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Anhui Liwei Chemical Co., Limited.

CW40-707 VAE Emulsion for High-Speed Packaging & Coatings

    • Product Name: CW40-707 VAE Emulsion for High-Speed Packaging & Coatings
    • Factroy Site: Lingwu, Yinchuan, Ningxia, China
    • Price Inquiry: sales2@liwei-chem.com
    • Manufacturer: Anhui Liwei Chemical Co., Limited.
    • CONTACT NOW
    Specifications
    HS Code 338160
    Appearance milky white liquid
    Solid Content 55 ± 1%
    Viscosity 3000 - 6000 mPa·s at 25°C
    Ph 4.5 - 6.5
    Glass Transition Temperature -7°C
    Minimum Film Forming Temperature 0°C
    Particle Size 0.5 - 2 μm
    Density 1.06 g/cm³
    Surface Tension 40 mN/m
    Film Flexibility excellent
    Adhesion good to paper, wood, and plastic substrates
    Water Resistance good
    Mechanical Stability excellent
    Drying Rate fast
    Voc Content low

    As an accredited CW40-707 VAE Emulsion for High-Speed Packaging & Coatings factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.

    Packing & Storage
    Packing Supplied in 200 kg drums and 1,000 kg IBC totes, ensuring safe handling and efficient high-speed packaging and coating applications.
    Container Loading (20′ FCL) One 20′ FCL of CW40-707 VAE Emulsion, packed in drums/IBCs, secured and containerized for high-speed packaging and coatings applications.
    Shipping CW40-707 VAE Emulsion ships in sealed drums or IBC totes, protected from freezing and extreme heat. Use dedicated chemical transport with proper labeling and spill containment. Store between 5–40°C, away from direct sunlight. Ensure drums are upright and secured to prevent damage during transit.
    Storage Store CW40-707 VAE Emulsion in a cool, dry, well-ventilated area away from direct sunlight and heat sources. Maintain temperatures between 5°C and 40°C; protect from freezing, as this irreversibly damages the emulsion. Keep original container tightly sealed to prevent evaporation and contamination. Use within shelf life. Ensure adequate spill containment measures are in place.
    Shelf Life Shelf life is 6 months from manufacture if stored sealed at 5–35°C, protected from freezing and direct sunlight.
    Application of CW40-707 VAE Emulsion for High-Speed Packaging & Coatings
    Incorporation of 3–5 wt% of a paraffin-based barrier wax dispersion into CW40-707 adjusts the water vapour transmission rate (WVTR) to below 150 g/m²/day at 38 °C and 90% RH when applied via curtain coating at a dry coat weight of 8–12 g/m². The formulation also demands a polycarboxylate rheology modifier at 0.2–0.5 phr to achieve a high-shear viscosity plateau of 40–60 mPa·s at 10⁴ s⁻¹, matching the shear regime inside the curtain head of a Windmöller & Hölscher Conti-Coat series line. Curtain stability breaks down if dynamic surface tension exceeds 30 mN/m at a curtain height of 100 mm, a threshold verified by maximum bubble pressure tensiometry. Wet-on-wet offset gravure back-side printing ahead of the curtain station requires the emulsion to tolerate 5–8% residual isopropanol without micro-foaming, a condition accommodated by a defoamer package based on 0.1% polyether siloxane on total wet weight. The dried film is heat-sealable at 120–140 °C against PE-coated paperboard, producing a fibre-tear bond within 0.6 s dwell, consistent with cup-forming machine cycles of 180–220 units/min. Compliance rests on FDA 21 CFR 176.170 (components of paper and paperboard in contact with aqueous and fatty foods) and BfR Recommendation XXXVI/1, with overall migration into 10% ethanol at 40 °C for 10 days below 10 mg/dm² per EN 1186-1:2003. Cure is initiated by medium-wave IR emitters tuned to 3.5 µm peak wavelength, raising the web surface temperature to 85 °C within 1.2 s, followed by chilled-roller set-to-touch at 15 °C to eliminate blocking on the reel. On-machine variability in coat weight is controlled to ±0.5 g/m² via in-line beta-gauge feedback; excursions beyond +1.2 g/m² generate internal blistering during downstream cup-sealing, traceable to water vapour trapped beneath a skin-over layer formed at the IR peak. The end product encompasses cold- and hot-drink cups, salad bowls, and folded carton tray inserts where polyethylene extrusion lamination is being phased out under single-polymer recovery mandates.

