| HS Code | 950043 |
| Appearance | White or slightly yellowish powder or granules |
| Degree Of Polymerization | 1700 ± 100 |
| Alcoholysis Degree | 88.0 ± 1.0 mol% |
| Viscosity 4 20c | 20.0 - 28.0 mPa·s |
| Volatile Content | ≤ 5.0% |
| Ash Content | ≤ 0.5% |
| Ph Value 4 Solution | 5.0 - 7.0 |
| Whiteness | ≥ 90% |
| Particle Size | ≥ 95% passes through 40 mesh (0.425 mm) |
| Residual Acetyl Group | ≤ 12.0 mol% |
| Bulk Density | 0.45 - 0.60 g/cm³ |
| Water Solubility | Soluble in water at 80 - 90 °C |
As an accredited Shuangxin XW-I PVA factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Shuangxin XW-I PVA is supplied in 25 kg multi-layer paper bags with a plastic inner lining for safe handling and storage. |
| Container Loading (20′ FCL) | Shuangxin XW-I PVA loaded in a 20′ FCL, securely palletized, properly sealed to prevent moisture damage. |
| Shipping | Shuangxin XW-I PVA is shipped in moisture-proof, sealed multi-layer bags or drums to protect its powder form. Transport should avoid rain, humidity, and extreme heat. Keep away from ignition sources and incompatible materials. Handle gently to prevent bag damage, ensuring product purity remains intact during transit. |
| Storage | Store Shuangxin XW-I PVA in a cool, dry, well-ventilated area away from direct sunlight, heat, and open flames. Keep the container tightly sealed to prevent moisture absorption. Avoid contact with oxidizing agents. Use appropriate handling precautions, and maintain good housekeeping. Follow manufacturer’s shelf-life recommendations for optimal performance. |
| Shelf Life | Shelf life is approximately 12 months when stored unopened in original packaging in a cool, dry place. |
In cotton, polyester/cotton, and spun viscose warp preparation, XW-I is introduced as a film-forming size resin whose cook concentration depends on the sizing machine’s solids-control loop and the fibre blend. The size-box solids are held between 4.0% and 8.0% for high-density cotton warps; replacement of native starch at 15% to 30% of dry size solids reduces shed sticking on high-speed air-jet looms without sacrificing tensile protection. The polymer is slurried in cold water at 25°C to 35°C in a high-turbulence jet cooker, heated to 93°C to 96°C under mechanical shear, and held for 25 min to 30 min until no undissolved granules remain when a film is drawn on a glass plate. Wax-based lubricants at 0.2% to 0.5% on dry solids and pressure-stable antifoam at 0.05% to 0.15% are metered into the storage kettle; the sizing machine’s prewetting and squeeze pressure are adjusted to a pick-up of 8% to 12% for ring-spun cotton. Drying cylinder surface temperature is maintained below 135°C for partially hydrolysed grades because film thermoplasticity can otherwise transfer size film to the cylinders and generate warp streaks. On the loom, sized yarn is conditioned at 22°C to 25°C and 65% to 70% relative humidity before weaving; yarn tenacity retention and abrasion resistance are measured according to ISO 2062 and ISO 12947-2 where the buyer specification requires. Desize effluent is handled under the mill’s existing COD consent because PVA contributes dissolved organic carbon that can persist in conventional activated sludge; anaerobic/oxic sequencing or recovery by ultrafiltration may be required under local discharge permits. Export formulations are screened under ZDHC MRSL v3.1 for restricted surfactants and size additives; waxy lubricants and emulsifiers in the total size package, rather than PVA alone, commonly determine MRSL status. The terminal product is sized warp beams for plain, twill, or dobby constructions in shirting, workwear, and home-textile fabric.
