| HS Code | 512673 |
| Product Name | SELVOL Polyvinyl Alcohol 350 |
| Chemical Name | Poly(vinyl alcohol) |
| Cas Number | 9002-89-5 |
| Molecular Formula | (C2H4O)n |
| Degree Of Hydrolysis | 98.0 - 98.8 mol% |
| Viscosity 4 Aqueous Solution At 20 C | 35.0 - 45.0 cP |
| Ph 4 Aqueous Solution | 5.0 - 7.0 |
| Appearance | White to off-white powder |
| Solubility | Soluble in hot water; practically insoluble in organic solvents |
| Specific Gravity | 1.25 - 1.31 |
| Melting Point | 190 - 230°C |
| Glass Transition Temperature | 75 - 85°C |
| Ash Content | ≤ 1.0% |
| Volatile Content | ≤ 5.0% |
As an accredited SELVOL Polyvinyl Alcohol 350 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | SELVOL Polyvinyl Alcohol 350 is supplied in 25 kg multiwall paper bags with polyethylene liner for moisture protection. |
| Container Loading (20′ FCL) | 20′ FCL loading of SELVOL Polyvinyl Alcohol 350: bagged and palletized, securely stowed in a dry container to prevent damage and moisture. |
| Shipping | SELVOL Polyvinyl Alcohol 350 ships as a non-hazardous powder in sealed, moisture-resistant bags or containers. Protect from humidity and direct contact with water to prevent clumping. Store in a dry, ventilated area away from ignition sources. Standard freight is acceptable; ensure secure palletization and proper labeling for safe transport. |
| Storage | Store SELVOL Polyvinyl Alcohol 350 in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Keep the container tightly sealed to prevent moisture absorption and contamination. Avoid generating dust. Separate from oxidizing agents and incompatible materials. Use proper labeling and follow good hygiene practices to maintain product stability. |
| Shelf Life | SELVOL Polyvinyl Alcohol 350 has a typical shelf life of 24 months when stored in sealed containers in a cool, dry area. |
In semi-batch emulsion polymerization of vinyl acetate homopolymers and vinyl acetate-ethylene copolymers, SELVOL Polyvinyl Alcohol 350 is introduced as a pre-dissolved 10% aqueous protective colloid at 0.8–1.5 L/min per 1,000 kg monomer charge, corresponding to a final loading of 1.8–4.0 wt% of total monomer for packaging adhesive emulsions. The reactor train consists of a 316L stainless or glass-lined jacketed vessel with a pitched-blade turbine operating at 45–55 rpm; pH is held at 3.8–4.5 with sodium bicarbonate or phosphoric acid, while redox initiation by sodium persulfate/sodium metabisulfite is controlled at 0.12–0.25 wt% of monomer mass. Jacket temperature is maintained at 65–72°C during the exotherm, and delayed PVOH feeding is trimmed so that the emulsion reaches a Brookfield viscosity of 2,000–4,500 mPa·s at 25°C before final letdown. Process experience on 2,000 L and 5,000 L scale lines has shown that feed rates above 1.5 L/min or agitation below 40 rpm induce PVOH-rich gel skins on baffle surfaces and heat-transfer walls, causing localized fouling and a bimodal particle size distribution. Compliance of the resulting emulsions for indirect food-contact packaging is anchored to FDA 21 CFR 175.105 for adhesive applications and to FDA 21 CFR 176.170 and FDA 21 CFR 176.180 for paper and paperboard sizing and coating; the polymer falls under the REACH Article 2(9) polymer exemption, with vinyl acetate monomer registered under REACH. Terminal product types include polyvinyl acetate homopolymer woodworking adhesives, vinyl acetate-ethylene laminating adhesives, board stock lamination emulsions, and interior architectural paints where PVOH contributes wet-rub resistance and heat-seal adhesion.
