| HS Code | 513576 |
| Product Name | KURARAY POVAL 48-80 |
| Chemical Name | Polyvinyl Alcohol (PVOH) |
| Cas Number | 9002-89-5 |
| Grade Type | Partially hydrolyzed polyvinyl alcohol |
| Appearance | White to pale yellow granular powder |
| Odor | Odorless or very mild odor |
| Degree Of Hydrolysis | 80.0-83.0 mol% |
| Viscosity | 48.0-56.0 mPa·s (4% aqueous solution at 20°C) |
| Ph | 5.0-7.0 (4% aqueous solution) |
| Ash Content | ≤0.5% |
| Volatile Content | ≤5.0% |
| Bulk Density | 0.4-0.6 g/cm³ |
| Solubility | Soluble in cold and hot water; forms viscous solutions |
As an accredited KURARAY POVAL 48-80 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | KURARAY POVAL 48-80 is supplied in 25 kg multi-layer paper bags with an inner polyethylene liner for moisture protection. |
| Container Loading (20′ FCL) | 20′ FCL: palletized bags of KURARAY POVAL 48-80 loaded securely, weight optimized for safe transport and efficient unloading. |
| Shipping | KURARAY POVAL 48-80 is a water-soluble polyvinyl alcohol powder shipped in sealed multi-layer bags or drums. It is non-hazardous for transport, but must be kept dry and protected from moisture. Store in a cool, ventilated area away from incompatible materials, and handle with standard industrial hygiene practices. |
| Storage | Store KURARAY POVAL 48-80 in a cool, dry, well-ventilated area, away from direct sunlight, heat, and ignition sources. Keep the original container tightly closed to prevent moisture absorption and contamination. Avoid generating dust; use appropriate local exhaust ventilation. Maintain stable temperatures and dry conditions to preserve quality and ensure safe handling. |
| Shelf Life | KURARAY POVAL 48-80 has a shelf life of two years from manufacture when stored in a cool, dry place with sealed packaging. |
In semi-batch vinyl acetate-ethylene (VAE) latex production, POVAL 48-80 is introduced as the primary protective colloid when a high aqueous solution viscosity and a partially hydrolyzed acetate residue are required to control particle nucleation and shear stability. At 4% aqueous concentration and 20°C, the grade exhibits a nominal viscosity of 48 mPa·s and a nominal hydrolysis degree of 80 mol%, which modifies the continuous-phase surface energy while preserving sufficient residual acetate groups for graft copolymerization with vinyl acetate. The protective colloid is pre-dissolved in demineralized water in a jacketed make-down vessel at 85–90°C for 30–45 min, cooled to 60°C, and metered into the reactor at a loading of 1.5–4.0 phm based on vinyl acetate monomer. A representative 55% solids wood adhesive formulation uses 2.5 phm POVAL 48-80, 0.15 phm potassium persulfate initiator, and 0.05 phm sodium bicarbonate buffer, polymerized at 70–80°C under ethylene pressure of 35–50 bar. On production-scale equipment, batch-to-batch viscosity drift is minimized when the make-down temperature does not exceed 95°C, because thermal cleavage of residual acetate groups can lower late-stage shear stability. The final latex typically shows a Brookfield viscosity of 3,000–8,000 mPa·s at 20 rpm and 25°C; deviations outside this band are most frequently traced to variation in PVA feed solids rather than monomer conversion. Compliance for wood adhesives and food-contact paper coatings relies on FDA 21 CFR 176.170 and FDA 21 CFR 176.180, while European converters should verify the final laminate structure against Regulation (EU) 10/2011 because the PVA layer is not intended to function as a barrier layer. Terminal products include D3/D4 wood assembly adhesives tested to EN 204, coated paper and paperboard for dry food packaging, and nonwoven binders used in air-laid absorbent cores.
Remoistenable adhesive coatings require a film that remains non-blocking in humid storage but rewets rapidly under water contact without dissolving completely into the paper surface. POVAL 48-80 is formulated into water-based remoistenable gums at a concentration of 8–14 wt%; the target coating viscosity is 800–2,500 mPa·s at 25°C, measured with a Brookfield LV spindle 3 at 30 rpm. Glycerol or sorbitol plasticizer is added at 5–15 wt% of dry PVA to shift film flexibility and prevent brittle cracking on envelope flap creases. The coating is applied by reverse gravure or air-knife coating to 60–90 g/m² base paper at a dry add-on of 3–8 g/m²; forced-air tunnel drying is held at 50–90°C, with final paper moisture controlled at 5–7% to maintain rewettability. A documented production failure occurs when the drying section exceeds 110°C for more than 20 s, producing surface insolubilization that reduces tack after rewetting. The formulation should not be thickened with borax or boric acid, because such additives can crosslink the 1,3-diol segments and create non-remistenable domains. For food-contact envelope and stamp applications, compliance is governed by FDA 21 CFR 175.105 for indirect food additives in adhesives; where the finished article reaches stationery or toy markets, migration testing under EN 71-3 may be required by the converter’s specification. Terminal products include remoistenable envelope flaps, wallpaper joints, paper labels, and paper splicing tapes.