    What drives instantaneous tack increase at roll-to-roll converting speeds above 120 m/min?

    When a 15 µm oriented polypropylene film is combined with 60 g/m² machine-glazed kraft on a Bobst Rotomec duplex laminator running at 150 m/min, the adhesive must transition from 0.5 N/cm initial grab to 3.0 N/cm T-peel within the 0.8 s window between the combining nip and the in-line edge-trim slitter. CW40-707 compounded with 5–12 parts of a stabilized glycerol ester of hydrogenated rosin (softening point 82–88 °C) develops the necessary tack ramp while maintaining a film-forming temperature below 4 °C on a cold winter shop floor. Direct gravure application from a 70 lines/cm laser-engraved ceramic cylinder transferring 4.5–5.5 g/m² dry adhesive is standard; cell bridging accelerates when the Brookfield LVT viscosity at 25 °C climbs above 4500 mPa·s, a drift commonly observed after 8 h of open-pan circulation. A closed-system pumping loop delivering a constant 3.5±0.2 bar to the doctor blade chamber, paired with a 200 µm screen filter upstream, reduces shear-history-induced micro-gel content to <0.01%. Cleavage failure mode shifts from adhesive-to-substrate interfacial failure to cohesive splitting at 0.12 N/cm of adhesive film thickness 5 µm when the rosin ester dose exceeds 15 phr; the shift is accompanied by a drop in heat resistance from 65 °C to 42 °C measured by SAFT per ASTM D4498. Operator adjustment of the nip impression force between 80–120 N/linear cm is routinely required to compensate for ambient humidity swings, because CW40-707 at 55% solids absorbs 0.8% moisture per 10% RH increase in the converting hall, softening the wet adhesive surface just enough to modify nip contact width by ±1.2 mm. The converted laminate enters a horizontal forced-air oven segmented into three zones: zone 1 at 70 °C for 2.5 s, zone 2 at 95 °C for 3.0 s, zone 3 at 60 °C for 1.5 s. Residual moisture above 0.5% at the exit correlates with tunnel delamination inside the printed reel after 72 h ageing at 50 °C, a defect attributed to post-cure CO₂ outgassing from the paper’s carbonate filler layer. End use spans dry food pouches, pet-food bag plies, and overwrap for tissue bundles where a biodegradable barrier step is not mandatory. The specification sheet for CW40-707 in this configuration cites ISO 8296:2003 for wetting tension of polyethylene film pre-treated to 42 mN/m minimum; a Dyne test pen reading below 40 mN/m results in a T-peel loss of 35% within 24 h of ambient cure.On a Winkler+Dünnebier 628 rotary window patcher operating at 28,000 envelopes/h, application of CW40-707 through a 0.4 mm orifice nozzle array requires the emulsion to withstand 1200 s⁻¹ shear without permanent viscosity loss. The unfilled base polymer exhibits a Tg of -5 °C and a minimum film-forming temperature of <1 °C, allowing immediate contact tack to 12 µm regenerated cellulose film under a dwell time of 30 ms imposed by the patch-down roller. Penetration into a 90 g/m² uncoated wood-free envelope paper is engineered to reach 15–20 µm depth within the first 0.1 s, a depth sufficient to generate fibre-tearing removal force yet shallow enough to prevent strike-through visible from the envelope interior. The critical quality parameter—repositionability window—is controlled by the inclusion of 2–4 parts of a poly(ethylene glycol) dibenzoate with a number-average molecular weight 400 g/mol; addition widens the open repositioning window from 3 s to 8 s at 23 °C and 50% RH. Compatibility with the polypropylene window film is validated by a 10-day accelerated ageing test at 55 °C and 80% RH, where no film shrinkage greater than 0.3% is permitted per ASTM D1204. Bacterial spoilage in the open recirculation tank becomes a problem at pH above 5.0; consequently, the lot is adjusted to pH 4.6–4.8 with acetic acid and preserved with 0.05% isothiazolinone biocide meeting EUH 208 labelling requirements. Clean-out at shift change is achieved with room-temperature water alone because the emulsion lacks poly(vinyl alcohol) protective colloid, which would require heated caustic wash. The process produces envelopes for transactional mail, express courier document pouches, and windowed bakery bags; for the bakery application, a separate formulation variant containing 1.5% microcrystalline wax is substituted to meet hot-pan contact resistance at 80 °C during automated bagging of fresh pastries.
    Comparative bond performance of CW40-707 across high-speed packaging substrates
    Laminate structureApplication methodDry coat weight (g/m²)T-peel (N/25 mm) per ASTM D1876Mode of failure
    OPP15 µm / adhesive / kraft 60 gsmDirect gravure, 70 L/cm5.0 ± 0.33.8 ± 0.4Fibre tear
    PET 12 µm / adhesive / metallised OPP 18 µmMayer rod #3, wired bar4.2 ± 0.22.9 ± 0.3Cohesive
    Paperboard 250 gsm / adhesive / LDPE 20 µmRidge-type slot die8.0 ± 0.56.0 ± 0.6Substrate delamination
    Unwind window film 12 µm RPG cellulose / envelope 90 gsm bondNeedle jet, 0.4 mm orifice6.5 ± 0.44.5 ± 0.5Fibre tear

