| HS Code | 811767 |
| Product Name | WH-PVAc 502 |
| Product Type | Polyvinyl Acetate (PVAc) Homopolymer Emulsion |
| Appearance | White milky liquid |
| Solid Content | 50% ± 1% |
| Viscosity | 8000–12000 mPa·s (Brookfield, 25°C) |
| Ph Value | 4.0–6.0 |
| Density | 1.05–1.10 g/cm³ at 25°C |
| Average Particle Size | 1–2 μm |
| Glass Transition Temperature Tg | 28°C |
| Minimum Film Formation Temperature Mfft | 10°C |
| Opening Time | 15–20 minutes at 20°C, 50% RH |
| Setting Time | Fast initial tack; full cure in 24 hours |
| Film Clarity | Transparent after drying |
| Voc Content | Negligible (<5 g/L) |
| Storage Stability | 12 months in original sealed container at 5–35°C |
As an accredited WH-PVAc 502 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | WH-PVAc 502 is supplied in 25 kg net weight, sealed in polyethylene-lined fiber drums with tamper-evident lids. |
| Container Loading (20′ FCL) | Loaded with WH-PVAc 502 in a 20-foot container, palletized, secured, and sealed for safe chemical transport. |
| Shipping | WH-PVAc 502 is a polyvinyl acetate dispersion shipped in sealed drums or IBC totes. Protect from freezing, excessive heat, and direct sunlight. Ensure containers are upright, clearly labeled, and accompanied by a safety data sheet. Under normal conditions, it is not classified as dangerous goods for road, rail, sea, or air transport. |
| Storage | Store WH-PVAc 502 in its original, tightly sealed container in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Protect from freezing; recommended storage temperature is 5–35°C. Keep away from incompatible chemicals and foodstuffs. Use within manufacturer’s shelf life, and stir gently before use. |
| Shelf Life | Shelf life is typically 12 months from date of manufacture when stored unopened in a cool, dry area, away from frost and direct sunlight. |
As an aqueous polyvinyl acetate homopolymer dispersion, WH-PVAc 502 is metered into a jacketed disperser at 18–25°C and diluted with deionized water only when the applicator requires a Brookfield viscosity of 8,000–12,000 mPa·s at 20 rpm. The dispersion is cast onto one substrate face with a ribbed-roll coater at a single-side spread of 120–180 g/m². Open time before joint closure is held below 8 min at 20°C and 55–65% RH. Pressing is carried out at 0.5–1.0 MPa for 12–20 min in a hydraulic cold press. Joints are conditioned for 7 days at 23°C and 50% RH before destructive shear testing. The relevant non-structural classification is EN 204; a D2-compliant joint is expected to retain adhesion after 4 days dry storage, 6 h immersion in cold water at 20°C, and 2 h redrying at 40°C. Tensile shear strength is measured by EN 205 using beech substrates with open and closed assembly times of 10 min each. Typical D2-grade PVAc homopolymer joints deliver dry shear above 8 MPa and wet shear above 3 MPa; published data for this specific grade under modified moisture cycling is limited. Calcium carbonate filler loadings above 12 wt% of total adhesive formulation reduce wet-strength retention below the threshold generally required for D3 service. This boundary is observed on hardwood stave lines where filler addition exceeds 12 wt% and the cold press is opened before 18 min. The working adhesive pH is maintained at 4.5–5.5; values below 4.0 promote acid hydrolysis of beech and oak substrates.
Starting-point formulation window for D2-type wood assembly adhesive using WH-PVAc 502.
| Ingredient or process parameter | Range | Control method |
|---|---|---|
| WH-PVAc 502 dispersion | 100 parts by mass as supplied | Brookfield viscosity 8,000–12,000 mPa·s at 20 rpm |
| Polyvinyl alcohol stabilizer | 3–6 parts of 10% solution | Dry shear by EN 205 |
| Dipropylene glycol dibenzoate plasticizer | 0–4 parts | Wet shear retention |
| Calcium carbonate filler | 0–12 parts | Wet shear after 6 h water soak |
| Defoamer | 0.05–0.15 parts | Foam density after 5 min at 3,000 rpm |
| pH adjustment | 4.5–5.5 | pH meter after 25°C calibration |
Spiral and convolute tube winders running 40–80 m/min require a pickup adhesive with a Brookfield viscosity of 1,800–3,800 mPa·s at 20°C. Above this range, the glue roll starves and the winding nip lacks a continuous transfer film; below 1,000 mPa·s, adhesive penetrates through lightweight kraft and causes release paper telescoping. WH-PVAc 502 is cut with water to a working solids of 45–50% and applied by a chromium-plated glue roll at 8–12 g/m² on 150–300 g/m² unbleached kraft. The glue roll speed is set 10–15% above paper line speed to maintain a uniform starved transfer. Transfer from glue roll to nip occurs within 0.5–2 s. Initial tack is measured by a T-peel fixture at 10 min and must exceed 0.5 N/mm on 110 g/m² liner. Drying is performed in-line at 70–90°C for 60–120 s, with residual moisture controlled to 6–9% by mass. Tensile retention is checked after conditioning with TAPPI T 494. Spiral tubes are also evaluated for curl using a 48 h flatness assessment at 23°C and 50% RH. A mineral-oil defoamer is added at 0.05–0.15 wt%; silicone-free grades are preferred because silicone transfer reduces water-based ink adhesion during subsequent printing.
