A Coating Change That Invalidates a Food Contact Declaration

Barrier

Applying liquid polymer formulations to paperboard creates a physical shield against fats, aqueous liquids, and mineral oils. Changing even one constituent in a water-based acrylic dispersion alters how the dry film performs. These water-borne coatings rely on a precise balance of synthetic binders, wax emulsions, wetting agents, defoamers, and rheology modifiers.

In the pressroom, operators often make quick chemical tweaks to solve runnability issues on the fly. But adding a surfactant to improve wet-out over dense offset inks lowers liquid surface tension, which disrupts the cross-linking density of the dried polymer matrix and leaves micro-fissures that ruin fat resistance.

Excessive heat breaks soft polymers. High temperatures in the drying tunnel force rapid solvent evaporation, creating pinholes across the coating. If a chemical blender swaps an ethoxylated fatty alcohol surfactant for an alkylphenol ethoxylate derivative to cut raw material costs, compliance under European Regulation 1935/2004 and FDA 21 CFR 175.300 drops out immediately.

The substitute carries different toxicological thresholds and specific migration limits. Regulatory compliance depends on the exact chemical identity of every compound contacting food, directly or indirectly. Even a change in supplier resin grade sold as an identical drop-in substitute alters the low-molecular-weight fraction that can migrate into food.

Aqueous Dispersion Formulations and Polymer Chemistry

Polymer binder selection dictates mechanical flexibility and liquid resistance. Styrene-acrylic copolymers provide strong hydrophobic properties and high grease resistance, measured via turpentine oil resistance and the Kit test under TAPPI T 559. Replacing styrene-acrylic resins with softer ethylene-vinyl acetate emulsions lowers the film’s glass transition temperature.

That lower transition temperature improves elasticity during scoring and folding, preventing corner cracking, but softer matrices have higher permeability coefficients for lipophilic compounds. Fat molecules move quickly through amorphous polymer regions, so a formulation change meant to fix corner cracking can end up accelerating fat migration into the paperboard fibers.

When Does a Resin Swap Trigger Compliance Invalidation?

Substituting raw chemical constituents invalidates a food contact declaration whenever the altered substance introduces unlisted monomers, changes the overall specific migration profile, or generates new reaction by-products. Chemical synthesis always leaves trace impurities, unreacted monomers, and catalyst residues behind. A converter buying a modified acrylic dispersion receives an updated safety data sheet with hazard classifications, but safety data sheets report worker safety thresholds, not dietary exposure limits, and do not serve as regulatory declarations.

A drop-in resin containing unlisted acrylic acid esters invalidates the supplier’s previous Declaration of Compliance under European Regulation 10/2011 Annex I. The buyer holds an invalid dossier the moment the modified coating touches the paperboard web.

Cross-linking agents carry substantial compliance risk during formulation changes. Polyfunctional aziridines and zirconium ammonium carbonate compounds boost water and grease resistance by binding carboxyl groups inside the acrylic polymer network. Adding extra cross-linker to compensate for low coat weight makes the film brittle, while unreacted aziridine monomers left in the cured matrix have high toxicity profiles.

When analytical screening detects unreacted cross-linking agents migrating into aqueous food simulants, the presence of these unapproved active compounds voids the functional barrier classification under Regulation 10/2011 Article 13.

Surfactant Shifts and Surface Energy

Wet-out behavior on offset-printed board depends on surface tension differentials between the wet coating fluid and the dry ink film. On long runs, press operators often add silicone leveling agents directly to press pans to eliminate fish-eyes and cratering. These silicone additives migrate to the surface during hot-air drying.

The hydrophobic tail of the silicone molecule repels water-based food simulants, altering surface energy measurements under ISO 8296 and changing the chemical profile of the food-contact surface. Extraction tests on modified surfaces show elevated levels of low-molecular-weight siloxanes in fatty food simulants.

Surfactant adjustments that lower wet surface tension below thirty dynes per centimeter consistently disrupt polymer chain packing during thermal drying.

Variations in dry coat weight exacerbate formulation failures. Dropping dry film application from eight grams per square meter down to four exposes raw cellulose fibers across the board topography. These exposed fibers act as wicking channels, bypassing the polymer barrier.

