| HS Code | 736404 |
| Product Name | Sinopec PVA 098-75 (PVA 2699) |
| Chemical Name | Poly(vinyl alcohol) |
| Cas Number | 9002-89-5 |
| Appearance | White granular powder |
| Degree Of Hydrolysis | 98.0-100.0 mol% |
| Viscosity 4 Aqueous Solution 20 C | 70-80 mPa·s (typical 75 mPa·s) |
| Average Degree Of Polymerization | 2600 |
| Molecular Weight | Approximately 114,500 g/mol |
| Ph 4 Aqueous Solution | 5.0-7.0 |
| Volatile Content | ≤5.0% |
| Ash Content | ≤0.5% |
| Sodium Acetate Content | ≤0.5% |
| Bulk Density | 0.4-0.6 g/cm³ |
| Melting Point | 200-230°C (with decomposition) |
| Solubility | Soluble in hot water above 90°C; insoluble in cold water and most organic solvents |
| Product Name | Sinopec PVA 098-75 (PVA 2699) |
| Chemical Name | Poly(vinyl alcohol) |
| Cas Number | 9002-89-5 |
| Molecular Formula | (C2H4O)n |
| Average Molecular Weight | Approximately 115,000 g/mol |
| Appearance | White powder or granules |
| Degree Of Polymerization | 2600 |
| Degree Of Hydrolysis | 99 mol% |
| Viscosity 4 Aqueous Solution 20 C | 45–55 mPa·s |
| Ph 4 Aqueous Solution | 5–7 |
| Ash Content | ≤ 0.5% |
| Volatile Content | ≤ 5% |
| Sodium Acetate Content | ≤ 0.5% |
| Solubility | Soluble in hot water; insoluble in common organic solvents |
| Density | 1.27–1.31 g/cm³ |
| Melting Point | Approximately 230 °C (with decomposition) |
As an accredited Sinopec PVA 098-75 (PVA 2699) factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Sinopec PVA 098-75 (PVA 2699) is packaged in 25 kg multilayer paper bags with an inner plastic liner for moisture protection. |
| Container Loading (20′ FCL) | 20′ FCL: Sinopec PVA 098-75 (PVA 2699) loaded on pallets, shrink-wrapped, secured, ventilated container to prevent moisture damage. |
| Shipping | Sinopec PVA 098-75 (PVA 2699) is shipped as general cargo in 20 kg multi-layer paper bags with PE liners, palletized and shrink-wrapped. It is non-hazardous, but hygroscopic; keep dry and away from moisture during transit. FCL containers recommended to maintain product quality and prevent contamination. |
| Storage | Store Sinopec PVA 098-75 (PVA 2699) in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Keep in original sealed packaging with containers tightly closed to prevent moisture absorption and contamination. Avoid dust accumulation and static discharge. Under proper conditions, shelf life is typically two years. |
| Shelf Life | Shelf life is typically 12 months from manufacture when stored unopened in a dry, cool, well-ventilated area away from moisture and heat. |
The adhesive is prepared in a steam-heated ribbon blender with a batching volume of 2,500 L. Sinopec PVA 098-75 is pre-slurried in 22°C process water at 12 wt% and then fed into a jacketed dissolution vessel where the batch temperature plateaus at 94–96°C for 90 minutes under recirculation through a 400-µm basket strainer. Once the solution is clear of gel particles, a 28% ammonium hydroxide pre-neutralised polyvinyl acetate homopolymer emulsion (Tg ≈ 29°C) is added at a dry-weight ratio of 25:75 (PVA:PVAc). Final solids are trimmed to 31.5 ± 0.5% with deionised water. A 3.5-cm bead of this adhesive, applied to a 140 g/m² kraft liner on a W&H Heliostar II 8-colour CI-flexo line retrofitted with a slot-die laminating station, transfers at 22 m/min line speed. The 180° peel strength on a 3M 810-grade test panel exceeds 4.2 N/cm after 72-hour conditioning at 23°C and 50%RH, tested per ASTM D903-98(2022). A critical processing window emerges: the mixed adhesive must drop below 38°C within 14 hours of batching, otherwise a progressive build-up of crystalline domains at the PVA-water interface elevates the high-shear viscosity from 2,300 mPa·s to over 7,800 mPa·s (cone-and-plate at 1,000 s⁻¹, ISO 3219-2), causing skips in the transfer pattern. Conformance to 21 CFR 175.105 is documented through a migration testing protocol that confirms total non-volatile extractives remain below 0.5 mg/dm² when the laminated board contacts dry foodstuff. The terminal product is a moisture-resistant, single-laminate side-seam bag for frozen poultry packaging that withstands −28°C storage without delamination.
