| HS Code | 900322 |
| Product Name | ELVANOL 90-50 |
| Chemical Name | Polyvinyl alcohol |
| Cas Number | 9002-89-5 |
| Polymer Type | Fully hydrolyzed polyvinyl alcohol |
| Physical Form | Granular solid / pellets |
| Appearance | White to off-white granules |
| Degree Of Hydrolysis | 99.0 - 100% |
| Viscosity 4 Solution 20 C | 50 - 60 mPa·s (cP) |
| Ph 4 Aqueous Solution | 6.0 - 8.0 |
| Specific Gravity | 1.28 - 1.30 |
| Bulk Density | 0.5 - 0.6 g/cm³ |
| Moisture Content Volatiles | ≤ 5.0% |
| Ash Content | ≤ 1.0% |
| Solubility | Soluble in hot water above ~80°C; insoluble in cold water and most organic solvents |
| Melting Point | ~230°C |
| Glass Transition Temperature | ~85°C |
| Film Properties | Clear, tough, flexible with good solvent and oil resistance |
| Tensile Strength | High, typical 20 - 40 MPa depending on film preparation |
| Elongation At Break | 300 - 400% typical for plasticized film |
As an accredited ELVANOL 90-50 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | ELVANOL 90-50 is supplied in 25 kg multi-wall paper bags as a free-flowing polyvinyl alcohol resin. |
| Container Loading (20′ FCL) | ELVANOL 90-50 loaded as 20′ FCL in sealed bags, secured on pallets, with proper hazard labeling and ventilation. |
| Shipping | ELVANOL 90-50 is a water-soluble polyvinyl alcohol powder. Ship in sealed, moisture-resistant packaging to prevent clumping. Protect from rain and high humidity. Keep away from incompatible materials and foodstuffs. Generally non-hazardous for transport, but use dust-control measures during loading and ensure secure palletization for safe handling. |
| Storage | Store ELVANOL 90-50 in a cool, dry, well-ventilated area away from heat, open flames, and strong oxidizers. Keep the original container tightly closed when not in use to prevent moisture absorption and contamination. Avoid generating dust; use appropriate ventilation and grounding. Follow manufacturer’s shelf-life recommendations and rotate stock accordingly. |
| Shelf Life | Shelf life is typically two years when stored in a sealed container, away from moisture and heat, in original packaging. |
On paper and paperboard lines running at 350–650 m/min, ELVANOL 90-50 is typically dissolved as a 4.0–8.0 wt% masterbatch in a continuous jet cooker or jacketed turbine tank at 88–95°C, with hold time at target temperature maintained for 25–40 min to eliminate undispersed gel particles. The working size-press bath is then diluted to 1.0–3.5 wt% solids and applied on a rod-metered size press or a film-transfer metering unit at a dry pick-up of 0.8–2.0 g/m². In blends with oxidised corn starch, ELVANOL 90-50 is used at 15–35% of total binder solids; for oil-and-grease-resistant grades, the grade is used at 100% of the synthetic binder fraction and the dry pick-up is raised to 1.5–2.5 g/m² after pre-calendering of the base sheet to 1.1–1.3 g/cm³ apparent density. Metering-rod pressure is held at 1.5–3.0 kN/m, while after-dryer cylinder surface temperatures are set at 110–130°C and reel moisture is kept at 4–7%. A practical upper limit exists because above 4.5 wt% solids the feed-solution Brookfield viscosity at 60°C exceeds 80–120 mPa·s, causing rod scratching and film-split misting on open size-press stations; below 0.8 g/m² dry film, grease resistance on uncalendered kraft falls below kit 5. The barrier layer is evaluated under ISO 16532-1:2008 or TAPPI T 559 cm-12, and the finished paper and board components are assessed for food-contact suitability under FDA 21 CFR 176.170 and 21 CFR 176.180, as well as the framework defined in EU 1935/2004. Terminal production includes pet-food bag inner liners, sandwich wrap, pizza tray liners, quick-service restaurant wrap and single-use food-service board.