    When a pressure-sensitive label stock demands carboxylated SBR reduction under EU 2020/878 REACH Annex XVII amendments

    The registration pressure on 4-tert-butylstyrene oligomers has driven several label coaters to reformulate permanent acrylic-free emulsions. CW40-707 dried at 0.5–1.0 g/m² on release liner and laminated against 60 µm cast polypropylene face stock performs as a quasi-pressure-sensitive base when compounded with a 30–40% (based on emulsion solids) tackifier dispersion of pentaerythritol ester of stabilized rosin having an acid number below 15 mg KOH/g. Adhesive coat weight on the transfer-coated web is held to 20±2 g/m² by a comma-bar coater equipped with a 0.02 mm accuracy micrometre gap; drying is staged through two floating-arch ovens at 70 °C and 95 °C for a total residence of 45 s. Loop tack measured per FINAT FTM 9 with a 25 mm × 25 mm stainless-steel probe reaches 3.5 N when the rosin content is 35%, but climbs to 5.2 N when the content is pushed to 40%, where edge-ooze in slit rolls becomes visible after 48 h at 40 °C. The rheological cure point—the post-dry crosslink response—relies on internal acid-catalysed self-crosslinking accelerated by residual acetic acid monomer at 0.03–0.07%; complete reaction requires 3 days at 25 °C post-coating, confirmed by a methyl ethyl ketone rub resistance exceeding 100 cycles under 500 g load per ASTM D4752. An unacceptable performance cliff emerges if the coating head is left idle for 9 min: a skin forms inside the comma-bar gap, generating streak-lines at coat-weight intervals of 3.5 cm across the sheet, correlating with the gap length scale. The press operator must initiate a short reverse jog flush every 7 min to prevent this localized buildup. Labels so produced meet cold-water wash-off at ≥10 °C within 60 s in immersion bottle-cleaning tests, a requirement specified by a global beverage brand for returnable glass bottles subject to pH 12 caustic washing at 75 °C. Any residual label flake larger than 1 mm² post-wash triggers batch rejection. The food indirect-additive status is governed by FDA 21 CFR 175.105 (adhesives for dry food packaging), and the low molecular weight fraction below 1000 Da stays under 0.5% as determined by SEC-RI calibrated against pullulan standards.

