| HS Code | 573398 |
| Product Name | KURARAY POVAL 32-80 |
| Chemical Name | Polyvinyl Alcohol |
| Cas Number | 9002-89-5 |
| Appearance | White granular powder |
| Degree Of Hydrolysis | 80.0 mol% |
| Viscosity 4 Aqueous Solution 20 C | 32 mPa·s |
| Ph 4 Aqueous Solution | 5.0 - 7.0 |
| Ash Content | ≤ 0.7% |
| Volatile Content | ≤ 5.0% |
| Bulk Density | 0.4 - 0.6 g/cm³ |
| Solubility | Soluble in hot water; practically insoluble in organic solvents |
As an accredited KURARAY POVAL 32-80 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | KURARAY POVAL 32-80 is supplied in 25 kg multi-layer paper bags with PE liner, ensuring dry, safe storage. |
| Container Loading (20′ FCL) | 20′ FCL: KURARAY POVAL 32-80 loaded in palletized, sealed bags, secured to prevent shift and moisture damage. |
| Shipping | KURARAY POVAL 32-80 is a polyvinyl alcohol resin supplied as free-flowing white granules. It ships non-hazardously in multi-layer paper bags or FIBCs, palletized and protected from moisture. Store in a cool, dry area away from heat sources, and minimize dust accumulation during handling. |
| Storage | Store Kuraray Poval 32-80 in a cool, dry, well-ventilated area in its original, tightly sealed container. Protect from moisture, humidity, direct sunlight, and heat sources. Keep away from oxidizing agents and ignition sources. Avoid generating dust; use appropriate handling controls. Maintain stable room temperature to preserve quality and prevent caking or degradation. |
| Shelf Life | Shelf life is typically 2 years when stored in a dry, cool place in original sealed packaging. |
On a 4.8 m wide metering size press running at up to 1,200 m/min, POVAL 32-80 is dissolved as a 9.0–10.0% stock solution in a jet cooker at 92–96°C for 30–45 min. The solution is then diluted to a working concentration of 2.0–4.0% dry basis and blended with oxidized corn starch at a mass ratio between 10:90 and 30:70 PVA to starch. In packaging grades where surface slip is critical, 0.3–1.0% of calcium stearate dispersion is added as a lubricant. The size press nip pressure is held between 22 kN/m and 38 kN/m, with a surface temperature of 55–65°C. The pickup is controlled to 0.8–1.8 g/m² per side. Under these conditions, the 32.0–38.0 mPa·s nominal solution viscosity improves film split stability and reduces misting at high line speed. The resulting surface property is evaluated by ISO 535 Cobb60, ISO 8791-2 surface roughness, and IGT AIC2-5 pick resistance. The main limitation is viscosity build-up in the recirculation tray when the starch paste retrogrades. The grade should not be run continuously for more than 72 h without cleaning, and hold-up temperature must not fall below 50°C.
POVAL 32-80 is charged into the pre-dissolving vessel at 4.0% solids and heated to 88–92°C under a low-shear three-blade propeller operating at 150–250 rpm. The solution is then cooled to 60–70°C before transfer to the main reactor. In a 5 m³ stirred reactor with a dual flight-anchor agitator at 90–120 rpm, the protective colloid is used at 2.0–4.0 wt% based on total monomer for high-viscosity interior paint binders. Vinyl acetate and ethylene are copolymerized at 55–65 bar and 70–85°C, with potassium persulfate as initiator. The addition of 0.1–0.3% sodium bicarbonate buffer maintains pH between 4.5 and 5.5. Coagulum levels on a 150 µm filter are typically lowest when the PVA-to-monomer ratio is kept below 5.0% because the 32.0–38.0 mPa·s grade creates a high continuous-phase viscosity. Above 6.0% PVA on monomer, mixer torque rises sharply and local overheating in the impeller zone can exceed 85°C, producing skin formation. Anti-foaming agents from 50 ppm to 200 ppm are used because partially hydrolyzed grades stabilize surface foam. The final dispersion is specified by ISO 2555 Brookfield viscosity at 25°C, ISO 3251 solids, ISO 976 pH, and ISO 13320 laser diffraction particle size. Residual POVAL 32-80 in the adhesive film is water sensitive. EN 204 D3 water resistance is not achieved without a blocked acid catalyst or crosslinking resin.