Ink solvent retention also increases whenever wet film thickness exceeds drying tunnel capacity. Solvents trapped beneath the skin of the rapidly drying coating migrate backward into the paperboard sheet, concentrating on the reverse food-contact side while stacked on pallets.

Monomer substitution maintains grease resistance provided drying tunnel settings compensate for the higher boiling point of the replacement solvent.

Migration

Chemical constituents in aqueous varnishes migrate through paper fibers under specific thermal conditions. Mass transfer happens through direct contact, vapor phase transport, or set-off during storage in rolls or sheets. Overall Migration Limits cap total non-volatile substances moving from packaging into food at ten milligrams per square decimeter of food contact area, while Specific Migration Limits restrict individual toxicological compounds based on tolerable daily intake calculations.

Swapping an overprint varnish alters transport rates and the spectrum of extractable substances. Replacing a photoinitiator in a UV-cured coating introduces fast-migrating cleavage fragments that can penetrate paperboard substrates within hours of printing.

Direct contact requires empirical proof. Compliance testing involves exposing converted packaging samples to chemical food simulants under standardized temperatures and times defined in EN 1186 and EN 13130. Simulant D2 uses vegetable oil, iso-octane, or ninety-five percent ethanol to model fatty food interactions.

Swapping acetyl tributyl citrate for a lower-cost phthalate plasticizer drastically alters extraction values in Simulant D2. Phthalates dissolve readily in lipophilic media, producing extraction figures that exceed legal SML thresholds during ten-day storage tests at forty degrees Celsius.

Thermodynamics of Low Molecular Weight Volatiles

Fickian diffusion governs the movement of small molecules through synthetic polymer layers. Diffusion coefficients depend heavily on molecular weight, matrix density, and temperature. Molecules under five hundred Daltons diffuse rapidly through uncross-linked acrylic films.

If an ink supplier modifies an aqueous dispersion with lower molecular weight resin fractions to improve clarity and gloss, diffusion rates jump significantly. Thermal processing of packaged food, including hot-fill applications or microwave reheating, further accelerates mass transfer kinetics. A coating formulation that passes migration limits at room temperature can fail catastrophically under hot-fill conditions at ninety degrees Celsius.

Simulant Matching for Aqueous and Fatty Foods

Regulatory verification requires precise matching between food types and analytical simulants. Simulant A models clear aqueous foods using ten percent ethanol; Simulant B models acidic foods using three percent acetic acid; Simulant C covers alcoholic foods up to twenty percent concentration; and Simulant D1 handles dairy products and stronger alcoholic media. Simulant E uses modified polyphenylene oxide, commercialized as Tenax, to capture adsorption profiles for dry foods with high surface fat.

Replacing a hydrophobic acrylic binder with a hydrophilic polyurethane dispersion improves flexural endurance but increases overall migration into Simulants A and B as the resin swells in aqueous media.

Set-off transfer occurs on the rewind roll or inside the delivery pile of a sheet-fed offset press. High stack pressure forces the outer coated layer into tight contact with the uncoated reverse side of the adjacent sheet. Volatile organic compounds, functional additives, and unreacted photoinitiators transfer onto that reverse food-contact surface directly without passing through the board matrix.

When operators increase pile height to maximize throughput, higher nip pressure at the bottom of the pallet accelerates set-off kinetics, contaminating the reverse side before the board ever reaches the carton gluer.

Mass Transfer Mechanics across Board Calipers

Paperboard thickness provides a physical buffer between outer printed surfaces and inner food-contact layers. Solid Bleached Sulfate board has uniform fiber density, offering a consistent path length for diffusing molecules. Folding Boxboard incorporates mechanical pulp inner layers containing natural resin acids, fatty acids, and phytosterols.

Replacing a thick caliper board with a lightweight substrate shortens the diffusion path, allowing low-molecular-weight varnish components to cross much faster. Solvents trapped inside thick board layers migrate slowly, sometimes generating off-odors inside sealed packages months after delivery.

Failure modes propagate rapidly when process controls drift during long production runs:

• Pinholing through thin dispersion films exposes raw pulp fibers directly to liquid fats, creating localized capillary transport into the underlying board structure.
• Set-off contamination in rolled stock transfers non-compliant coating chemicals from the top surface to the food-contact reverse side under high winding tension.
• Unreacted photoinitiator residual diffusion occurs when ultraviolet lamps lose efficiency, leaving volatile cleavage products free to move through the paper substrate.
• Plasticizer exudation under thermal stress forces low-molecular-weight softening agents out of the polymer matrix directly into contact with dry fatty foods.