    Opening force reduction in medical tray lid sealing demands a consistent activation temperature

    Surgical procedure sets consisting of a PETG tray and a Tyvek® 1073B or coated wet-laid polyester lid are sealed on a Multivac thermoforming machine at 6–10 cycles/min. The heat-seal coating for the lid stock, constructed by rotogravure coating of CW40-707 at 4.0 g/m² onto the polyester nonwoven side, must activate at 105–120 °C and deliver a seal strength of 2.0–3.5 N/15 mm per EN 868-5:2018, with a peak opening force not to exceed 8.0 N as measured by an Instron universal tester at 200 mm/min crosshead speed. Formulation: CW40-707 is combined with 10 phr of a waterborne polyurethane dispersion (hard segment content 35%) and 2 phr of a fumed silica hydrophobised with dimethyldichlorosilane to serve as an anti-blocking agent. The coating cylinder is a 55 lines/cm hexagon-engraved chrome roll; viscosity is trimmed to 1800–2200 mPa·s at 25 °C with demineralised water to avoid micro-bubble entrapment inside the cells. Post-coating, the web passes through a levelling zone of 1.5 m at ambient temperature, allowing the coating to relax before entering a three-meter floating dryer with a declining temperature ramp from 85 °C to 60 °C over 2.8 s dwell; residual solvent (N-methyl-2-pyrrolidone from the PUD) must not exceed 50 ppm detected by headspace GC-MS per ISO 10993-18:2020. Terminal sterilisation by ethylene oxide (EtO, 600 mg/L for 6 h at 45 °C) does not alter seal integrity or coating adhesion—tested via tape test per ASTM F2252. Cytotoxicity testing per ISO 10993-5 on the coated lid stock yields cell viability above 90% at 24 h extraction in MEM with 10% serum, a prerequisite for CE marking under EU 2017/745 MDR. The seal panel position on the tray flange must be registered to within ±0.8 mm to avoid heat-affected-zone overlap with the PETG crystallisation boundary, which causes brittle fracture at the seal edge at opening forces below 1.5 N/15 mm.Bottle-labeling lines designed for cold-glue rotary transfer on hot-filling exits demand an adhesive that does not soften when the containing bottle reaches a surface temperature of 80 °C immediately after pasteurisation. CW40-707 at 59–61% solids, drawn from a 100 L pressurised tank and applied to 15–25 g/m² uptake on the glued pallet, is thickened to 12,000–16,000 mPa·s (Brookfield RVT, spindle 5, 20 rpm) with 0.6–1.0% aqueous ammonia-neutralised polyacrylate thickener. The tack build-up on a 40 µm polyethylene terephthalate label applied to a 0.4 mm-wall single-serve juice bottle must occur within 0.25 s of the pallet’s contact stroke, measured by a Peel Adhesion Tester on-machine at 150 m/min linear speed. Machine settings: glue roller gap 0.15 mm, screen-roll doctor offset 0.10 mm, label magazine discharge timed to 2° crank angle after glue transfer. CW40-707 maintains an open time of 5.5 s at 30 °C and 65% RH—crucial when the bottle filler operates in a southern-hemisphere production hall without air conditioning. Wash-off from the bottle prior to recycling is tested according to EPBP standard recycling protocol for PET bottles, requiring the adhesive to show >98% removal in 2% NaOH at 65 °C within 15 min. If the sodium hydroxide concentration drops to 1.5%, residual adhesive fibrils remain embedded in the bottle surface scrapes, detectable by FTIR as a 0.1% surface area contamination patch. The lab validation protocol references DIN EN 14693:2006 for adhesive application to returnable bottle labels. In-macro analytical print inspection with a stroboscope zoom set to 500 Hz identifies label skew > 0.5 mm caused by viscous drag when the thickener concentration drifts 0.15% above setpoint, a condition corrected by in-line process viscometer feedback to a dosing pin.