Because protective colloid molecular weight distribution controls both latex viscosity and shear stability, XW-I is charged as an aqueous solution in semicontinuous vinyl acetate emulsion polymerisation at 70°C to 80°C. The normal colloid addition is 2.0% to 6.0% based on total monomer, with the lower range used for low-viscosity laminating emulsions and the upper range for wood-working adhesives that require high wet tack. On production-scale jacketed reactors of 10 m³ to 20 m³, an initial XW-I solution at 8% to 12% solids is charged before monomer addition; impeller power draw is monitored during the first 15 min because viscosity rise can exceed the anchor agitator’s torque limit if the initial charge is too high. An initial 5% monomer precharge is polymerised before the remaining vinyl acetate is fed semicontinuously over 3 h to 5 h; a peroxide or persulfate initiator is used, and the reaction is held to below 0.2% residual vinyl acetate monomer, measured by headspace gas chromatography according to ISO 13741-1. Defoamer additions are kept below 0.1% because excessive surfactant can compete with the protective colloid and widen particle size distribution. The resulting anionic or nonionically stabilised dispersion can be evaluated for food-contact adhesive applications under FDA 21 CFR 175.105 and for paper and paperboard use under FDA 21 CFR 176.170 and 176.180, subject to the extraction limits and the resin’s residual monomer specification. The terminal output is a VAE or PVAc homopolymer dispersion for furniture assembly, paperboard lamination, and wood-working glue.
For a unit-dose detergent film, XW-I is dissolved at 10% to 18% solids in deionised water at 80°C to 95°C, then cooled to 50°C to 60°C for casting. Glycerol or sorbitol plasticiser is added at 10 to 20 phr on dry PVA to reduce brittleness after the film dries; silicone-free defoamer is used at 0.05% to 0.2% because surface defects on the cast film directly degrade seam strength. The dope is cast onto a chromium-plated belt or stainless steel drum at 75°C to 95°C surface temperature, and residual film moisture is brought to 8% to 12% before slitting and converting. Cold-water disintegration is limited by the alcoholysis degree and the crystallinity of the cast film; partially hydrolysed grades below 88 mol% alcoholysis generally dissolve more readily at 20°C, but published data for the XW-I grade in this specific cast-film configuration is limited, so end-users should generate a dissolution curve at 10°C and 20°C rather than relying on generic PVA values. Borate-containing detergent salts should not be placed in direct contact with the film because borate crosslinks the PVA and produces water-insoluble skins that fail to disintegrate in the wash. The film is not automatically food-contact-compliant; European migration evaluations under EU 10/2011 and Regulation (EC) 1935/2004 are only relevant where the film is placed in direct food contact. Industrial laundry unit-dose films are typically screened for ready biodegradability using OECD 301B and for residual vinyl acetate monomer using an internal gas chromatographic protocol aligned with ISO 13741-1. The terminal product is a heat-sealed water-soluble sachet for detergents, agrochemical preweighed packs, or dyestuff release packaging.
When surface sizing is applied on a puddle or metered size press, XW-I is combined with oxidised starch and added at 0.5% to 2.0% of dry fibre mass as a surface strength binder and hold-out agent. The size press starch is cooked to 18% to 20% solids, then XW-I solution at 8% to 12% solids is mixed into the starch batch at 50°C to 70°C; the press roll nip is set to deposit 1.5% to 3.0% dry add-on. Borax can be used at 0.1% to 0.3% on dry starch to increase viscosity and surface film cohesion, but levels above 0.5% can produce gel bodies that plug size press screens and create film split defects. The treated sheet is dried on cylinders below 120°C; high drying temperatures can carry PVA film to the dryer can surface and cause picking. Paper grades for food contact are evaluated under FDA 21 CFR 176.170 and 176.180 extraction limits and under the German BfR Recommendation XXXVI for fine paper and board; overall migration testing follows EN 1186 where EU 1935/2004 compliance is requested. Surface strength and liquid resistance are measured by IGT pick testing to ISO 3783, Cobb water absorption to ISO 535, and Parker Print Surf roughness to ISO 8791-4. Terminal products include white-top linerboard, sack paper, inkjet office paper, and folding boxboard with improved lint resistance and print density.