High pressure across tight winding rolls accelerates mass transfer while ink dries. Chromatographic screening confirms whether migrating species originate from the external coating layer or internal board sizing agents. When testing reveals unlisted volatile compounds exceeding SML thresholds, the original food contact declaration loses legal validity across all downstream supply points.

Differentiating between trace background oligomers from recycled pulp and newly introduced low-molecular-weight species from modified acrylic binders remains an operational challenge for analytical laboratories.

Pore

Microscopic voids in folding boxboard allow liquid vehicles to penetrate deep into the fiber matrix. Board topography features noticeable surface roughness, with peaks and valleys across the fiber network. A continuous coating must cover these fiber peaks entirely to form an effective barrier against moisture and fat.

When a converter reduces wet coat weight to trim costs, the liquid coating drops into pulp crevices, leaving thin coverage over raised fibers. Exposed fiber peaks then act as physical bridges where moisture vapor and liquid oils can enter, bypassing the polymer layer and weakening the package.

Paperboard absorbs liquid quickly. Substrate absorbency, quantified by the Cobb value under ISO 535, dictates how fast liquid vehicles drain away from the surface into the web core. High Cobb values indicate porous fiber structures that pull in water-based coatings during application.

If coating fluid sinks deep into the pulp layer before drying, the remaining surface layer lacks enough polymer to form a continuous film, leaving open capillary pathways through the board caliper.

Substrate Microstructure and Fluid Absorption

Cellulose fibers have hydrophilic surface chemistry, pulling aqueous fluids into inter-fiber pores through capillary action. Pore radius distribution inside mechanical and chemical pulps dictates fluid pickup dynamics. Recycled board contains short fibers, ash fillers, and residual starch, creating small voids that generate high capillary pressures.

Solid Bleached Sulfate contains long chemical softwood fibers with larger pore diameters, requiring higher coating viscosity to prevent excessive strike-through. Altering the binder ratio or pulp blend changes surface pore geometry, invalidating prior coat weight qualifications.

Coat Weight Distribution across Fiber Networks

Maintaining uniform dry film mass across high-speed webs demands precise metering. Air-knife coaters, curtain coaters, and metering rod assemblies deposit distinct film profiles over uneven board surfaces. Metering rods scrape high fiber peaks, leaving thin resin deposits on raised structures while pooling heavy liquid volumes in surface valleys.

Curtain coaters lay down a uniform film thickness following the underlying board contour. Switching from curtain coating to a flexographic chambered doctor blade application alters dry coat weight distribution, often causing pinholes over raised fiber clusters.

Inadequate dry film weight over rough paperboard topographies guarantees micro-porosity, allowing lipophilic compounds to bypass the functional barrier layer entirely.

Verifying continuous film coverage relies on fluid penetration testing. Dye stain tests using ethanol and magenta dye highlight micro-voids on dried surfaces within thirty seconds. Mercury intrusion porosimetry quantifies total pore volume distribution inside coated board structures; dropping dry coat weight from ten grams per square meter down to six increases total open surface pore volume by over three hundred percent on rough recycled liners.

Drying Speeds and Solvent Retention

Water-based acrylic dispersions dry in two phases: water evaporation followed by polymer particle coalescence. High line speeds reduce residence time inside hot-air drying tunnels. If dryer temperatures are set too high, the surface skins over prematurely, trapping residual water and volatile co-solvents underneath.

This trapped moisture slows particle coalescence and prevents complete resin consolidation around fiber bases, leaving microscopic channels open beneath the dry skin that invite chemical migration and barrier failure.

1. Mount raw paperboard roll onto press unwind stand and set web tension to standard substrate baseline.
2. Measure raw substrate Cobb 60 water absorption values across front, center, and drive-side web positions.
3. Adjust drying tunnel air velocity and infrared lamp intensities to balance solvent evaporation with polymer particle coalescence rates.
4. Apply aqueous dispersion coating at nominal target wet coat weight using calibrated metering rods.
5. Extract dry board samples immediately post-dryer and perform dye penetration testing to confirm film continuity.
6. Check stack temperature at delivery pile to ensure web temperature remains below resin blocking limits.