| Standard / regulation | Boundary condition |
|---|---|
| FDA 21 CFR 175.105 | Adhesives permitted for indirect food contact; PVOH admissible as an adhesive component when migration limits are observed |
| FDA 21 CFR 176.170 | Paper and paperboard in contact with aqueous and fatty foods; PVOH admissible as a size and coating binder |
| FDA 21 CFR 176.180 | Paper and paperboard in contact with dry food; PVOH admissible as a barrier and binder component |
| REACH Article 2(9) | Polymer exemption applies; vinyl acetate monomer is registered under REACH |
On metered size presses running fine paper and bleached board, PVOH 350 is pre-dissolved at 90–95°C for 30 min as a 10–15% aqueous solution and then blended into a cooked oxidized starch base at 0.8–2.0 wt% dry solids of total size press solids. The final size press solids are maintained at 8–12%, with a size press pickup of 1.5–3.0 g/m² per side to limit internal sizing disruption and preserve print density. The running configuration uses a rod-metering or blade-metering unit with nip linear load of 20–45 kN/m, size bath temperature of 60–70°C, and after-drying cylinder surface temperatures of 90–110°C. Final web moisture is held at 4.5–6.0% to avoid re-moistening and blocking in the sheet stack. The targeted surface is typically a Cobb value of 25 g/m² or lower under ISO 535, with water absorptiveness verified by TAPPI T441. Mill experience indicates that addition above 2.5 wt% dry solids of PVOH 350 increases size bath extensional viscosity and leads to metering rod deposition, streaking, and build-up on fast-drying sections. Compliance is maintained under FDA 21 CFR 176.170 and FDA 21 CFR 176.180 for paper and paperboard food-contact use. Terminal product types include high-speed inkjet papers, offset printing grades, folding carton board, and release liner base papers requiring a dense surface film without furnace-side curl fluctuation.
Warp slashing of ring-spun polyester/cotton and combed cotton yarns for air-jet looms requires a size film with sufficient tensile strength, elongation, and fatigue resistance to survive 600–1,200 picks/min cyclic abrasion. In single-box and two-box slasher operations, PVOH 350 is charged into the size bath at 6–10 wt% of total size-box solids, with size-box solids maintained at 8–12% and final size add-on controlled at 8–13% of yarn weight. The polymer is cooked at 85–95°C for 20–30 min before being combined with modified starch or acrylic co-binders; size bath temperature during slashing is held at 70–80°C, while squeeze rolls apply 15–25 kN/m linear nip pressure. Drying cylinder profiles are staged from 110°C to 135°C, with final yarn moisture at 6–8% to avoid brittle size failure at low moisture and size shedding at high moisture. Production-scale fault data from air-jet weaving lines indicate that first-dryer can surface temperatures above 125°C promote PVOH skin formation on the yarn surface, causing dust accumulation at the reed and warp stops. After weaving, the size is removed in a hot-water desizing bath at 80–90°C, without enzymatic assistance. Chemical compliance is documented through ZDHC MRSL v3.1 screening and OEKO-TEX ECO PASSPORT certification for textile chemical safety, while residual formaldehyde and heavy-metal control follows ISO 14184-1. Terminal product types include apparel woven fabrics, home textile sheeting, pocketing fabrics, and technical woven substrates for coated abrasives and filtration media.
In spray-dried press granulate and tape-casting slip preparation, PVOH 350 is added at 0.8–2.0 wt% of dry ceramic solids for press granulate and at 4.0–8.0 wt% of ceramic powder for tape-casting slip, introduced as a 15% aqueous solution. High-purity alumina slip at 50–60 wt% solids is ball-milled for 18–24 h with a polyelectrolyte dispersant, after which the PVOH pre-solution is added under low-shear stirring for 30–60 min. The slip is de-aired at 0.1 bar before spray drying at inlet 180–220°C and outlet 85–95°C, or before tape casting at a wet gap of 0.3–1.0 mm. Tape drying proceeds at 40–80°C, and binder burnout follows a ramp of 0.5°C/min to 450–550°C with a 1–2 h hold to evolve pyrolysis gases without cracking dense sections. Process data show that PVOH addition above 8 wt% in tape-cast slip increases green strength but raises pyrolysis shrinkage and edge cracking when the dried tape thickness exceeds 300 µm. Cleanroom processing of electronic-grade tapes is conducted under ISO 14644-1, and fired density, porosity, and water absorption are measured by ASTM C373-18. The polymer is monitored under REACH Annex XVII restrictions for ceramic processing additives. Terminal product types include alumina electronic substrates, zirconia oxygen sensors, ceramic cores, and technical ceramic tapes used in high-frequency circuit packaging.
Seed film coating of maize, sugar beet, and oilseed rape batches uses a water-soluble binder deposited as a thin continuous layer over the testa to reduce dust-off and improve treatment retention. PVOH 350 is incorporated into the coating slurry at 4–8 wt% of total dry coating solids, with spray application rates of 0.6–1.2 L/min per 100 kg seed batch and a final dry coating add-on of 1.0–3.0 wt% of seed mass. The coating line consists of a batch rotary pan with air-atomized nozzles; inlet air is maintained at 35–45°C, seed bed temperature at 28–32°C, and atomization pressure at 1.5–2.5 bar. Coating cycles are interrupted with forced-air drying to prevent seed-to-seed adhesion and gloss banding, and dust-off control follows the International Seed Federation dust adhesive protocol with periodic stereomicroscopic inspection for cracked coating edges. The fully hydrolyzed film provides mechanical integrity during pneumatic transfer and singulation in planters without requiring organic solvent recovery systems. For food-use seed treatments, the binder is applied within the inert ingredient tolerance exemption under US EPA 40 CFR 180.920; polymer compliance is further supported by the REACH Article 2(9) polymer exemption. Terminal product types include film-coated maize and soybean seeds, pelleted sugar beet seed, and vegetable seed pellets for precision planting.
