrow SKUs. - The optimizer nests sizes to minimize trim on the corrugator.

Virgin Fiber

Fiber sourced directly from wood or non-wood plants that has not been previously used or recycled; offers strength and cleanliness advantages.

Examples: - Virgin kraft improved strength at the same basis weight. - We used virgin for food-contact compliance on primary packs. - Virgin-recycled blends balanced cost and performance.

VOC (Volatile Organic Compounds)

Organic chemicals that evaporate easily, contributing to air pollution; regulated in printing and coating operations.

Examples: - Low-VOC inks eased air permit constraints. - We installed oxidizers to control VOC emissions from coating. - Switching to water-based flexo reduced VOCs and odor.

Wet-End Retention Aid

Chemicals (often high-molecular-weight polymers) added to the stock to retain fines, fillers, and additives in the sheet and improve drainage.

Examples: - A cationic PAM improved fines retention by 15%. - Microparticle systems with bentonite stabilized drainage. - Overdosing retention aid caused deposits at the wet end.

Yankee Dryer

A large, steam-heated cylinder used in tissue/towel manufacturing for drying and creping; critical for softness, bulk, and runnability.

Examples: - Crepe ratio increased after adjusting the Yankee coating. - Steam pressure and hood balance improved tissue bulk. - Doctor blade setup on the Yankee controlled softness and dusting.

Z-direction Tensile (ZDT)

The tensile strength through the thickness of a paper or board, indicating inter-fiber bonding; also called plybond in some contexts.

Examples: - Higher ZDT reduced ply separation during converting. - Starch and wet-press adjustments lifted ZDT by 20%. - Low ZDT correlated with dusting on the die cutter.