| HS Code | 315850 |
| Appearance | White granular powder |
| Degree Of Alcoholysis | 99.8-100.0 mol% |
| Viscosity 4 Solution 20 C | 20.0-30.0 mPa·s |
| Average Degree Of Polymerization | 1700 |
| Molecular Weight | Approximately 74,800 g/mol |
| Density | 1.27-1.31 g/cm³ |
| Bulk Density | 0.4-0.6 g/cm³ |
| Melting Point | 230°C |
| Water Solubility | Soluble in water above 80°C |
| Ph 4 Solution | 5.0-7.0 |
| Volatile Content | ≤5.0% |
| Ash Content | ≤0.5% |
As an accredited Ningxia Dadi PVA 1799 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Ningxia Dadi PVA 1799 is supplied in 25 kg multi-layer paper bags with an inner polyethylene liner for safe, dry storage. |
| Container Loading (20′ FCL) | 20′ FCL container loading for Ningxia Dadi PVA 1799: 25kg bags palletized, shrink-wrapped, secured to prevent shifting during transit. |
| Shipping | Ningxia Dadi PVA 1799 is shipped in sealed, moisture-proof kraft paper or woven bags, typically 25 kg each. It should be transported in clean, dry containers or vehicles, avoiding rain, humidity, and direct sunlight. Handle gently to prevent bag damage, and store in a cool, ventilated warehouse away from ignition sources. |
| Storage | Store Ningxia Dadi PVA 1799 in a cool, dry, well-ventilated area, away from direct sunlight, heat sources, and open flames. Keep containers tightly sealed to prevent moisture absorption and contamination. Avoid contact with strong oxidizers. Maintain stable temperatures and low humidity. Under proper conditions, the product remains stable for 12 months from manufacture date. |
| Shelf Life | Shelf life is approximately 2 years when stored in a cool, dry, well-ventilated area away from moisture. |
In vinyl acetate homopolymer and vinyl acetate-ethylene copolymer emulsion trains where Ningxia Dadi PVA 1799 with 99 mol% hydrolysis and a 1,700 degree-of-polymerization backbone is specified as the primary protective colloid, a 4.0 wt% aqueous stock solution prepared at 90–95 °C in a jacketed dissolver equipped with a 1,500 rpm turbine agitator is metered into the aqueous phase at 2.5–5.0 phm of vinyl acetate monomer. The high-viscosity colloid network suppresses droplet coalescence during delayed monomer feed in a 5,000 L glass-lined reactor fitted with a retreat-curve impeller operating at 72–78 °C, with persulfate-tartaric acid redox initiation controlling free-monomer conversion below 0.3 wt% before post-polymerization stripping. Residual grit larger than 150 µm is removed through an 80-mesh stainless steel in-line filter, and emulsion viscosity at 20 rpm and 25 °C is adjusted only after confirmatory free-monomer analysis, because alkali addition onto unpolymerized vinyl acetate accelerates saponification and generates ethyl acetate off-notes in the dried film. Terminal adhesive grades classified under EN 204 D3 and D4 for load-bearing wood assembly are produced, alongside paper-tube laminating adhesives and foil-to-paper laminating systems. Compliance for indirect food-contact laminated substrates references 21 CFR 175.105 for adhesive components, with residual vinyl acetate monomer held at 5 mg/kg maximum in the dry film and REACH Annex XVII restrictions applied to monomer handling. The principal process boundary is the partial gelation of PVA 1799 at pH below 4.5; visible seed gel can form in the monomer feed line, so neutralization to pH 5.0–6.0 with sodium bicarbonate before colloid addition is mandatory, and prolonged storage of the aqueous stock above 70 °C increases viscosity drift due to thermal cleavage of acetyl residues.
