| HS Code | 159735 |
| Product Name | SELVOL Polyvinyl Alcohol 305 |
| Appearance | White powder |
| Degree Of Hydrolysis | 98.0 - 98.8 mol% |
| Viscosity 4 Percent Solution 20c | 4.8 - 5.8 mPa·s |
| Ph | 5.5 - 7.5 |
| Ash Content | ≤ 1.0% |
| Volatile Matter | ≤ 5.0% |
| Specific Gravity | 1.26 |
| Bulk Density | 0.6 - 0.7 g/cm³ |
| Molecular Weight | Approximately 22,000 |
| Solubility | Soluble in water |
| Tensile Strength | High |
| Glass Transition Temperature | Approximately 85°C |
As an accredited SELVOL Polyvinyl Alcohol 305 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | SELVOL Polyvinyl Alcohol 305 is supplied as a free-flowing powder in 25 kg multi-wall paper bags with a moisture-proof inner liner. |
| Container Loading (20′ FCL) | Container Loading (20′ FCL): A 20-foot full container load of SELVOL Polyvinyl Alcohol 305, bagged on pallets, secured for safe transport. |
| Shipping | SELVOL Polyvinyl Alcohol 305 is a white granular powder, non-hazardous under standard transport regulations. It is supplied in multi-layer paper bags or FIBCs. Protect from moisture and store in dry conditions. No UN number or dangerous goods classification required for road, rail, sea, or air shipment. |
| Storage | Store SELVOL Polyvinyl Alcohol 305 in a cool, dry, well-ventilated area, keeping the original container tightly closed when not in use. Protect from moisture, humidity, direct sunlight, and heat sources. Keep away from ignition sources and incompatible materials. Avoid dust accumulation; use appropriate ventilation and grounding. Follow manufacturer’s guidelines for shelf life. |
| Shelf Life | Store in a cool, dry place in original sealed container; shelf life is typically two years. |
Kuraray SELVOL Polyvinyl Alcohol 305 is supplied as a fully hydrolysed medium-viscosity polyvinyl alcohol. Aqueous dissolution requires cold-water slurrying at room temperature followed by heating to 85–95°C for 30–60 min under slow agitation. Solutions at 10–15% solids are pumpable above 55°C. The application scenarios below are limited to downstream sectors where the grade’s film strength, shear resistance, gelation behaviour, and hot-water solubility are critical process variables.
Alkaline fine paper and linerboard operations use PVA 305 as a partial replacement for oxidized or cationic starch. The grade is cooked separately at 10–12% solids. It is blended with starch at a dry ratio between 1:3 and 1:8 PVA to starch. The mixing point is a jacketed starch kitchen tank held at 55–65°C. The blended size is supplied to a film press or rod-metered size press at 50–60°C. Fully hydrolysed PVA forms a continuous film at lower add-on than starch. Dry pickup on fine paper is normally controlled between 0.8 and 2.5 g/m² per side. Metering rod pressure is set from 15 to 35 kN/m. At substitution levels above 25% of total size solids, the film split shifts from short starch split to filament-forming transfer behaviour at the rod. Operators observe more frequent rod cleaning and higher mist extraction capacity around the coater.
Sheet sizing response is measured with the Hercules Size Test under TAPPI T 530 om-16. Water absorption is measured with ISO 535. PVA 305 raises HST efficiency per unit dry pickup relative to starch. Published data for specific mill furnishes is limited. Papermakers validate the size press formulation by measuring HST at 80% reflectance endpoint. They also measure Cobb60 values. For food-contact grades, the applied PVA is assessed under 21 CFR 176.170 for aqueous and fatty food paper. Dry-food paper is assessed under 21 CFR 176.180. The material is also handled under REACH when exported to EU converters. Operational boundary: cooked PVA solution must not drop below 50°C in storage lines. Fully hydrolysed solutions can form stiff gels over 12–24 h at room temperature.
In high-speed air-jet weaving of 20s–50s Ne spun cotton and polyester/cotton yarns, PVA 305 is cooked to 12% solids. It is metered into a starch-based size mix at a dry ratio of 0.35:1 to 0.55:1 PVA to starch. Total size solids are maintained at 8–12% by refractometer. The size box temperature is held at 82–88°C. Squeeze roll pressure is set between 25 and 40 kN/m. Yarn add-on is controlled from 8% to 14% of yarn mass. The higher film strength of fully hydrolysed PVA lowers hairiness and improves weaving efficiency. The effect is measurable only when add-on remains above 6%.