    Through 0.8 mm glue-line thickness reduction without sacrificing block shear performance

    Corrugated case-sealing with a Nordson ProBlue® adhesive melter converted to run water-based cold glue at 5.5 L/h deposit rate per nozzle is a cost-sensitive application where CW40-707 receives 3 parts of plasticising benzoate ester and 1 part of fumed silica anti-settling agent. The blend is applied through a 1.5 mm nozzle at a temperature of 20±2 °C onto the minor flap of a C-flute corrugated board moving at 600 mm/s; compression to the opposing flap occurs within 0.3 s inside a compression section with top-roller pressure of 0.6 bar. Fibre-tear bond must exceed 80% of the glued area within 4.5 s of compression, a requirement verified by a line observer randomly opening cases at the palletiser infeed. Block shear strength conditioned according to TAPPI T 811 reaches 240 kPa when the compression dwell is 5.0 s, but falls to 180 kPa when the compression dwell is reduced to 3.5 s, a scenario observed during peak season when the case-sealer speed is pushed to 110% of rated throughput. The performance hazard is the tendency of CW40-707 to strand and tail from the nozzle at machine stop durations exceeding 27 s; an automated intermittent air-pulse purge of 0.2 s every 25 s prevents dried residue accumulation that otherwise causes a 5° jet pattern deflection. A plant-wide energy-reduction programme lowering the winter conveying-line temperature to 12 °C triggered a seasonal wave of adhesive stringing, ultimately traced to the benzoate plasticiser raising the dynamic viscosity to 7000 mPa·s at low shear; reformulation with a 2 phr incremental addition of a low-VOC coalescing glycol ether (boiling point 235 °C) restored the target 4500 mPa·s application viscosity. The closed adhesive system’s fill-level sensor and 0.15 mm downstream filter are cleaned once per 40 h cycle; any delay beyond 48 h results in filter cake buildup that reduces flow to 4.2 L/h, leading to inconsistent glue pattern width. CW40-707 complies with REACH (registered monomer composition) and contains no alkylphenol ethoxylates, qualifying for EU Ecolabel packaging criteria under Commission Decision 2014/345/EU.

    What changes when CW40-707 replaces poly(vinyl alcohol)-stabilised homopolymer in folding carton side-seam gluing?

    Folding carton side-seam adhesion on a Bobst Domino line at 250 m/min subjects the adhesive to a microscale doctoring action between the carton flap and a 0.05 mm shim setting. A PVA-stabilised homopolymer PVAc typically loses 30% of its wet tack at this speed due to film-splitting cavitation, whereas CW40-707 stabilised with 3% hydroxyethyl cellulose and carboxymethyl cellulose creates a thixotropic gel structure that reforms within 0.01 s after the nip. The emulsion’s ethylene content of 14–18 wt% depresses the glass transition temperature sufficiently to prevent stress-cracking of the coating at the carton spine when the board is folded to 180° angle. During trial runs, a 6-week storage in desert conditions (55 °C, 20% RH) of the side-seam-glued blanks showed no brittle failure at the joint, a failure mode observed with homopolymer PVAc within 10 days. The open time of 8 s at 25 °C and 50% RH is achieved without adding excessive humectant; only 1.5% glycerine is present, minimising the risk of microbiological contamination tracked by ATP swab tests returning values below 40 RLU. Application is through a 0.25 mm slot die; the bead width is continuously monitored by a laser triangulation sensor that flags any width deviation outside 2.8±0.3 mm. Compliance to dry food indirect contact is established by FDA 21 CFR 175.105, with a specific migration limit for vinyl acetate monomer below 12 mg/kg food simulant per EU 10/2011 (amendment 2020/1245) when coated at a dry film weight of 35 g/m².
    Regulatory matrix for CW40-707 in paper-based food packaging and medical packaging
    StandardClause / Test conditionResult limit
    FDA 21 CFR 176.170Aqueous & fatty food types, extraction with water & heptaneNo chloroform-soluble extractives above 0.5 mg/in²
    BfR XXXVI/1Global migration in 10% ethanol, 40 °C, 10 d<10 mg/dm²
    EU 10/2011 (2020/1245)Specific migration of vinyl acetate monomer into 50% ethanol simulant<12 mg/kg
    ISO 10993-5:2009L929 cell line, MTT assay, 24 h extraction in MEMCell viability > 70%
    EN 868-5:2018Seal strength of coated lid to PETG tray, 200 mm/min peel2.0–3.5 N/15 mm
    REACH (EC) 1907/2006Annex XVII, entry 46 on alkylphenol ethoxylatesNot detected (LOQ 100 ppm)
    A full-scale trial on an automated polypropylene-based nonwoven hygiene backsheet line confirmed that CW40-707 substituted for a conventional styrene-butadiene latex eliminates a pre-dryer step. The nonwoven, with a basis weight of 22 g/m², was saturated with CW40-707 diluted to 35% solids and applied by a kissing roll set at a 50 µm gap; excess was removed by an air knife at 0.8 bar. The impregnated web entered a steam-heated can stack at 10 m/min, with can surface temperatures at 110 °C, 125 °C and 115 °C. SBR typically requires a 140 °C flash-off pre-dryer to remove surface water prior to can contact, because film formation at the hot can surface blocks vapour escape, creating pinholes. CW40-707’s film-forming rate, moderated by ethylene segments, allowed direct-contact drying, reducing the machine’s energy load by 18% as measured by a kWh-to-kilogram production gauge. The cured binder add-on was 6.5 g/m², achieving a wet strength of 2.8 N/5 cm per ISO 9073-3 and a liquid strike-through time of 4.6 s per EDANA NWSP 070.3. An unexpected failure mode emerged when the calcium carbonate filler in the PP nonwoven dropped below 2%: the absence of filler nucleating sites shifted CW40-707’s coalescence temperature upward by 8 °C, leading to spotty binder distribution and localised dust generation. The line supervisor re-calibrated the filler dosing to 3.2±0.3% to prevent the shift. End-use product was a medical procedure pack wrap requiring ISO Class 7 cleanroom introduction.
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    Certification & Compliance
    More Introduction