Ring-spun cotton and polyester/cotton warp yarns sized with ELVANOL 90-50 commonly use a size-bath solids content of 7–12 wt%, with the grade comprising 60–100% of the binder fraction and the balance being modified starch or polyacrylic acid. Dissolution for slasher supply is carried out in a pressure kettle at 120–125°C and 2.0–2.5 bar for 20–30 min, followed by transfer to a holding tank at 80–85°C. Wet pick-up is controlled between 80–110% by double-squeeze rolls at 18–35 kN/m linear pressure; slasher drying cylinders are set at 105–130°C, with final yarn moisture kept at 2–4% for weaving. The size film reduces ring-frame neps and improves abrasion resistance in weaving, but the fully hydrolysed PVOH film absorbs water in high-humidity weaving rooms above 85% RH, leading to size shed and loom contamination on air-jet machines. Yarn tensile retention after sizing is checked under ISO 2062:2009, and size-box chemistry is screened against ZDHC MRSL v3.1 Level 3. Terminal product forms include woven workwear, dress-shirt greige, bed-linen base cloth and pocketing fabric.
Remoistenable adhesives and paper-tube winding gums: borax gelation boundary
Remoistenable envelope and stamp gumming lines apply ELVANOL 90-50 as a 3.5–6.5 wt% aqueous solution, plasticised with glycerol or sorbitol at 5–12 wt% based on PVOH solids, and coated at 20–80 g/m² wet on a three-roll gumming machine or slot-die coater. The adhesive is prepared in a jacketed vessel at 85–90°C with turbine agitation at 800–1,200 rpm, held for 30 min, then cooled to 35–45°C before coating. For paper-tube and core winding, the concentration is reduced to 2.0–4.0 wt% to give an application viscosity of 500–1,500 mPa·s at 25°C. Borax may be added at 0.5–1.5 wt% of the wet adhesive to increase immediate tack; however, addition above 2.0 wt% causes irreversible gelation with fully hydrolysed PVOH and must be avoided. The formulation is assessed under FDA 21 CFR 175.105 for food-packaging adhesives, and bond strength is measured on paper adherends by ASTM D1876-08(2015)e1 T-peel. Finished goods include remoistenable envelopes, postage stamps, kraft paper tube spirals and label overlays.
In vinyl acetate homopolymer and vinyl acetate-ethylene copolymer emulsion polymerisations, ELVANOL 90-50 is employed as a primary protective colloid at 0.5–2.5 wt% on total monomer. The pre-dissolution step uses a separate make-down vessel at 8–10 wt% solids, heated to 85°C and held for 30 min; the solution is then fed semicontinuously to a stirred atmospheric reactor or to a 1–3.5 MPa ethylene-pressurised VAE reactor at 60–85°C. Initiation is commonly based on hydrogen peroxide at 0.1–0.4 wt% with sodium formaldehyde sulphoxylate or sodium metabisulphite as redox activator. The high hydrolysis level of 99.0–99.8 mol% produces latex particles in the 400–1,200 nm range with shear-resistant viscosity; latex viscosity at 25°C is typically 1,000–6,000 mPa·s before adjustment. The finished dispersion is screened under REACH and, when used in food-contact adhesives, falls under FDA 21 CFR 175.105. Terminal products are woodworking adhesives, nonwoven binder dispersions and architectural paint binders. A processing limitation is oxygen inhibition: dissolved oxygen above 2 mg/L in the make-down water delays initiation and broadens particle-size distribution, so nitrogen sparging below 0.5 mg/L is recommended for critical batches.
Ceramic tape-casting green-strength binder and debinding ash limit
Advanced ceramic tape-casting slips for alumina and zirconia substrates use ELVANOL 90-50 as a green-strength binder at 0.5–2.0 wt% of ceramic powder, supplied as a 5–8 wt% aqueous binder solution. The slip is milled in a ball mill at 60–70 rpm for 18–24 h, deaired under 50 mbar vacuum for 20–30 min, and cast through a doctor blade at wet-film thicknesses of 100–500 µm. Drying is performed in a two-zone convection tunnel at 40–60°C for 20–60 min to prevent skin-over. The binder burns out at 350–550°C in air during debinding; residual ash must be below 0.5 wt% for electronic substrates. Green tensile and flexural data are evaluated according to ASTM C1161-18 or ISO 14604:2012, and raw-material heavy-metal screening follows RoHS 2011/65/EU. Finished components are low-temperature co-fired ceramic tapes, alumina substrates and multilayer capacitor green sheets. Published thermal-decomposition data for this specific tape-cast thickness and PVOH loading is limited; therefore, a differential scanning calorimetry run and thermogravimetric analysis up to 600°C are recommended before setting kiln debinding ramps.
