AKD Emulsion Sizing (Alkyl Ketene Dimer Cellulose-Reactive) Tank Selection
AKD Emulsion Sizing (Alkyl Ketene Dimer C16-C18 Fatty-Chain Dimer in 6-15% Active Aqueous Emulsion with Cationic Starch and Cationic Polymer Stabilizer for Cellulose-Reactive Internal Hydrophobicity at Neutral and Alkaline Wet-End Papermaking) — Bulk Tank Selection at Integrated Fine-Paper, LWC, Coated Paperboard, and Tissue Mill Stock-Prep and Approach-Flow Operations
AKD emulsion sizing (alkyl ketene dimer CAS 144245-85-2 typical hydrogenated tallow + palm + stearic + palmitic fatty-chain C16-C18 dimer at typical 6-15% active dry-AKD basis dispersed as a sub-micron oil-in-water emulsion stabilized by cationic starch + cationic polymer + minor surfactant package; emulsion droplet size median 0.4-1.5 micron at premium colloidal-stability specification; specific gravity 1.00-1.05 of finished emulsion; pH 2.5-4.0 of finished emulsion; viscosity 5-50 cP at 25C; melting point 45-55C of dry AKD; hydrolysis half-life 1-30 days at typical alkaline-papermaking conditions depending on storage pH + temperature + cationic-starch stabilizer + cationic-polymer-charge state; supplied as ready-to-use 6-15% active emulsion at 250-330-gallon poly IBC + 4500-6500-gallon DOT 412 cargo tank delivery; AKD-grade specification calls out dry-AKD active assay 6.0-15.0% +/- 0.3% target + free-stearic-acid less-than-0.5% + colloidal stability greater-than-30 day at storage 4-25C + free-formaldehyde less-than-1 ppm at premium specification) is the dominant cellulose-reactive sizing chemistry at integrated fine-paper + LWC + coated paperboard + tissue mill wet-end at neutral + alkaline papermaking pH 7.0-8.5 stock-line operation, providing internal hydrophobicity (water-resistance) at the finished sheet via covalent ester-bond formation between the AKD lactone reactive group + the cellulose hydroxyl.
U.S. and Canadian AKD emulsion throughput is concentrated at major paper-chemistry producers (Kemira Oyj Helsinki Finland + Atlanta Georgia + Vancouver Washington, Solenis Wilmington Delaware + multiple paper-mill sites, BASF Ludwigshafen Germany + Charlotte North Carolina + USA distribution, Buckman Memphis Tennessee + USA distribution, ChemTreat Glen Allen Virginia + USA distribution, Ecolab Saint Paul Minnesota + USA distribution, Hercules subsidiary Solenis paper-chemistry, Harima Chemicals Japan + USA distribution, Seiko PMC Japan + USA distribution, Arakawa Chemical Japan + USA distribution). Mill-side AKD emulsion is delivered at 250-330-gallon poly IBC or 1000-3000-gallon stainless or HDPE-lined cargo tank with on-board agitation to maintain emulsion homogeneity.
The eight sections below cite OSHA Hazard Communication 29 CFR 1910.1200 + TAPPI T441 Cobb water-absorbency + T530 sizing + EPA TSCA + EU REACH + FDA 21 CFR 176.170 + 176.180 indirect food-contact paper + 21 CFR 178.3850 reactive size + USDA Food Safety Inspection Service paper-packaging compliance + EU Food Contact Regulation + ISO 9001 + ISO 14001 + customer-OEM paper-grade specification framework + DOT 49 CFR 173 (typically not regulated as hazardous; may carry minor freezing-temperature precaution) + EPA Effluent Limit Guideline 40 CFR Part 430 Pulp Paper Paperboard Point-Source Category + state-specific industrial-discharge permit + state-specific paper-mill bulk-storage code + routine operating practice at North American + Western European + Asian integrated paper-mill AKD emulsion receipt + bulk + day-tank service.