In single-end slasher sizing of 40 Ne cotton warps, the sizing bath is maintained at 85–95°C and POVAL 48-80 is applied at 6–12 wt% in demineralized water through a double-squeeze nip at 2.0–4.0 bar, producing a dry add-on of 8–12% on the yarn bundle. The high polymerization degree of the grade contributes to sized-yarn tensile strength retention measured by ISO 2062, but the partially hydrolyzed acetate groups reduce film-to-metal adhesion on drying cylinders; cylinder temperatures are therefore staged from 100°C to 130°C to avoid skinning on the first can. Wax and antistatic agents are added at 0.3–0.8 wt% and 0.1 wt% of the bath, respectively, to control abrasion and static build-up on high-speed looms. Desizing after weaving uses hot water at 80–90°C with a residence time of 30–60 s in an open-width wash range; no amylase enzyme is required for this PVA grade, but residual size must fall below 0.3 wt% on fabric before dyeing if the mill seeks ZDHC MRSL v3.1 conformance and Oeko-Tex Standard 100 certification. Terminal woven products from these warps include denim, twill workwear fabrics, and automotive upholstery substrates.
Ceramic tape casting and dry pressing operations use POVAL 48-80 as a temporary organic binder when green bodies are subsequently machined or punched and must retain edge sharpness without powder breakout. The binder is first dissolved in water at 5–10 wt% solids and added to a ball-milled ceramic slurry at 0.8–2.5 wt% of dry ceramic powder; spray drying at inlet 180–220°C and outlet 80–110°C produces spherical granules with residual moisture of 0.5–1.5 wt%. During uniaxial pressing at 100–150 MPa, the high-molecular-weight PVA phase increases green strength determined by three-point flexure per ASTM C1161, without excessive elastic springback. Binder migration can occur when the pressing cycle is shorter than 10 s, producing density gradients across thin alumina substrates. Debinding must be performed in air or nitrogen with a heating rate no higher than 2°C/min from 200°C to 450°C; rapid burnout produces carbon residues and blisters because PVA decomposition products cannot escape through partially densified pore channels. Compliance for electronic ceramic components is evaluated against RoHS Directive 2011/65/EU for restricted substances in the final fired part and ISO 9001:2015 process control for binder preparation, although the PVA is removed before final qualification. Terminal product types include alumina substrates, MLCC dielectric layers, and silicon carbide kiln furniture.
When vinyl chloride monomer is dispersed in water at 0.9–1.1 MPa, POVAL 48-80 is injected as a co-dispersant alongside a fully hydrolyzed primary suspending agent in a 105 m³ stirred reactor operated at 55–65°C. The co-dispersant charge is 0.01–0.03 parts per 100 parts vinyl chloride monomer, dissolved in hot demineralized water and premixed for 60 min before addition; this low level modulates interfacial tension and narrows the PVC grain size distribution to 100–180 μm. Agitation is maintained at 150–220 rpm with a two-blade Pfaudler impeller, and the water-to-monomer ratio is held at 1.2–1.4:1. The partially hydrolyzed acetate groups of POVAL 48-80 reduce coalescence during the early stage of suspension stabilization, but overdosing above 0.05 parts per 100 VCM increases the proportion of translucent PVC particles and lowers plasticizer absorption; the resulting resin may fail the plasticizer absorption limit in GB/T 5761-2018 or ASTM D1755. Final PVC grades are used for rigid pipe, window profiles, and calendered sheet.
POVAL 48-80 is added to cementitious dry-mix mortars when longer open time and improved adhesion to low-porosity substrates are required without replacing the main redispersible polymer powder system. The addition ratio is 0.3–1.5 wt% of cement; the powder is dry-blended with Portland cement, sand, and cellulose ether in a twin-shaft batch mixer for 3–5 min, then combined with water at a water-to-powder ratio of 0.20–0.25. The PVA dissolves gradually under alkaline pH and contributes to tensile adhesion of the cured mortar assessed according to ISO 13007-1:2014 and EN 12004. Above 1.5 wt%, air entrainment and retardation become measurable, and the mixed mortar becomes sticky on the trowel, reducing workability. This application is limited to non-structural tile adhesives and skim coats, not to structural concrete repair where PVA is not a direct substitute for redispersible polymer powders. Terminal products include C1/C2 tile adhesives, interior repair mortars, and gypsum skim coats.
