| HS Code | 833015 |
| Product Name | KURARAY POVAL 17-94 |
| Chemical Name | Polyvinyl alcohol |
| Cas Number | 9002-89-5 |
| Appearance | White granular powder |
| Degree Of Hydrolysis Mol Percent | 94.0 - 96.0 |
| Average Degree Of Polymerization | Approx. 1700 |
| Viscosity 4 Percent Aqueous Solution At 20c Mpa S | 26.0 - 30.0 |
| Ph | 5.0 - 7.0 |
| Volatile Content Percent | <= 5.0 |
| Ash Content Percent | <= 0.7 |
| Solubility | Soluble in hot water |
| Bulk Density G Per Cm3 | 0.4 - 0.6 |
As an accredited KURARAY POVAL 17-94 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Kuraray Poval 17-94 is packaged in 25 kg multi-wall paper bags with a polyethylene liner for moisture protection. |
| Container Loading (20′ FCL) | 20′ FCL: KURARAY POVAL 17-94 securely packed on pallets, containers ventilated, dry, and protected from moisture. |
| Shipping | KURARAY POVAL 17-94, a polyvinyl alcohol resin, ships as free-flowing powder in moisture-resistant multi-wall paper bags. Non-hazardous, yet hygroscopic, it requires dry, ventilated transport and storage. Protect from humidity, direct sunlight, and water contact. Handle with standard industrial hygiene practices to preserve product integrity and safety. |
| Storage | Store KURARAY POVAL 17-94 in a cool, dry, well-ventilated area away from direct sunlight and heat sources. Keep containers tightly closed to prevent moisture absorption and contamination. Avoid generating dust; keep away from ignition sources. Use proper labeling and follow local regulations. Maintain good housekeeping to prevent spills. |
| Shelf Life | Shelf life is typically 2-3 years when stored in a cool, dry place, protected from moisture and direct sunlight. |
In alkaline papermaking systems operating within a wet-end pH range of 7.5–8.5, Poval 17-94 functions as a surface sizing film former in which the measured solution viscosity of 20–26 mPa·s at 4% solids and 20°C per JIS K6726 permits replacement of oxidized starch at 15–30 parts per 100 parts dry starch without exceeding the metering rod pressure limits of a puddle size press running above 800 m/min. The degree of hydrolysis of 86–89 mol% and residual acetate groups keep cold-water solubility high enough for continuous size-press operation at 50–60°C, while the higher molecular weight provides film strength on uncoated and recycled liner. Batch cooking is carried out by dispersing the powder in cold water at 25–30°C under 60–100 rpm, heating to 90–95°C for 30 min, then cooling and filtering through a 100 μm in-line strainer to remove fisheyes.
Typical size-press working solids are 4–8%; pickup is controlled at 0.8–1.5 g/m² per side for fine paper and 1.2–2.5 g/m² for recycled board. In pigmented coating color, 0.5–1.5 parts dry Poval 17-94 per 100 parts pigment is added to raise dry pick and to act as a carrier for optical brightening agents; the color pH is maintained at 8.0–9.0 with ammonium hydroxide. For food-contact board, the dried film is evaluated under FDA 21 CFR 176.170 and 176.180 component limitations for aqueous and fatty foods, and the converting mill issues a Declaration of Compliance under Regulation (EC) No 1935/2004. Borax or boric acid must not be used in the size-press formulation because trace levels as low as 0.5 wt% on dry PVA produce cold-water-insoluble gel particles that accumulate on the metering rod and cause blade streaks. Calcium hardness above 100 ppm in dilution water can likewise reduce the solubility of the dried film at the returning edge of the size press.
At 25°C, the aqueous adhesive prepared from Poval 17-94 at 15–20% solids behaves as a smooth film former; Brookfield LV viscosity at 60 rpm is typically in the range of 4,000–12,000 mPa·s before borax addition. The addition of borax decahydrate at 0.5–2.0 wt% of wet adhesive converts the hydroxy groups on the PVA backbone into reversible didiol-borate crosslinks, producing a sharp viscosity increase and a tack maximum at 1.0–1.5% borax. The peak tack shift is measured at 23°C and 50% relative humidity with a probe tack tester according to ASTM D2979; remoistenable formulations are accepted only when the tack peak occurs within 2–5 s after rewetting.