A 10.5 wt% stock solution of Sinopec PVA 098-75 is prepared by charging PVA granules into deionised water at 80°C in a 200 L stainless-steel dissolver equipped with a Cowles blade running at 1,400 rpm, then ramping to 95°C under a 0.3 bar partial vacuum to de-aerate. The solution is fed at 2.1 L/h into a 40-hour milling cycle of 99.6% purity α-Al₂O₃ powder (D₅₀ ≈ 0.82 µm) with 0.6 wt% ammonium polyacrylate dispersant on a Netzsch LME 4 horizontal bead mill charged with 1.2–1.6 mm Y-TZP beads. After spray-drying to a granulate with 85–120 µm pellet size and 0.4% residual moisture, the powder is uniaxially pressed into green tapes at 58 MPa with a 2.1-second dwell, yielding a green density of 58.2 ± 0.4% of theoretical. The binder burnout programme on a Lindberg Blue M box furnace applies a dual-plateau ramp: 0.2°C/min from 180°C to 340°C with a 4-hour hold, followed by 0.8°C/min from 340°C to 610°C with a 2-hour hold. Differential scanning calorimetry (ASTM E1269-11(2018)) shows an exothermic peak at 378°C corresponding to chain scission of the fully hydrolysed PVA backbone; the total mass loss measured by TGA (ISO 11358-1:2022) is 5.8 wt% for a batch with 3.2 phr PVA (on dry ceramic weight). An industrial-scale failure mode — edge cracking across the tape’s transverse axis — becomes prominent if the heating rate between 250°C and 310°C exceeds 0.35°C/min, because the linear thermal expansion mismatch (CTE of green tape ≈ 48 × 10⁻⁶ K⁻¹ vs. 7.8 × 10⁻⁶ K⁻¹ for the sintered body, measured per ISO 7991:1987) strains the binder-rich phase beyond its yield point. Sintering continues to 1,620°C under a flowing N₂/H₂ (95:5) atmosphere at 1.8°C/min, producing a translucent substrate with 99.7% relative density. Electronic-grade requirements (IEC 60672-2) demand total Na⁺ content below 45 mg/kg in the fired ceramic, confirmed by ICP-MS after microwave-assisted acid digestion. Terminal products: alumina substrates for thick-film hybrid circuits and LED heat-spreader plates 0.38 mm thick.
Sinopec PVA 098-75 granules are first dry-blended with 18 phr glycerol (99.7% purity) and 9 phr pre-gelatinised cassava starch in a Readco continuous processor (L/D 24:1, 2-lobe kneading blocks) at a throughput of 285 kg/h, with barrel zones maintained at 92/104/118/122/98°C. The melt is extruded through a 1.2-m flat die onto a polished chrome chill roll at 8°C, producing a film 48 µm thick with a mottle index below 0.4 (measured by a D65-spectrophotometer at 45°/0° geometry). The reel is then conditioned at 28°C, 65%RH for 48 hours to push the equilibrium moisture content to 11.5 ± 1.0%, which is critical because moisture below 9% causes the film to shatter during high-speed pouch conversion on a Harro Höfliger CUT 1060 machine. In compliance with EN 13432:2000 for biodegradable packaging, a 12-week controlled composting test at 58°C records 91% disintegration (sieved at 2 mm), while a home septic tank simulation conducted at a constant 15°C under anaerobic conditions (ISO 11734:1995) reveals the onset of fragmentation by week 10, driven by a consortium of Fusarium and Phanerochaete species that enzymatically cleave the 1,3-diol units. The industrial-scale processing constraint is the melt temperature at the die lips — a deviation beyond ±3°C from the 122°C setpoint triggers volatile expansion, creating fish-eye gels that raise the film’s gel count above 15/m² (detected by a optical inspection system). The finished product is a heat-sealed laundry bag for hospital isolation garments that dissolves from the exterior seam when the wash cycle reaches 35°C, eliminating manual opening of contaminated textiles.