Competitive SELVOL Polyvinyl Alcohol 350 prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615380400285 or mail to sales2@liwei-chem.com.
We will respond to you as soon as possible.
Tel: +8615380400285
Email: sales2@liwei-chem.com
Flexible payment, competitive price, premium service - Inquire now!
Introduced as a partially hydrolysed polyvinyl alcohol resin, SELVOL Polyvinyl Alcohol 350 is manufactured by Sekisui Specialty Chemicals and supplied as a white to cream granular powder. The resin is identified by CAS No. 9002-89-5 and is controlled to a degree of hydrolysis of 87.0–89.0 mol%, leaving a residual acetate content of 11–13 mol%. The 4% aqueous solution viscosity at 20°C is specified as 12.0–15.0 cP when measured with a Brookfield rotational viscometer in accordance with JIS K6726 and ISO 15023-2. The 4% solution pH is 4.5–6.5, volatiles are limited to a maximum of 5.0%, and ash expressed as Na₂O is limited to a maximum of 0.6%. The solution viscosity is the release proxy for average chain length; no separate molecular weight specification is applied to the commercial granulate. The granulate dissolves in water to form clear-to-slightly hazy solutions, depending on residual acetate distribution and dissolution temperature.
| Property | Test method | Specified range |
|---|---|---|
| 4% aqueous viscosity at 20°C | Brookfield rotational viscometer, JIS K6726 / ISO 15023-2 | 12.0–15.0 cP |
| Degree of hydrolysis | JIS K6726 / ISO 15023-2 | 87.0–89.0 mol% |
| pH, 4% solution | JIS K6726 | 4.5–6.5 |
| Volatiles | JIS K6726 | max 5.0% |
| Ash as Na₂O | JIS K6726 | max 0.6% |
| Appearance | Visual assessment | White to cream granular powder |
Within the partially hydrolysed SELVOL series, the 350 grade occupies the mid-viscosity position. A direct comparison with SELVOL 325 shows that both grades share the same hydrolysis range of 87.0–89.0 mol%, while the 4% aqueous viscosity of SELVOL 325 is controlled at 4.0–5.0 cP under the same test conditions. This difference in chain length produces measurable changes in dried film performance; tensile properties are evaluated in accordance with ASTM D882, and the higher chain length of SELVOL 350 increases tensile strength at break and modulus at equivalent plasticiser loading. The shear-thinning behaviour of SELVOL 350 is more pronounced under high-shear mixing because the longer chains exhibit greater entanglement density. The granular resin also requires longer dissolution time at 70–85°C than SELVOL 325; lump formation is reduced by pre-slurrying in cold water at a 3:1 water-to-resin ratio before heating. Fully hydrolysed SELVOL grades in the 800 series require solution temperatures of 90–95°C and produce films with lower moisture regain; that comparison is relevant where water resistance rather than redispersibility is the primary specification.
| Grade | 4% aqueous viscosity at 20°C | Degree of hydrolysis | Relative chain length |
|---|---|---|---|
| SELVOL 325 | 4.0–5.0 cP | 87.0–89.0 mol% | Lower |
| SELVOL 350 | 12.0–15.0 cP | 87.0–89.0 mol% | Mid-range |
In aqueous adhesive compounding, the 12.0–15.0 cP resin specification translates to a working viscosity that is formulation-dependent rather than an intrinsic property. For a 25 wt% solids solution at 25°C, adhesive viscosity can range from 2,000–6,000 mPa·s before plasticiser addition, measured in accordance with ASTM D1084. SELVOL 350 is used in remoistenable adhesive coatings because the dried film is resistant to re-dissolution in water below 15°C and activates under moisture and heat above 50°C. Borax addition at 1–2 wt% of PVOH solids raises low-shear viscosity through cis-diol crosslinking; published data for this specific configuration is limited, but general PVOH literature reports viscosity increases of one to two orders of magnitude. Excess borax reduces open time and produces brittle failure at film folds. For paper surface sizing, SELVOL 350 is applied at size press temperatures of 55–65°C; surface strength is assessed by ISO 3783 and air permeance by ISO 5636-3. Optimisation of starch-PVOH ratios is required to avoid film splitting at the metering rod on high-speed paper machines. Textile warp sizing with SELVOL 350 is conducted at size box concentrations of 6–9 wt% solids; the film remains flexible at 65% RH and is removed in hot-water desizing at 80–90°C. The partial hydrolysis band allows lower desizing energy than fully hydrolysed grades, but the film is not suitable for continuous immersion below 40°C without crosslinking. Aqueous solutions are susceptible to microbial growth; storage beyond 24 h at ambient temperature requires biocide addition.