Cementitious dry-mix batches for C2TE classified tile adhesives under EN 12004-1:2017 are produced by dry-blending PVA 1799 into a 1,200 kg twin-shaft paddle mixer at 0.3–0.8 wt% of dry mix, with a typical production window of 0.5 wt% when open time and early strength must be balanced. Field data from horizontal ribbon blenders and twin-shaft paddle mixers indicates that addition above 1.0 wt% on cement mass entrains air beyond 8 vol%, reduces 28-day compressive strength on ASTM C109/C109M-21 cubes by more than 10% relative to control, and reverses the flexural gain measured on ASTM C348-21 prisms. Open time measured by EN 1346:2007 at 23 °C and 50% RH extends from 20 min to 30–35 min at the 0.5 wt% dosage, while slip resistance and tensile adhesion after water immersion remain within the ISO 13007-2:2013 acceptance limits for C2 products. The downstream production process incorporates PVA 1799 as a pre-blend with cellulose ether, calcium formate, and limestone filler; after water addition, the mortar is mixed at 600–900 rpm for 3 min, matured for 5 min, and remixed for 1 min to fully hydrate the polymer film. Storage above 60% RH requires moisture-protective packaging because partially hydrolyzed polyvinyl alcohol grades absorb water vapor and agglomerate in the dry blend, causing lumps in the mixed mortar. Terminal product types include large-format porcelain tile adhesives, thin-bed repair mortars, and base-coat formulations for external thermal insulation composite systems, where the polymer contributes water retention, wet-out on low-absorption substrates, and controlled open time without displacing the hydraulic binder matrix.
Size paste formulation for 65/35 polyester-cotton warp yarns contains 8–12 wt% PVA 1799 on paste weight, with a target size add-on of 9–13 wt% on dry yarn for high-density looms running at 650–850 rpm. The paste is cooked in an atmospheric 1,500 L size kettle at 95 °C for 30–40 min until it passes a 75 µm negative-pressure filter without gel particles, then supplied to a single-end sizing machine with a size box maintained at 85–90 °C. Squeeze nip pressure is set at 20–35 kN/m to achieve the specified add-on, while dry-can surface temperature is stepped from 110 °C to 60 °C to prevent surface skinning and maintain yarn elongation. Warp hairiness and tensile integrity are verified by ASTM D2256/D2256M-21 singles yarn tensile testing, with linear density checked by ISO 2060:1994; loom shed stability improves when the sized yarn retains 1.5–2.5% moisture and the weaving room is controlled at 60–70% RH and 25–28 °C. Compliance for fabric safety references OEKO-TEX Standard 100 Annex 4 Class I limits for textile auxiliaries, and the sizing house operates under the ZDHC MRSL 3.0 prohibition on alkylphenol ethoxylates and intentionally added perfluorinated compounds. Desizing effluent carries a high chemical oxygen demand from PVA 1799; ultrafiltration recovery at 80–90 °C achieves 60–80% recovery efficiency depending on wax and fiber fragment contamination in the wash water. Terminal product types include high-count woven outerwear, industrial workwear, and tightly constructed bed sheeting, where the fully hydrolyzed film former provides abrasion resistance during weaving and is removed before dyeing or printing to avoid uneven color uptake.
At a 1.5 wt% PVA 1799 addition on starch dry basis in a puddle size press running 400–700 m/min, the size solution is held at 60–70 °C to maintain apparent viscosity between 30–50 mPa·s at 100 s⁻¹. The film-forming fraction lowers Cobb 60 s water absorption on ISO 535:2023 from 45 g/m² to 25–30 g/m² on recycled linerboard while preserving Scott bond internal strength within TAPPI T 569 specifications for folding cartons. Compliance for food-contact packaging follows 21 CFR 176.170 for components of paper and paperboard in contact with aqueous and fatty foods, and EC 1935/2004 requires overall migration below 10 mg/dm² for the finished sheet. The production process requires separate PVA 1799 dissolution at 90–95 °C in a high-shear batch cooker, cooling to 60 °C, and dosing into starch makedown before the size press; ammonium zirconium carbonate crosslinker at 0.1–0.2 wt% of size solids increases wet-rub resistance but reduces repulpability, so no crosslinker is used for repulpable grades. Trace borax contamination causes instantaneous gel-ball formation in the size press feed line and must be controlled by excluding borate-based preservatives; system cleanout uses hot 1.0 wt% sodium hydroxide at 80 °C to restore flow. Terminal product types include recycled folding carton stock, gypsum board liner with improved surface strength, and corrugated medium where the surface sizing layer reduces linting during high-speed printing and converting.