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KURARAY POVAL 48-80 is a partially hydrolysed polyvinyl alcohol grade produced by alcoholysis of polyvinyl acetate. The product carries CAS registry number 9002-89-5. The grade designation encodes a nominal solution viscosity of 48 and a nominal hydrolysis level of 80 mol%. Supplier technical literature lists the following typical data: degree of hydrolysis 79.0–81.0 mol%; viscosity of a 4% aqueous solution at 20 °C 44.0–52.0 mPa·s, measured in accordance with JIS K6726; pH 5.0–7.0; volatile matter ≤5.0%; ash content ≤0.5%. The average degree of polymerisation is approximately 4,800. The product is supplied as a white to pale-yellow granular powder. These values are lot-release ranges for bulk resin; a specific certificate of analysis should govern any production specification. The powder is hygroscopic and should be stored at 20–30 °C in sealed packaging. Warehouse conditions above 60% RH promote lump formation and require pre-drying at 50–60 °C for 2–4 h before solution preparation.
Residual acetate groups in 48-80 interrupt interchain hydrogen bonding and reduce crystallite density compared with fully hydrolysed grades. This structural difference allows water molecules to penetrate at 20–30 °C, whereas grades with 98–99 mol% hydrolysis generally require heating above 80 °C for complete dissolution. The trade-off is higher equilibrium moisture uptake and lower wet strength. Conditioning at 23 °C and 50% RH in accordance with ISO 291 produces higher film moisture content than 48-98 conditioned under identical conditions. Water-resistance tests such as ISO 535 for paper or immersion testing under ISO 2812-1 are used to differentiate grades. The lower crystallinity also reduces oxygen barrier performance; if barrier data are required, film samples should be measured using ISO 15106-2 or ISO 15106-6. Published comparative data for this specific grade is limited; therefore, grade substitution should be validated on the target substrate rather than inferred from hydrolysis level alone.
Adhesive compounding with 48-80 often targets remoistenable paper gumming and paper packaging adhesives. In a typical polyvinyl acetate or starch blend, the dry powder is added at 2–5 wt% of total wet adhesive. The high molecular weight increases green tack and static shear resistance; adhesion is measured by ISO 11339 T-peel after conditioning at 23 °C and 50% RH. Viscosity is monitored with a Brookfield viscometer at 20 rpm using a No. 4 spindle, and finished adhesive viscosity may exceed 5,000 mPa·s at 25 °C. Borax addition causes diol complexation and a viscosity maximum, so the grade is not combined with borax at high concentration unless rheology modification is intentional. Published data for this specific configuration is limited; production trials are required to establish line-speed limits for roller coating.
Concentrated solutions of 48-80 are pseudoplastic. At 10% solids, Brookfield viscosity measured at 20 rpm and 25 °C may reach several thousand millipascal-seconds, while the same solution measured at 100 rpm shows lower apparent viscosity because of shear thinning. This non-Newtonian response influences slot-die coating and roller coating. The viscosity ratio obtained at 10 rpm and 100 rpm is a practical lot-consistency indicator; a ratio change greater than 0.1 should trigger review of solution preparation and raw-material moisture. Inline viscometers on coating supply tanks should be calibrated with a reference Newtonian oil, and temperature should be controlled at ±2 °C because viscosity may fall by approximately 2–3% per 1 °C increase in the 30–50 °C range. For all high-shear preparation, local temperatures above 95 °C should be avoided because surface skinning and coil fouling can occur. Published data for this specific grade is limited, but the Arrhenius-type temperature dependence of PVOH solution viscosity is well established.
In ceramic tile and refractory granulate processing, 48-80 is evaluated as an aqueous binder at addition levels of 0.8–1.5 wt% of dry body weight. Spray-dried powder compacts pressed at 25–35 MPa on hydraulic presses with clamp force capacities of 1,000–2,500 kN are tested for green flexural strength using ISO 10545-4 or ASTM C1161 after drying at 110 °C. The binder forms an interparticle film that increases green strength, but the ≤0.5% ash specification must be accounted for in whiteware firing. Burnout profiles are typically run to 450 °C at 2–5 °C/min; carbon residue depends on kiln air excess and granulate porosity. Published data for this specific configuration is limited, so kiln trials are required before replacing established binders.
