| HS Code | 636604 |
| Product Name | Ningxia Dadi PVA 2699 |
| Chemical Family | Polyvinyl Alcohol |
| Appearance | White granular powder |
| Degree Of Hydrolysis | 99.0-100.0 mol% |
| Average Degree Of Polymerization | 2600-2700 |
| Viscosity | 65.0-75.0 mPa·s (4% aqueous solution, 20°C) |
| Ph | 5.0-7.0 |
| Ash Content | ≤0.5% |
| Volatile Content | ≤5.0% |
| Solubility | Soluble in hot water above 90°C |
As an accredited Ningxia Dadi PVA 2699 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Ningxia Dadi PVA 2699 is packaged in 25 kg net multi-layer bags with inner polyethylene liner, palletized and shrink-wrapped. |
| Container Loading (20′ FCL) | 20′ FCL: 20-foot container loaded with Ningxia Dadi PVA 2699, secured, protected from moisture, ready for safe export shipment. |
| Shipping | Ningxia Dadi PVA 2699 is a non-hazardous polyvinyl alcohol powder, shipped in sealed 25 kg multi-wall paper bags with PE liner. Protect from moisture, rain, and direct sunlight during transit. Transport in clean, dry containers or trucks, avoiding high temperatures and excessive pressure to maintain product quality. |
| Storage | Store Ningxia Dadi PVA 2699 in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Keep containers tightly sealed to prevent moisture absorption and contamination. Maintain moderate humidity, avoid dust accumulation, and segregate from oxidizing agents. Follow safe handling practices; under proper conditions, shelf life is typically 12–24 months. |
| Shelf Life | Shelf Life: 2 years when stored in original sealed packaging in a cool, dry place away from moisture and direct sunlight. |
For high-density cotton and polyester-cotton warp yarns entering air-jet or water-jet looms, the size film must withstand cyclic abrasion from drop wires, heddles, and reed dents without fragmenting into shed deposits. PVA 2699 is dissolved in a high-shear jet cooker at 90–95°C before being metered into the size mix at 6–9 wt% based on dry solids. The grade is a fully hydrolysed granular polyvinyl alcohol whose 4 wt% aqueous solution viscosity is normally reported between 26 and 32 mPa·s at 20°C, with hydrolysis degree in the 99.0–99.8 mol% range. On multi-cylinder sizing machines supplied by Toyota or Karl Mayer, size-box viscosity is typically held at 12–18 s as measured by a 3 mm Zahn cup at 85°C. Squeeze roller pressure of 10–16 kN/m and size uptake of 8–12% based on yarn mass are common starting points, with drying cylinder surface temperature staged from 110°C to 140°C to prevent skinning and film embrittlement. The formulation is often compounded with native corn starch at a PVA-to-starch dry weight ratio of 60:40 to 70:30 and with 0.5–1.0 wt% of a lubricant or wax based on total size solids. Cast film tensile strength measured according to ASTM D882 is typically in the range of 45–60 MPa, with elongation at break of 80–120%. Raising PVA 2699 above 15 wt% of total size solids increases mix viscosity and can reduce weaving efficiency by raising shedding and reed accumulation; dropping below 4 wt% lowers abrasion resistance and increases end breakage. Desizing after weaving is performed in hot-water tanks with oxidative desizing agents at 85–95°C, and the fully hydrolysed resin requires sufficient residence time because cold-water solubility is negligible. For export lots supplied to mills in South Asia, Southeast Asia, and Latin America, the certificate of analysis should state 4 wt% aqueous viscosity at 20°C, hydrolysis degree, volatile matter, and ash, because these values control dissolution time and size-bin consistency on the production floor.