Envelope and stamp flap gums are compounded with 100 parts Poval 17-94, 0.5–2.0 parts borax, 5–15 parts glycerin or sorbitol, and 0.1–0.3 parts defoamer, dispersed to 20–25% solids. The PVA powder is first dispersed at 25–30°C for 10 min, heated to 85–90°C for 30–45 min, cooled to 25–30°C, and then the borax solution is metered at 0.5 kg/min into a 500 kg low-speed anchor mixer. Borax dosing above 2.5 wt% of the wet adhesive drives viscosity beyond 50,000 mPa·s and produces a brittle film; metering pumps with ±0.1 wt% accuracy and pH buffering at 7.5–8.5 with sodium carbonate are specified. The gum is applied to envelope flaps at 5–10 g/m² wet, dried at 70–90°C, and is shipped as a dry, non-blocking film. For indirect food contact, the finished adhesive is covered by FDA 21 CFR 175.105; in Europe, migration testing under EN 1186-1 is required when the adhesive is not separated from food by a functional barrier.
When vinyl acetate monomer is emulsion-polymerized in a 6 m³ stirred reactor equipped with a 4-blade pitched-turbine impeller operating at 1.0–1.5 kW/m³, Poval 17-94 is charged at 3–6 wt% of the initial aqueous phase. The 86–89 mol% hydrolysis level provides sufficient surface activity for monomer emulsification while the residual acetate sequences allow controlled chain transfer to polymer; this produces a grafted protective colloid layer that stabilizes the latex against shear-induced coagulation. The aqueous phase is heated to 50–60°C, vinyl acetate is dosed over 3.5–4.5 h, and the jacket temperature is held at 65–75°C with a redox initiation system until free monomer falls below 0.5 wt%. The resulting polyvinyl acetate homopolymer latex typically reaches 52–55% solids, Brookfield viscosity 6,000–15,000 mPa·s at 25°C, and a mean particle size of 0.5–1.5 μm. A 50 μm in-line strainer is installed upstream of the spray dryer to remove coagulum generated by high-shear monomer feed at the start of the run.
For adhesive formulation, the latex is compounded with 5–10% plasticizer and 0.5–1.0% hardener; the bond is tested under EN 204 for D3 durability class on beech, with wet bond strength after the specified cold-water soak used as the controlling property. The protective colloid also controls application viscosity for laminating adhesives applied at 80–120 g/m² and dried at 90–110°C; the final adhesive film is tested by T-peel according to ASTM D1876, with fibre tear recorded as the acceptance criterion. Poval 17-94 solutions are incompatible with aluminium sulfate above 1 wt% because the polyvalent cation precipitates the colloid as a gelled complex, which increases coagulum and destabilises the latex during storage. For food-contact paper and board laminates, the dried adhesive is assessed under FDA 21 CFR 176.170 component limitations.
Continuous polyester filament warps sized at 160–180 m/min require a film former that remains flexible at loom shed temperatures of 28–32°C and 60–65% relative humidity. Poval 17-94 is compounded with low-viscosity maize starch at 60–80 parts PVA and 20–40 parts starch per 100 parts dry size; size-box solids are maintained at 8–12% and the squeeze pressure is set at 15–25 kN/m roll width. Warps are pre-wet in a 70–80°C water bath before entering the size box to improve film coverage at 1.0–2.0% add-on for filament polyester. A polyalkylene glycol defoamer at 0.05–0.2 wt% is added at the size-box supply tank because silicone defoamers leave residues that cause dye spots. The size bath is buffered to 6.5–7.5; below pH 4.5 starch compatibility drops and the film becomes brittle.
Desizing is carried out in a 60–80°C washing range without strong alkali; the water-soluble PVA component is removed down to a residual size level below 0.05% on fabric weight to avoid interference with subsequent mercerization. Finished woven fabrics include polyester-cotton shirting, pocketing, and printed lining. For export apparel, the size bath is evaluated under OEKO-TEX Standard 100 criteria for formaldehyde and heavy metals; Poval 17-94 does not introduce formaldehyde because it is not a condensation resin. If the fabric is destined for interlining or coating, residual PVA should be monitored by extraction with 0.1 M hydrochloric acid at 80°C for 30 min and quantified by UV absorbance at 690 nm after iodine complexation.