Sized yarn tensile is tested under ASTM D2256. Yarn abrasion resistance is checked on a Zweigle G558 hairiness tester or equivalent. Weave room humidity is maintained at 60–65% RH for polyester blends. Low-humidity embrittlement of the PVA film can increase shed dusting. After weaving, the size is removed in a hot desize bath at 85–95°C with 0.5–1.0 g/L non-ionic surfactant. Fully hydrolysed PVA 305 is not reliably removed by cold-water enzymatic desizing. Hot wet-out is the controlling boundary. Where discharge regulations apply, sizing effluent is treated by ultrafiltration for PVA recovery before biological treatment.
PVA 305 serves as the primary protective colloid in vinyl acetate homopolymer and vinyl acetate-ethylene latices. The grade is pre-dissolved at 10% solids in deionised water at 90–95°C. The solution is cooled to reactor temperature and charged at 3–5 parts per 100 parts vinyl acetate monomer. A typical semi-continuous batch uses potassium persulfate at 0.2–0.5 parts and sodium bicarbonate at 0.1–0.3 parts. The delayed monomer feed is run for 180–240 min at 72–78°C. The pH is held at 4–5 to balance persulfate decomposition and PVA hydrolysis stability. Final solids are commonly 50–55%. Brookfield viscosity is measured at 25°C with a Brookfield RVT spindle 3 at 20 rpm under ISO 2555.
The fully hydrolysed grade produces latices with higher water resistance than partially hydrolysed protective colloids. The steric stabilisation window narrows as electrolyte level increases. Addition of aluminium chloride or polyvalent cations above 0.05 mol/L in the letdown can destabilise the latex. The main terminal products are wood adhesives and paper laminating adhesives. Bonding performance is evaluated under EN 204 durability classes for thermoplastic wood adhesives. Food packaging adhesives are formulated for 21 CFR 175.105 or 21 CFR 176.170 depending on the substrate. For reactor scale-up from 10 L to 10,000 L, agitation power per unit volume should be kept at 0.5–1.0 kW/m³ to reproduce particle size distribution and coagulum level.
Solution-cast films based on PVA 305 require plasticiser concentrations above 12 phr to avoid brittle fracture at 23°C and 50% RH. Typical formulations use glycerol at 15–25 phr with sorbitol at 5–10 phr. The polymer is dissolved in demineralised water at 18–22% solids by heating to 90–95°C for 60–90 min. The solution is deaerated under vacuum at 0.08–0.09 MPa before casting on a PET carrier or stainless steel belt. Drying is staged from 80°C to 100°C. Staged drying limits skin-over and microvoid formation. Final film thickness is controlled at 35–75 µm. Tensile properties are measured under ASTM D882 after conditioning at 23±2°C and 50±5% RH for 48 h.
This fully hydrolysed grade has limited cold-water solubility. It is not the preferred PVOH for cold-water unit-dose detergent film. Complete dissolution below 20°C is outside the operational window. The relevant boundary is hot-water soluble or warm-water soluble converting at 60°C or above under agitated immersion. Terminal products include hot-water soluble laundry bags for infection control, dye transfer sachets, and agrochemical packaging where the pack is dissolved in a heated make-up tank. European users must address REACH registration for imported film. US food-contact use is evaluated under 21 CFR 177.1670 when the film itself is the food-contact layer.
In advanced ceramic forming, PVA 305 is used as a temporary binder in spray-dried granules for alumina, zirconia, and silicon nitride. A 5–8% aqueous PVA solution is added to the ceramic slip before spray drying. Dry binder content is held between 0.5% and 2.0% of ceramic mass. Higher addition increases green strength but reduces pressed density and can produce laminations. Spray drying is operated at 180–220°C inlet and 90–110°C outlet. The resulting granules are free-flowing. Bulk density is correlated to slip solids and binder level. Uniaxial pressing is performed at 50–150 MPa depending on the component. Green flexural strength is tested under ASTM C1161 on conditioned bars after 24 h at 23±2°C and 50±5% RH.
Binder burnout is a two-stage profile. The dehydroxylation and depolymerisation stage occurs from 200°C to 300°C. Oxidative decomposition is completed between 450°C and 550°C in flowing air. Kiln ventilation must maintain a minimum air exchange rate to prevent carbon residue. Residual carbon above 500 ppm can reduce sintered density and increase internal porosity. Terminal products include alumina electronic substrates, zirconia oxygen sensor components, and silicon nitride wear tooling. Users should validate the burnout profile by thermogravimetric analysis at the same heating rate as the production kiln. Published data for this specific grade in co-milled systems is limited.