In recycled liner and corrugating medium production, surface sizing at the size press or film press is used to control water absorption and increase surface strength. PVA 2699 enters the formulation as a minor but rheologically significant component. When blended with oxidised corn starch at 1.0–3.0 dry wt% of starch solids, the PVA phase raises low-shear viscosity and changes the film split pattern at the metering nip. Rod-metering film press data recorded at 900–1,200 m/min on OCC-based liner show that PVA addition reduces Cobb 60 s water absorption from approximately 55 g/m² to 25–35 g/m² when tested according to ISO 535. Surface pick strength assessed on an IGT printability tester in the range of 2.5–3.5 m/s is commonly improved by 15–30% relative to a starch-only control, though published data for this specific configuration is limited and must be verified by mill trial. The high molecular weight of PVA 2699 creates a more continuous film than low-viscosity grades, but the resulting viscosity increase limits maximum starch solids to about 8–10 wt% in a flooded size press unless a rod or film press is installed. Sheet porosity measured by ISO 5636-3 may decline by 5–10% when PVA content exceeds 3 parts per 100 parts starch; for grades requiring high Gurley holdout that is acceptable, but for high-bulk medium it may impair drainage. Dissolution temperature must be held at 90–95°C because the fully hydrolysed grade does not disperse in a cold starch slurry. For export buyers supplying indirect food-contact paperboard, the relevant compliance framework includes FDA 21 CFR 176.170 and FDA 21 CFR 175.300, with EU 10/2011 documentation required for EU converters.
High-speed corrugated lamination of pre-printed liner to single-wall or double-wall board demands a bond that resists shear at hot rollers but remains dispersible in the repulper. PVA 2699 is cooked separately as a 12–16 wt% aqueous solution at 90–95°C and then compounded with plasticiser, defoamer, and viscosity modifier. The final adhesive is commonly adjusted to a Brookfield viscosity of 3,000–5,000 mPa·s at 40°C using spindle 4 at 20 rpm. Where the glue station runs at 150–200 m/min, the adhesive is applied at 20–35 g/m² wet by roller or slot die to the corrugated tips. Borax is generally not added to this fully hydrolysed PVA because borate crosslinking can produce a green viscosity climb and inconsistent roller transfer. Instead, 5–10 wt% glycerol or sorbitol based on PVA solids is used to plasticise the film and reduce blocking. Bond strength is evaluated by the pin adhesion test for combined board and by ISO 3037 edgewise crush resistance for the finished carton; typical combined board values of 5.0–7.0 kN/m are influenced more by medium and liner basis weight than by adhesive alone. The key operational boundary is gelation: when the adhesive sump temperature drops below 35°C, the high-viscosity PVA solution forms a skin and can clog doctor blades; above 80°C under low shear, molecular entanglement maintains a high but stable viscosity. Repulpability is confirmed by TAPPI T 275 or an equivalent mill repulping test with a 20 minute soak at 50°C and a laboratory disintegrator; the PVA film disperses more slowly than starch, so a longer soak time is required.
At reactor temperatures of 55–65°C and pressures of 0.7–1.0 MPa, suspension-grade PVC particle morphology is regulated by the ratio of primary to secondary suspending agents. PVA 2699 serves as the secondary suspending agent in formulations where a partially hydrolysed PVA of 72–88 mol% hydrolysis is the primary dispersant. The secondary agent is pre-dissolved at 4–8 wt% in demineralised water and charged into the polymerisation autoclave at 0.02–0.08 parts per 100 parts vinyl chloride monomer, giving a total PVA charge of 0.06–0.15 phr. The fully hydrolysed high-viscosity PVA increases plasticiser absorption and lowers the apparent bulk density of the dry resin. Production-scale trends observed in agitated stainless-steel autoclaves equipped with three-blade retreat-curve impellers show that raising the secondary PVA fraction within the stated window shifts the mean particle size at 50% cumulative mass from roughly 130 µm toward 150–160 µm as determined by sieving according to ISO 1624. Plasticiser absorption measured by ASTM D3367 typically moves from 18–22 g/100 g resin to 24–30 g/100 g resin when the secondary PVA is increased, while apparent bulk density following ISO 60 may fall by 0.03–0.06 g/cm³. These shifts are not monotonic; above 0.08 phr of PVA 2699 the aqueous phase becomes excessively viscous, heat transfer at the reactor wall declines, and reactor fouling increases. Below 0.02 phr the secondary effect is lost and the coarse fraction may rise. The resin is then dried in fluidised bed dryers at inlet air temperatures of 55–65°C, with residual VCM content controlled below 1 µg/g for EU market grades. For export transactions, residual VCM, sieve fractions, and plasticiser absorption are commonly specified in the sales contract, not only on the PVA certificate.