In gypsum-based skim coats and ready-mix joint compounds, WH-PVAc 502 is dispersed into a pre-slurried water-retention system containing 0.25–0.45 wt% modified hydroxyethyl cellulose at 400–800 rpm. The binder addition is held at 8–12 wt% of wet compound when calcium carbonate filler exceeds 60 wt%. Below 6 wt%, the cured surface shows micro-cracking at a film thickness of 2 mm and an applied pressure of 0.4 MPa. Mixer speeds above 800 rpm entrain air; pinholes appear in the troweled surface after drying. Workability is evaluated with a Brookfield helipath spindle T-E at 5 rpm; production-ready joint compounds typically read 480,000–650,000 cP. The compound is applied to recessed joints with a 150 mm stainless steel trowel and air-dried at 20°C and 45% RH for 24 h. Bond to paper joint tape is measured by ASTM C474 using a 90° peel fixture; the failure mode must be cohesive paper fiber tear, not interfacial delamination. Shrinkage is measured by linear differential displacement after 24 h and is maintained below 0.5%. pH is adjusted to 7.0–7.8 with a 10% sodium carbonate solution because lower pH reduces MHEC gelation and allows settling of 20–60 µm limestone particles.
High-PVC interior flat formulations use WH-PVAc 502 at 12–20 wt% of total paint to bind titanium dioxide and 5–15 µm calcium carbonate. Grinding is performed on a high-speed disperser with a tip speed of 18–25 m/s for 20–30 min. The letdown is cooled to below 35°C before binder addition to avoid pre-coalescence. The final PVC is 78–84%, with a pigment volume concentration to critical pigment volume concentration ratio of 0.90–0.98. This places the coating just below the CPVC edge where scrub failure occurs rapidly. At PVC above 84%, scrub cycles fall below 200 under ASTM D2486-17; below 78%, the finish moves toward eggshell and no longer meets flat sheen specifications. Scrub resistance is tested by ASTM D2486-17 on 200 µm wet films applied to black vinyl scrub panels; a target of more than 500 cycles before visible erosion is standard for contractor-grade flat paints. Wet adhesion is measured by ASTM D3359-17 using a crosshatch after 10 min of water soak. Formaldehyde emission is suppressed by avoiding amino crosslinkers; dry-film emission after 24 h is assessed by ISO 16000-3 using a 0.5 m³ chamber at 0.5 air changes per hour. The binder’s minimum film-forming temperature is near 18°C; below this, 2–4 wt% coalescing solvent on binder solids is added to prevent mudcracking at 5°C.
At a two-roll nip pressure of 20–30 N/mm, wetlaid and carded nonwovens are saturated with WH-PVAc 502 at a dry add-on of 12–18% using a padder. The dispersion is diluted to 10–15% solids with deionized water. The pH is buffered to 5.0–6.0 with sodium acetate to avoid precipitation of the anionic wetting agent. Drying is performed on a through-air belt at 105–125°C for 90–150 s. The binder cures by water evaporation and coalescence, not by crosslinking, so the processing window is broader than that of a thermoset acrylate. Tensile strength is determined by ISO 9073-3 with a 200 mm gauge length and 100 mm/min jaw speed. Trapezoidal tear resistance is measured by ISO 9073-4; a dry value above 15 N is typical for a 40 g/m² wetlaid cellulosic web. Nip pressure above 30 N/mm forces binder to the web surface and produces a glossy, brittle face after drying; below 20 N/mm, add-on uniformity falls below acceptable limits. Wet tensile retention is lower than that of self-crosslinking styrene-acrylate or vinyl acetate-ethylene formulations; applications requiring wet retention above 50% are not suitable for this homopolymer grade. Terminal uses include cellulosic air-laid pads and filtration media where moderate dry tensile, low solvent content, and controlled ash after 600°C incineration by ASTM D5630 are specified.
