| HS Code | 884009 |
| Product | Ningxia Dadi PVA 2099 |
| Chemical Name | Polyvinyl Alcohol |
| Cas Number | 9002-89-5 |
| Grade | 2099 |
| Appearance | White granular powder |
| Viscosity 4 Aqueous Solution 20 C | 20.0-30.0 mPa·s |
| Hydrolysis Degree | ≥99.0 mol% |
| Ph 4 Aqueous Solution | 5.0-7.0 |
| Ash Content | ≤0.5% |
| Volatile Content | ≤5.0% |
| Average Degree Of Polymerization | 2000 |
| Solubility | Soluble in hot water, insoluble in cold water and most organic solvents |
As an accredited Ningxia Dadi PVA 2099 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Ningxia Dadi PVA 2099 is packaged in 25 kg multi-layer paper bags with inner plastic lining. |
| Container Loading (20′ FCL) | 20′ FCL container loading: Ningxia Dadi PVA 2099 packed in 25kg bags, palletized, secured, and stowed for safe transport. |
| Shipping | Ningxia Dadi PVA 2099 ships as a water-soluble powder in sealed, moisture-proof bags, typically on pallets and containerized. Protect from humidity, rain, and excessive heat during transit. Keep away from ignition sources and incompatible materials. Standard non-hazardous cargo classification applies for most routes; verify local regulations prior to shipment. |
| Storage | Store Ningxia Dadi PVA 2099 in a cool, dry, well-ventilated area, away from heat, ignition sources, and direct sunlight. Keep containers tightly closed to prevent moisture absorption and contamination. Avoid dust accumulation; protect from oxidizing agents. Maintain stable temperatures and follow local regulations for safe handling and storage. |
| Shelf Life | Shelf life is typically 12 months when stored unopened in a cool, dry place away from moisture and sunlight. |
Ningxia Dadi PVA 2099 is a fully hydrolyzed polyvinyl alcohol with a nominal degree of polymerization of 2000 and a hydrolysis level of 99.0–99.8 mol%. The 4% aqueous solution viscosity at 20°C typically falls between 20.0 mPa·s and 28.0 mPa·s when measured by the method aligned with GB/T 12010.2-2010. In high-density 40s cotton warp sizing, the grade is cooked as part of a ternary size formulation rather than used alone because its solution viscosity under size-box conditions is too high for low add-on application. A production formulation for 40s cotton sheeting contains 7.0–9.0 wt% PVA 2099 on total size solids, 50.0–60.0 wt% oxidized starch, 25.0–30.0 wt% modified starch, 3.0–5.0 wt% acrylic copolymer, and 0.3–0.8 wt% paraffin wax. The solids content is adjusted to 10.0–12.0 wt% and the paste is cooked in a jet cooker at 120–130°C for 20–30 min, followed by holding at 85–90°C in the service tank. At the size box, the Zahn cup #3 efflux time is kept between 12 s and 18 s at 85–90°C; below 75°C surface skinning and gel particle formation are observed on unagitated overflow weirs. A two-roll squeeze mangle with 70–75 Shore A rubber bowls is set at 15–25 daN/cm to deposit 12–15% size add-on on dry yarn mass. The sized yarn is dried over multi-cylinder cans with the first can surface temperature limited to 100–110°C; can temperatures above 150°C cause heat-induced insolubilization of the PVA film and reduce oxidative desizing efficiency to below 80%. Desizing before dyeing uses 6–10 g/L hydrogen peroxide and 2–5 g/L sodium hydroxide padded at 20–30°C, steamed at 100–102°C for 10–15 min, and washed at 85–95°C. Residual PVA on greige fabric is assessed qualitatively by iodine–boric acid staining because uneven removal produces dye resist marks on jig dyeing machines. The end product is woven greige fabric for workwear and bottomweight goods, with weaving performance measured by loom stops per 100,000 picks and yarn tensile retention after sizing according to ASTM D2256.