Press operators must hold tight line speed controls to prevent incomplete film curing. Chemical changes that lower dispersion viscosity cause liquid run-off prior to dryer entry, accumulating heavy edge-beads and leaving thin center-web coverage. Micro-voids formed through improper drying or insufficient wet coat application destroy the functional barrier status guaranteed in legal food contact declarations.

Heavy board calipers with open fiber structures demand higher wet coat weights to guarantee continuous film coverage across deep score lines.

Dossier

Legal compliance records trace every raw chemical component from synthesis to finished package. A Declaration of Compliance is a legally binding document under European Regulation 1935/2004 Article 16 and Regulation 10/2011 Annex IV. The packaging supply chain relies on a steady exchange of technical data between chemical suppliers, ink formulators, board mills, converters, and food packers.

A simple certificate of analysis from a chemical vendor stating that a raw material meets basic purity standards does not satisfy legal requirements for a complete food contact compliance file, which demands detailed analytical screening data, toxicological evaluations, and clear operational boundaries for safe package usage.

Upstream chemical modifications break the documentation chain unless explicitly declared. When a coating blender switches raw material suppliers, they must evaluate whether the new raw material introduces non-intentionally added substances (NIAS), such as reaction impurities, degradation products, or side-reaction compounds from polymer synthesis. Failing to update downstream documentation with new NIAS profiles invalidates the food packer’s compliance file, and regulatory audits routinely reject declarations based on outdated safety assessments.

Chain of Custody and Upstream Supply Transparency

Traceability requires batch tracking across every conversion pass. Regulation EC 2023/2006 establishes Good Manufacturing Practice guidelines for food contact materials, mandating record-keeping systems that link raw material lot numbers directly to finished packaging runs. If an ink formulator substitutes an acrylic emulsion without issuing an updated compliance statement, the converter unknowingly passes along a legally void packaging declaration to the food manufacturer.

Audit trails must document incoming raw material inspections, press operator logs, and finished goods release approvals.

Declaration of Compliance Structural Requirements

A legally sound Declaration of Compliance sets precise operational parameters, identifying authorized food types, maximum contact temperatures, exposure durations, and surface-area-to-volume ratios. Broad statements asserting general compliance carry no legal weight during audits. Declarations must also disclose dual-use additives ~ compounds permitted both as food packaging additives and direct food ingredients under Regulation 1333/2008 or Regulation 1334/2008.

Undeclared dual-use additives create serious compliance risks for food processors, who must account for potential migration when calculating ingredient limits in retail products.

Standard documentation must fulfill explicit statutory structural criteria to remain valid:

• Identity of the issuing entity detailing corporate address, manufacturing site location, and legal representative authorization signatures.
• Chemical identity of restricted substances including specific CAS registration numbers, SML values, and toxicological threshold limits.
• Dual-use food additive disclosure specifying food additive reference numbers to enable downstream food processor mass balance calculations.
• Functional barrier confirmation establishing that non-listed substances behind the barrier remain strictly below 0.01 milligrams per kilogram analytical detection limits.

Functional barrier claims require complete physical isolation. Regulation 10/2011 permits unlisted chemical substances behind a functional barrier only if migration into food stays below 0.01 milligrams per kilogram. A polymer coating change that weakens film continuity invalidates that claim, subjecting every chemical in the formulation to full toxicological evaluation and specific migration testing.

Packaging contracts must specify that any raw material modification requires ninety days advance written notification supported by updated migration test data.

Failing to maintain accurate chemical declarations exposes converters to severe commercial liability. Supply agreements with food brand owners warrant that delivered goods comply with all applicable food contact laws. If a coating supplier modifies a varnish formula unannounced, the converter remains directly liable to the buyer for delivering non-compliant packaging, absorbing scrap costs, downtime penalties, and legal fees associated with regulatory enforcement.

Section 14.2 of the master supply agreement specifies that any unannounced alteration of coating raw materials transfers financial liability for retail packaging withdrawals back to the ink manufacturer.

Verification

Analytical testing confirms whether chemical transfer limits stay within legal thresholds after a raw material substitution. Screening protocols rely on high-performance instruments to identify and quantify migrating species: Gas Chromatography coupled with Mass Spectrometry (GC-MS) detects volatile and semi-volatile organic compounds like solvent residues, photoinitiators, and plasticizers, while Liquid Chromatography coupled with Mass Spectrometry (LC-MS) identifies high-molecular-weight non-volatile compounds such as coating oligomers, surfactants, and specialized additives. Establishing screening thresholds requires rigorous calibration against known reference standards.