When warp density exceeds 40 yarns/cm, woven jacquard upholstery is backcoated with WH-PVAc 502 at 60–80 g/m² wet add-on using a knife-over-roller coater with a gap setting of 0.2–0.4 mm. In previously run textile trials, the dispersion is thickened with 0.3–0.6 wt% alkali-swellable polyacrylate to a viscosity of 8,000–12,000 mPa·s at 20 rpm. This keeps the coating from penetrating through the face yarn during the 2–3 s residence time before drying. Drying is performed in a four-zone stenter with zone temperatures of 90°C, 110°C, 120°C, and 100°C, and a dwell of 40–60 s. Seam slippage is assessed by ISO 13936-2:2004; the coated fabric is expected to maintain seam opening below 0.5 mm at the specified transverse force. At wet add-on below 60 g/m², seam opening exceeds 0.7 mm on 300 g/m² jacquard. The terminal fabric is used in upholstery and mattress ticking where the backcoating prevents yarn movement during stretching over foam profiles.
| Downstream segment | Process window | Acceptance method | Critical boundary |
|---|---|---|---|
| Wood edge-gluing, D2 | 0.5–1.0 MPa, 12–20 min, 18–25°C | EN 205, EN 204 | Wet shear >3 MPa; filler <12 wt% |
| Paper tube winding | 40–80 m/min, 8–12 g/m² | TAPPI T 494 | Viscosity 1,800–3,800 mPa·s |
| Gypsum joint compound | 400–800 rpm, 8–12 wt% binder | ASTM C474 | Filler >60 wt%; binder <6 wt% causes cracking |
| Interior flat paint | 18–25 m/s tip speed, 78–84% PVC | ASTM D2486-17 | Scrub >500 cycles |
| Wetlaid nonwoven | 20–30 N/mm nip, 12–18% add-on | ISO 9073-3 | Wet retention <50% |
| Upholstery backcoating | 60–80 g/m², 0.2–0.4 mm gap | ISO 13936-2:2004 | Seam opening <0.5 mm |
Competitive WH-PVAc 502 prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615380400285 or mail to sales2@liwei-chem.com.
We will respond to you as soon as possible.
Tel: +8615380400285
Email: sales2@liwei-chem.com
Flexible payment, competitive price, premium service - Inquire now!
WH-PVAc 502 is an aqueous polyvinyl acetate homopolymer dispersion supplied as a ready-to-use adhesive for cellulosic and polar porous substrates in non-structural woodworking, paper converting, and flat lamination. The product is polyvinyl-alcohol-stabilized rather than surfactant-dominated; this stabilizer selection affects wet tack, dried-film hardness, and shear response. Non-volatile content measured by ISO 3251 is controlled at 52 ± 1 %. Brookfield viscosity by ISO 2555 at 25 °C, spindle 6 at 20 rpm, is 12,000–16,000 mPa·s. pH by ISO 976 at 25 °C is 3.2–4.5. Minimum film-forming temperature by ISO 2115 is 5 °C with the standard coalescent package. Dried-film density by ISO 2811 is 1.08 ± 0.02 g/cm³. These values define the release specification, not end-use performance limits.
In standard packaging, WH-PVAc 502 is filled into 200 L HDPE drums and 1,000 L IBCs under nitrogen blanket to reduce skinning. Storage between 5 °C and 35 °C gives a nominal shelf life of 12 months. After 6 months, pH drift greater than 0.5 units from the certificate-of-analysis value indicates possible hydrolysis; such material should not be blended with fresh stock without qualification. Freeze-thaw resistance is limited: one cycle at −5 °C can produce irreversible grit larger than 100 µm as measured by sieve retention on a 100 µm screen. Thawing under low-shear agitation below 100 rpm does not restore the original film quality.