Partially hydrolysed PVOH films provide oxygen barrier through intermolecular hydrogen bonding that restricts free volume in the amorphous phase. Oxygen transmission rate is measured in accordance with ASTM D3985; typical PVOH films show an oxygen permeability coefficient below 1.0 cm³·mm/(m²·day·atm) at 0% RH, while the coefficient rises by more than one order of magnitude at 75% RH. SELVOL 350 at 87.0–89.0 mol% hydrolysis is less moisture-sensitive than grades below 80 mol% but more moisture-sensitive than fully hydrolysed 98 mol% PVOH. The residual acetate groups disrupt crystallinity and increase free volume, which reduces water resistance but improves cold-water redispersibility. Barrier coatings based on SELVOL 350 are therefore specified only when end-use relative humidity is below 50% or when the PVOH layer is coextruded between polyolefin layers that limit water ingress. Pre-drying is required at storage or processing relative humidity above 60%; moisture regain alters both melt viscosity and oxygen transmission performance.
In vinyl acetate and vinyl acetate-ethylene emulsion polymerisation, the protective colloid influences particle nucleation, latex viscosity and dried film water sensitivity. SELVOL 350 has a higher average degree of polymerisation than SELVOL 325 at equivalent hydrolysis; the thickening effect per unit mass is therefore greater. Substitution of SELVOL 350 for SELVOL 325 generally requires the protective colloid concentration to be reduced toward the lower end of the 3–5 wt% range based on total monomer to maintain a latex viscosity of 2,000–4,000 mPa·s at 55% solids. The higher chain length shifts the particle size distribution toward larger mean particle diameters, which can reduce coagulum formation during high-shear transfer but may reduce film clarity. Residual PVOH grafted onto latex particles increases hydrophilicity; SELVOL 350 produces greater wet-state tensile strength than SELVOL 325 but lower water resistance unless a crosslinker such as glyoxal or ammonium zirconium carbonate is used at 0.5–1.0 wt% of polymer solids. Polymerisation is maintained at 70–80°C with delayed initiator addition to avoid chain scission of the colloid. Published data for this specific configuration is limited; formulation adjustments are typically validated by Brookfield viscometry in accordance with ISO 2555 and water absorption in accordance with ASTM D570.
SELVOL 350 may be referenced in food-contact adhesive formulations under 21 CFR 175.105, in paper and paperboard components under 21 CFR 176.170 and 176.180, and in polyvinyl alcohol films under 21 CFR 177.1670. The cited clearances are conditional on extraction limits and end-use conditions, not on the resin supply alone; final article compliance must be verified against the specific conditions of use. Under EU REACH, polyvinyl alcohol is considered a polymer and is exempt from registration, while the vinyl acetate monomer is registered under the applicable EC number. RoHS documentation is supplier-issued and states that SELVOL 350 is not intentionally doped with lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls, or polybrominated diphenyl ethers above the threshold limits of Directive 2011/65/EU. The product is not classified as hazardous under the CLP Regulation; however, dust generated during handling should be controlled to avoid explosive dust-air mixtures under processing conditions described by ATEX Directive 2014/34/EU equipment requirements.
Melt extrusion of partially hydrolysed PVOH is feasible only within a narrow thermal window; the onset of thermal discolouration occurs near 200°C, while the crystalline melting endotherm requires barrel temperatures above 170°C. SELVOL 350, at 87.0–89.0 mol% hydrolysis, has a lower melting endotherm than fully hydrolysed PVOH and can be processed at 180–195°C when plasticised with 10–20 phr of sorbitol, glycerol, or trimethylolpropane. On a 40:1 L/D co-rotating twin-screw extruder, melt filtration through 40–60 mesh screen packs is used to remove gel particles; venting under a vacuum of −0.08 MPa strips residual moisture. The resin must be predried to less than 0.5 wt% moisture in a desiccant dryer with a dew point of −40°C; at ambient storage above 60% RH, moisture regain exceeds 5 wt% within 24 h and causes bubble formation and melt viscosity fluctuation. Processing without plasticiser is not recommended because shear heating accelerates chain scission. The resin is incompatible with strong oxidising agents at elevated temperatures, which can cause chain scission and discolouration. Published data for SELVOL 350 in this specific configuration is limited; the practical processing window is narrow, and deviations of more than 10°C above the set point produce yellowing and gel defects.
