| HS Code | 133300 |
| Product Name | KURARAY POVAL 3-85 |
| Chemical Family | Polyvinyl alcohol (PVOH) |
| Cas Number | 9002-89-5 |
| Appearance | White granular powder |
| Degree Of Hydrolysis | 85.0 ± 1.0 mol% |
| Viscosity 4 Aqueous Solution At 20 C | 3.0 ± 0.5 mPa·s |
| Ph 4 Aqueous Solution | 5.0 - 7.0 |
| Ash Content | ≤ 0.3 wt% |
| Volatile Content | ≤ 5.0 wt% |
| Average Degree Of Polymerization | 300 |
| Average Molecular Weight | ≈ 15,000 g/mol |
| Bulk Density | 0.45 - 0.55 g/cm³ |
| Water Solubility | Soluble in water |
As an accredited KURARAY POVAL 3-85 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | KURARAY POVAL 3-85 is supplied in 25 kg multi-layer paper bags with polyethylene liner, ensuring safe handling and storage. |
| Container Loading (20′ FCL) | 20′ FCL container loading of KURARAY POVAL 3-85: palletized bags, stowed securely, protected from moisture, ensuring safe transport. |
| Shipping | Kuraray Poval 3-85 ships as a non-hazardous, water-soluble polyvinyl alcohol powder. It should be transported in sealed, moisture-proof bags or containers, kept dry and protected from dust dispersion. Avoid excessive heat, humidity, and direct contact with strong oxidizers. Standard dry cargo conditions with adequate ventilation ensure safe delivery. |
| Storage | Store KURARAY POVAL 3-85 in a cool, dry, well-ventilated area, tightly sealed in its original container. Protect from moisture, humidity, and direct sunlight. Keep away from heat, flames, and incompatible materials. Prevent dust accumulation and static discharge. Use clean equipment to avoid contamination. Follow polymer storage guidelines and rotate stock to maintain quality. |
| Shelf Life | KURARAY POVAL 3-85 has a typical shelf life of two years when stored in a cool, dry place away from moisture. |
During semi-batch vinyl acetate/ethylene (VAE) polymerisation in jacketed stainless steel reactors, KURARAY POVAL™ 3-85 functions as a grafted protective colloid and particle-size regulator, with a nominal degree of hydrolysis of 84–88 mol% and a 4% aqueous solution viscosity of 3.0–3.6 mPa·s at 20 °C. The powder is pre-dissolved in demineralised water at 6–8 wt% and fed to the reactor at 1.5–3.0 wt% based on total vinyl acetate monomer, while the reactor also receives potassium persulfate at 0.05–0.15 wt%, sodium bicarbonate buffer to maintain pH 4.5–5.5, and, only when bimodal particle-size distribution is required, a nonionic surfactant at 0–0.5 wt%. The polymerisation is run at 70–85 °C with anchor impeller tip speed 0.9–1.8 m/s; the resultant dispersion has solids 55–62 wt%, Brookfield viscosity 2,000–8,000 mPa·s, and pH 4.0–5.0. In 10 m³ production reactors fitted with wall-scraping anchor impellers, batch-to-batch dispersion viscosity is controlled within ±10% by feeding the POVAL 3-85 solution at 0.8–1.2 L/min; at ambient relative humidity above 60% RH, the powder must be pre-dried to avoid lumping during solution make-up. Use of POVAL 3-85 in this segment must observe the limitations of its graftability—excessive persulfate levels above 0.20 wt% can degrade the PVOH backbone and depress final adhesive shear strength under EN 204 D3/D4—and the compound is incompatible with borate ion additions in the finished adhesive, which can raise viscosity uncontrollably. Terminal dispersions are used in polyvinyl acetate wood glues meeting EN 204 D3/D4, paperboard laminating adhesives, nonwoven binders, and architectural coatings. Compliance references include FDA 21 CFR 175.105 for food-contact adhesives, FDA 21 CFR 176.170 and 176.180 for paper and paperboard food-contact components, EU 10/2011 where the final article is a plastic food-contact material, REACH registration, and RoHS 2011/65/EU for electrical/electronic articles if the dispersion enters such a supply chain.