The burnout profile of Poval 17-94 in a dry-pressed alumina body is governed by heating rate and oxygen diffusion through the open pore network. Thermogravimetric analysis in air at 10°C/min shows first mass-loss onset at 190–220°C, rapid volatilisation between 280–350°C, and final oxidative removal of carbon residue below 500°C; for parts with cross-sections above 5 mm, the kiln controller must hold at 350–400°C for 60–120 min to avoid core carbon retention. Dry-pressed alumina granules are prepared with 0.8–2.0 wt% Poval 17-94 as dry binder per 100 parts alumina, combined with 0.3–0.6 wt% polyethylene glycol plasticizer and 0.1–0.3 wt% ammonium polyacrylate dispersant. Pressing is carried out at 100–150 MPa uniaxial pressure; green strength after pressing is tested by three-point flexure according to ASTM C1161 and must be sufficient for automatic handling without edge crush.
| Heating zone | Temperature range | Ramp rate | Hold | Control purpose |
|---|---|---|---|---|
| Drying | 20–180°C | 1.0–2.0°C/min | 30 min | Remove free water without steam pressure |
| Binder burnout | 180–480°C | 0.5–1.0°C/min | 60–120 min at 350–400°C | Remove volatiles without carbon core |
| Sintering ramp | 480–1,550°C | 3.0–5.0°C/min | none | Final densification |
For electronic ceramic substrates, the clean burnout requirement is linked to final metal contamination limits; Poval 17-94 has an ash residue of ≤0.5% per JIS K6726, which is subtracted from the maximum sodium and iron specification in the fired ceramic. RoHS 2011/65/EU is not triggered by the organic binder because the restricted metals are not present above the maximum concentration values; post-firing analysis confirms lead below 0.1 wt%, cadmium below 0.01 wt%, mercury below 0.1 wt%, and hexavalent chromium below 0.1 wt% in homogeneous material. Gas evolution between 280°C and 350°C creates a pressure gradient in closed-pore regions; heating rates faster than 2°C/min in parts with wall thickness over 10 mm cause lamination cracks. Iron oxide in the ceramic powder above 0.5 wt% catalyses decomposition and narrows the burnout window; thus the kiln ramp must be redesigned for iron-rich alumina formulations.
In dry-mix production of C1-class tile adhesives, the powder is compounded at 0.2–0.8 wt% of total dry blend to increase water retention and tack; it is pre-blended with fine quartz filler 0.1–0.3 mm in a 2,000 L horizontal ribbon blender at 20–30 rpm before cement, redispersible polymer powder, and cellulose ether are added. During application, a 6–10 mm notched trowel is used; open time measured under EN 1346 is extended by the free-water retention of the polymer, but skin formation appears at open times above 20 min at 23°C and 50% RH because the water-soluble PVA migrates to the mortar surface. The skin prevents proper tile wetting and must be controlled by limiting Poval 17-94 to 0.5 wt% in large-format tile adhesives and by adding a low-viscosity cellulose ether at 0.5–1.5 wt%. Shear adhesion after 28 days is tested under EN 12004:2007+A1:2012; for C2 classification, a separate redispersible polymer powder at 2.5–4.5 wt% is required because PVA alone does not provide the deformability measured under EN 12002. Poval 17-94 dosage must be controlled by ±0.05 wt% gravimetric dosing; above 1.0 wt%, calcium sulfate screeds may flash set and mortar strength falls. The product is incompatible with high-alkali water glass formulations above pH 12.5 because acetyl groups hydrolyse and calcium ions are consumed, reducing final strength.
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KURARAY POVAL 17-94 is a partially hydrolysed poly(vinyl alcohol) resin manufactured by Kuraray Co., Ltd. The grade designation encodes two specification variables: the first numeral refers to the nominal viscosity of a 4% aqueous solution at 20°C, expressed as 17 mPa·s, and the second numeral refers to a degree of hydrolysis of 94 mol%. In batch-release terms, the viscosity is typically controlled within 17.0–19.0 mPa·s and the degree of hydrolysis within 93.0–95.0 mol%. The residual acetyl content is therefore approximately 6 mol%. This places the material between cold-water-soluble 88 mol% grades and higher-crystallinity fully hydrolysed grades, giving an intermediate dissolution temperature and intermediate dried-film water sensitivity. The product is used as a protective colloid in vinyl acetate and vinyl acetate-ethylene emulsion polymerisation, as a binder in paper and ceramic green bodies, and in remoistenable adhesives where controlled water redispersibility is required.