| Attribute | 0.02 phr PVA 2699 | 0.05 phr PVA 2699 | 0.08 phr PVA 2699 |
|---|---|---|---|
| Mean particle size (ISO 1624) | 125–140 µm | 140–155 µm | 150–165 µm |
| Plasticiser absorption (ASTM D3367) | 18–22 g/100 g | 22–26 g/100 g | 26–30 g/100 g |
| Apparent bulk density (ISO 60) | 0.52–0.56 g/cm³ | 0.50–0.54 g/cm³ | 0.47–0.52 g/cm³ |
| Reactor fouling tendency | low | moderate | high if cooling shear is inadequate |
The above ranges are indicative for suspension-grade production settings and reactor geometry; actual values shift with primary PVA hydrolysis, agitation power, and polymerisation temperature profile.
PVA 2699 can be converted into continuous film on chill-roll or steel-belt casting lines when the dry resin is first dispersed in cold water and then heated under shear to 90–95°C for 60–90 minutes. The casting solution is typically prepared at 10–15 wt% solids because the high molecular weight yields a Brookfield viscosity of 8,000–25,000 mPa·s at 60°C, which limits degassing and filtration. The solution is degassed under vacuum, filtered through 20–40 µm stainless steel mesh, and cast at 60–70°C onto a polished chrome-plated drum heated to 120–130°C. Films of 30–80 µm thickness produced from fully hydrolysed PVA exhibit tensile strengths of 50–65 MPa and elongation at break of 150–220% when conditioned at 23°C and 50% relative humidity and tested according to ASTM D882. The fully hydrolysed structure does not dissolve in cold water; it softens above 70°C and dissolves above 90°C when immersed with agitation. This property makes the film suitable only for hot-water-dissolvable release inserts or temporary stiffening applications, not for cold-water laundry bags. Plasticiser addition of 5–15 wt% glycerol reduces the glass transition temperature and lowers tensile strength, but increases blocking risk on the roll. Production lines should maintain film moisture at 3–5 wt% because overdrying below 2 wt% induces curl and brittleness, while moisture above 8 wt% causes blocking in roll form. For EU and US use, film intended as an indirect food-contact layer must comply with FDA 21 CFR 175.300 and EU 10/2011; documentation should confirm monomer residual and heavy metal limits.
In machine-applied gypsum plaster, PVA 2699 is added at 0.2–0.6 wt% of the dry mix to reduce water loss into highly absorbent substrates. At addition above 0.8 wt%, the high-viscosity aqueous phase retards setting and can produce surface tack on the trowel. Water retention is tested according to EN 13279-2 or GB/T 28627 under controlled vacuum; typical water retention values for PVA-modified plasters fall between 85% and 95%, depending on the base gypsum and cellulose ether dosage. The PVA should be dry-blended with the mineral fraction before water addition to prevent lumping.