Spiral-wound paper tube lamination and carton side-seam assembly require a high-viscosity PVA solution that wets the fibre surface quickly and retains tack after application. XW-I is cooked at 8% to 15% solids in a jacketed make-down vessel at 90°C to 95°C, then cooled to 40°C to 50°C before adhesive application. Glycerol or sorbitol at 5 to 15 phr reduces film brittleness; defoamer is limited to 0.05% to 0.2%. Borax addition at 0.1% to 0.5% based on dry PVA increases wet tack and clean-running viscosity, but overdosing produces a rubbery gel that cannot be transferred by glue wheels. To meet EN 204/205 D3 durability after 4 days of water immersion, the formulation may require a glyoxal or zirconium salt crosslinker; glyoxal requires the pH to be held between 3.5 and 4.5 and pot life must be validated on the production line, because viscosity drift after crosslinker addition is the main batch failure mode. Cationic wet-strength resins and amine-based additives should not be mixed with XW-I solution because ionically driven precipitation occurs and blocks transfer lines. Adhesives intended for food-contact carton side seams are evaluated under FDA 21 CFR 175.105, and finished paper-core crush strength is tested according to ISO 11093-9. The terminal product is a converted paper tube, laminated multi-wall bag, or carton side-seam bond for packaging lines operating at 20 m/min to 60 m/min.
| Application segment | Reference method or specification | Measured parameter | Typical test condition |
|---|---|---|---|
| Warp sizing | ISO 2062 | yarn tenacity retention | 22°C, 65% RH |
| Paper surface sizing | ISO 535 | Cobb water absorption | 60 s contact, 23°C |
| Water-soluble film | OECD 301B | ready biodegradability screening | 28 days, 22±2°C |
| Adhesives | EN 204/205 D3 | bond strength after water immersion | 4 days immersion, 23±2°C |
| Emulsion polymerisation | ISO 13741-1 | residual vinyl acetate monomer | headspace gas chromatography |
In gypsum-based skim coats, C1T tile adhesives, and wall putty dry mixes, XW-I is dry-blended with fillers, cellulose ether, and calcium formate or other accelerators at 0.1% to 0.5% of the total dry formulation weight. The addition range is narrow because PVA acts as a water-soluble film former rather than a redispersible latex powder; above 0.5% the mix can become sticky under trowel shear and may increase surface tack after drying. Batch mixing is carried out in a horizontal paddle mixer or continuous twin-screw dry mixer at 20°C to 30°C; the PVA powder should be preblended with fine calcium carbonate to prevent balling and ensure dispersion when water is added. The mixed mortar is applied as a skim coat or tile adhesive bed; open time, slip resistance, and tensile adhesion are tested according to ISO 13007-1 and ISO 13007-2 for tile adhesives, while gypsum plaster consistency and setting time follow EN 13279-1 and EN 13279-2. Formaldehyde and VOC emission requirements for indoor wall treatment products in the EU are controlled under the Construction Products Regulation and related national schemes; Chinese interior wall putty is screened against GB 18582 limits where applicable. The terminal product is a hand-applied or machine-applied gypsum skim coat or a polymer-modified tile adhesive layer for interior walls and floors.
Dry-pressed ceramic bodies acquire green strength through temporary binder films; XW-I is therefore introduced as an aqueous binder solution at 1.0% to 2.5% concentration in alumina, zirconia, and silicon carbide powder processing. The binder solution is added during slurry preparation before spray drying; the slurry is atomised in a rotary or nozzle spray dryer with inlet air at 180°C to 220°C and outlet air at 90°C to 110°C, producing free-flowing granules with controlled moisture for die filling. Uniaxial pressing is performed at 80 MPa to 150 MPa depending on the ceramic system; green density is measured by Archimedes method according to ISO 18754 before sintering. The PVA binder must be removed during the debinding step before densification; a slow ramp of 2°C/min to 5°C/min up to 600°C with a 1 h to 2 h hold in air is typical, because oxygen-starved burnout can leave carbon residue that reduces sintered translucency or electrical performance. Debinding off-gas is treated through an oxidiser or thermal afterburner under local air permit limits. The terminal product is a pressed green body for electronic ceramic substrates, oxygen sensors, valve plates, or cutting tool blanks.