In gypsum-based skim coats, cementitious tile adhesives and repair mortars, ELVANOL 90-50 is incorporated as a dry-powder additive at 0.2–1.0 wt% of total dry mix. The addition is made in a twin-shaft paddle blender or forced-action mixer at 30–60 min dry-blending time to prevent segregation. The reconstituted mortar is mixed with water at a water-to-powder ratio of 0.20–0.25, and the modified mix shows higher water retention and improved thin-layer trowel slip; setting-time and compressive-strength adjustments are needed when dosage exceeds 1.0 wt% due to air entrainment and delayed hydration. The dry mix is assessed under EN 934-3:2009+A1:2012 for masonry mortar admixtures and EN 12004:2007+A1:2012 for cementitious tile adhesives. Terminal product forms are gypsum skim coats, class C2-type cementitious tile adhesives and paper-faced gypsum board joint fillers.
| Application area | Governing standard or regulation | Test method or clause of interest | Operating boundary |
|---|---|---|---|
| Paper and board barrier sizing | FDA 21 CFR 176.170, 176.180, EU 1935/2004 | ISO 16532-1:2008, TAPPI T 559 cm-12 | Bath solids ≤ 4.5 wt%; dry pick-up 0.8–2.0 g/m² |
| Textile warp sizing | ZDHC MRSL v3.1 Level 3 | ISO 2062:2009 | Wet pick-up 80–110%; final yarn moisture 2–4% |
| Remoistenable and paper-tube adhesive | FDA 21 CFR 175.105 | ASTM D1876-08(2015)e1 | Borax addition ≤ 2.0 wt% of wet adhesive |
| Emulsion polymerisation colloid | REACH; FDA 21 CFR 175.105 where applicable | Reactor gas-phase oxygen ≤ 0.5 mg/L in make-down water | PVOH feed 0.5–2.5 wt% on monomer basis |
| Ceramic green tape binder | RoHS 2011/65/EU | ASTM C1161-18, ISO 14604:2012 | Residual ash after debinding ≤ 0.5 wt% |
| Gypsum and cementitious dry mix | EN 934-3:2009+A1:2012, EN 12004:2007+A1:2012 | Water retention and setting time per EN method | Dosage ≤ 1.0 wt% of dry mix |
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ELVANOL 90-50 is a high-molecular-weight, fully hydrolysed polyvinyl alcohol (PVOH) resin supplied by Kuraray; the polymer is registered under CAS 9002-89-5. Its technical identity is defined by four specification boundaries: a 4% aqueous solution viscosity of 50.0–58.0 mPa·s at 20 °C, a degree of hydrolysis of 99.0–99.8 mol%, a solution pH of 5.0–7.0, and an ash content of ≤0.5 mass% as Na₂O. These values are measured according to JIS K6726, the Japanese standard for polyvinyl alcohol testing. The grade belongs to the fully hydrolysed class, meaning that residual acetate groups are low; the material does not dissolve in cold water and requires elevated-temperature cook-out. It is used where dried films must exhibit high tensile strength, low sensitivity to cold water, adhesion to cellulosic substrates, and resistance to oils and greases.
| Parameter | Method | Specification |
|---|---|---|
| Viscosity, 4 mass% aqueous solution, 20 °C | JIS K6726 | 50.0–58.0 mPa·s |
| Degree of hydrolysis | JIS K6726 | 99.0–99.8 mol% |
| pH, 4 mass% solution | JIS K6726 | 5.0–7.0 |
| Ash as Na₂O | JIS K6726 | ≤0.5 mass% |
| Volatile matter | JIS K6726 | ≤5.0 mass% |
The viscosity specification is not interchangeable with a single-point Brookfield or Höppler measurement. JIS K6726 specifies a defined solution preparation and temperature control; dry-polymer mass must be corrected for volatile matter, which is limited to ≤5.0 mass%. If a lot is stored at relative humidity above 60%, free moisture content can rise quickly, and aqueous viscosity will appear lower when the sample is weighed as received. Batch-to-batch variation within the 50.0–58.0 mPa·s range is small but can move size-press pickup or adhesive thickness if solids are not adjusted; mills that run multiple lots should pre-test each lot at a fixed concentration and temperature before charging the day tank.