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Ningxia Dadi PVA 2699 is a fully hydrolyzed polyvinyl alcohol resin whose grade code follows the conventional Chinese PVA nomenclature. The prefix 26 identifies a nominal degree of polymerization of 2600, and the suffix 99 identifies a nominal alcoholysis degree of 99.0 mol%. The resin is supplied as white to off-white granules or powder with bulk density commonly reported in the range of 0.40–0.60 g/cm³. It is intended for aqueous solution processing rather than direct melt extrusion; the as-received polymer is not melt-dispersible without plasticizer and controlled thermomechanical treatment. Dissolution requires hot water and shear, normally 85–95 °C, because the fully hydrolyzed acetate-to-alcohol conversion reduces cold-water affinity relative to partially hydrolyzed grades such as 2695. The combination of high molar mass and high hydrolysis degree raises solution viscosity, increases dry-film tensile strength, and reduces cold-water solubility relative to lower-DP or lower-hydrolysis PVA grades. Lot-specific release testing should be based on the supplier’s certificate of analysis; published data for Ningxia Dadi PVA 2699 as an independent grade is limited.
The representative grade-class specification matrix is shown below. Actual release limits are lot-specific and should be confirmed against the producer’s certificate of analysis.
| Property | Representative grade-class range | Test basis |
|---|---|---|
| Degree of polymerization | 2600 nominal | Viscosity-average molar mass; designation per ISO 15023-1:2017 |
| Alcoholysis degree | 99.0–99.8 mol% | Supplier certificate of analysis; titration method |
| Viscosity, 4% aqueous solution, 20 °C | 60–70 mPa·s | Rotating viscometer; protocol aligned with GB/T 12010.2-2010 |
| Volatile matter | ≤ 5.0% | Oven drying method |
| Ash content | ≤ 0.7% | Muffle furnace method |
| pH | 5–7 | pH meter on aqueous dispersion |
Release limits for ash and volatile matter can vary with production campaign and packaging type. For applications requiring food-contact compliance, the formulator must verify the supplier’s compliance declaration against the target market regulation, such as EU 10/2011 or FDA 21 CFR 175.300, because the base resin grade alone does not establish finished-article compliance.
For solution make-down, the 4% viscosity range of 60–70 mPa·s is a grade-class reference; at 8% solids, the viscosity increases disproportionately because chain entanglement in the concentrated regime scales with concentration raised to a power greater than one. High-shear mixing equipment should therefore be selected with a low-shear impeller sweep and a high-shear rotor-stator zone to break up partially swollen granules without creating excessive mechanical shear that can reduce molar mass. The temperature ramp should not exceed 2 °C/min below 90 °C; too-rapid heating produces a viscous skin on the granule surface that encloses dry polymer and forms fisheyes. Once the solution reaches 95 °C, a hold time of 30–45 min under moderate agitation is common in open kettles, but jet cookers with high turbulence can achieve full dissolution in 15–20 min. Filtering the solution through 60–100 mesh before use is a practical control for undissolved gel specks. These operating windows are equipment-dependent; published data for this specific grade in all mixer geometries is limited.
The nominal degree of polymerization 2600 places the product above PVA 1799, PVA 2099, and PVA 2499 in molar mass and solution viscosity. The fully hydrolyzed character remains close to PVA 1799 and PVA 2499, so the primary difference is rheological and film-strength related rather than alcoholysis related. A higher molar mass increases chain entanglement, which raises the 4% solution viscosity from approximately 25–31 mPa·s for PVA 1799 to 60–70 mPa·s for PVA 2699 under identical aqueous solution conditions. This increase permits lower use concentration in warp size and adhesive formulations, but it requires longer cooking time and more aggressive agitation. The comparative matrix below collates grade-class values commonly reported in technical data sheets; it is not a statement of equivalence across producers.