Alumina tape casting binder preparation with PVA 1799 begins by dispersing a 6–10 wt% aqueous stock solution into an aqueous or non-aqueous ceramic slurry at 2–5 dry wt% of ceramic powder, alongside dispersant, plasticizer, and defoamer. The slurry is vacuum-degassed at 20–50 mbar for 10–20 min before casting through a doctor blade with a gap of 200–400 µm onto silicone-coated polyethylene terephthalate carrier film at 0.3–1.0 m/min. Drying is staged at 25 °C for 4 h and 40 °C for 12 h to avoid skin-over and edge curling, after which the green tape is punched, laminated, or vias filled. Binder burnout follows a ramp of 0.5 °C/min to 550 °C with a 2 h hold; residue content is verified by thermogravimetric analysis in air referencing ISO 11358-1:2022, with ash held below 0.05 wt%. Published data for this specific configuration is limited, but production-scale green tape tensile measurements per ISO 527-3:2018 typically fall between 2 MPa and 4 MPa at 50 µm green thickness, sufficient for multilayer punching and fine-line via formation. Terminal product types include alumina substrates for power electronics, piezoelectric ceramic discs, and multilayer ceramic capacitor green sheets. The operational boundary is calcium ion contamination: soluble calcium above 0.5 wt% in the slurry induces viscosity build and microgel formation through polymer-bridging interactions, so sequestering agents or deionized water are mandatory when the ceramic powder leaches divalent cations.
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Ningxia Dadi PVA 1799 is a fully hydrolyzed polyvinyl alcohol resin produced by alcoholysis of polyvinyl acetate, with a nominal degree of polymerization of 1700 and a nominal alcoholysis degree of 99.0 mol%. The grade designation follows the conventional PVA coding system: the prefix “17” denotes the nominal degree of polymerization divided by 100, and the suffix “99” denotes the nominal degree of hydrolysis in mole percent. The high alcoholysis level leaves residual acetyl groups typically below 1.0 mol%, producing a semi-crystalline polymer with dense intermolecular hydrogen bonding. The product is supplied as white to off-white granules or powder; particle size distribution varies by packaging lot, and bulk density is commonly in the range 0.45–0.60 g/cm³. The viscosity-average molecular weight is approximately 74,000–79,000 g/mol based on the nominal degree of polymerization. The material is characterized under JIS K6726 and related GB/T 12010 methods. Representative industrial release ranges are presented in Table 1; these ranges are not a substitute for a batch-specific certificate of analysis.
| Parameter | Unit | Typical range or release value | Test method |
|---|---|---|---|
| Degree of alcoholysis | mol% | ≥99.0 | JIS K6726 |
| Viscosity of 4% aqueous solution at 20°C | mPa·s | 25.0–31.0 | JIS K6726 |
| Volatile matter | wt% | ≤5.0 | JIS K6726 / GB/T 12010.3 |
| Ash content | wt% | ≤0.5 | JIS K6726 / GB/T 12010.3 |
| pH of 4% solution | — | 5.0–7.0 | JIS K6726 |
| Degree of polymerization | — | 1700±50 | calculated from viscosity, JIS K6726 |
Compared with partially hydrolyzed grades, the 99.0 mol% hydrolysis level reduces the number of residual acetyl side groups that would otherwise disrupt crystallization and water uptake. This gives PVA 1799 higher tensile strength in dried films, lower hygroscopicity after drying, and higher hot-water resistance than PVA 1788 or PVA 1792. At the same time, the fully hydrolyzed structure raises the temperature required for complete dissolution and increases the tendency to form gel skins at the solution surface. These trade-offs define the applications in which PVA 1799 is preferred: textile warp sizing, paper surface sizing, polyvinyl butyral feedstock, emulsion polymerization, and high-strength adhesive compounding. A comparative summary of common PVA grades is given in Table 2. The values in Table 2 are representative typical ranges for commercial PVA grades and should be confirmed with individual producer certificates; published data for specific Ningxia Dadi configurations may differ.
