| HS Code | 754123 |
| Product Name | Shuangxin SX-II PVA |
| Appearance | White granular powder |
| Degree Of Hydrolysis | 86.0 - 89.0 mol% |
| Viscosity 4percent Solution 20c | 20.0 - 30.0 mPa·s |
| Ph 4percent Solution | 5.0 - 7.0 |
| Ash Content | ≤ 0.5% |
| Moisture Content | ≤ 5.0% |
| Volatile Content | ≤ 3.0% |
| Purity | ≥ 99.0% |
| Bulk Density | 0.4 - 0.6 g/cm³ |
| Water Solubility | Soluble in water above 90°C |
| Particle Size | 20 - 80 mesh |
As an accredited Shuangxin SX-II PVA factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Shuangxin SX-II PVA is packaged in 25 kg net multilayer paper bags with an inner plastic liner for moisture protection. |
| Container Loading (20′ FCL) | Shuangxin SX-II PVA loaded into 20′ FCL container, palletized, securely braced, labeled, and sealed for safe transport. |
| Shipping | Shuangxin SX-II PVA is shipped as a free-flowing powder in sealed multi-layer kraft paper bags with PE liners, palletized and stretch-wrapped for protection. Keep dry and avoid moisture, humidity, and direct heat during transit and storage. Use clean, ventilated transport to preserve quality. |
| Storage | Store Shuangxin SX-II PVA in a cool, dry, well-ventilated area away from direct sunlight, heat, and moisture. Keep containers tightly sealed when not in use. Avoid contact with oxidizing agents and incompatible substances. Maintain moderate humidity to prevent clumping or degradation. Follow manufacturer’s shelf-life recommendations and handle with clean equipment to preserve product quality. |
| Shelf Life | Shelf life: 12 months from manufacture date when stored sealed, cool, and dry. |
On a single size box processing 14.5 tex combed cotton warps at 600 m/min, partial replacement of a low-viscosity gelatinised maize starch with Shuangxin SX-II PVA at 25.0–35.0 wt% of total size solids raises size bath viscosity from 18.0–22.0 mPa·s to 28.0–35.0 mPa·s at 90°C as determined by Brookfield LV, spindle 1 at 60 rpm. The formulation window is constrained by the squeeze roller configuration: when a 70 Shore A nip operates at 0.35 MPa linear pressure, add-on settles at 9.0–12.0 wt% for 14.5 tex yarn; below 8.0 wt% add-on, hairiness reduction deteriorates above 5.0 hairs/10 cm on a Zweigle G566. The size is cooked in a high-pressure jet cooker at 125°C for 20 min, then held in a service tank at 85–90°C before application. Regulatory alignment for EU apparel requires the size film to be removed under oxidative desizing conditions, with effluent COD monitored under the site discharge permit; conformance to OEKO-TEX® Standard 100 Annex 4, Class I is managed through exclusion of alkylphenol ethoxylates and heavy-metal catalysts. ZDHC MRSL v3.1 prohibits borate-based crosslinkers in the same formulation because SX-II reacts with borate ions to generate a diol-complex gel that blocks size box filters and produces unweavable hard size. Sized warp beams are converted into flat-woven denim, sheeting and chambray. Published data for woven fault rates in this exact SX-II formulation is limited; however, a sized yarn tensile retention above 95% of unsized yarn strength measured by ISO 2062:2009 correlates with fewer loom stops, provided the after-wax application does not exceed 0.5 wt% of size solids.
A 10,000 L glass-lined emulsion reactor is charged with a 10.0 wt% SX-II stock solution prepared at 90–95°C for 60 min in demineralised water; the protective colloid concentration is set at 4.0–6.0 parts per 100 parts vinyl acetate monomer before a semi-continuous monomer feed of 3.5–4.0 h. The initial reactor charge holds 2.5–3.0 wt% of the monomer, while ammonium persulfate at 0.2–0.4 wt% of monomer is fed as a separate aqueous solution to maintain an exotherm between 68°C and 74°C; the temperature ceiling of 74°C prevents grafting density from collapsing the colloid layer and causing coarse particle formation above 1.0 wt% screen residue on a 200-mesh filter. The finished dispersion is adjusted to 50.0–55.0 wt% solids, and residual vinyl acetate is reduced below 0.5 wt% by post-polymerisation initiator addition. For food-contact packaging adhesives, the dispersion is formulated within FDA 21 CFR 175.105 conditions, with all defoamers and preservatives cleared for the intended contact layer. Woodworking adhesives using this dispersion are tested under EN 204:2016 D2/D3 classifications, with bond strength after cold-water immersion reported against the corresponding thresholds. The terminal product range includes white wood glue, paper sack bottom paste, and textile flocking adhesive. Incompatibility arises when borax or aluminium sulfate is added downstream, because residual SX-II complexation causes viscosity jumps exceeding 500% and can destabilise the dispersion into a rubbery coagulum.