| Designation | Scope | End-use condition |
|---|---|---|
| FDA 21 CFR 175.105 | Adhesives for food contact | VAE/PVAc adhesives for paperboard lamination |
| FDA 21 CFR 176.170 | Paper and paperboard in contact with aqueous/fatty foods | Surface sizing and coating binders |
| FDA 21 CFR 176.180 | Adhesives and coatings for paperboard | Envelope and label remoistenable adhesives |
| EU 10/2011 | Plastic materials and articles intended for food contact | Overall migration limit 10 mg/dm² |
| REACH | Chemical safety and registration | No SVHC classification for PVOH |
| RoHS 2011/65/EU | Electrical/electronic equipment hazardous substances | Not relevant unless final article enters EEE supply chain |
Remoistenable adhesive formulations for envelope flaps, paper stamps, and label stock combine KURARAY POVAL™ 3-85 with modified corn dextrin and humectant plasticiser at 45–55% total solids. The dry-basis composition is 10–20 wt% PVOH 3-85, 30–50 wt% dextrin, 10–25 wt% glycerol or sorbitol, and 5–10 wt% urea or sodium nitrate; mixing is conducted at 60–70 °C in a jacketed paddle mixer until the dextrin is fully gelatinised, then cooled to 25–30 °C and adjusted to pH 6.0–7.5. Slot-die coat weight variability is held within ±1 g/m² by maintaining adhesive viscosity at 1,000–3,000 mPa·s at 25 °C; air-release agents are used to prevent foam-induced pinholes. The compound is applied by reverse roll or slot die coating at 5–20 g/m² dry coat weight onto paper substrates and dried to 4–6% moisture. Rewet open time is tested under TAPPI T 432 cm-19 water absorbency and ISO 535:2023 Cobb conditions; on high-speed envelope converting lines the surface must re-tack within 0.5–2.0 s of water application. The low 4%-solution viscosity of POVAL 3-85 is a processing advantage for slot-die rheology, but its low degree of hydrolysis means that blocking may occur at storage relative humidity above 70% RH; addition of 0.5–2.0 wt% calcium stearate dispersion reduces blocking. Terminal products include envelope front seals, mounting adhesives for stamps, pre-pasted wallpaper, and repositionable label adhesives. Compliance references: FDA 21 CFR 175.105 for adhesive components, EU 10/2011 where the paper is in indirect contact with food, REACH, and the BfR Recommendation XXXVI for paper and board food contact where applicable.
In pigment-free inkjet receptivity coatings and surface sizing for direct thermal paper, KURARAY POVAL™ 3-85 is used at 2–6 wt% in a 6–10% solids aqueous solution at the size press or blade coater, or at 1.0–3.0 parts per 100 parts fumed silica or alumina pigment in a microporous coating. Metered size press conditions at 40–60 °C and 400–1200 m/min web speed achieve dry pickup of 0.5–2.0 g/m²; infrared drying follows at 90–120 °C surface temperature. Because POVAL 3-85 solutions thicken at low temperature, holding tanks are maintained at 45 °C; filtration through 50 µm bag filters eliminates gel specks in high-resolution coated grades. The resulting coated paper is evaluated under ISO 8791-2:2021 for Parker Print Surf smoothness, ISO 2470-2:2017 for D65 brightness, and ISO 536:2021 for grammage stability. POVAL 3-85 limits image bleed and improves dye-dye charge interaction; conversely, its low molecular weight imposes a ceiling on cohesive film strength, so combined use with 1–2 wt% of a higher viscosity PVOH grade is necessary when coating crack resistance under ASTM D522/D522M-17 cylindrical bend is specified. Terminal substrates include matte and glossy inkjet photo papers, direct thermal receipt facestocks, and food-contact paperboard liners. Compliance references include FDA 21 CFR 176.170/176.180 for paper and paperboard, EU 1935/2004 framework regulation, REACH, and ISO 14001:2015 for mill environmental management where required by the convertor.