For 65/35 polyester-combed cotton warp yarn with linear density 19.7 tex, POVAL 32-80 is cooked at 90–95°C for 30 min in a stainless steel jet cooker. The size mix contains 18.0 kg of POVAL 32-80 per 1,000 L, 45.0 kg of modified starch, 2.0 kg of hydrogenated tallow wax, and 0.5 kg of polyester resin binder. The final viscosity is adjusted to 5.0–7.0 seconds in a Zahn cup #2 at 85°C. Warp sizing at 8.0–10.0% dry pick-up is then applied in a pre-wet size box. Drying cylinder surface temperature is staged from 105°C to 130°C to avoid film skinning. On a high-speed air-jet loom at 720 rpm, end breaks per 100,000 weft insertions are measured. The sized yarn tensile strength is tested according to ASTM D2256. Hairiness can be assessed with ASTM D5647. Desizing is conducted in hot water at 80–85°C with 0.5 g/L wetting agent. Because the grade is partially hydrolyzed, the film dissolves without enzyme treatment. Operational boundary: the sizing bath must be maintained above 75°C at all times. Starch-PVA phase separation is observed below 70°C, causing deposits on the squeeze roll.
Spiral tube plants running 80–150 m/min require a clean-splitting adhesive film with fast tack development. POVAL 32-80 is cooked at 15.0% solids in a dissolving tank with a side-scraped wall at 85–90°C. The adhesive is then extended with 10.0–15.0% kaolin clay and diluted to 23.0–28.0% total solids. Viscosity at 50°C is maintained between 2,500 mPa·s and 4,500 mPa·s using a Brookfield LV viscometer. The adhesive is applied with a steel roller at 0.2–0.4 mm wet film thickness on 350–500 g/m² recycled paperboard. Bond strength on a lab spiral tube tester is evaluated by pulling the lap joint according to an in-house method based on ISO 1924-2 tensile breaking strength. When POVAL 32-80 replaces oxidized starch above 50.0% of the binder solids, the tack-free open time on the winder is reduced to a point that requires faster roll setting. 1.0–2.0% urea is added as a humectant. Wet strength can be raised with 0.2% ammonium zirconium carbonate, but pH must remain below 7.5. Borax addition is not recommended above 0.1% because the resulting PVA-borate complex creates irreversible gel lumps in the doctoring system.
| Application scenario | Measured property | Standard/test method | Process parameter used for control |
|---|---|---|---|
| Paper surface sizing | Water absorption | ISO 535 | Pickup 0.8–1.8 g/m² per side |
| VAE emulsion polymerization | Dispersion viscosity | ISO 2555 | PVA addition 2.0–4.0 wt% on monomer |
| Textile warp sizing | Yarn tensile strength | ASTM D2256 | Dry pick-up 8.0–10.0% |
| Spiral tube winding | Bond strength | ISO 1924-2 | Clay extension 10.0–15.0% of adhesive solids |
In alumina-mullite substrate processing, POVAL 32-80 serves as a temporary green binder at 0.5–1.2 wt% of dry ceramic powder. The grade is dissolved at 80–85°C as a 4.0–5.0% solution and blended into the slip after viscosity reduction. Spray-dried granules prepared with this binder show higher granule strength and fewer dust fines when inlet-air temperature is controlled between 180°C and 220°C. Green bodies are uniaxially pressed at 100–200 MPa and machined in the green state. The high solution viscosity of 32.0–38.0 mPa·s improves edge retention during green machining and reduces lamination defects after burnout. Thermal removal is carried out at 1°C/min to 350°C, then at 2°C/min to 450°C. The ash content of ≤0.5% is low enough for technical ceramics, but sodium acetate residues influence slip rheology after repeated recycling. Slip viscosity is monitored by ISO 3219 rotational viscometry. Green flexural strength is evaluated with ISO 14704. Compatibility with high-solids ceramic slurries must be verified above pH 8.0; alkali-soluble additives may affect steric stabilization.
Air-laid nonwoven binder applications use POVAL 32-80 at 5.0–8.0% solution concentration. A 14 g/m² air-laid web is sprayed with 4.0–6.0% dry binder add-on and dried at 120–135°C in a through-air oven. Tensile strength is measured under ISO 9073-3. The key limitation is nozzle blockage at high solution viscosity. The fluid temperature must be retained above 60°C and the nozzle orifice must be at least 0.3 mm to maintain continuous spray operation.