WH-PVAc 502 is not a crosslinked dispersion and does not contain a latent hardener. Its durability under EN 204 is classified as D2 when tested by the EN 205 lap-shear protocol on beech at 23 °C and 50 % relative humidity. Crosslinked D3 dispersions generally retain higher wet strength after 4 h cold-water soak, but they also demand shorter pot life after addition of the acid catalyst, typically 4–12 h. WH-PVAc 502 has no such pot-life limitation because it is used as supplied. Compared with WH-PVAc 501, a lower-viscosity grade for spray application, WH-PVAc 502 carries 4–5 percentage points higher non-volatile content and a spindle-6 Brookfield viscosity approximately 6,000–10,000 mPa·s higher. Compared with a 40 % solids surfactant-stabilized EVA dispersion, the polyvinyl alcohol colloid of WH-PVAc 502 yields a dried-film glass transition midpoint by ISO 11357-2 of 31–34 °C, roughly 6–10 K above the EVA reference. The result is a harder bond line and better static load resistance at 50 °C, but lower elongation at break and poorer unprimed adhesion to low-energy films such as oriented polypropylene.
| Property | WH-PVAc 502 | WH-PVAc 501 | EVA 40 % |
|---|---|---|---|
| Non-volatile content by ISO 3251 | 52 ± 1 % | 48 ± 1 % | 40 ± 1 % |
| Brookfield viscosity at 25 °C by ISO 2555 | 12,000–16,000 mPa·s | 5,000–8,000 mPa·s | 8,000–12,000 mPa·s |
| pH by ISO 976 | 3.2–4.5 | 4.0–5.0 | 4.0–5.0 |
| Minimum film-forming temperature by ISO 2115 | 5 °C | 10 °C | 0 °C |
| Dried-film glass transition midpoint by ISO 11357-2 | 31–34 °C | 33–36 °C | 0–5 °C |
| Wood adhesion class by EN 204/EN 205 | D2 | D1 | D1 |
| Open assembly time on beech at 23 °C, 50 % RH | 6–10 min | 8–12 min | 10–14 min |
For high-speed paper tube winding and carton side-seam bonding, WH-PVAc 502 is applied at 30–70 g/m² through a grooved application roller onto clay-coated or uncoated recycled board. Wet tack measured as minimum fiber-tear bonding time on 80 g/m² kraft under 0.4 bar nip pressure is approximately 5–8 s. The formulation tolerates machine speeds up to 120 m/min when board moisture content is between 6 % and 10 %; above 12 % moisture, bond development slows and open time shortens due to interfacial dilution. Chalked or heavily coated boards with surface absorption below 5 g/m² Cobb value under ISO 535 require corona or primer treatment because the water-borne dispersion cannot penetrate sufficiently to form fiber tear.
WH-PVAc 502 is suitable for engraved roll application and roller coaters but is not intended for airless spray without dilution above 3 wt% water. At shear rates typical of roller coater gaps—1,000–5,000 s⁻¹—apparent viscosity falls to 3,000–6,000 mPa·s, permitting uniform transfer at 120–180 g/m² on flat-rolled veneer. Pre-drying in ovens above 70 °C surface temperature causes premature skinning in the wet film; infrared pre-drying at 55–65 °C for 2–4 s removes only surface water. In a high-speed laminating line with a 600 mm nip roll, roll surface temperature 60–80 °C, and line speed 15–25 m/min, hot-press contact time should exceed 20 s to achieve fiber-tearing bonds on birch veneer. Lower line speeds shall be used when ambient relative humidity is below 30 % because the open film skins faster.
Lot-to-lot apparent viscosity at 25 °C is controlled by the manufacturer to a maximum deviation of ±1,000 mPa·s from the reference batch after 24 h equilibration in a closed container. In drum-offloading and homogenizer operations, low-shear impeller mixing below 300 rpm is recommended. Gear pumps with internal clearances exceeding 0.1 mm can generate local shear heating above 45 °C, producing coagulum that appears as microgrit in the dried film. On roll-coater reservoirs, recirculation through 100 µm filter bags increases pressure drop within 2 h if the dispersion has aged beyond 9 months, indicating particle-size growth. In such cases the adhesive should be screened and tested before use.
The product does not contain a latent hardener; therefore, open assembly time is governed by water loss, substrate porosity, and ambient humidity. At 35 °C and 30 % relative humidity, open time on beech veneer is approximately 6–10 min. If assembled panels remain unpressurized beyond 10 min, the applied film develops a dry skin and subsequent cold pressing at 0.8 N/mm² does not recover fiber tear. In environments above 60 % RH, store containers sealed and pre-dry the substrate to 8–10 % moisture content to avoid surface pooling. Avoid combining with amine-based additives or hardeners intended for urea-formaldehyde or epoxy systems; pH elevation above 6.0 destabilizes the acetate-protected dispersion and produces coagulum within 2 h.