Warp yarns sized with KURARAY POVAL™ 3-85 exhibit reduced filament protrusion at 600–1000 rpm loom speeds because the film-forming and abrasion-resistance properties of the partially hydrolysed PVOH reinforce oxidised corn starch and polyacrylic ester size blends. The size formulation contains 2.0–4.0 wt% POVAL 3-85 on total size solids, equivalent to 8–12 kg per 1000 L of size liquor, with add-on on cotton warp controlled at 8–14 wt% dry size relative to yarn mass. Slasher processing uses a pre-wet box at 60–70 °C, squeeze roll pressure 2.5–4.0 bar, drying cylinder surface temperature 90–110 °C, and final warp moisture 6–8%. Batch-to-batch size viscosity is controlled within ±0.5 s via mixing tanks; deionised water hardness below 50 ppm as CaCO₃ is recommended to prevent ionic interactions with anionic size components. The low viscosity of POVAL 3-85 at 4% solids enables uniform film formation on cotton warp and polyester filament without excessive drag on high-speed single-end sizing machines. After weaving, desizing is performed with amylase or oxidative desizing at 70–90 °C; fabric suitability is verified under ISO 105-C06:2010 wash-fastness testing and ISO 4892-2:2013 UV exposure protocols for exterior textiles. Terminal fabrics include denim, shirting, bed linen, and upholstery. Compliance references: REACH, ZDHC MRSL Level 2, OEKO-TEX Standard 100 Annex 4, and ISO 14184-1:2011 for formaldehyde release when urea-based additives are used.
KURARAY POVAL™ 3-85 acts as a temporary organic binder in aqueous ceramic tape casting for alumina, barium titanate, and low-temperature co-fired ceramic (LTCC) glass-ceramic powders, added at 2–5 wt% of dry PVOH relative to ceramic powder mass, pre-dissolved at 8–12% aqueous concentration and plasticised with glycerol or polyethylene glycol at 0.5–1.5 wt% of ceramic mass. The slurry is prepared in a planetary ball mill with dispersant at 0.3–0.6 wt%, milled for 4–12 h at 60–80 rpm, then deaired under vacuum at 20–50 mbar before tape casting on PET carrier with a wet gap of 0.2–1.0 mm and belt speed 0.3–1.5 m/min. Drying at 60–90 °C reduces residual moisture below 2%, producing green tapes of 20–200 µm thickness. The critical processing window occurs during binder burnout: heating rates between 0.5–1.0 °C/min from 250 °C to 500 °C are used to prevent decomposition gas pressure from cracking the tape, and residual carbon is held below 0.05% by controlled air flow in a seven-zone kiln. Published data for the exact residual carbon of POVAL 3-85 in low-K LTCC multilayer stacks is limited; the 0.05% residual carbon threshold is representative of PVOH binder specifications for similar mid-hydrolysis grades. Green tape tensile strength is measured under ASTM D882-18 at 2–5 MPa for unfired tapes to confirm handling robustness before stacking. Terminal products include multilayer ceramic capacitors, LTCC substrates for RF modules, piezoelectric actuators, and oxygen sensors. Compliance references include ISO 9001:2015 for process control, RoHS 2011/65/EU for lead-free LTCC dielectric compositions, and REACH for binder handling.
In water-based flexographic ink manufacture for corrugated board, KURARAY POVAL™ 3-85 is introduced as a pigment-stabilising and film-forming binder after pigment grinding, at 2–5 wt% of the finished ink formulation. The PVOH is dissolved separately at 15–20% aqueous concentration and added to the let-down vessel, where the final ink is adjusted to pH 8.5–9.5 and a viscosity of 20–60 s by ISO 2431:2019, 4 mm cup at 20 °C. High-shear dispersion of organic pigments takes place in a bead mill with zirconium dioxide media at 0.5–1.0 mm diameter and tip speed 8–15 m/s, while POVAL 3-85 is reserved for the let-down phase to avoid shear-induced chain scission. Foam control with 0.1–0.3 wt% defoamer and inline filtration at 10 µm prevents print mottle on high-coverage solid areas. The ink is applied by flexographic printing at 100–300 m/min to kraft liner and corrugated board, with anilox rolls of 60–120 lines/cm and cell volume 8–20 cm³/m². Terminal printed items include corrugated shipping boxes, paper bags, and paper cups. Compliance references include EU Packaging Ink Guidelines 2023, FDA 21 CFR 175.105 for adhesive-adjacent applications, REACH, and ISO 2846-3:2017 for water-based packaging ink colour conformity.