1. Material Compatibility Matrix
AKD emulsion is a colloidally-stabilized oil-in-water dispersion at slightly acidic pH 2.5-4.0 with low chemical-corrosion risk against most polymeric + alloyed metal construction; the dominant operating-discipline issue is hydrolysis-stability + temperature-control discipline (AKD lactone reactive group hydrolyzes to inactive ketone + fatty acid at storage temperature greater than 35C OR storage pH greater than 8.0 OR storage time greater than 30 day at typical conditions; storage at 4-25C + pH 2.5-4.0 buffered + 14-30 day maximum-hold inventory turnover is mandatory), gentle-agitation discipline (continuous gentle mechanical or recirculating-pump agitation to prevent emulsion separation + creaming + droplet-coalescence is required, while high-shear or excessive-velocity flow drives droplet coalescence + emulsion breakdown), freeze-protection discipline (AKD emulsion freezes at sub-zero-Celsius temperatures + does not recover after thaw; insulated jacket + heat-trace at any cool-climate installation), and FDA 21 CFR 176.170 + 176.180 + 178.3850 indirect food-contact paper compliance discipline.
| Material | AKD Emulsion @ 25C | AKD Emulsion @ 40C | Notes |
|---|---|---|---|
| HDPE rotomolded | A | B | Standard at AKD emulsion bulk + day-tank service across 1,500-10,000-gallon range; hydrolysis-acceleration at temperature greater than 35C drives reduced shelf-life |
| XLPE rotomolded | A | B | Standard; FDA 21 CFR 177.1520 polyethylene compliance at indirect food-contact paper application |
| Polypropylene (PP) | A | B | Standard at smaller specialty + dosing day-tank service |
| FRP vinyl-ester resin | A | A | Standard at larger specialty bulk service |
| 304 stainless steel | A | A | Standard at high-value AKD bulk + day-tank service; preferred where temperature control + sanitary specification drives need |
| 316L stainless steel | A | A | Premium at premium fine-paper + tissue mill service; preferred at sanitary + premium specification |
| Carbon steel uncoated | C | C | Acceptable at brief contact only; iron-contamination + sizing-emulsion-discoloration drift; not preferred |
| Aluminum 5083 / 6061 | B | B | Acceptable at brief contact; mild-acid surface attack at long-hold |
| EPDM | A | A | Standard gasket + lining |
| Viton (FKM) | A | A | Standard at higher-temperature pump + valve seat |
| PVC Sch 80 | A | B | Standard at piping; temperature-derated above 40C |
| CPVC Sch 80 | A | A | Preferred at higher-temperature piping |
| PVDF (Kynar) | A | A | Premium at high-purity specialty service |
| PTFE | A | A | Premium gasket + diaphragm + valve seat |
| Nitrile (Buna-N) | B | B | Acceptable at brief contact; not preferred at long-hold |
The dominant industrial pattern at North American + Western European + Asian integrated fine-paper + LWC + coated paperboard + tissue mill AKD emulsion storage is HDPE or XLPE rotomolded vertical bulk tank in the 1,500-10,000-gallon range at the mill stock-prep area with gentle continuous mechanical or recirculating-pump agitation + insulation + heat-trace at outdoor + cool-climate installation + temperature-control at less than 25-30C target + secondary-containment pan integration. 304 + 316L stainless steel construction is reserved for premium fine-paper + tissue + sanitary specification + larger 5,000-15,000-gallon bulk tank service. OneSource Plastics' 5-brand HDPE network (Norwesco, Snyder Industries, Chem-Tainer, Enduraplas, Bushman) covers the typical 1,500-10,000-gallon paper-mill AKD emulsion bulk + day-tank specification across the integrated fine-paper + LWC + coated paperboard + tissue paper-mill envelope.
2. Real-World Industrial Use Cases
Neutral and Alkaline Fine-Paper Wet-End Sizing (Dominant Use). Fine-paper + writing-paper + book-paper + uncoated freesheet + woodfree paper grade operations at neutral + alkaline papermaking (pH 7.0-8.5 stock-line) use AKD as primary cellulose-reactive sizing at typical 0.5-3.0 lb dry-AKD per ton dry-fiber-basis; AKD covalently bonds to cellulose hydroxyl during press + dryer-section curing producing internal hydrophobicity at TAPPI T441 Cobb water-absorbency target 18-26 g/m2 + TAPPI T530 sizing target 100-500 seconds at finished sheet. Storage envelope: 1,500-10,000-gallon HDPE or XLPE vertical bulk tank with gentle agitation + insulation + heat-trace at mill stock-prep area.
Coated Paperboard + LWC Wet-End Sizing. Coated paperboard + LWC + super-calendered paper grade operations use AKD at the wet-end (0.3-2.0 lb/ton dry-fiber-basis) for internal hydrophobicity prior to the coater; coater + surface-sizing at the size-press complements internal sizing for combined water-resistance + ink-receptivity at the printing customer.