| Grade code | Nominal DP | Hydrolysis degree | Typical 4% solution viscosity at 20 °C | Processing implication |
|---|---|---|---|---|
| PVA 1799 | 1700 | 99.0–99.8 mol% | 25–31 mPa·s | Easier cold-water dispersion; lower film strength |
| PVA 2099 | 2000 | 99.0–99.8 mol% | 35–45 mPa·s | Intermediate viscosity; used in size blends |
| PVA 2499 | 2400 | 99.0–99.8 mol% | 50–60 mPa·s | High film toughness; slower dissolution |
| PVA 2699 | 2600 | 99.0–99.8 mol% | 60–70 mPa·s | Maximum viscosity in this series; highest dry-film tensile strength |
Published data for direct side-by-side comparison is limited; the table collates grade-class values commonly reported in technical data sheets rather than lot-specific release data. When Ningxia Dadi PVA 2699 is compared with a partially hydrolyzed 2695 grade, solubility and surface activity differ: 2699 requires higher dissolution temperature and yields films with higher water resistance, while 2695 hydrates more readily at lower temperature and is preferred where cold-water solubility or surface activity in emulsion polymerization dominates.
In cotton and polyester-cotton warp sizing, Ningxia Dadi PVA 2699 is cooked in a jet cooker or open kettle at 92–98 °C before delivery to the size box of a slasher. Size-box temperature is maintained at 85–90 °C to prevent surface skinning, and wet pick-up is controlled by squeeze-roll pressure of 8–12 kN/m across the warp width. At 4% solids, the grade yields a highly viscous solution with mild shear thinning; viscosity drift outside ±5% of the target value can shift add-on percentage and alter weaving efficiency. The high molar mass contributes to film toughness, but it also raises the minimum cooking temperature compared with PVA 1799, which must be considered when converting existing size-kitchen equipment from low-viscosity grades. Sized-yarn tensile retention is commonly assessed by ASTM D2256-22; abrasion resistance is evaluated on a loom or abrasion tester rather than by a single universal standard. Batch-to-batch viscosity variation is controlled by the supplier’s certificate of analysis, but mills operate under closed-loop size-box solids monitoring to compensate for evaporation and yarn water uptake. Overshooting the cook temperature above 98 °C for extended periods can induce polymer chain scission, which lowers size viscosity and weakens the sized yarn under high-speed weaving.
In vinyl acetate and vinyl acetate-ethylene emulsion polymerization, PVA protective colloids are usually selected from partially hydrolyzed grades because their residual acetate groups increase surface activity and reduce aqueous solution viscosity at equivalent molar mass. Ningxia Dadi PVA 2699 can be used when the dried adhesive film requires high water resistance or when the formulation can tolerate higher cook temperature and higher reactor viscosity. The polymer is dissolved in the water phase at 90–95 °C before radical initiation; insoluble gel particles must be removed by filtration through 80–120 mesh stainless steel screens to avoid seed instability. The high degree of hydrolysis increases the onset temperature of phase separation relative to partially hydrolyzed grades, and the solution must be held above 60–70 °C during transfer to prevent gelation. Reactor viscosity during polymerization may rise more rapidly than with 2695; published data for this specific configuration is limited, so pilot-scale evaluation is required before full production. Residual salt content, particularly sodium acetate from hydrolysis, can interact with ionic initiators and should be tracked against the certificate of analysis limit when reactor reproducibility shifts.
In packaging and paper-converting adhesives, Ningxia Dadi PVA 2699 is formulated with plasticizers such as glycerol or sorbitol, defoamer, and preservative to produce remoistenable or water-activated adhesive layers. A typical high-shear dispersion step uses a sawtooth dissolver with tip speed of 10–15 m/s at 80–90 °C; polymer is added slowly under vortex to prevent fish-eye formation. The high viscosity of the 4% solution supports adhesive film build on coaters running at 30–80 m/min, depending on rod or roll coating configuration. The fully hydrolyzed grade has limited solubility in alcohol-rich solvent blends; formulators should keep ethanol content below the point of polymer precipitation and avoid combination with borate ions, which can induce viscosity spikes and gelation through diol-borate complexation. Open time and set speed depend more on substrate absorptivity and plasticizer level than on polymer viscosity; formulation-specific testing per TAPPI T 441 om-20 for water resistance is required when moisture contact is specified. For remoistenable grades, dried film block resistance is affected by equilibrium moisture uptake above 60% RH, and storage in sealed polyethylene-lined sacks is recommended for the as-supplied resin.