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KURARAY POVAL 3-85 is a partially hydrolysed polyvinyl alcohol grade supplied as a free-flowing powder. The grade name encodes two controlling variables: the viscosity band and the nominal degree of hydrolysis. For POVAL 3-85, a 4% aqueous solution at 20 °C exhibits a viscosity of 3.2–3.6 mPa·s when determined by JIS K6726 or ISO 1652. The degree of hydrolysis is specified between 84.5 mol% and 86.5 mol%; the residual acetate groups limit crystallite formation, reduce dissolution energy input, and provide cold-water solubility that is absent from fully hydrolysed PVOH grades such as POVAL 3-98. Typical additional release parameters include volatile matter not exceeding 5.0 wt%, ash no more than 0.4 wt% as Na₂O, and a 4% solution pH of 5.0–7.0. The product is used as a protective colloid in emulsion polymerisation, a surface size for paper and paperboard, a warp size for textiles, a binder for water-soluble and remoistenable adhesives, and a temporary binder in ceramics and pigment processing. The selection of POVAL 3-85 over POVAL 4-88 or POVAL 5-88 is generally made when the process requires lower solution viscosity at equal solids or when the end-use film must be removable in cold water. In contrast to POVAL 3-98, the lower hydrolysis level reduces film tensile strength and moisture resistance but improves adhesion to hydrophobic substrates and permits dissolution at 20–40 °C.
| Parameter | KURARAY POVAL 3-85 | Reference method |
|---|---|---|
| Viscosity (4% aqueous, 20 °C) | 3.2–3.6 mPa·s | JIS K6726 / ISO 1652 |
| Degree of hydrolysis | 84.5–86.5 mol% | JIS K6726 |
| Volatile matter | ≤5.0 wt% | JIS K6726 |
| Ash as Na₂O | ≤0.4 wt% | JIS K6726 |
| pH (4% aqueous) | 5.0–7.0 | JIS K6726 |
Batch release is therefore directed toward properties that influence downstream processing rather than a single performance claim. Because the viscosity test is carried out on a 4% aqueous solution, the preparation history of the solution must be controlled. Incoming inspection should include screen residue, volatile matter, and viscosity on the as-received powder after pre-drying at 60 °C for 4 h if the ambient relative humidity has exceeded 65% during storage. Powder screening at 500 µm before dissolution prevents hydrated gel fragments from interfering with capillary viscometry.
In a 1000 L jacketed stainless steel vessel equipped with a low-shear anchor impeller at 20–30 rpm, the powder is added to deionized water at 15–25 °C. The addition rate is controlled to 0.5–1.0 kg/min for a 500 L batch to prevent the formation of gel-coated lumps. Once the powder is dispersed, the batch is heated to 85–90 °C and held for 45–60 min. At 10 wt% solids, the solution remains pumpable at 60–70 °C; cooling below 40 °C increases viscosity sharply, particularly in concentrated solutions above 12 wt%. Heat-traced transfer lines maintained at 60–70 °C avoid gel-like stagnation, and filtration through a 100 µm bag filter removes hydrated agglomerates. Because the grade contains no added plasticiser, dried films cast from the solution are firm and may be brittle at low relative humidity; a plasticiser such as glycerol at 5–20 parts per hundred PVA is added when film flexibility is required. High-shear rotor-stator mixers above 5000 rpm are not required and may entrain air; when such mixers are used, defoamer levels of 0.1–0.3 wt% are typical.In vinyl acetate and vinyl acetate-ethylene emulsion polymerisation, KURARAY POVAL 3-85 is used as a protective colloid at 2–5 wt% based on total monomer. The colloid is charged as a 10 wt% aqueous solution at 60–65 °C. In a 1000 L reactor with an anchor impeller at 20–30 rpm, the lower viscosity of 3-85 compared with 4-88 is observed as reduced torque during the high-viscosity phase of polymerisation. The resulting latex particle size is typically controlled between 0.5 µm and 1.5 µm by adjusting the POVAL 3-85 level and initiator feed. Residual acetate groups in the colloid contribute to colloidal stability by steric repulsion, but the pH should be kept above 3.5 during storage to limit acid-catalysed hydrolysis of the acetate groups. Process water should be softened; calcium levels above 100 ppm may cause haze or filtration fouling when the latex is compounded with borax-free formulations. Polyvalent metal salts, particularly aluminium sulphate above 0.5 wt%, can destabilise the colloid and should be avoided unless a controlled coagulation step is desired.