Production-scale flat lamination of melamine-faced MDF to particleboard with WH-PVAc 502 uses a roller coater set at 150–200 g/m² and a short radiant pre-dry of 2–4 s at 55–65 °C surface temperature. Under a platen press at 1.2 N/mm² and 25 °C, press time of 30–45 min is required for high-pressure laminate to reach final handling strength; on a heated press at 80 °C, the same stack reaches sufficient green strength in 3–5 min. The adhesive’s thermoplastic film softens when panel surface temperature exceeds 60 °C in secondary processing, which limits post-forming heat exposure to 55 °C unless mechanical fastening is used.
For edge-glued softwood and hardwood panels, a spread rate of 120–180 g/m² on each prepared face, closed assembly within 5 min, and clamp pressure of 0.6–1.0 N/mm² for 20–30 min at 20–25 °C produces bonds that pass EN 204 D2 after 7 days conditioning. Joints clamped below 10 °C show retarded water evaporation and should remain under pressure for 2–3 h; below 5 °C, the dispersion no longer forms a continuous film and bond strength drops below the 2 N/mm² internal release threshold.
Temperature exerts a non-linear effect on apparent viscosity. At 10 °C, spindle-6 viscosity rises to 25,000–35,000 mPa·s; at 35 °C, it falls to 6,000–9,000 mPa·s. Coating lines without jacketed reservoirs should not start below 15 °C because transfer weight increases and may exceed 200 g/m². A viscosity-controlled water addition loop using a process viscometer with a target of 14,000 mPa·s maintains coat weight within ±5 % on a 400 mm two-roll coater at 30 m/min.
Minimum film-forming temperature is 5 °C, but complete coalescence and full bond development require the wet film to remain above 10 °C for at least 30 min. At 5–10 °C, dried films exhibit microcracking, apparent as a hazy bond line with reduced tensile strength. The coalescent package is phthalate-free and does not contain butyl glycol ether; this limits film hardness reduction but narrows the low-temperature application window relative to some D2 grades formulated with glycol ether coalescents.
The acetate dispersion is incompatible with dolomite, calcium carbonate fillers above 5 wt%, and zinc oxide accelerators; these materials neutralize the acidic stabilizer and can cause viscosity increase or gelling within 24 h. If filler addition is required, a pre-dispersion of calcium carbonate in water with pH adjustment to 4.0–5.0 should be evaluated, but no more than 3 wt% is recommended for flat-lamination applications.
On oily tropical wood species such as merbau or teak, surface extraction with solvent or sanding immediately before adhesive application is required to obtain an open porous surface. The product’s wet tack on these species is 2–3 s slower than on beech, and open time is shortened by less interfacial water absorption. A 100 g/m² primer coat of WH-PVAc 502 diluted 5 wt% with water improves adhesion by filling open pores, but total dry-film thickness above 50 µm reduces wood failure percentage. Published data for specific tropical species configurations is limited; end-use trials are required for species with high extractive content.
The product is not formulated with formaldehyde-donor preservatives, phthalate plasticizers, or intentionally added boron compounds. It is not classified as hazardous under CLP Regulation (EC) No 1272/2008 as supplied; however, acidic rinse water and wet adhesive can corrode uncoated carbon steel, so contact parts should be 304 or 316 stainless steel. Emissions from the dried film under EN 16516 chamber testing are typically below the lower limit of quantification for formaldehyde, but published data for this specific product configuration is limited and end-use emission testing is required.
| Standard/Regulation | Property or requirement | Status/Typical value |
|---|---|---|
| EN 204 / EN 205 | Non-structural wood adhesive durability classification | D2 |
| RoHS Directive 2011/65/EU | Restricted hazardous substances in homogeneous material | No intentionally added Pb, Hg, Cd, Cr⁶⁺, PBB, PBDE above limits |
| REACH Regulation (EC) No 1907/2006 | Substances of very high concern | No SVHC above 0.1 % w/w per article, based on supplier declarations |
| FDA 21 CFR 175.105 | Adhesives for indirect food contact | Formulation-specific; end-use extraction testing required |
| EN 16516 | VOC and formaldehyde emission from building materials | Not classified; site testing required for final panel |
In hot-melt adhesive replacement evaluations for paper/paperboard overlays, WH-PVAc 502 is compared against EVA hot melts by line speed and bond development. Unlike EVA hot-melt, the water-based dispersion requires drying/water removal before full bond formation; therefore bond strength at the winder is not instantaneous. At 200 m/min, if the board has a Cobb value above 20 g/m² by ISO 535, water uptake is sufficient for mechanical interlocking but trapped moisture may produce curl. The product is not suitable for closed-cell foams, untreated polyethylene, polypropylene, or films with surface energy below 38 mN/m without primer.