| Grade | Nominal hydrolysis | Nominal degree of polymerization | 4% solution viscosity | Cold-water behavior | Primary processing limitation |
|---|---|---|---|---|---|
| PVA 1799 | ≥99.0 mol% | 1700 | 25.0–31.0 mPa·s | requires heating to ≥90°C | high viscosity above 10% solids |
| PVA 1788 | 87.0–89.0 mol% | 1700 | 20.0–26.0 mPa·s | partial dispersion at 25°C | lower film strength |
| PVA 1792 | ≥92.0 mol% | 1700 | 22.0–28.0 mPa·s | requires warm water | intermediate moisture sensitivity |
| PVA 2099 | ≥99.0 mol% | 2000 | 38.0–45.0 mPa·s | requires heating to ≥90°C | long dissolution time, high mixing torque |
| PVA 2488 | 87.0–89.0 mol% | 2400 | 44.0–50.0 mPa·s | partial dispersion at 25°C | high thickening, difficult coating |
Cold-water dissolution is limited primarily by the dense inter- and intra-chain hydrogen-bond network of the fully hydrolyzed backbone. At 25°C water temperature, PVA 1799 granules swell but do not yield a clear solution; complete dissolution requires sustained heating to 90–95°C under high-shear agitation. Production-scale preparation commonly employs a jacketed 316L stainless steel mixing vessel with a high-shear disperser and a recirculation loop through a 100-mesh screen. Dry powder is introduced through an inductor into the vortex to prevent fisheye formation, a condition in which wetted but undissolved granules develop a gelatinous outer layer that blocks further water diffusion. For a 4 wt% solution, cooking time at 95°C is typically 30–45 min; complete dissolution is judged by visual clarity and absence of gel particles on the screen. After dissolution, the solution is held at 60–70°C for immediate use or transferred through heat-traced lines because viscosity rises sharply on cooling.
Direct steam injection without forced circulation is not recommended because localized temperatures can exceed 100°C and produce gel aggregates. The viscosity of a 10 wt% solution at 20°C may exceed 1000 mPa·s, so transfer lines, pumps, and filters should be sized for high-viscosity service and heated to at least 70°C. At concentrations above 12 wt%, gelation can occur during cooling even before the solution reaches room temperature. Published data for exact dissolution time as a function of mixer tip speed at full production scale for this specific grade are limited; plant trials are required to define the shortest heating time consistent with downstream filtration and coating.
PVA 1799 is hygroscopic and is not soluble in cold water or common organic solvents such as ethanol, acetone, and toluene. Borax, boric acid, and certain metal salts such as cupric salts can form strong hydrogen-bonded networks with the hydroxyl groups and should be avoided where solution stability is required. Strong oxidizing acids and strong bases at elevated temperature promote chain scission and discoloration. The dust generated during handling is combustible and should be controlled in accordance with NFPA 654 or equivalent facility safety standards.
In warp sizing of cotton, polyester/cotton, and high-count blended yarns, PVA 1799 is used to produce a tough size film with low cold-wet tack and good abrasion resistance. Size box solids are typically maintained at 7–10 wt%, with size box temperature at 70–80°C. Viscosity at the size box is commonly measured with a Zahn cup #3; a working range of 6–10 s is used on conventional two-roll squeeze sizing machines. At add-on levels of 8–12% dry weight on yarn, the dried film withstands reed impact and abrasion on air-jet and rapier looms. In starch-blended formulations, PVA:starch ratios between 30:70 and 40:60 are common; the PVA fraction improves film cohesion and reduces dusting during weaving. Size film tensile strength can be evaluated on cast films according to ASTM D638-14; reported values above 40 MPa are achievable in formulated films, but direct correlation with weaving performance depends on add-on uniformity and loom conditions.
Desizing is a key operational boundary. The fully hydrolyzed grade requires hot-water desizing at ≥70°C, commonly assisted by oxidative agents such as hydrogen peroxide at 2–4 mL/L or sodium persulfate at 1–3 g/L. Incomplete desizing can cause stiffness in finished fabric and dyeing nonuniformity. Compared with PVA 1788, grade 1799 exhibits lower cold-water sensitivity and higher tensile strength but raises the minimum desizing temperature and may increase desizing energy demand.
Paper surface sizing formulations have incorporated PVA 1799 at 2–5 wt% of size press solids in starch-based systems to increase surface strength and reduce linting on linerboard and corrugating medium. On a puddle or rod-metered size press, the fully hydrolyzed grade forms a film that contributes to surface pick resistance. TAPPI T441 om-90 60-s Cobb values measured on linerboard can be reduced by 10–20% when PVA replaces a portion of starch, although the result depends on internal sizing level, base sheet porosity, and size press pickup. The high solution viscosity of PVA 1799 restricts its use in high-solids size press formulations; above 8 wt% PVA in the size press solution, transfer and leveling problems have been observed on flooded-nip machines. The grade is more suitable where film strength and lint reduction are valued, and less suitable where the primary objective is deep penetration into the sheet.