In paper surface sizing, POVAL 3-85 is blended with oxidised starch at 1–3 wt% PVA on dry starch to increase film strength and water retention. The size-press bath is held at 60–70 °C; at this temperature the 4% viscosity of 3.2–3.6 mPa·s is sufficiently low for rod or film-press metering at line speeds above 600 m/min. Compared with POVAL 3-98, the partially hydrolysed grade does not require a fully hydrolysed dissolution temperature of 90–95 °C, which reduces steam use and permits size circulation at lower temperatures. In textile warp sizing on a multi-cylinder sizing machine, a size formulation containing 6–10 wt% POVAL 3-85 can be removed in a 40–60 °C wash bath without caustic soda. The lower tensile strength of the partially hydrolysed film relative to POVAL 3-98 limits its use on high-abrasion cotton warps at low sizing add-on; for high-tensile film requirements, a fully hydrolysed grade or a higher-viscosity partially hydrolysed grade should be evaluated.
Adjacent grades in the Kuraray Poval line are differentiated primarily by the viscosity band and the degree of hydrolysis. A comparison of release values illustrates the selection logic for converting operations.| Grade | Viscosity (4% aqueous, 20 °C) | Hydrolysis | Cold-water solubility | Typical processing boundary |
|---|---|---|---|---|
| POVAL 3-85 | 3.2–3.6 mPa·s | 84.5–86.5 mol% | Soluble at 20–40 °C | Emulsion stabiliser; paper and textile sizing |
| POVAL 3-98 | 3.2–3.6 mPa·s | 98.0–99.0 mol% | Requires 80–95 °C | Water-resistant film; hot-wash-resistant sizing |
| POVAL 4-88 | 4.3–4.7 mPa·s | 86.5–88.5 mol% | Soluble at 20–40 °C | Higher-viscosity adhesive; higher film strength |
| POVAL 5-88 | 5.0–5.7 mPa·s | 86.5–88.5 mol% | Soluble at 20–40 °C | Thicker films; higher binder strength |
The comparative table does not contain tensile strength values because published comparative data for non-plasticised films across these exact grades is limited. Selection should therefore be based on the viscosity and hydrolysis values on the certificate of analysis together with a laboratory cast-film test.
Formulations for remoistenable adhesives and water-soluble films use POVAL 3-85 at 10–15 wt%. The solution is prepared as described above and may be cast onto a release liner and dried at 80–100 °C. The film obtained from POVAL 3-85 redissolves in water at 20–25 °C; this behaviour distinguishes it from POVAL 3-98, which requires hot water or heated alkali for removal. In adhesive applications, plasticisers are necessary to reduce edge curl and brittleness. Glycerol, sorbitol, or polyethylene glycol 200–400 at 5–20 parts per hundred PVA are common. Borax or boric acid should be avoided above 0.5 wt% because crosslinking with the 1,3-diol units can cause rapid viscosity increase and gelation. Strongly alkaline pH above 10 should be avoided during long-term storage because the residual acetyl groups undergo base-catalysed hydrolysis, shifting the polymer toward fully hydrolysed behaviour and reducing cold-water solubility. Dried film properties are inferior to POVAL 3-98 in terms of tensile strength and water resistance; therefore POVAL 3-85 is not specified when the final film must remain intact under hot-water contact.
Because KURARAY POVAL 3-85 is hygroscopic, storage at relative humidity above 70% can raise volatile matter above 5.0 wt% and reduce powder flow through rotary valves. Bulk silos are fitted with desiccant dryers and vibratory dischargers. The powder is combustible as a dust; explosion protection measures follow EN 60079-10-2 zone classification and local dust extraction requirements. For food-contact applications, the end user must verify the specific compound against the relevant positive list and the migration limits of Regulation (EU) No 10/2011 or FDA 21 CFR 175.105 where applicable. The final certificate of analysis includes viscosity, degree of hydrolysis, volatile matter, ash, pH, and screen residue; no additional thermal or mechanical testing is performed at release. The grade is packaged in 20 kg multi-wall bags or 500 kg bulk bags.