In semi-batch vinyl acetate polymerisation, 48-80 is dissolved in deionised water at 8–10% solids and charged to a glass-lined reactor equipped with a two-stage anchor impeller rotating at 60–120 rpm. Initiation with ammonium persulfate at 0.2–0.5 wt% of monomer is performed at 65–75 °C. The grade contributes to particle size control and shear stability of the final latex, but its high molecular weight raises low-shear viscosity. Particle size distribution is measured by laser diffraction using ISO 13320:2020. If latex Brookfield viscosity at 60% solids exceeds 10,000 mPa·s, transfer pump selection should shift from centrifugal to positive-displacement equipment. Compared with 48-88, 48-80 gives less thickening at low temperature but also reduces water resistance of dried films; substitution should be validated by film immersion testing according to ISO 2812-1. Published data for this specific configuration is limited.
Aqueous film-casting trials with 48-80 are structured around plasticiser demand and drying profile. A formulation containing 15–25% plasticiser based on dry PVOH is cast from 10–15% solids onto a chrome-plated drum at 60–80 °C. Drying is performed in multi-zone ovens with zone temperatures from 80 °C to 110 °C. Tensile strength and elongation are measured according to ISO 527-3; films from 48-80 typically show lower tensile strength but greater cold-water solubility than 48-98 films at identical thickness. Dissolution time of a 40 µm film at 15 °C may exceed 120 s; this is not a lot-release specification. Published data for this specific grade is limited, and drum temperature must be reduced if film sticks to the casting surface. The addition of starch or silica at 0.5–2.0% may be used to control blocking during roll winding.
| Grade | Hydrolysis (mol%) | 4% solution viscosity, 20 °C (mPa·s) | Nominal degree of polymerisation | Cold-water dissolution |
|---|---|---|---|---|
| 48-80 | 79.0–81.0 | 44.0–52.0 | 4,800 | Soluble at 20–30 °C |
| 48-88 | 86.0–89.0 | 44.0–52.0 | 4,800 | Complete dissolution at 40–60 °C |
| 48-98 | 98.0–99.0 | 44.0–52.0 | 4,800 | Requires heating above 80 °C |
The bulk polymer is characterised by JIS K6726, which specifies test methods for polyvinyl alcohol, including viscosity, pH, volatile matter and ash. Because 48-80 is processed from aqueous solution rather than as a melt, ISO 1133-1:2022 is not directly applicable. Food-contact use must be evaluated under 21 CFR 175.105 for adhesives and 21 CFR 176.170 for paper and paperboard components; migration testing using food simulants according to EU 10/2011 is required for EU placement. REACH registration under EC 1907/2006 should be confirmed from the current safety data sheet; polymer responsibilities and Article 33 communication duties remain with the downstream user if a substance of very high concern is present. RoHS 2011/65/EU applies to the finished electrical or electronic product, not the bulk PVOH powder.
| Standard/Regulation | Scope | Application to 48-80 |
|---|---|---|
| JIS K6726 | Polyvinyl alcohol test methods | Viscosity, pH, volatile matter, ash |
| ISO 13320:2020 | Laser diffraction particle size analysis | Latex or powder particle size measurement |
| 21 CFR 175.105 | Food-contact adhesives | Subject to final formulation and migration testing |
| 21 CFR 176.170 | Paper and paperboard food contact | Subject to final formulation and migration testing |
| EU 10/2011 | Plastic food-contact migration | Required for EU food-contact validation |
| REACH EC 1907/2006 | Chemical registration and communication | Confirm polymer status with current SDS |
| RoHS 2011/65/EU | Hazardous substances in electrical equipment | Finished-article responsibility; bulk resin not directly covered |
In paper wet-end addition, 48-80 is used as a strength aid in combination with cationic starch. At 0.25–0.75% dry fibre mass, the grade swells quickly in cold water and is less sensitive to alkaline cooking temperature than 48-88. Blending with cationic starch in a jet cooker at 120–130 °C for 1–3 min may cause shear-induced molecular weight reduction if the pressure-screen pressure drop exceeds 1.5 bar. Final paper water absorption is measured by ISO 535 and burst strength by ISO 2758; because 48-80 imparts less water resistance, it is selected for tissue and release papers where absorbency is a target, whereas 48-88 is selected for liner and board requiring lower Cobb values. Published data for this specific configuration is limited.