In protective-colloid-grade vinyl acetate emulsion polymerization, substituting a low-DP partially hydrolyzed PVA with Ningxia Dadi 2099 shifts the locus of grafting and the rheology of the finished latex. The grade is dissolved as a 10.0 wt% stock solution in deionized water at 85–90°C for 60 min and held at 50°C before feeding. The typical protective colloid addition is 3.0–6.0 wt% based on total monomer, with the lower end used for 55% solids poly(vinyl acetate) homopolymers and the upper end for lower-solids vinyl acetate–ethylene copolymer dispersions. A stainless steel jacketed reactor with a double-helical ribbon impeller at 80–120 rpm is used; initial monomer charge is 10–15%, potassium persulfate is dosed at 0.3–0.5 wt% on monomer, and the pH is held between 3.5 and 5.5 with sodium bicarbonate. The fully hydrolyzed 2099 grade produces shear-stable latex particles with volume mean diameters in the 0.5–2.0 μm range when measured by laser diffraction per ISO 13320, but the high degree of polymerization raises final latex viscosity. Formulations above 6.0 wt% protective colloid on monomer frequently exceed 25,000 mPa·s at 25°C on a Brookfield viscometer per ISO 2555, causing reactor wall skinning and poor heat transfer on 10 m³ production reactors. A common failure mode is microfloc formation when the initiator feed is interrupted and monomer-starved conditions allow excessive PVA grafting. The latex is used in wood assembly adhesives meeting EN 204 durability classes D2 and D3, and in paper-converting adhesives. Compliance of the unpolymerized residual PVA in food-contact adhesives is evaluated under FDA 21 CFR 175.105 where the adhesive is separated from food by a functional barrier. Published industrial data for this specific high-DP fully hydrolyzed grade in high-pressure vinyl acetate–ethylene systems is limited; plant trials generally begin with 20% substitution of the existing protective colloid to balance viscosity and shear stability.
At machine speeds above 120 m/min, the limiting variable is not pump shear but the film-split instability generated by the high-DP PVA fraction in oxidized starch size press formulations. On recycled linerboard and white-top testliner, Ningxia Dadi 2099 is added at 1.0–3.0 wt% of the size solution, while oxidized starch is held at 6.0–9.0 wt% and total solids are maintained at 8.0–12.0 wt%. The starch is jet-cooked separately and the PVA is dissolved as a 10.0 wt% stock at 85–90°C; the two streams are blended at 60–70°C immediately before the size press to avoid retrogradation. The blended size solution viscosity is kept between 20 mPa·s and 50 mPa·s at 60°C using a Brookfield LV spindle. A rod-metered size press running at 80–120 m/min applies 1.5–2.5 g/m² dry size per side. Compared with starch-only controls, the inclusion of PVA 2099 reduces 60 s Cobb values from 60–80 g/m² to 25–40 g/m² when tested to ISO 535, and raises IGT pick strength by 15–30% on a standard IGT AIC2-5 printability tester at 2.5 m/s. The operational boundary is concentration and speed dependent: above 3.0 wt% PVA or above 150 m/min, filament breakup in the transfer nip creates size misting and uneven film distribution across the web. Calender blocking is observed when reel moisture exceeds 10% before the after-dryer; moisture is therefore controlled to 6.0–8.0% at the reel. The finished paperboard is used for secondary packaging and corrugated containers, including food-contact secondary packaging where the PVA component falls under FDA 21 CFR 176.170 as a component of paper and paperboard. Mill experience shows that microbial degradation of the starch-PVA blend in the run tank becomes significant after 8 h at 60°C, causing a viscosity drop and odor; the run tank must be drained or treated with an approved biocide according to mill hygiene protocols.
Tape casting of 0.8–1.2 μm alumina substrates requires a temporary binder that leaves residual ash below 0.2% of green sheet mass after burnout. Ningxia Dadi PVA 2099 is prepared as an 8.0 wt% solution in deionized water at 85–90°C, cooled to 25°C, and combined with 55–65 wt% alumina powder, 1.0–2.0 wt% polyethylene glycol 400 plasticizer, 0.3–0.6 wt% ammonium polyacrylate dispersant, and 0.05–0.1 wt% defoamer, with the binder level expressed as 4.0–6.0 wt% of dry ceramic powder. The slip is ball-milled for 12–24 h and deaired under 50–100 mbar for 30 min to remove bubbles that would form pinholes in the cast tape. A doctor blade gap of 0.3–1.0 mm is used with a casting carrier speed of 0.5–1.5 m/min, and the tape is dried at 60–80°C. Green tape tensile strength falls in the range of 2.0–4.0 MPa with elongation of 5–15% when measured according to ASTM D882. The high DP of the 2099 grade increases green strength but also raises slip viscosity; when the viscosity exceeds 8,000 mPa·s at 25°C, air removal becomes difficult and the tape surface shows bubble defects. Burnout is performed in a controlled air kiln at 5°C/min to 450°C with a 2 h hold, followed by free cooling. The residual ash specification for the binder is ≤0.7% on dry PVA; this matters in low-temperature co-fired ceramic substrates where alkali and alkaline earth residues alter dielectric loss. The end products include alumina substrates, multilayer ceramic capacitor green sheets, and LTCC tapes. A known process boundary is that the grade is not suitable for freeze-drying or low-temperature casting operations requiring cold-water solubility, because fully hydrolyzed PVA solutions gel on prolonged standing at below 20°C.