Direct chemical identification requires thorough extraction runs. Testing facilities submerge packaging samples in food simulants inside specialized migration cells under times and temperatures that simulate worst-case storage conditions. Ten days at forty degrees Celsius models long-term ambient storage, while ten days at sixty degrees Celsius accelerates testing for extended shelf-life requirements.

If GC-MS analysis reveals an unknown chromatographic peak corresponding to an unlisted synthesis impurity exceeding ten parts per billion, the sample is flagged as non-compliant.

Laboratory Analytical Screening Protocols

Headspace GC-MS screening isolates residual volatile solvents trapped inside dry coating films. Laboratory technicians cut coated paperboard samples into uniform surface areas, seal them in glass vials, and heat them to drive volatile compounds into the gas phase. Quantifying peak areas against internal standards determines total residual solvent concentration per unit area.

Excessive isopropyl alcohol, ethyl acetate, or ethoxypropanol signals poor drying tunnel efficiency, and high residual solvent levels accelerate the migration of non-volatile coating ingredients by plasticizing the dried polymer matrix.

Sensory and Odor Assessment via Robinson Testing

Chemical compliance does not guarantee sensory acceptance. Volatiles migrating below toxicological thresholds can still impart off-odors or off-flavors to sensitive foodstuffs. The Robinson Test, defined in DIN 10955, evaluates sensory changes caused by packaging materials.

Test specimens sit in sealed glass chambers alongside sensitive stimulants like milk chocolate, butter, or water for forty-eight hours at room temperature or forty degrees Celsius. A trained panel then evaluates the stimulant against blind controls on an intensity scale from zero (no perceptible taste modification) to four (strong taste modification).

A score of two or higher invalidates the packaging batch for odor-sensitive food applications. Modified acrylic coatings containing trace residual butyl acrylate monomers frequently pass chemical migration limits but fail Robinson sensory testing due to exceptionally low human odor perception thresholds. Sensory failures force complete batch rejections, even when the underlying coating chemistry fully complies with toxicological migration limits.

Consider a practical economic example. A packaging operation produces five hundred thousand folding cartons for a butter manufacturer using a baseline compliant aqueous dispersion coating applied at eight grams per square meter. The ink supplier substitutes the primary acrylic binder with a lower-cost emulsion containing an unlisted surfactant, trimming liquid coating costs by 0.004 euros per unit.

The press runs at full speed, generating fifty thousand euros worth of finished cartons, before quality assurance isolates the lot for routine verification prior to shipping.

The financial ledger highlights the risk of unverified coating changes. Saving two thousand euros on raw materials creates a sixty-three thousand euro net loss when the substituted batch fails analytical screening. Quality inspectors rejected twelve pallets of grease-resistant folding cartons when gas chromatography revealed unlisted phthalate plasticizers in the overprint varnish.

Pre-run analytical screening acts as essential risk mitigation, catching non-compliant chemical modifications before committing material and machine resources to full production runs.

Verification workflows follow structured decision sequences to prevent non-compliant material release:

• Raw material certificate validation checking incoming raw material lot numbers against supplier food contact declarations and approved master chemical formulation databases.
• Drawdown sample preparation applying fresh coating batches onto target board substrates using laboratory wire-wound metering rods to match press coat weights.
• Accelerated laboratory drying curing test drawdowns in forced-air ovens under controlled thermal profiles to match commercial drying tunnel conditions.
• Solvent retention analysis performing headspace gas chromatography to quantify total volatile organic compounds remaining within dried drawdown films.
• Migration cell mounting exposing cured drawdown surfaces to Simulant D2 for accelerated extraction screening inside temperature-controlled laboratory incubators.
• Mass spectrometry quantification screening extracted simulants via GC-MS and LC-MS to detect unlisted chemical species exceeding specific migration limits.

Every raw chemical modification must trace back to the monomer supplier. This failure mode occurs most frequently during rapid press changeovers. Laboratory protocols must remain rigorous, as minor chemical shifts generate substantial financial liabilities when non-compliant packaging reaches commercial distribution lines.