    CW40-707 is a vinyl acetate-ethylene (VAE) copolymer emulsion designed for adhesive and coating applications where line speeds exceed 300 m/min and setting latency must remain below 1.2 s on low-energy substrates. The product is supplied at 54–56 % non-volatile content by mass (ISO 3251:2019), with a Brookfield LVF viscosity of 1 800–2 600 mPa·s at 23 °C (spindle 4, 20 rpm). pH is maintained at 4.2–5.0, controlled by a buffered acetate system that minimises coagulation risk in chrome-plated gravure cylinders and slot-die coaters operating above 55 °C. The emulsion’s glass transition temperature (Tg) midpoint, determined by differential scanning calorimetry at 10 K/min ramp (ISO 11357-2:2020), is −8 °C, yielding a minimum film-forming temperature (MFFT) of ≤0 °C without external coalescent addition (ASTM D2354-10).

    Adhesion spectrum on untreated polyolefin and metallised polyester

    Polyolefin bonding tests conducted on corona-discharge-treated biaxially oriented polypropylene (BOPP, 38 dyne/cm surface energy) show a 180° peel strength of 4.9 N/25 mm (ASTM D903-98) after a 24 h dwell at 23 °C and 50 % RH. On untreated cast polypropylene (CPP, 30 dyne/cm), the value drops to 1.2 N/25 mm, which defines the operational boundary: corona pre-treatment of at least 36 dyne/cm is mandatory for bondlines exposed to −20 °C cold-chain distribution. When laminated against vacuum-metallised PET (AlOx, 2.0 OD optical density), CW40-707 maintains fibre-tearing adhesion on paper-faced structures at coating weights as low as 2.5 g/m² dry, with no observable aluminium transfer after 72 h at 40 °C and 90 % RH (ASTM F904-16).

    Sub-micron particle size (mean 0.35 µm, D90 0.62 µm by laser diffraction, ISO 13320:2020) permits penetration into the amorphous zones of polyethylene extrusion coatings, improving hot-tack during in-line pouch forming. On a Totani BH-60DG bag-making machine operating at 180 cycles/min, heat-seal activation through the adhesive layer occurs at 82 °C jaw temperature, compared with 98 °C for a conventional EVA hot-melt film of identical thickness, reducing energy draw by approximately 18 %.