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Shuangxin XW-I PVA is a polyvinyl alcohol resin grade supplied by Shuangxin for aqueous formulation and selective thermoplastic conversion. The product designation XW-I identifies a single resin type within the manufacturer’s PVA portfolio; batch-specific certification data should be obtained from the certificate of analysis because published third-party data for this exact grade remains limited. Polyvinyl alcohol resins are characterised by the degree of hydrolysis of polyvinyl acetate to PVA, the viscosity of a defined aqueous solution, residual acetate content, ash, volatile matter, and pH. The model code XW-I does not itself state viscosity or hydrolysis; users should verify whether the grade falls within a partially hydrolysed, medium-viscosity class by referencing the manufacturer’s technical data sheet and ISO 15023-2:2019 property designations. The product is typically supplied as white granules or powder and is used in textile warp sizing, paper surface sizing, aqueous adhesive compounding, emulsion polymerisation stabilisation, and water-soluble packaging film.
Acceptance testing for PVA grades of this type should follow the property set given in ISO 15023-2:2019. The usual certificate-of-analysis entries are degree of hydrolysis, 4 wt% aqueous solution viscosity at 20 °C, volatile matter, ash residue, and pH of a defined aqueous solution. Viscosity is measured with a Brookfield LV viscometer at 60 rpm using a spindle selected for the expected range; reported units are mPa·s. A partially hydrolysed PVA grade will typically show degree of hydrolysis in the 86.0–89.0 mol% band, with a 4% solution viscosity of 20.0–30.0 mPa·s for medium-viscosity types; a fully hydrolysed PVA will show 98.0–99.0 mol% hydrolysis and may require heating above 85 °C to dissolve completely. However, XW-I-specific values must not be assumed from these class intervals. Table 1 gives the analytical methods used to assess each parameter and the typical PVA class envelope for a partially hydrolysed, medium-viscosity resin.
| Parameter | Method | Typical partially hydrolysed medium-viscosity envelope | XW-I specific value |
|---|---|---|---|
| Degree of hydrolysis | ISO 15023-2:2019 | 86.0–89.0 mol% | Confirm against batch certificate |
| 4 wt% solution viscosity at 20 °C | Brookfield LV, 60 rpm | 20.0–30.0 mPa·s | Confirm against batch certificate |
| Volatile matter | ISO 3251:2019 | ≤5.0 wt% | Confirm against batch certificate |
| Ash residue | ISO 3451-1 | ≤0.5 wt% | Confirm against batch certificate |
| pH of 4% aqueous solution | Calibrated glass electrode at 20 °C | 5.0–7.0 | Confirm against batch certificate |
In continuous solution preparation for size boxes and coating lines, the resin is added to ambient water under high-shear dispersion. The order of addition matters: adding dry powder directly to heated water above 50 °C produces gel-coated lumps that require a rotor-stator mixer with tip speeds of 15–20 m/s or a venturi eductor to break down. For partially hydrolysed grades, dissolution is accelerated between 20 °C and 40 °C; heating above 60 °C risks forming surface skin in open tanks. Viscosity stability after complete dissolution should be checked after 2 h and 24 h; drift greater than 10% indicates incomplete hydration or microbiological activity. Production lines that pre-slurry PVA in a 20 wt% suspension and then inject the slurry into a steam-heated jet cooker at 90–95 °C achieve reproducible viscosity with less undissolved gel than dry charging.
Film properties of partially hydrolysed PVA are controlled by the degree of hydrolysis and the 4% solution viscosity. Residual acetate groups disrupt interchain hydrogen bonding, lower the crystalline melting range, and increase elongation at break while reducing water resistance. For films cast from a 10 wt% aqueous solution and dried at 23 °C and 50% RH, tensile strength measured according to ASTM D882-18 usually falls in the 25–40 MPa range for medium-viscosity partially hydrolysed grades; elongation at break may lie between 150% and 250%. These are class-level values and grade-specific XW-I data should be generated using the exact batch. Fully hydrolysed PVA films of similar viscosity can show higher tensile strength, often 40–60 MPa, but require water temperatures above 80 °C for dissolution and show higher crystallinity. XW-I is therefore selected where ambient-temperature solubility and moderate film toughness are required.
XW-I is also applied as a protective colloid in vinyl acetate and acrylate emulsion polymerisation. In this use, the solution viscosity and hydrolysis degree determine particle size and shelf stability. Partially hydrolysed PVA with lower molecular weight produces finer latex particles but lower colloidal stability under freeze-thaw cycles. Polymerisation reactors equipped with pitched-blade impellers at 150–200 rpm are used; upper impeller speed above 300 rpm can shear the PVA protective colloid and generate coagulum. The recommended PVA concentration typically ranges from 2.0 to 5.0 wt% on monomer, but XW-I-specific optimisation is required.