1. Quarantine incoming chemical batches immediately upon delivery and verify raw material safety data sheets.
2. Pull wet coating samples directly from press pans before starting commercial production runs.
3. Prepare lab drawdowns on target production board stock to verify surface energy and film continuity.
4. Run headspace gas chromatography screening to confirm complete solvent removal prior to palletizing.
5. Submit finished carton samples to accredited third-party laboratories for formal migration testing.

Analytical screening via GC-MS detection limits set at ten parts per billion remains the global standard for identifying unlisted non-intentionally added substances.

Air freight and laboratory re-testing charges reached twenty-four thousand euros when an unannounced defoamer change in an aqueous barrier varnish caused off-odor rejection across three container loads of frozen pastry cartons.

Recall

Commercial consequences escalate rapidly when non-compliant packaging reaches consumer distribution networks. Regulatory agencies possess broad statutory powers under national food safety laws to enforce immediate product withdrawals and market recalls. If regulatory testing reveals an unapproved migrating substance inside retail packaging, the food brand owner must retrieve every affected product lot from retail shelves.

The packaging converter sits at the center of financial liability claims, facing direct recovery actions for food spoilage, reverse logistics expenses, brand damage, and administrative fines.

Warehouse quarantine is the first line of defense once non-compliant material is identified. Physical segregation prevents affected packaging lots from entering active fulfillment chains. Converting facilities use red quarantine tags, physical cages, and computerized inventory blocks to hold suspicious stock.

If non-compliant cartons mix with compliant stock during staging operations, the entire warehouse inventory faces quarantine pending analytical verification.

Quarantine Logistics and Warehousing Friction

Isolating non-compliant stock consumes warehouse space and creates operational friction. Palletized packaging occupies valuable rack locations, accruing daily storage fees while legal and technical teams evaluate contamination risks. Material handling crews must systematically scan every pallet barcode to trace affected batches across distribution centers.

Any breakdown in traceability during isolation forces quality teams to expand quarantine boundaries, locking down adjacent compliant production runs to guarantee no non-compliant stock escapes into retail channels.

Commercial Indemnification and Supplier Recovery

Legal contracts shift financial damages back up the manufacturing chain. Master packaging agreements typically contain indemnification clauses holding converters liable for direct and consequential damages resulting from non-compliant deliveries. When a coating change invalidates a food contact declaration, the converter seeks recovery from the ink or chemical supplier who introduced the altered formulation.

These recovery claims rely entirely on documentary evidence showing that the supplier modified the product without prior written notification or formal qualification testing.

Insurance coverage often excludes liabilities arising from unannounced raw material modifications. Standard commercial general liability policies exclude product recalls, requiring specialized recall endorsements. Insurers routinely deny coverage if the packaging converter failed to perform adequate incoming quality control testing or relied on invalid supplier documentation, leaving the converter to absorb the full cost of scrapped stock, downtime penalties, and customer compensation payouts out of operating cash.

Substrate Salvage and Waste Stream Management

Disposing of non-compliant printed and coated paperboard creates significant waste management challenges. Laminated or heavily coated boards containing non-compliant synthetic polymers cannot easily return to standard repulping streams. Chemical contamination invalidates the material for standard recycling, forcing conversion facilities to send hundreds of tons of printed packaging to high-temperature incinerators or landfills.

Incineration fees, transportation surcharges, and extended producer responsibility penalties add to the total financial loss.

Salvaging raw substrate presents a difficult technical challenge. If non-compliant overprint varnish was applied off-line, raw board rolls already converted into printed, folded, and glued cartons cannot be recovered. Strip-down operations to salvage paperboard fibers incur labor costs exceeding the virgin pulp value of the substrate.

Waste stream accounting must record non-compliant disposal weights to satisfy environmental reporting mandates and corporate sustainability metrics.

Direct communication protocols must initiate immediately upon confirming compliance invalidation. Converter technical managers notify food brand quality executives, providing batch numbers, production dates, and specific analytical findings. Transparent disclosures allow food manufacturers to evaluate real-world health risks accurately and coordinate measured regulatory responses.

Concealing chemical non-compliance escalates legal exposure into criminal liability for senior management across both converting and food packaging operations.

The converter isolation procedure locks all affected pallets into dedicated storage areas while quality assurance completes chromatographic screening of the raw board stock.