Remoistenable envelope gum stock uses PVA 305 in combination with dextrin at 15–30 parts per 100 parts PVA and glycerol at 5–10 parts. Total solids are adjusted to 35–45% for reverse gravure or wire-wound rod application. Dry coat weight is managed from 3–7 g/m² on the paper surface. Drying is carried out at 100–130°C for 5–15 s. Drying maintains flat release without overcuring the dextrin phase. The PVA fraction contributes high remoistening tack and reduced dusting. The dextrin fraction prevents delayed tack development and improves adhesion to gummed paper under 65% RH storage.
Blocking is tested by placing coated sheets face-to-face under 50°C and 85% RH for 24 h. The PVA grade is selected because fully hydrolysed film resists cold flow better than low-hydrolysis grades. For food packaging adhesives, formulation components are selected for 21 CFR 175.105. For paper and paperboard food contact, 21 CFR 176.170 is the relevant regulatory reference. End products include envelope flaps, postage stamp gum, and label splice tabs.
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SELVOL Polyvinyl Alcohol 305 is a partially hydrolyzed polyvinyl alcohol resin supplied as a granular solid. The grade is defined by a Brookfield solution viscosity of 5.2–6.2 mPa·s on a 4 % aqueous solution at 20 °C and a hydrolysis degree of 87.0–89.0 mol%. The residual acetyl content is therefore 11.0–13.0 mol%. Typical lot-release data include volatile matter ≤5.0 %, ash content ≤0.5 % as Na₂O, and pH 5.0–7.0 in solution. The product combines low solution viscosity with partial acetate retention, which is significant when cold-water solubility, adhesive film clarity, or emulsion latex particle stability must be controlled.
| Property | Analytical method | Expected range |
| Viscosity | 4 % aqueous solution, Brookfield LVF, 20 °C, ISO 15023-2 | 5.2–6.2 mPa·s |
| Hydrolysis degree | Titration per JIS K6726 | 87.0–89.0 mol% |
| Volatile matter | Loss on drying at 105 °C to constant mass | ≤5.0 % |
| Ash | Residue on ignition at 700 °C | ≤0.5 % as Na₂O |
| pH | 4 % solution, 20 °C, ISO 15023-2 | 5.0–7.0 |
Residual acetate groups interrupt the regular hydrogen-bonding sequence of the polyvinyl alcohol chain. Because the acetate side groups are larger and less hydrophilic than hydroxyl groups, they reduce crystallinity after drying and lower the energy barrier to hydration. SELVOL 305 hydrates and begins to swell in water at 20–25 °C, although complete industrial dissolution is routinely conducted at 65–80 °C in a jacketed vessel with an agitator tip speed of 1.0–2.5 m/s to avoid shear-induced foam and lump formation. The dissolved polymer remains free of visible gel particles at 20 °C for 24 h under neutral pH, but microbially induced viscosity loss can occur in non-preserved solutions held above 30 °C. Films cast from SELVOL 305 are typically lower in dry tensile modulus than films from fully hydrolyzed grades. Actual comparisons should be made with ISO 527-3 film specimens because drying temperature and relative humidity exert a first-order effect on crystallinity.
For solution make-up, an eductor or venturi disperser is preferred because dry granules added directly to an open-tank vortex can form lumps with a wetted outer layer and a dry core. A two-stage make-down system with a low-shear axial impeller at 200–400 rpm in the hydration tank and a positive displacement pump through a 250 μm bag filter removes gels before storage. The solution exhibits near-Newtonian behaviour below 10 % solids; above 15 % solids, viscosity increases non-linearly and the fluid can develop slight pseudoplasticity. Sodium chloride at 1.0 % and above should be evaluated for salting-out tendency because PVOH solutions are sensitive to electrolyte concentration. In adhesive compounding, a recirculation loop with a gear pump or rotary lobe pump should be designed for the highest production viscosity, not the nominal 4 % solution value.