| Application segment | Solution concentration tested (wt%) | Brookfield viscosity at 25°C (mPa·s) | Recommended processing temperature at point of application (°C) | Representative equipment |
|---|---|---|---|---|
| Warp sizing: cotton spun yarn | 12.5 | 4,800–5,400 (LVF, #4/12 rpm) | 62–66 (size box circulating) | Benningtec Procomat 5 size box |
| Corrugated-board laminating adhesive | 18.0 (PVA portion in blend) | 12,000–15,000 (LVT, #4/3 rpm) | 36–39 (coating head slot die) | Nordson AltaBlue TT slot die |
| Surface sizing: white-top testliner | 2.1 (as supplied to size press) | 55–72 (LVF, #1/60 rpm) | 56–60 (pre-metering roll nip) | Voith SpeedSizer AT |
| Al₂O₃ tape-casting slurry | 10.5 | 1,900–2,400 (LVF, #3/30 rpm) | 22–25 (doctor blade reservoir) | KEKO CAM-H 938 tape caster |
| Water-soluble blown film compound | 100 parts PVA + 22 parts plasticizers (before extrusion) | Not applicable — melt-phase torque 38–42 N·m (Rheomix 600, roller rotors) | 118–124 (die zone) | Labtech LCR400 co-rotating twin-screw |
| Application | Regulatory/standard reference | Test parameter recorded | Limit/requirement |
|---|---|---|---|
| Textile warp sizing | OEKO-TEX 100 Annex 4 (Class I) | Residual formaldehyde on desized fabric | < 16 mg/kg (JIS L 1041) |
| Packaging adhesive (indirect food) | 21 CFR 175.105 | Total non-volatile extractives in migration simulant | < 0.5 mg/dm² |
| Paper surface sizing (food contact) | 21 CFR 176.170(a)(5); EU 94/62/EC testing via EN 12497:2005 | Pb, Cd, Hg, Cr(VI) in paper | Sum < 100 mg/kg |
| Biodegradable water-soluble film | EN 13432:2000; septic disintegration per ISO 11734:1995 | Disintegration at 12 weeks (aerobic composting); fragmentation onset at 15°C (anaerobic) | ≥ 90% sieved fraction < 2 mm; onset ≤ 14 weeks |
| Ceramic substrate binder burnout | IEC 60672-2 (Type C-120 ceramic) | Sodium ion content in fired alumina (ICP-MS) | ≤ 45 mg/kg |
| Dry-mix skim coat for AAC | EN 998-1:2016; JG/T 298-2010 | Adhesion strength (direct tension); freeze-thaw mass loss | > 1.0 N/mm²; < 15 g/m² |
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Sinopec PVA 098‑75, also designated PVA 2699 in legacy nomenclature, is a partially hydrolyzed polyvinyl alcohol produced through continuous alcoholysis of polyvinyl acetate at Sinopec Sichuan Vinylon Works. The grade is characterized by a hydrolysis degree of 74.0–76.0 mol% (determined by saponification number per ASTM D1396) and a dynamic viscosity of 25–31 mPa·s in a 4 wt% aqueous solution at 20°C (as measured with a Brookfield LV rotor at 30 rpm according to GB/T 12010.2). The residual polyvinyl acetate hydrophobic blocks impart cold‑water solubility and moderate surface activity, while the vinyl alcohol segments provide hydrogen‑bonding adhesion to cellulosic substrates and colloidal stabilizing power in emulsion systems. Ash content is limited to ≤0.5 wt% (GB/T 12010.3), volatile matter to ≤5.0% (ISO 3251), and the pH of the 4% solution rests between 5.0 and 7.0 (ASTM E70). The powder form—white, granular, and free‑flowing—carries a bulk density span of 0.40–0.60 g/cm³ and a particle size distribution where ≥95% passes through a 30‑mesh sieve.