Charging a fully hydrolyzed 2000 DP grade to a PVB condensation train alters the degree of butyralization, the residual hydroxyl content, and the plasticizer compatibility of the finished interlayer. The PVA is dissolved in deionized water at 8.0–10.0 wt% and cooled to 20–30°C. n-Butyraldehyde is fed at 0.60–0.75 mol per vinyl alcohol unit, and hydrochloric acid is added at 0.2–0.5 wt% of the aqueous phase as catalyst. The exothermic condensation is held at 20–50°C for 2–6 h, with strong agitation because the reaction mixture thickens as the product precipitates. A glass-lined baffled reactor operating at 150–200 rpm is required to prevent wall scaling and local hot spots. The resulting PVB is precipitated, neutralized with sodium hydroxide to pH 5.0–6.0, and washed until chloride content is below 0.05 wt%. For laminated glass interlayer, the PVB made from PVA 2099 typically contains 68–76 wt% butyral groups, 17–21 wt% hydroxyl groups, and below 1.0 mol% residual acetate. Intrinsic viscosity in ethanol–chloroform at 25°C generally falls between 0.8 dL/g and 1.2 dL/g, which corresponds to a high-molecular-weight interlayer with elevated melt viscosity. The operational boundary is the high solution viscosity of the PVA feed; at 10.0 wt%, the PVA solution may exceed 3,000 mPa·s at 25°C, and dilution or higher dissolution temperature is needed for metering pumps. Excess butyraldehyde or acid above the stated windows causes intra-particle gelation and reactor fouling. The PVB film is extruded and tested for penetration resistance, optical quality, and adhesion to glass under ISO 12543. End products include automotive windscreen interlayers, architectural laminated glass, and photovoltaic encapsulant films where low residual acetate and high hydroxyl content improve glass adhesion but require careful plasticizer selection to maintain low-temperature impact strength.
Paper core winding adhesives formulated with PVA 2099 exhibit a sharp borate sensitivity threshold that limits tackifier addition. A stock solution is prepared at 5.0–8.0 wt% PVA in a jacketed mixer at 65–75°C, then cooled to 50–60°C for application. Borax is added at 0.1–0.3 wt% of the wet adhesive to increase wet tack on spiral wound paper cores; above 0.3 wt%, the fully hydrolyzed high-DP grade forms a three-dimensional borate crosslinked gel that cannot be pumped by gear pumps. The adhesive viscosity is maintained between 2,500 mPa·s and 5,000 mPa·s at 25°C using a Brookfield viscometer per ISO 2555. On core winding lines running at 80–150 m/min, the adhesive is applied by spiral nozzle or roll transfer to 150–300 g/m² coreboard. The wet tack requirement is 20–30 s on a standard drop test, and the final core crush strength is evaluated after conditioning at 23°C and 50% RH. PVA 2099 gives high bond strength but can cause stringing and roller buildup at machine speeds above 120 m/min; in such cases, the solids are reduced to 3.5–4.5 wt% and the application temperature is raised to 65–75°C. The adhesive is used for paper cores for PET film, pressure-sensitive labelstock, and tape rolls. When used in food packaging adhesives, the formulation is assessed under FDA 21 CFR 175.105. A relevant limitation is that the high-DP fully hydrolyzed grade is not suitable for re-wettable cold-water adhesive applications because the dried film does not readily re-dissolve at below 40°C.
Aqueous barrier coatings on paper-based food service board use plasticized Ningxia Dadi 2099 films to reduce oxygen transmission and grease penetration. The coating formulation contains 8.0–12.0 wt% PVA 2099, 10.0–25.0 wt% glycerol or sorbitol on dry PVA, 0.1–0.3 wt% defoamer, and 0.05–0.1 wt% wetting agent. The solution is prepared at 85–90°C and coated at 40–50°C using a rod or air-knife coater at 80–150 m/min. A dry coat weight of 2.0–4.0 g/m² reduces flat-surface grease resistance to below 1.0% stained area after 24 h contact with turpentine according to TAPPI T 454. The higher DP of the 2099 grade improves film toughness and tear resistance but increases the viscosity of the coating color; at 12.0 wt% solids the viscosity exceeds 1,500 mPa·s at 40°C, requiring slot-die or curtain coating rather than roll metering. The end product is repulpable food service board for bakery bags and sandwich wraps. Compliance is evaluated under FDA 21 CFR 176.170 and the relevant BfR Recommendation XXXVI for paper and board in food contact. The operational boundary is the drying demand: fully hydrolyzed PVA films retain moisture and require lower dryer temperatures below 110°C to avoid blisters.