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KURARAY POVAL 32-80 is a partially hydrolyzed poly(vinyl alcohol) resin produced by alcoholysis of poly(vinyl acetate). The grade designation encodes two specification parameters: nominal viscosity of a 4 wt% aqueous solution at 20 °C is 32.0 mPa·s, and degree of hydrolysis is 80.0 mol%. Under JIS K6726 and ISO 15023-2:2019 methods, viscosity is determined by rotational viscometer, and hydrolysis is expressed as the molar percentage of vinyl alcohol units in the polymer chain. The residual 20 mol% vinyl acetate units disrupt hydrogen-bonded crystallite formation, lower the dissolution temperature, and reduce equilibrium water resistance compared with fully hydrolyzed grades. Commercial documentation typically lists pH 5.0–7.0 for a 4 wt% solution, ash not exceeding 0.5%, volatile content not exceeding 5.0%, and minimum solution transmittance; these values are lot-controlled and should be confirmed against the current certificate of analysis.
Aqueous stock solution preparation requires controlled wetting because the grade has medium-high molecular weight and partial hydrolysis. Powder added too rapidly to cold water forms swollen lumps that can persist for hours. Standard make-down practice uses a jacketed vessel with low-speed anchor agitation: the powder is slurried in cold water to separate particles, then heated to 80 °C for 30 min before cooling. High-shear rotor-stator mixers are generally avoided because they introduce shear heating and foam without significantly reducing lump formation. Once dissolved, the solution exhibits shear-thinning flow; apparent viscosity at low spindle speed may exceed the nominal value due to non-Newtonian response.
In vinyl acetate and vinyl acetate-ethylene emulsion polymerization, POVAL 32-80 is metered as a 6–10 wt% aqueous solution at 0.5–4.0 wt% based on monomer mass. The 32-series viscosity contributes to reactor broth viscosity, shear stability, and latex rheology; the 80.0 mol% hydrolysis provides a hydrophilic protective layer that stabilizes nucleating particles without excessive water sensitivity. Production-scale 20 m³ stirred-tank reactors with pitched-blade turbine agitation are sensitive to protective-colloid addition profile: premature addition can generate bimodal particle size distributions and coarse fraction, while delayed addition reduces nucleation. Particle size distribution is measured by laser diffraction according to ISO 13320:2020. Because 32-80 has higher aqueous viscosity than 5-80 or 13-80, it lowers the protective-colloid dose required for stability, but increases the risk of viscosity overshoot during the nucleation stage. Batch-to-batch latex viscosity variation of ±10–15% is commonly observed when monomer quality, initiator addition, or agitator shear rate varies; published data for specific plant configurations is limited, so addition profiles should be established by pilot trials.
A 6–8 wt% aqueous solution of 32-80 is applied on metering size presses for woodfree printing and writing papers. The high-viscosity grade deposits a continuous film at low coat weight and controls surface strength, but runnability is sensitive to temperature. At 20 °C the solution viscosity is near target; below 20 °C viscosity increases steeply, so jacketed storage and transfer lines are maintained within ±5 °C of 35 °C. Film splitting at the roll nip is influenced by extensional viscosity, and misting is reduced relative to lower-molecular-weight grades. Water absorption is assessed according to ISO 535:2014; surface pick strength is assessed by IGT methods under ISO 3783:2006. The residual acetate groups prevent complete crystallization and allow cleaner repulping and reuse, whereas fully hydrolyzed grades are selected when wet-rub resistance dominates.