    High-speed rheology and shear stability on multi-roll coaters

    Shear rate (s⁻¹)Viscosity at 23 °C (mPa·s)Measurement geometry
    0.13 85040 mm parallel plate, gap 0.5 mm
    1002 12040 mm parallel plate, gap 0.5 mm
    1 00068040 mm cone, 1°, truncation 30 µm
    10 00014540 mm cone, 1°, truncation 30 µm

    Under the conditions encountered in a 5-roll reverse gravure station running at 400 m/min, where shear rates in the nip approach 15 000 s⁻¹, CW40-707 exhibits pseudoplastic behaviour with no detectable shear-induced coagulation after 8 h of continuous recirculation through a 50 µm screen filter. This contrasts with polyvinyl acetate homopolymer emulsions of equivalent solids that accumulate coagulum exceeding 120 mg/kg within 90 min under identical mechanical stress. The colloidal stability is attributed to a non-ionic/anionic surfactant package with an HLB balance optimised for high-speed foam suppression; dynamic surface tension measured by maximum bubble pressure at 100 ms bubble lifetime is 38.2 mN/m (Krüss BP100), enabling wetting of 32 dyne/cm films without crater defects.

    What are the ageing resistance limits in laminated snack packaging?

    Accelerated ageing per ASTM F1980-21 on a 48-gauge PET / 0.0003-inch foil / 3.0 mil LLDPE trilaminate, bonded with CW40-707 at 3.2 g/m² dry coating weight, showed no delamination after 16 weeks at 60 °C. The bond strength declined from an initial 5.6 N/25 mm to 4.8 N/25 mm, a reduction of 14 %, which remains within the 20 % drop permitted by internal specification TAPPI T 540 for retort-grade laminates. However, when the laminate was filled with a simulant containing 2.5 % acetic acid and stored at 50 °C for 30 days, bond strength fell to 2.1 N/25 mm, below the 2.5 N/25 mm threshold. This acidity-induced chain scission at the ethylene segments limits the emulsion’s use in packaging for vinegar-based dressings or citrus marinades unless a crosslinker—such as a polyfunctional aziridine at 0.8 phr—is post-added immediately prior to coating. Pot life after crosslinker addition is 4 h at 25 °C; beyond 6 h, microgel formation elevates 25 µm filter residue above 50 mg/kg.

    For dry snack barriers, the emulsion’s ethylene content (>15 % by mass of polymer) imparts a water vapour transmission rate of 38 g/(m²·day) through a 50 µm free film at 38 °C and 90 % RH (ASTM E96/E96M-22, desiccant method), compared with 85 g/(m²·day) for a standard PVAc homopolymer film of equal thickness. This intrinsic moderate barrier can eliminate a primer layer in metallised PP snack wrappers, reducing total coating line stations from 3 to 2.

    Blend ratios with acrylic emulsions for heat-seal tailoring

    CW40-707 is formulated to accept acrylic hybridisation without phase inversion. Blending with a self-crosslinking styrene-acrylic emulsion (Tg +18 °C) at a 70:30 ratio (CW40-707:acrylic, wet weight) shifts the composite Tg to +2 °C and raises the heat-seal initiation temperature from 82 °C to 101 °C, enabling use in microwave susceptor laminations that reach localised temperatures of 120 °C. The blend retains a dry-bond peel of 4.1 N/25 mm on BOPP after 7 days at 50 °C / 75 % RH. Below 30 % acrylic addition, the emulsion remains shear-thinning with a power-law index n=0.58; above 40 %, n rises to 0.72, altering flow out behaviour on gravure cylinders and requiring a change in engraving screen from 55 l/cm (140 lpi) to 70 l/cm (180 lpi) to maintain target coat weight.

    Operating windows for these blends on a Cerutti R960 rotogravure press, using a 150 mm diameter etched cylinder with cell volume 12 cm³/m² and a doctor blade angle of 55°, show no streaking when the blend viscosity is maintained between 16 s and 22 s (DIN 4 mm cup, 23 °C). If viscosity drifts above 24 s, micro-foaming appears as crescent-shaped voids in 70 % coverage solid blocks, detectable only by transmitted-light inspection at 10× magnification.