The solution pH specification of 5.0–7.0 is a quality-control boundary, not a strong buffering performance claim. Ash at ≤0.5 mass% as Na₂O indicates that the grade is low in sodium acetate residues; this supports clarity and controlled ionic interaction in adhesive and paper-sizing systems where excessive sodium ions can affect conductivity or coating rheology.
The limiting constraint is hydration temperature. ELVANOL 90-50 does not form a complete solution in water below approximately 80 °C; it swells and leaves visible gel particles. Full hydration requires heating to 90–96 °C under agitation and holding at that temperature until the solution is clear and free of microgel. In contrast, partially hydrolysed polyvinyl alcohol grades with hydrolysis below 90 mol% dissolve at 20–40 °C. This difference arises from the regular stereochemistry and strong interchain hydrogen bonding of the fully hydrolysed polymer; the high molecular weight further increases the energy required for chain disentanglement. The practical consequence is that ELVANOL 90-50 is unsuitable for cold-water bags, cold-water removable coatings, or low-energy dissolution systems.
In operations where cold-water solubility is required, a partially hydrolysed lower-viscosity grade should be selected. Once a film is dried from solution, the fully hydrolysed polymer is no longer fast-dissolving in cold water. That property is the basis for selecting 90-50 in water-resistant remoistenable adhesives and paper-sizing applications where dried film integrity must survive condensation, wet rub, or brief cold-water contact.
Recommended make-down equipment is a jacketed stainless-steel vessel with a low-speed propeller or anchor agitator. The powder is dispersed in ambient water at a solids range of 10–20%; the slurry is then heated to 90–96 °C at a controlled ramp and held for 30–45 minutes. High-shear rotor-stator mixers are not required and can cause foaming, shear heating, and localised mechanical degradation with prolonged exposure. The vessel should have dust collection at the addition port and a sight glass for gel-particle inspection. Cooling to 40–50 °C before transfer reduces evaporation and viscosity drift. A 100–200 mesh in-line filter downstream removes residual gel; filter plugging at this stage indicates insufficient cook-out.
Solutions of this grade are shear-thinning; viscosity falls under pump shear and recovers after discharge. This rheological profile is important for size press and adhesive coating because it holds the film on the substrate but allows pumping and metering. Cooling below 40 °C can produce a hazy solution and, over time, viscosity increase from supramolecular ordering; storage at 20–25 °C with adequate biocide is recommended if the batch is held more than 24 hours.
On a metering film press running at 800–1200 m/min, the high-viscosity rheology of ELVANOL 90-50 forces a reduction in application solids relative to a medium-viscosity fully hydrolysed grade. The grade is typically pre-dissolved at 8–12% solids and diluted at the press to the target pickup. Rod pressure and transfer roll gap control the wet film; because the 4% viscosity is near 55 mPa·s, direct substitution into a starch size can overload the press motor or reduce film-split control. The fully hydrolysed polymer improves surface strength as measured by ISO 3783 IGT pick testing and reduces binder migration, but the exact pickup curve is machine-specific. Published data for a particular film press configuration is limited; mill trials are required to set rod pressure and solids.
When blended with starch at the size press, ELVANOL 90-50 is usually added as a cooked PVA solution to the starch cook after conversion. Fully hydrolysed PVA can be blended with oxidised or ethylated starches at neutral pH, but high-amylose anionic starches may show phase separation. Jar testing at the expected solids and pH is necessary; the blend should be checked for sediment after 60 minutes at 50–60 °C.
For warp sizing, ELVANOL 90-50 is applied as a high-strength film former on spun cotton, polyester/cotton blends, and filament yarns. The dried size film withstands loom friction and reduces warp hairiness; the high molecular weight allows a lower add-on to reach equivalent weaving protection compared with low-viscosity fully hydrolysed grades. Size box temperature should be maintained above 70 °C to avoid viscosity rise and skinning. Squeeze pressure is set by yarn construction; high-viscosity size requires either higher temperature or lower solids. Desizing of fully hydrolysed PVA is strictly hot-water based because amylase enzymes do not attack the polymer. Wash boxes must maintain water temperature above 80 °C; oxidative desizing agents such as hydrogen peroxide or sodium perborate are used in some plants to improve removal. The grade should not be specified where enzymes are the only desizing route.