On high-speed warp-sizing machines running 60–80 m/min, a switch from a fully hydrolysed 1799-type PVA to a partially hydrolysed XW-I class resin reduces the size-box temperature requirement from 85–95 °C to 60–75 °C. The lower temperature decreases energy input and steam consumption but also lowers the boiling margin, so subsequent drying cylinder temperatures must be rebalanced to maintain size film integrity. Weave-room humidity above 65% RH may plasticise the partially hydrolysed size film and increase yarn-to-yarn sticking; desizing with hot water above 40 °C remains possible without enzymatic additives. A mill trial with a 10% size solids formulation should include split-row viscosity checks every 15 min and a minimum 8 h run to detect foam accumulation or size-box skinning. Foam generated by partially hydrolysed PVA can be controlled with 0.05–0.15 wt% defoamer on size solids, but excessive defoamer may weaken size film adhesion to polyester warp yarns.
Although PVA is normally solution-cast, XW-I may be considered for thermoplastic compounding when plasticised with glycerol, sorbitol, or polyethyleneglycol. Melt-processing window is narrow because the onset of thermal degradation occurs near 200 °C while the melting range of partially hydrolysed PVA is between 180 °C and 190 °C. Extrusion on a co-rotating twin-screw extruder with L/D ratio 36:1 and barrel zones set to 160 °C/170 °C/178 °C/185 °C/185 °C/180 °C is used, but a temperature overshoot above 200 °C leads to acetaldehyde and conjugated polyene formation, yellowing, and viscosity loss. A 5 °C overshoot in the die zone is enough to initiate discolouration; screw speed and feed rate must be balanced to keep specific mechanical energy input below 0.30 kWh/kg. For XW-I, published data for melt extrusion is limited; process trials should be run with a torque rheometer before scale-up.
Storage of XW-I requires humidity control below 60% RH because PVA is hygroscopic and caking can occur above 65% RH. Silos should be purged with dry air at a dew point of -20 °C. Bags should be conditioned to room temperature before opening to avoid surface condensation. Incompatibility with strong oxidisers and certain metal salts is known; avoid contact with concentrated acids and bases during storage. For aqueous solution preservation, a biocide may be required if storage exceeds 24 h at 20–30 °C, as PVA solutions are susceptible to microbial degradation.
Table 2 compares the expected XW-I category with other PVA hydrolysis and viscosity classes. The XW-I column is not a substitute for the batch certificate; it lists the class-level expectations that should be confirmed before commercial use.
| Property | XW-I expected class | Fully hydrolysed medium-viscosity PVA | Low-viscosity partially hydrolysed PVA |
|---|---|---|---|
| Degree of hydrolysis | Confirm by CoA; partially hydrolysed class 86.0–89.0 mol% | 98.0–99.0 mol% | 86.0–89.0 mol% |
| 4% solution viscosity at 20 °C | Confirm by CoA; medium-viscosity class 20.0–30.0 mPa·s | 20.0–30.0 mPa·s | 5.0–15.0 mPa·s |
| Cold-water solubility | Expected at 20–40 °C if partially hydrolysed | Requires >80 °C | Soluble at 20–30 °C |
| Main processing difference | Lower crystallinity; foam and skinning require size-box control | Higher film tensile and water resistance | Lower film strength; deeper penetration into porous substrates |
Regulatory status should be confirmed from the safety data sheet and the manufacturer’s compliance statement. For food-contact use, the user must verify compliance with relevant positive lists including FDA 21 CFR 175.105 adhesives, 21 CFR 176.170 paper and paperboard, or EU Regulation 10/2011 for plastic food contact materials; PVA appears in several of these, but the specific grade and residual vinyl acetate monomer must be checked. REACH and RoHS compliance should also be confirmed against the supplied substance identity profile. Shuangxin XW-I PVA is not considered flammable under normal storage conditions, but dust-air mixtures containing fine PVA powder can form a combustible dust cloud; conveying systems should be grounded and equipped with explosion venting where fine particle fractions are generated.