Tissue Mill Towel + Wipe Internal Sizing. Tissue mill paper-towel + wet-strength specialty wipe + napkin grade operations use AKD at lower dose (0.2-1.0 lb/ton) for water-resistance + wet-strength program contribution at premium tissue-towel + paper-towel grade.
Liquid Packaging Board LPB Internal Sizing. Liquid packaging board operations (carton-stock for milk + juice + dairy + non-carbonated beverage + edible-oil) use AKD as primary internal sizing at higher dose (1.5-4.0 lb/ton) for premium water + edible-oil resistance combined with FDA 21 CFR 176.170 + 176.180 + 178.3850 + USDA-FSIS food-contact compliance.
Specialty Paper + Filter + Decor Grade. Specialty filter + decor + lamination + label + release-liner paper grade operations use AKD at variable dose specification per the customer-OEM specification.
3. Regulatory Framework
OSHA 29 CFR 1910.1200 Hazard Communication. AKD emulsion at typical 6-15% active formulation is classified as Skin Irritant Cat 2 or Not Hazardous per CLP / GHS depending on specific formulation; minor cationic-polymer + cationic-starch + surfactant component drives mild eye + skin-irritant classification at concentrated formulation. Worker SDS + container labeling + PPE + emergency-shower + eye-wash discipline.
FDA 21 CFR 176.170 + 176.180 + 178.3850 Indirect Food-Contact Paper. AKD reactive sizing for food-contact paper is regulated at FDA 21 CFR 176.170 (paper + paperboard for aqueous + fatty food contact) + 176.180 (paper + paperboard for dry food contact) + 21 CFR 178.3850 reactive components of finished food-contact paper + paperboard. AKD compliance at finished paper-product specification requires AKD-supplier letter-of-no-objection + customer-OEM food-packaging specification.
USDA Food Safety Inspection Service Paper-Packaging Compliance. Meat + poultry + dairy paper-packaging operations require USDA-FSIS letter-of-no-objection at finished paper-product specification.
EU Food Contact Regulation. EU Regulation EC 1935/2004 + 10/2011 + EU Council of Europe Resolution AP(2002)1 paper + paperboard food-contact compliance applies at EU-marketed paper + paperboard finished product.
EPA Effluent Limit Guideline 40 CFR Part 430. Pulp Paper Paperboard Point-Source Category effluent guidelines establish industrial-discharge limit for the integrated paper-mill envelope. AKD-residual + biological-oxygen-demand BOD + total-suspended-solids + pH discharge to NPDES + POTW is regulated at state-specific NPDES + EPA + delegated-state framework.
EPA TSCA and EU REACH. AKD is on the EPA TSCA Inventory at chemical-substance listing + registered under EU REACH framework with no current restriction.
TAPPI Test Method Specification. Paper-grade AKD + finished paper QC participates at TAPPI T441 Cobb water-absorbency + T530 sizing + T494 tensile + T403 burst + T411 paper bulk specification at customer-OEM paper-grade specification.
DOT 49 CFR 173. AKD emulsion is typically not regulated as hazardous material; cargo-tank shipping uses standard non-hazardous bulk-liquid placarding with freezing-temperature precaution + insulated trailer specification at winter delivery.
4. Storage System Specification
Mill-Side AKD Emulsion Bulk Receiving Tank. Integrated paper-mill AKD emulsion receipt: 1,500-10,000-gallon HDPE or XLPE rotomolded vertical flat-bottom or shallow-cone-bottom atmospheric tank, 1.0 specific-gravity rated; mounted on level reinforced-concrete pad with secondary containment via integral catch-basin or external concrete-bermed pad sized to 110% of largest-tank volume; 3-4 inch flanged top fill with cargo-tank cam-lock or IBC discharge connection + atmospheric vent with insect screen; 2-3 inch flanged bottom outlet with full-bore PVC ball valve; 18-24 inch top manway for inspection + cleaning; ultrasonic + radar level transmitter; sample valve at 12 inches above bottom outlet; gentle continuous mechanical agitator (top-mounted with bottom impeller at 15-40 rpm at low-shear specification to avoid droplet coalescence) OR continuous recirculating-pump loop (bottom outlet to top return at 50-300 gpm with low-shear progressive-cavity or peristaltic pump) is RECOMMENDED at long-hold storage; insulated jacket + heat-trace at outdoor or cool-climate installation to maintain temperature 4-25C target; cooling-water jacket at hot-climate installation if mill ambient exceeds 30C target.