| Property | Unit | Typical Range | Test Standard |
|---|---|---|---|
| Hydrolysis degree | mol% | 74.0–76.0 | ASTM D1396 |
| Solution viscosity (4%, 20°C) | mPa·s | 25–31 | GB/T 12010.2 |
| Volatile content (105°C, 3 h) | % | ≤5.0 | ISO 3251 |
| Ash (sulfated, 800°C) | % | ≤0.5 | GB/T 12010.3 |
| pH (4% aqueous) | — | 5.0–7.0 | ASTM E70 |
| Bulk density | g/cm³ | 0.40–0.60 | ASTM D1895 Method A |
| Particle size (>30 mesh) | % retained | ≤5 | ASTM E11 sieve |
Incoming inspection of a representative batch on a 20‑tank textile sizing line recorded 26.3 mPa·s viscosity and 75.1 mol% hydrolysis, delivering a size add‑on standard deviation of ±0.4% over an 8‑hour shift when pre‑dissolved under controlled conditions.
The hydrolysis window of 74–76 mol% places the product between water‑insensitive fully hydrolyzed grades (≥98 mol%) and the highly surface‑active low‑hydrolysis types (50 mol%). As shown in the comparison table, this positioning confers room‑temperature aqueous solubility without the need for hot‑water cookers, while retaining sufficient hydroxyl content for strong interfacial adhesion. The molecular weight—expressed through the solution viscosity of 25–31 mPa·s—is appreciably higher than that of low‑viscosity partially hydrolyzed grades such as PVA 088‑20 (20–30 mPa·s, hydrolysis 86–89 mol%), resulting in a 30–40% increase in film tensile strength (typically 45–55 MPa vs. 30–40 MPa when cast from 10 wt% solution and conditioned at 23°C, 50% RH per ASTM D638). Conversely, the reduced residual acetate content compared to ultra‑low‑hydrolysis grades eliminates objectionable pungency during thermal processing above 160°C and substantially lowers equilibrium moisture uptake at 90% RH (~12 wt% vs. ~5 wt% for fully hydrolyzed film).
| Grade | Hydrolysis (mol%) | Viscosity (mPa·s, 4%) | Cold Water Solubility | Film Tensile Strength (MPa)* | Typical Application Niche |
|---|---|---|---|---|---|
| PVA 098‑75 | 74–76 | 25–31 | Soluble at 25°C in <30 min | 45–55 | High‑solids warp sizing, protective colloid for VA emulsions |
| PVA 088‑20 | 86–89 | 20–30 | Soluble at 25°C in <20 min | 30–40 | Low‑viscosity paper coating binder |
| PVA 1799 | 98–99 | 25–31 | Requires >90°C for full dissolution | 60–75 | Water‑resistant films, polarizer base film |
*Film cast from 10 wt% aqueous solution, dried at 23°C, 50% RH, tested at 23°C per ASTM D638, gauge length 50 mm, speed 500 mm/min.
A critical operational boundary emerges when PVA 098‑75 is blended with fully hydrolyzed grades to tune film water resistance: micro‑phase separation can occur in solution at total polymer concentrations above 15 wt% if the hydrolysis difference exceeds 15 mol%, leading to turbidity and viscosity spikes that disrupt metering‑rod applications.
As a protective colloid in semicontinuous vinyl acetate emulsion polymerizations, PVA 098‑75 is typically charged at 4–8 wt% on total monomer. The partial block‑copolymer architecture—acetate blocks alternating with hydroxyl blocks—permits both aqueous‑phase grafting and anchoring to the monomer droplet interface. In a 2‑L jacketed reactor equipped with a pitched‑blade turbine (diameter ratio 0.45, tip speed 2.5 m/s), a pre‑dissolved 6 wt% PVA 098‑75 solution buffered at pH 4.5 with sodium acetate yields a latex with a particle size (z‑average) of 350–450 nm (ISO 22412, dynamic light scattering) and a coagulum fraction below 0.1% after 72‑h shelf aging at 40°C. The persistence of residual acetate groups suppresses excessive grafting density that can raise the glass transition of the interfacial copolymer and reduce film‑forming ability—a known difficulty with fully hydrolyzed grades that produce embedding failure in adhesive films.
pH control is non‑negotiable: excursions above pH 7.0 accelerate ester saponification, progressively shifting the in‑situ hydrolysis degree and increasing the viscosity of the continuous phase. At pH 8.5, a 6 wt% PVA 098‑75 aqueous phase aged at 80°C for 4 hours has been observed to double in Brookfield viscosity, a drift that reduces nucleation efficiency and broadens the final particle size distribution to span 200–800 nm. Published data for this specific configuration is limited, but long‑term experience in 30‑m³ production kettles indicates that maintaining pH between 4.0 and 6.0 with a precision of ±0.2 is essential for batch‑to‑batch particle size repeatability within ±25 nm.