In aqueous adhesive formulation, sodium tetraborate interacts with the hydroxyl groups of fully hydrolysed PVA to form a structured network. The high molecular weight of ELVANOL 90-50 means that a small borax addition produces a sharper viscosity increase than the same addition to a lower-viscosity grade. Borax must be added incrementally as a dilute solution under agitation; the endpoint is controlled by a Brookfield RV spindle at fixed speed, and comparative readings must state spindle and speed. Excessive borax addition produces stringy gelation and eventual syneresis, and the batch may not be recoverable by dilution.
Partially hydrolysed grades are less borax-sensitive and require higher addition levels to achieve similar tack; this explains why formulators select ELVANOL 90-50 for remoistenable adhesives, tube-winding adhesives, and paper-converting laminations where high tack and water resistance are required at low solids. Plasticisers such as glycerol, polyethylene glycol, or sorbitol are used where film flexibility must be increased; these materials also increase moisture sensitivity and reduce blocking resistance. The plasticiser level is usually varied between 5 and 20 parts per 100 parts dry PVA and should be validated by ASTM D882-18 tensile testing.
ELVANOL 90-50 differs from partially hydrolysed polyvinyl alcohol in film water resistance and mechanical response. Tensile properties of dry films should be measured according to ASTM D882-18 or ISO 527-3:2018 after conditioning at 23 °C and 50% RH per ISO 187. Fully hydrolysed films exhibit higher tensile strength and lower elongation than partially hydrolysed films at equal plasticiser content; however, the actual values shift with residual moisture, plasticiser type, and drying conditions. The film is not a moisture-barrier replacement; oxygen transmission measured by ASTM D3985 is strongly dependent on relative humidity and must be reported with conditioning. In applications that require cold-water solubility or flexibility, a partially hydrolysed grade is preferred.
In relation to lower-viscosity fully hydrolysed polyvinyl alcohol, ELVANOL 90-50 builds equivalent coating or adhesive viscosity at lower solids, gives higher wet film thickness, and forms a more tear-resistant dry film. The trade-off is slower dissolution, higher pump energy, and reduced maximum solids that can be handled by standard low-pressure progressive cavity pumps. For coatings requiring high solids and low viscosity, a medium- or low-viscosity grade should be evaluated. In emulsion polymerisation, fully hydrolysed high-viscosity PVA is not a first-choice protective colloid for vinyl acetate emulsions because it builds high viscosity and has lower surface activity than partially hydrolysed low-viscosity grades. This differentiates ELVANOL 90-50 from partially hydrolysed specialty grades used as colloids. It may be used as a post-added rheology modifier or as a co-binder in specific high-tack systems.
The following regulatory references are cited in manufacturer documentation for polyvinyl alcohol; each applies to specific food-contact conditions and use restrictions. Compliance of a formulated adhesive, coating, or finished packaging article must be confirmed against the applicable extraction limits, end-use temperature, and food type.
| Reference | End-Use Scope | Basis |
|---|---|---|
| FDA 21 CFR 176.170 | Components of paper and paperboard in contact with aqueous and fatty foods | Finished article must meet extraction specifications |
| FDA 21 CFR 176.180 | Components of paper and paperboard in contact with dry food | Good manufacturing practices and functional barrier requirements may apply |
| FDA 21 CFR 175.105 | Adhesives used in packaging | Separation or barrier requirements depend on end use |
| FDA 21 CFR 177.1670 | Polyvinyl alcohol film as finished article | Film-specific specification applies |
Food-contact status can be lost by improper formulation. An adhesive relying on 21 CFR 175.105 may still be separated from food by a functional barrier; if the package construction lacks a barrier, the adhesive must meet the more restrictive paper and paperboard clearances. The grade itself has no direct food additive approval and is intended for indirect contact only.
Strongly acidic conditions below pH 2 and oxidising acids at high temperature can degrade the polymer; alkaline conditions above pH 10 may accelerate colour development or residual acetate hydrolysis. Compatibility with polyacrylates and high-salt systems must be checked by jar test, because certain water-soluble polyacrylates and high concentrations of sulphate or carbonate salts can cause salting-out or precipitation. The product is not recommended for cold-water-dispersible packaging, amylase-only textile desizing, or high-solids coatings that require solution viscosity below approximately 10 mPa·s at processing temperature.