POVAL 32-80 dissolves in water at 20–40 °C under medium shear. In contrast, POVAL 32-98 requires 85–95 °C for dissolution because the near-absence of acetate groups permits more extensive crystallite formation. The residual 20 mol% acetate groups in 32-80 reduce crystallite size and melt-like dissolution barrier, at the expense of lower dry tensile modulus and higher equilibrium moisture uptake in cast films. Tensile comparisons are conducted on 100 µm cast films conditioned at 23 °C and 50% RH according to ISO 527-3. The following nominal comparison is derived from manufacturer technical data:
| Grade | Nominal viscosity 4 wt% at 20 °C | Degree of hydrolysis | Typical dissolution temperature |
|---|---|---|---|
| POVAL 5-80 | 5.0 mPa·s | 80.0 mol% | 20–30 °C |
| POVAL 22-80 | 22.0 mPa·s | 80.0 mol% | 20–40 °C |
| POVAL 32-80 | 32.0 mPa·s | 80.0 mol% | 20–40 °C |
| POVAL 32-98 | 32.0 mPa·s | 98.0–99.0 mol% | 85–95 °C |
The selection between 32-80 and 32-98 is therefore a balance between dissolution temperature and end-use water resistance. For applications requiring high wet strength or low equilibrium swelling, 32-80 is not recommended, and fully hydrolyzed grades or crosslinked PVOH should be used. The residual acetate content also reduces dry tensile strength compared with fully hydrolyzed grades when films are equilibrated at 50% relative humidity.
Ceramic tape casting at wet thicknesses below 100 µm requires a binder that disperses ceramic powders without generating excessive shear stress. POVAL 32-80 is combined with plasticizers such as glycerol at 10–20 wt% of binder solids. After casting on polyethylene terephthalate carriers, the dried green tape must reach sufficient tensile strength for release and cutting; ISO 527-3 tensile tests on 100 µm green tapes are used to compare binder efficiency. Thermogravimetric analysis shows that PVOH binder burnout completes below 500 °C in air, leaving an ash residue governed by the polymer specification. In aqueous alumina slurries at pH 9–10, borate-containing dispersants are incompatible with 32-80 because borate ions form reversible gels. Published data for specific ceramic formulations is limited; dispersant compatibility and green density should be established by pilot evaluation.
In cotton and cotton-polyester warp sizing, the size box is maintained at 75–85 °C. The 32-80 grade forms a tough elastic film on yarn and is removed by hot-water desizing at 60–80 °C without oxidizing agents. The 80.0 mol% hydrolysis provides sufficient adhesion to hydrophobic polyester fiber while maintaining low-temperature wash-off. Compared with 5-88 or 22-88 grades, the higher viscosity of 32-80 permits lower size add-on to reach equivalent yarn hairiness reduction, but requires higher size box concentrations and more robust pumping. Yarn tensile measurements under ISO 2062:2009 are commonly used to track size performance.
In water-soluble packaging films, 32-80 is processed by solution casting or by extrusion with plasticizers such as glycerol or sorbitol at 15–25 wt% of total solids. The 80 mol% hydrolysis grade dissolves more rapidly at cold-water temperatures than 88 mol% or 98 mol% grades, but the resulting film has lower tensile strength and higher moisture sensitivity. Melt processing is constrained by the onset of thermal degradation near 200 °C; therefore twin-screw extrusion requires tight temperature control and may use an L/D ratio of 40:1 to complete plasticization without excessive residence time. Film tensile properties are measured according to ISO 527-3 after conditioning at 23 °C and 50% RH.
In remoistenable envelope and label adhesives, 32-80 is formulated with humectants and preservatives. The 80 mol% hydrolysis grade provides fast rewetting because water penetrates acetate-rich amorphous regions. Open time is controlled by solution viscosity; the grade contributes pseudoplastic flow and low yield stress. However, aqueous solutions above 25 °C without preservative are susceptible to microbial growth, and storage beyond 48 h requires an isothiazolinone or equivalent biocide. The solution must not be combined with borate ions if clear low-viscosity handling is required; borate forms reversible shear gels. Viscosity stability after 30 days is measured by ISO 2555:2018, and lot-to-lot variation should be monitored with a rotational viscometer.
Under EN ISO 1043-1, the polymer is designated PVOH. The product is registered under REACH (EC) No 1907/2006; relevant food-contact status is specified in 21 CFR 177.1670 for certain applications, subject to end-use limits. Heavy-metal and residual solvent data are provided in the manufacturer’s long-term compliance statement. Warehousing at relative humidity above 60% causes progressive caking of partially hydrolyzed PVOH; bulk handling systems with vacuum conveying may show reduced transfer rates. The product should be consumed within 12 months from production when stored in original packaging at 5–35 °C. These constraints are operational boundaries documented in handling guidance.