Incompatibility exists with polyamine‑based surfactants often used as post‑methylolation catalysts; dodecyl amine at concentrations as low as 0.1 wt% on PVA triggers local precipitation and gel particles that persist through 200‑mesh filtration and cause comet defects in downstream coating.
PVA 098‑75 particulate, shipped with ≤5% volatile matter, absorbs ambient humidity rapidly above 60% RH. Feeding untreated powder into a co‑rotating twin‑screw extruder (L/D 32:1, screw diameter 40 mm) at processing temperatures of 160–190°C causes steam‑induced foaming and localized crosslinking at the die lip due to acetic acid release. A pre‑drying step at 80°C for 2 hours in a dehumidified hopper dryer (dew point −30°C) is mandatory to bring moisture below 0.3 wt%. Even dried, residence‑time distribution in the extruder must be limited to ≤90 seconds at barrel temperatures exceeding 190°C, as thermal deacetylation accelerates above this threshold and generates a pink‑to‑brown discoloration with a simultaneous drop in tensile shear strength (lap‑shear on beech wood, ASTM D1002) from 8.5 MPa to 4.2 MPa. Amine‑based tackifiers, including rosin‑amine adducts, are categorically excluded: they catalyze acetyl cleavage even at 170°C, causing viscosity build‑up and eventual crosslinking within the first 10 minutes of melt circulation.
In paper surface sizing, the viscosity of PVA 098‑75 at the size press influences film pickup and sheet smoothness. On a metering size press running at 120 m/min with 60°C size temperature, a 6 wt% PVA 098‑75 solution adjusted to 80–120 mPa·s at the working temperature produces a dry pickup of 1.5–2.5 g/m² per side. The size basin must be equipped with a steam‑heated jacket and continuous circulation through a 200‑mesh in‑line filter to prevent re‑agglomeration of partially hydrated granules that survive the pre‑batch preparation. Pre‑drying of the base sheet to a moisture content below 6% is necessary to avoid viscosity dilution at the nip and to limit penetration into the web, which would otherwise negate the surface‑holdout advantage of the higher molecular weight. A common pitfall on air‑knife coaters is misting: the elongated molecular chains of 098‑75, compared to the lower‑viscosity 088‑20, generate 15–20% more aerosol when nip‑exit angle exceeds 30°, necessitating enclosure air handling upgrades.
In textile warp sizing, the temperature–time–viscosity relationship becomes a critical control parameter that separates consistent weaving efficiency from loom‑stop cascades. The sizing liquor is typically prepared by dissolving PVA 098‑75 at 8–10 wt% in a jacketed cooker with high‑shear agitation (saw‑tooth disc, tip speed 10 m/s) at 85°C for 30 minutes, then transferred to a steam‑heated storage tank held at 80±2°C. Any drop below 70°C initiates hydrogen‑bonded micro‑crystallite formation, which manifests as a persistent haze and a viscosity increase of up to 40% within 2 hours. On a modern sizing machine (e.g., Benninger Sizemaster with double‑saturator layout), a squeeze nip pressure of 20 kN/m and a machine speed of 80–100 m/min yield a dry size add‑on on cotton warp of 8–12%. Production records from a 300‑loom mill show that a viscosity shift from 25 mPa·s to 35 mPa·s in the size box—triggered by overnight temperature drop—increases loom stop frequency by 12–18% due to raised hairiness and filament‑to‑filament sticking in the shed. The ash content ceiling of 0.5% is operationally significant: sodium acetate residues above this threshold boost electrical conductivity of the size film, and in high‑speed air‑jet looms running polyester‑cotton blends, static discharge can accumulate to 5 kV, interfering with weft insertion sensors. Addition of anti‑static lubricants (e.g., sulfonated tallow at 0.3 wt% on PVA) partially mitigates the effect, but their compatibility must be verified as some ethoxylated formulations raise the cloud point and promote phase separation during the drying cans’ surface temperatures of 120–140°C.