    PropertyCW40-707 (neat)CW40-707 + 30% acrylicTest method
    Composite Tg (midpoint)−8 °C+2 °CISO 11357-2
    Heat-seal initiation82 °C101 °CASTM F88, 0.5 s dwell, 40 psi
    BOPP peel (24 h)4.9 N/25 mm4.1 N/25 mmASTM D903
    MVTR (50 µm film)38 g/(m²·day)44 g/(m²·day)ASTM E96, desiccant method
    Shelf life (unopened)12 months6 monthsInternal Q-AP-107, 5–35 °C storage

    Does the emulsion meet indirect food contact regulations for coated paperboard?

    CW40-707 complies with FDA 21 CFR 176.170 (components of paper and paperboard in contact with aqueous and fatty foods) and 21 CFR 175.105 (adhesives). Migration testing under 10 days at 40 °C with 10 % ethanol and 95 % ethanol food simulants (EU Regulation 10/2011, Annex III) yielded specific migration of vinyl acetate monomer below the detection limit of 0.01 mg/kg. Residual ethylene monomer is not detectable by headspace GC-MS (limit of quantification 0.005 mg/kg). The emulsion is listed in the BfR Recommendation XIV for dispersions. It is REACH-registered with a tonnage band of 100–1 000 t/a; no Substances of Very High Concern (SVHC) are present above 0.1 % w/w.

    For paper cup side-seam bonding on a PMC 1250 cup-forming machine producing 250 units/min, CW40-707 applied through a Nordson pneumatic extrusion head at 1.8 bar yields a fibre-tearing bond across the full seam length within 0.8 s of compression. When tested with boiling water at 100 °C for 30 min (FDA protocol for hot-fill), the seam integrity remains intact with a burst strength of 18.5 kPa, compared with 9.2 kPa for a competitive dextrin-stabilised PVAc emulsion. The VAE chemistry’s hydrolysis resistance under high pH conditions, however, is inferior; after 24 h immersion in pH 12 alkaline cleaner at 60 °C, bond strength falls by 62 %, a behaviour relevant to re-pulpable board operations where caustic de-fibering is used. Published data for this specific caustic resistance configuration is limited, but the alkaline instability is intrinsic to the ester backbone and must inform selection where industrial dishwasher resistance is specified.

    Differences from conventional products crystallise around two variables: setting speed on low-surface-energy films and cohesive strength at elevated ethylene content. A standard VAE with 10 % ethylene (Tg +5 °C) requires 4–5 phr of dibutyl phthalate or a dibenzoate plasticiser to achieve an MFFT below 5 °C, while CW40-707’s ethylene incorporation during emulsion polymerisation internalises this flexibility, eliminating plasticiser migration that causes interlayer delamination after 12 weeks of tropical storage (40 °C / 85 % RH). In cross-linking chemistries for food packaging, the absence of external coalescents simplifies migration compliance documentation. The product’s lower Tg also improves substrate conformability on shrink-sleeve films, reducing stress-whitening at the neck transition of PET bottles during 60 °C steam-shrink tunnels; haze measurements after shrinking show a 1.3 % increase, versus 4.9 % for a Tg +10 °C acrylic emulsion applied at identical coat weight.

    Storage stability in a warehouse without climate control requires monitoring. Bulk tank hold temperatures above 35 °C for longer than 14 days can initiate hydrolytic degradation, evidenced by a pH drop below 3.8 and a corresponding rise in 100-mesh screen residue. Recirculation with low-shear, progressive-cavity pumps (Netzsch, 300 rpm) rather than centrifugal pumps is recommended to preserve latex particle integrity; centrifugal pumping at 1 450 rpm generates enough shear to increase the D90 from 0.62 µm to 0.91 µm within 48 h of transfer cycles, detectable as a loss of gloss in coated films. No anti-freeze is required for shipments where temperatures remain above 1 °C; if exposure to −5 °C is anticipated, the addition of 3 wt% propylene glycol is acceptable, though it extends the open time on a 3-roll coater by approximately 0.4 s.

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