Addition levels in vinyl acetate and vinyl acetate-ethylene emulsion polymerization typically fall between 2–5 wt% based on monomer. The fully hydrolyzed high-DP grade contributes to high latex viscosity, shear stability, and adhesion to polar substrates, but requires complete pre-dissolution at 85–90°C before reactor charging. Polymerization temperature is usually maintained at 60–80°C; during radical polymerization the PVA does not function only as a steric stabilizer but also undergoes grafting, which influences particle size distribution and latex rheology. If undissolved gel particles enter the reactor, they can create filter-blocking coagulum and batch-to-batch viscosity drift. Compared with PVA 1788, grade 1799 yields higher final latex viscosity at equal colloid loading, may reduce thickener demand, but increases the risk of shear-induced gelation during devolatilization and transfer.
The process window narrows at the upper temperature limit; above 80°C partial degradation of the PVA backbone in the aqueous phase can increase discoloration and reduce protective efficiency. Brookfield viscosity of the final latex may exceed 10,000 mPa·s at moderate shear depending on solids content and colloid loading. Published data for grafting efficiency specific to Ningxia Dadi PVA 1799 in vinyl acetate-ethylene systems are limited, so bench-scale grafting and latex stability studies are necessary before commercial formulation lock-in.
For polyvinyl butyral resin production, PVA 1799 is dissolved in demineralized water at 10–12 wt% and 90–95°C, then acetalized with butyraldehyde under acid catalysis. Low ash and low residual acetyl content are critical because inorganic residues and unconverted acetate groups affect haze, yellowness index, and electrical properties of the resulting PVB interlayer. Ash content in the feedstock should be ≤0.5 wt%; for optical interlayer applications, lower-ash variants or additional washing are often specified. The high degree of polymerization provides high intrinsic viscosity to the PVB resin, which translates into elevated glass interlayer stiffness and penetration resistance. In adhesive compounding, PVA 1799 is used to formulate water-resistant adhesives for paper and board where hot-water removal is acceptable. Typical formulated adhesive solids are 10–20%, with plasticizer such as glycerol at 10–20 wt% based on PVA, and preservative where storage conditions require.
Dried PVA 1799 begins to show thermal discoloration above 180°C in air; thermogravimetric analysis under nitrogen generally records the main decomposition onset near 200°C, with the exact value depending on heating rate and residual moisture. For PVB feedstock, ash residue is often measured by combustion at 550°C according to JIS K6726 or equivalent; the fully hydrolyzed grade can exhibit ash values up to 0.5 wt% unless additional washing is applied. Sodium acetate, the main residual ash component, is a potential haze promoter in optical PVB film and must be monitored in incoming lots. The product should be stored in sealed containers below 30°C and protected from moisture; caking and microbial growth may occur at relative humidity above 60%. Pre-drying at 60°C for 2–4 h is sometimes necessary before compounding.
For food contact and pharmaceutical applications, the specific PVA grade and final packaging article must be assessed under FDA 21 CFR 177.1670 or EU Regulation 10/2011 as applicable; standard industrial PVA is not automatically compliant. REACH registration status should be confirmed with the supplier for the intended market. These regulatory boundaries are process-critical when the resin is specified for indirect food packaging or moisture-barrier coatings.
Cast film from PVA 1799 exhibits high tensile strength but requires plasticization to avoid brittleness. Glycerol or sorbitol is added at 15–25 wt% based on PVA; films cast from such formulations can show tensile strengths above 40 MPa when tested according to ASTM D638-14, with elongation at break typically in the range 80–150% depending on plasticizer content and relative humidity. The fully hydrolyzed grade yields films that remain water-resistant at room temperature but dissolve in water above 80°C; this property is used in hot-water-soluble release films and specialty packaging. Film performance is highly dependent on drying conditions and final moisture content; conditioning at 50% RH and 23°C is required before tensile testing. Differences from lower-viscosity grades such as PVA 1792 include higher solution viscosity and higher film strength, but the high molecular weight also makes defoaming and coating more difficult at high solids. Published data for Ningxia Dadi PVA 1799 in cast film formulations are limited; laboratory evaluation is required before production specification.