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Polyvinyl alcohol grade Ningxia Dadi PVA 2099, produced by Ningxia Dadi Chemical Co., Ltd., is a high-viscosity, fully hydrolysed vinyl alcohol homopolymer supplied as white to pale-yellow granules or powder. In Chinese PVA grade nomenclature, the terminal 99 denotes a saponification degree of approximately 99 mol%, while the 20-series prefix indicates a viscosity band above the standard 1799 homopolymer. The grade is specified by alcoholysis degree, 4% aqueous solution viscosity at 20°C, volatile matter, ash, and pH, with methods drawn from GB/T 12010.2-2010, GB/T 12010.3-2010, GB/T 12010.4-2010, and GB/T 12010.5-2010. Storage and handling should be maintained below 60% RH; pre-drying is required if volatile matter exceeds 5.0 wt%. Particle size is typically controlled in the 20–80 mesh range for bulk handling; dust formation is managed by local exhaust and conductive grounding. Because published data for this specific configuration is limited, the manufacturer’s lot certificate of analysis remains the controlling document for formulation design.
| Parameter | Typical range or limit | Test condition / method |
|---|---|---|
| Appearance | White to pale-yellow granules or powder | Visual inspection |
| Alcoholysis degree | 99.0–99.8 mol% | GB/T 12010.2-2010 |
| Viscosity of 4% aqueous solution | 20.0–30.0 mPa·s | 20°C, rotational viscometer, GB/T 12010.2-2010 |
| Volatile matter | ≤5.0 wt% | GB/T 12010.3-2010 |
| Ash content | ≤0.7 wt% | GB/T 12010.4-2010 |
| pH of 4% solution | 5.0–7.0 | GB/T 12010.5-2010 |
The principal differences from other PVA grades are molecular weight, dissolution temperature, and crystallisation tendency. When 1799 is replaced with 2099, solution viscosity and film toughness increase but cold-water handling becomes more difficult. When 2699 is used instead of 2099, the higher viscosity contributes more thickening per unit mass but filter plugging and solution stringiness increase. Partially hydrolysed 2488 dissolves readily in cold water and provides lower water resistance, making it preferable for cold-water-soluble packaging but less suitable for water-resistant barrier layers.
Fully hydrolysed 2099 does not dissolve in cold water without heat. In batch solution preparation, the powder is slurried in water at 20–25°C and then heated to 85–95°C under high-shear agitation; a dissolver with a cowles blade or 45° pitched-blade turbine at tip speed 5–12 m/s is typically specified. During hydration, apparent viscosity can exceed 50 mPa·s before complete dissolution, and uncontrolled powder addition can form gelatinous fisheyes that require filtration through 80–120 mesh screens. For cast film production, deaerated solutions at 20–25°C are deposited on a chill roll at 60–80°C and dried in multi-zone ovens; final film moisture is usually controlled between 8 and 12 wt% for dimensional stability. Tensile properties are dominated by plasticizer type and content. When tested according to ISO 527-3, low-plasticizer films from this grade generally show higher tensile strength and lower elongation than films from partially hydrolysed 2488; exact values require lot-specific characterisation.
The high degree of hydrolysis imposes a critical processing window. Solution temperatures below 80°C leave residual microgel, while prolonged heating above 95°C can accelerate thermal oxidative chain scission when dissolved oxygen is not purged. Nitrogen blanketing and jacket temperature control are therefore recommended for solution storage exceeding 4 h. In melt-extrusion operations, 2099 must be plasticised with water, glycerol, or polyether polyols; a vented twin-screw extruder with L/D 40–48 is used because the polymer decomposes near its melt-processing range. Feedstock moisture outside 2–6 wt% can cause surging, vent clogging, or uncontrolled hydrolysis.
Textile warp sizing at production scale employs PVA 2099 in size boxes of high-speed slashers, where size pick-up is controlled by solids concentration, squeeze pressure, and liquor viscosity. A typical formulation contains PVA 2099, oxidised starch, and lubricant wax at 8–14 wt% total solids; the liquor is maintained at 85–90°C and monitored with a Zahn cup No. 3 or equivalent rotational viscometer. Because the 4% solution viscosity of the grade controls final size-box viscosity, a lot-to-lot shift from 20 mPa·s to 30 mPa·s can alter size add-on by 0.5–1.5 percentage points and affect loom shed behaviour. Compared with 1799, the 2099 grade produces a tougher size film and fewer shedding defects, but the higher solution elasticity may require increased defoamer dosage in the size box.