AKD Emulsion Day-Tank. Day-tank at the wet-end stock-prep dosing point: 500-3,000-gallon HDPE or XLPE rotomolded vertical atmospheric tank with gentle continuous agitation + sanitary 2-inch flanged bottom outlet + low-shear progressive-cavity or peristaltic dosing pump + flowmeter + dosing-injection quill at the stock-line; sizing-on-paper telemetry (online Cobb absorbency or Hercules sizing tester at the dryer or off-line lab) closed-loop dose control to mill DCS for variable-grade operation.
IBC Receipt and Make-Down Station. Mill-side 250-330-gallon poly IBC receipt: IBC heel-pump emptying with low-shear progressive-cavity or peristaltic pump into bulk receiving tank or directly to day-tank; IBC inventory turnover at 14-30 day maximum-hold to limit hydrolysis drift.
Off-Spec / Hydrolyzed Emulsion Recovery Tank. Hydrolyzed or destabilized AKD emulsion (failed in-process specification + creamed + separated emulsion) is staged at separate 500-2,000-gallon HDPE rotomolded recovery tank for off-site disposal as non-hazardous waste OR re-disposition into a lower-grade or non-sizing-critical paper-machine.
Containment and Spill Pad. All AKD emulsion bulk storage requires secondary containment per EPA SPCC + state-specific code; concrete-bermed pad with epoxy or polyurea liner; spill-collection sump with HDPE or PVDF transfer pump.
5. Field Handling Reality
Handler PPE. AKD emulsion bulk handling: nitrile or neoprene chemical-resistant glove specification at any contact, chemical splash goggles at any open-system handling, chemical-resistant Tyvek or equivalent suit at extended exposure, closed-toe steel-toe footwear with chemical-resistant overshoe, eye-wash station + emergency shower per OSHA 29 CFR 1910.151 within 10 seconds of work area.
Cargo-Tank or IBC Receipt and Bulk Transfer. AKD emulsion bulk cargo-tank delivery: 1000-3000-gallon stainless or HDPE-lined cargo tank with on-board gentle agitation + bottom-discharge or 250-330-gallon poly IBC delivery. Off-loading: facility-side air-operated diaphragm pump with PTFE diaphragm + EPDM seat + low-shear progressive-cavity or peristaltic transfer pump at AKD-specific service; transfer pipe 2-3 inch PVC or HDPE with EPDM gasket; cargo-tank seal with EPDM. Pump rate 25-100 gpm typical at AKD bulk delivery (slower than typical to avoid droplet coalescence); cycle time 30-60 minutes per 1000-3000-gallon delivery.
Temperature-Control Discipline. AKD lactone reactive group hydrolyzes to inactive ketone + fatty acid at storage temperature greater than 35C OR storage pH greater than 8.0 OR storage time greater than 30 day at typical conditions; storage at 4-25C target + pH 2.5-4.0 buffered + 14-30 day maximum-hold inventory turnover is mandatory. Temperature monitoring at top + bottom of bulk tank + day-tank with high-temperature alarm at 30C is mandatory at premium-grade service.
Gentle-Agitation Discipline. AKD emulsion droplet coalescence at high-shear flow + excessive-velocity transfer drives premature emulsion breakdown + sizing-loss + reduced wet-end performance; low-shear progressive-cavity + peristaltic pump + transfer-pipe velocity at less than 5 ft/sec specification + low-shear gentle agitator at 15-40 rpm + low-shear blade design is mandatory.
Freeze-Protection Discipline. AKD emulsion freezes at sub-zero-Celsius temperatures + does not recover after thaw; insulated jacket + heat-trace at any cool-climate installation + insulated trailer specification at winter delivery is mandatory at northern + Canadian operation.
QC Sampling and Verification. Each cargo-tank or IBC receipt requires sample collection: appearance check (uniform white-to-pale-yellow milky emulsion without sedimentation or creaming or oil-phase separation), specific gravity verification, dry-AKD active assay via solvent-extraction-and-titration or titration-against-cationic-titrant (6.0-15.0% +/- 0.3% target), pH verification at 2.5-4.0, droplet-size distribution via laser-diffraction or microscopy, colloidal-stability verification at 7-day or 14-day accelerated storage at 35C.
Spill Response. AKD emulsion spill response: small-volume spill is absorbed with vermiculite or absorbent boom + bagged for non-hazardous solid-waste disposition; large-volume spill is contained at secondary-containment + recovered via vacuum-truck for re-disposition or non-hazardous waste-staging.
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