As a partially hydrolysed PVOH, 17-94 retains a small but functionally significant acetyl population. These residual acetate groups disrupt intramolecular and intermolecular hydrogen bonding, suppress crystallinity relative to fully hydrolysed PVOH, and increase the mobility of polymer chains in water. The technical consequence is that a 17-94 solution can be prepared at lower temperatures than a fully hydrolysed grade but does not exhibit the pronounced cold-water tack and high-moisture sensitivity of an 88 mol% grade. On a production scale, dissolution is normally carried out in steam-jacketed stainless steel vessels equipped with high-shear dispersers, followed by slow anchor agitation to release entrained air. Published data for the exact minimum dissolution temperature of this specific grade is limited; users should determine the clear-point temperature under their own shear and particle-size conditions.
The manufacturer’s certificate of analysis for 17-94 typically reports the properties shown in Table 1. The aqueous viscosity is measured at 20°C on a 4% solution prepared according to JIS K6726, which is the Japanese test method for poly(vinyl alcohol) resin. Viscosity is a molecular-weight indicator; at 17 mPa·s, the grade provides sufficient cohesive strength for adhesive film formation while remaining processable in size-press and coating circuits. The degree-of-hydrolysis range is critical because even small shifts in residual acetyl content alter surfactant behaviour, water resistance, and compatibility with additives. Volatile matter is controlled to avoid weighing errors and caking during silo storage; ash content is controlled because residual sodium acetate influences aqueous solution conductivity and film colour.
| Property | Typical value | Test method |
|---|---|---|
| Degree of hydrolysis | 93.0–95.0 mol% | JIS K6726 |
| Viscosity of 4% aqueous solution at 20°C | 17.0–19.0 mPa·s | JIS K6726 |
| Volatile matter | ≤5.0 % | JIS K6726 |
| Ash as Na₂O | ≤0.7 % | JIS K6726 |
| pH of 4% solution at 20°C | 5.0–7.0 | JIS K6726 |
Incoming material should be checked against the certificate of analysis before compounding. Because PVOH is hygroscopic, bags or bulk containers should be closed immediately after sampling. The test methods cited above are not substitutes for application-specific rheology testing; viscosity in the presence of co-solvents, plasticisers, or fillers will differ from the 4% aqueous value. Laboratory preparation of the 4% solution for viscosity determination follows JIS K6726, which specifies dispersion in distilled water and heating under reflux or in a sealed vessel until complete dissolution. In industrial preparation, lump formation is avoided by adding the powder to the vortex of cold water under high shear before steam heating. If powder is added too rapidly to warm water, gel particles can form at the surface and require extended cook times. The dissolution endpoint is usually confirmed by visual clarity and viscosity stabilisation; turbidity indicates undissolved material or contamination. Because 17-94 has a partially hydrolysed structure, solutions are less prone to retrogradation than fully hydrolysed grades but can still increase in viscosity on prolonged cooling. Published data for retrogradation kinetics of this specific configuration is limited; users should measure viscosity recovery after cold storage in their own systems.
In vinyl acetate and vinyl acetate-ethylene emulsion polymerisation, 17-94 is normally introduced as a pre-dissolved protective colloid at 10–20% aqueous concentration, depending on reactor solids and particle-size target. The residual 6 mol% acetyl groups reduce interfacial tension at the vinyl acetate-water interface and contribute steric stabilisation during particle nucleation and early growth. Compared with fully hydrolysed PVOH at equal viscosity, 17-94 generally yields lower aqueous surface tension and more uniform particle-size distributions in continuous stirred-tank reactors. On production lines, the solution phase is prepared in jacketed stainless steel tanks; high-shear dispersion is applied until the clear point is reached, then the agitator speed is reduced to avoid viscosity loss from excessive aeration. Residual sodium acetate acts as a buffer in the polymerisation water phase. Emulsion viscosity and shear stability are influenced by the PVOH content, the degree of hydrolysis, and the presence of anionic surfactants; no single correlation applies without reactor-specific calibration.