Adhesive formulators select Ningxia Dadi PVA 2099 over 1799 when dried bond lines require lower wet creep and higher cohesive strength. The higher molecular weight and lower residual acetate concentration increase the density of crystallisable hydrogen-bonded domains after film drying. In polyvinyl acetate emulsion polymerisation, the grade is used as protective colloid at 1.0–3.0 wt% based on monomer mass. The resulting emulsion shows higher viscosity than an equivalent 1799-stabilised emulsion at equal solids; this shift is commonly in the range of 30–60% and must be offset by reducing colloid level or adding nonionic surfactant to avoid reactor fouling in continuous stirred-tank reactors. The particle size distribution narrows when colloid molecular weight increases, altering shear stability and thickening response. For water-resistant wood adhesives, 2099 may be crosslinked with glyoxal or melamine-formaldehyde resins; pot life is shorter than 1799-based formulations because the higher hydroxyl density accelerates crosslinking above 30°C.
Paper surface sizing operations use PVA 2099 as a strength and barrier additive in starch-based size press formulations. The fully hydrolysed structure reduces rewetting of the dried sheet and improves oil and grease resistance in packaging grades. At size press solids of 4–8 wt%, partial replacement of starch with PVA 2099 at 10–30 dry wt% of total binder can increase surface strength, but the higher viscosity relative to 1799 may restrict runnability on machines above 1,200 m/min. Filtration through 100 mesh screens and viscosity control at 60–70°C are used to prevent surface streaks. Use levels above 30 dry wt% can cause size press picking and dryer deposits; lower levels improve runnability but reduce barrier performance.
The fully hydrolysed structure of 2099 has a high degree of intermolecular hydrogen bonding between vinyl alcohol units in amorphous and crystalline phases. Crystalline domains act as physical crosslinks and dissolve only when the water temperature exceeds the hydrated PVA crystal melting point, which for 99 mol% hydrolysed material is above 80°C. Below this temperature, water diffuses into amorphous regions but leaves swollen crystallites intact, producing a turbid gel rather than a true solution. By contrast, partially hydrolysed PVA 2488 with 88 mol% alcoholysis dissolves at 20–40°C because residual acetate groups disrupt chain regularity. This difference explains why 2099 is selected for water-resistant coatings and hydrophobic barrier layers but is unsuitable for cold-water-soluble film applications; it also means cleaning of solution tanks and transfer piping requires hot water above 80°C. A fully dissolved 2099 solution remains transparent to translucent after cooling, whereas partially dissolved material exhibits Tyndall scattering and should be filtered through 200 mesh before film or coating use.
In construction dry-mix mortars, PVA 2099 is used as a water-retention and rheology-modifying admixture at 0.5–1.5 wt% of cementitious binder. The fully hydrolysed grade increases open time and water retention in tile adhesives and skim coats, but produces higher aqueous viscosity than 1799 at equal dosage, which may require adjustment of superplasticizer or cellulose ether content. Open time extension is evaluated by EN 1346, while water retention can be measured by filter-paper method or parallel-plate rheometry. At high shear rates in continuous mortar mixers, the polymer solution can generate significant viscous heating; batch temperature should be maintained below 60°C to prevent premature dehydration and lump formation.
Solutions of 2099 are incompatible with borate ions; borax addition causes reversible gelation through diol complexation, and this sensitivity increases with degree of hydrolysis. Gelation thresholds for 2099 in alkaline buffer are lower than for 2488, so formulations containing sodium tetraborate should be segregated until gelation behaviour has been mapped. Strong oxidising acids and hot persulfate solutions degrade the polymer backbone and should not be admitted to the process stream. The shelf life in unopened original packaging is typically 12–24 months from manufacture under 25°C and 50% RH; caking may occur if bags are stacked beyond 10 layers or exposed to moisture. For food-contact packaging, compliance is evaluated under FDA 21 CFR 176.170 or corresponding regional provisions; additive carryover and migration limits are site-specific.
When applied as a high-barrier coating on paper or board, PVA 2099 can reduce oxygen and grease transmission after thermal annealing. Coating lines operate at 45–60°C with roll or blade applicators; drying temperatures above 100°C may cause skin-over and blistering if the film surface dries before internal moisture can migrate. Oxygen transmission rate reductions can be quantified by ASTM D3985-17 at 23°C and 0% RH; however, the barrier property deteriorates sharply above 70% RH because PVA is moisture-sensitive. For humid conditions, crosslinking with glyoxal or melamine-formaldehyde improves wet barrier but reduces flexibility. The higher molecular weight relative to 1799 increases web tension and may require higher drying capacity for the same coat weight, a trade-off accepted when improved barrier performance and block resistance are required.