In vinyl acetate and vinyl ester ethylene emulsion polymerisation, SELVOL 305 is charged into the aqueous phase at 2.0–5.0 % based on total monomer mass. A jacketed 316L stainless steel reactor equipped with a twin axial-flow impeller and baffles is heated to 70–80 °C; the PVOH is dissolved before initiator addition, and the residual acetate groups permit chain grafting to PVOH during polymerisation, contributing to particle steric stabilisation. At addition levels above 6.0 %, latex viscosity can exceed 1,000 mPa·s at 25 °C and reduce lobe-pump transfer rates. The transition is not linear. In high-solids systems above 55 % solids, the relationship between PVOH concentration and Brookfield viscosity should be measured on the actual latex rather than predicted from aqueous solution data. On production-scale batches, reactor headspace oxygen level and initiator feed rate often produce greater particle-size variance than PVOH certificate-of-analysis variation. Qualification should therefore include at least three consecutive batches using the same monomer feed profile.
For aqueous adhesives and paper surface sizing, SELVOL 305 is formulated at 4.0–10.0 % solids with plasticiser, dextrin, or clay depending on the substrate. Low viscosity permits rod-metered application at 50–150 mPa·s at 25 °C; solids are adjusted upward to maintain this window because solution viscosity is sensitive to concentration. The partially hydrolyzed grade provides wet tack and redispersibility, but dry-film water resistance is lower than that of fully hydrolyzed PVOH. If water resistance is required, a reactive crosslinker such as glyoxal or zirconium ammonium carbonate is added at 0.5–1.5 % on PVOH solids. Pot-life then shortens, and pH must be maintained above 5.0 to avoid premature acetal formation. In comparative trials against fully hydrolyzed low-viscosity grades, SELVOL 305 exhibits faster cold-water removal from cellulose and lower re-wet angle measured by ASTM D2578; however, the higher moisture sensitivity restricts its use in tropical packaging grades unless top-coated or crosslinked.
| Operating condition | SELVOL 305, partial hydrolysis | Fully hydrolyzed low-viscosity grade |
| Practical dissolution temperature | 20–80 °C | 70–90 °C |
| Film water sensitivity | Readily soluble at 25 °C | Requires sustained immersion |
| Latex grafting tendency | Moderate to high depending on initiator | Low |
| Relevant film test | ISO 527-3 | ISO 527-3 |
Dry granular handling of SELVOL 305 in production conveyors is sensitive to relative humidity. At storage conditions above 60 % RH, the material can gain moisture and bridge in screw feeders; hoppers should be purged with dehumidified air or maintained at 40–50 % RH. Vacuum conveying systems should keep line velocity below 15 m/s to reduce dust and static charge accumulation, and conductive hoses with earthing clamps are recommended. When the product is used as a water-soluble carrier in a co-rotating twin-screw extruder with 32:1 L/D, pre-drying at 80 °C for 4 h reduces moisture to below 1.0 %. Higher residual moisture can produce die pressure fluctuation and surface roughness on the specific line; published data for this exact configuration is limited. The grade is incompatible with concentrated strong oxidizers. Borate salts such as sodium tetraborate at 0.5 % on solids can raise Brookfield viscosity by an order of magnitude through didiol complexation. Aqueous solutions should not be held in uninsulated carbon steel vessels for more than 48 h because iron contamination can appear as haze and accelerate oxidative viscosity loss.
In water-soluble film and unit-dose packaging, SELVOL 305 dissolves more rapidly in cold water than a fully hydrolyzed grade of equivalent solution viscosity. The substitution is not drop-in because film tensile strength, elongation at break, and puncture energy are lower. Qualification testing should follow ISO 527-3 on films conditioned at 23 °C and 50 % RH for 48 h; glass-transition data should be compared as a function of plasticiser loading, typically evaluated from 10 phr to 30 phr. Dissolution time depends on film thickness, substrate geometry, and water temperature; no universal value can be assigned from viscosity alone. In trials on cast film lines, SELVOL 305 can be blended with a higher-viscosity PVOH to raise puncture resistance while retaining cold-water dispersibility. The blend ratio is best determined by response-surface experiments on the specific die and chill-roll configuration; published data for this exact configuration is limited, but the property trade-off is well documented in PVOH film literature.
Because SELVOL Polyvinyl Alcohol 305 is a synthetic water-soluble polymer, compliance with food-contact requirements depends on the final application and extraction testing. The grade may be evaluated under 21 CFR 175.105 for adhesives and 21 CFR 176.170 for paper and paperboard components, but the relevant end-use limitations and migration thresholds must be confirmed on the finished article. Industrial hygiene data should be referenced from the current safety data sheet.