Solution viscosity is not fixed by molecular weight alone; thermal and shear history during dissolution affect the final rheological response. If 17-94 is cooked at 90–95°C for intervals exceeding 60 minutes, solution viscosity can drift downward due to chain scission, while insufficient cooking leaves microgel particles that produce filter plugging and surface defects. Jacketed stainless steel cook tanks with high-shear dispersion followed by low-speed anchor agitation provide reproducible clear points. For size-press and coating circuits, dissolved 17-94 is typically held at 55–65°C before application. Viscosity drift during an 8-hour production shift is managed by controlling solution temperature and avoiding extended hold above 70°C. The grade is compatible with starch and styrene-acrylate surface-sizing dispersions, but high electrolyte loading can cause viscosity increase or precipitation; ionic additives should therefore be evaluated in jar tests before bulk addition. The 5.0–7.0 pH range of the 4% solution is low enough to avoid alkali yellowing of optical brighteners in fine paper grades. Machine speed, rod pressure, and drying capacity affect surface pick and film continuity more strongly than the hydrolysis difference alone.
Replacement is generally justified when the dried film must retain enough aqueous redispersibility for remoistening but not the aggressive moisture absorption associated with 88 mol% grades. In remoistenable paper adhesives, the dried adhesive is re-wetted at the packaging line; 17-94 provides slower moisture uptake than lower-hydrolysis grades while still allowing tack recovery. Tensile data for PVOH-based films are commonly determined under ISO 527-3; however, results are highly sensitive to plasticiser concentration, conditioning relative humidity, and draw ratio. Specimens should be conditioned at 23°C and 50% relative humidity before testing because moisture plasticises PVOH and reduces yield stress. For temporary ceramic green-body binders, the low ash limit of ≤0.7% is relevant to fired-part residue control, and the grade can be removed during the debinding step. High-humidity storage of the dry powder is a known handling constraint; when moisture uptake exceeds the volatile-matter limit, the powder can form lumps in screw feeders and require pre-drying before extrusion or dry blending.
On heated size-press machines, 17-94 is typically cooked in steam-jacketed stainless steel tanks at 90–95°C, then held at 55–65°C for application. The 17 mPa·s nominal viscosity contributes to metering nip film split and pickup control. In textile warp sizing, the grade is applied as part of a size formulation containing starch, wax, and lubricants. The film formed on the yarn must balance elasticity and abrasion resistance during weaving and then be removable by washing. The 94 mol% hydrolysis gives better adhesion to cellulosic fibres than low-hydrolysis PVOH and easier desizing than fully hydrolysed PVOH. Size-mix preparation uses jet cookers or autoclaves; filtration through a 200-mesh screen is common to remove gel particles. Experience on production slashers indicates that size-box temperature should be maintained within ±5°C to avoid viscosity variation and uneven pick-up; published data for this specific configuration is limited.
PVOH used in paper and paperboard food-contact applications may fall under FDA 21 CFR 176.170 and 176.180, subject to limitations on extractives and end-use conditions. Users must verify the current regulatory status for the intended food type and contact time; 17-94 itself is not a food-contact end product. The powder should be stored in sealed bags or silos away from strong acids, strong oxidizers, and aldehydes. Aqueous solutions are susceptible to microbial growth after approximately 24 hours at ambient temperature; preservative addition is required for extended hold unless the solution is refreshed or cooked. Bulk handling in silos requires dry air and hopper vibration because the powder exhibits cohesive flow. Dust generated during pneumatic transfer should be controlled under local combustible organic dust limits. Regulatory status under REACH and RoHS should be confirmed against the current database for the final article; published data for this specific configuration is limited where end-use additives and formulations are involved.
The principal differences from other PVOH grades are expressed through the hydrolysis–viscosity matrix rather than through viscosity alone. At equal nominal 17 mPa·s viscosity, a lower-hydrolysis 88 mol% grade dissolves at lower temperature and yields a more moisture-sensitive dried film, whereas a fully hydrolysed 98–100 mol% grade requires higher dissolution temperature and yields a more crystalline, water-resistant film. 17-94 occupies the intermediate position: it delivers reduced cold-water tack relative to 88 mol% grades and improved aqueous processability relative to fully hydrolysed grades. The residual acetyl groups also modify surfactant behaviour in emulsion polymerisation, making the grade useful where a balance between latex stability and dried-film water resistance is required. Users should not select 17-94 as a direct drop-in for either extreme without adjusting cook temperature, solids, or plasticiser loading.