Cast films from Ningxia Dadi PVA 2699 are evaluated after conditioning at 23 °C and 50% RH because moisture acts as a plasticizer and reduces tensile strength. Film tensile properties are measured according to ISO 527-3; the fully hydrolyzed backbone increases crystallinity and reduces equilibrium moisture regain relative to partially hydrolyzed grades, but the exact tensile modulus depends on drying temperature, draw ratio, and plasticizer content. Glycerol addition at 10–20 wt% lowers the glass transition and improves flexibility, but migration of plasticizer to the film surface can occur at relative humidity above 60%, changing surface tack and seal behavior. For water-soluble packaging applications, this grade dissolves slowly at 20–30 °C and more rapidly above 70 °C; if cold-water solubility is required, a partially hydrolyzed lower-DP grade should be substituted. The high crystallinity of the dried film also limits heat-seal initiation temperature and may require the addition of lower-hydrolysis PVA or polyethylene glycol to widen the seal window. Thickness control below 25–30 µm is critical when the film is used as an interleaving layer because uneven caliper creates local stress concentration during transverse stretching.
Surface sizing on a film press or rod metering size press uses Ningxia Dadi PVA 2699 at dry pick-up of 2–6 g/m² to improve surface strength, oil-holdout, and print quality on packaging grades and release base papers. The size solution is cooked separately and blended with oxidized starch at 10%–30% PVA on starch dry basis; continuous Brookfield or Viskomat viscosity measurement at 50 °C is used to maintain constant film-press transfer. High molar mass increases film-forming capability but also raises size-press misting at machine speeds above 1200 m/min; equipment with enclosed nip and mist extraction is preferable. The product’s fully hydrolyzed nature reduces rewetting and helps meet oil-holdout requirements measured by TAPPI T 559 or ISO 16532-1 for grease resistance. Overdosing above the starch compatibility limit can produce film splitting and rod streaks; a jar test at target solids and temperature is a standard pre-run control. Addition of a defoamer is often required because high-viscosity size solutions entrain air during return-flow pumping, and entrained air reduces size-press metering uniformity.
In alkaline textile or paper formulations, PVA 2699 is sensitive to chromophore-forming degradation reactions when the size-kitchen pH exceeds 9 and the cook temperature remains above 95 °C for more than 2–3 h. The fully hydrolyzed backbone can undergo chain scission and oxidation at the secondary alcohol positions, producing conjugated unsaturation and a yellow-brown tint. The degradation rate is influenced by dissolved oxygen, alkali concentration, and the presence of starch or reducing sugars; closed cookers with nitrogen blanketing and temperature control below 95 °C reduce viscosity loss. Because the 2699 grade has a higher initial viscosity, the relative viscosity loss after thermal aging is more visible than in lower-DP grades. Processors using caustic starch thinning should avoid simultaneous PVA addition until the starch slurry is neutralized or cooled, as the combination of high pH and high temperature accelerates polymer degradation. If the final size film exhibits discoloration, the fault is commonly traced to alkali over-addition rather than to the PVA resin itself.
Storage of Ningxia Dadi PVA 2699 should follow closed-warehouse conditions at 5–35 °C and relative humidity below 60% RH. The resin is hygroscopic; moisture uptake increases caking tendency and can reduce the accuracy of gravimetric dosing. The product is not classified as a hazardous substance under GHS in the supplier’s safety data sheet, but airborne dust can form combustible dust clouds. Handling systems should use conductive grounding and dust extraction designed for organic particulate, with an ignition source excluded from the vicinity of open bag unloading. Pallets should not be stacked more than the supplier’s specified layer count because granule compaction under load increases the proportion of fused agglomerates that require longer cook times. Where high-humidity ambient conditions exceed 60% RH, the resin should be kept in sealed polyethylene-lined sacks and conditioned before use only to the extent necessary to avoid static discharge.