Surface size formulations based on oxidised tapioca starch and SX-II at a co-binder ratio of 6.0–12.0 parts per 100 parts starch solids are run at 6.0–9.0 wt% total solids on a Valmet SymSizer at 1,200 m/min. The addition of SX-II raises dynamic surface tension to 42.0–46.0 mN/m, which controls misting but requires rod pressure above 0.6 bar to maintain target film thickness. In pigmented coating, SX-II is post-added at 0.5–1.5 parts per 100 parts ground calcium carbonate alongside 8.0–12.0 parts styrene-butadiene latex, with coating colour solids held at 60.0–65.0 wt%. The coated sheet is dried to 5.0–6.5% equilibrium moisture and calendered at 80°C steel temperature to reach a Parker Print Surf roughness below 1.2 µm by ISO 8791-2:2013. For grades intended for direct food contact, the formulated surface size must comply with FDA 21 CFR 176.170, and extractive testing follows the migration protocols set out in EU Regulation 10/2011. The terminal articles include high-speed inkjet paper, coated art paper, and release liner base. Process limits are defined by viscosity at the metering nip: above 12.0 wt% total solids, misting and blade streak frequency increase unless a lower-viscosity starch is substituted. Water absorption below 25 g/m² by ISO 535:2014 Cobb60 is generally achieved on woodfree base of 80 g/m².
In a dry-mix plant producing C2-class cementitious tile adhesive, SX-II is added at 0.6–1.0 wt% of total dry mortar and blended for 180 s in a 1,500 kg horizontal paddle mixer before cellulose ether and redispersible polymer powder are introduced. The blended powder is mixed with water at 22.0–26.0 wt% of dry mortar for 60 s, left to slake for 5 min, and re-mixed for 30 s; the resulting adhesive is trowelled with an 8 mm notched trowel over cementitious screed. SX-II contributes to wet-tack and open time by increasing the viscosity of the aqueous phase, but the hydration path of ordinary Portland cement remains the primary strength-forming reaction. For CE-marked floor and wall adhesives, performance is evaluated against EN 12004:2007+A1:2012 and ISO 13007-1:2014, with tensile adhesion specimens prepared and pulled in accordance with EN 1348:2007 after 28-day dry, water-immersion, and freeze-thaw conditioning. Terminal product types include large-format porcelain tile adhesives, low-slip wall adhesives, and gypsum skim coats. Field limitations are observed above 1.5 wt% SX-II: air entrapment increases compressive strength loss beyond 20% in control mixes, and the mortar becomes gluey under the trowel; SX-II is therefore not recommended for structural concrete or patch repair mortars requiring early compressive strength above 10.0 N/mm² at 7 days.
| Tensile adhesion after water immersion | EN 12004:2007+A1:2012 | ≥ 1.0 N/mm² |
| Open time after 20 min | EN 1348:2007 | ≥ 0.5 N/mm² |
| Freeze-thaw tensile adhesion | EN 12004:2007+A1:2012 | ≥ 1.0 N/mm² |
A casting dope prepared from SX-II at 16.0 wt% solids with glycerol at 10.0–15.0 parts per 100 parts PVA and sorbitol at 5.0–8.0 parts per 100 parts PVA is cast onto a PET carrier at 80–110°C belt surface temperature. The film is dried in three zones from 80°C to 110°C, and residual moisture is brought below 8.0 wt% before slitting. Dissolution time in 25°C deionised water is influenced by the ratio of glycerol to sorbitol: glycerol-rich films disintegrate faster but exhibit higher blocking tendency at RH > 60%, so storage requires heat-sealed barrier packaging. For detergent unit-dose applications, the finished film is tested for child-resistant closure performance under EU Regulation (EC) No 1272/2008 CLP packaging provisions, and any migration of film-borne additives into detergent fill is evaluated under the relevant detergent packaging standards. Terminal articles include monodose laundry detergent pouches, dishwasher tablet sachets, and water-soluble transfer printing backsheets. Extrusion of SX-II above 190°C is not recommended without plasticiser pre-absorption because main-chain scission and yellowing become measurable; solution casting is the preferred conversion route for this grade. Published dissolution data for SX-II in this exact cast-film configuration is limited, and film converters should request lot-specific OECD 301B or ISO 14851:2019 biodegradation data from the dope formulator rather than assume equivalence across PVA grades.
In aqueous tape casting of 96.0 wt% alumina substrate slurry, SX-II is introduced as a 4.0 wt% binder on ceramic powder basis after ball-milling the alumina with an anionic dispersant in deionised water at pH 9.0–9.5. The slurry is de-aired under vacuum at 20–30 kPa for 30 min, then cast at 0.5–1.0 m/min onto a Mylar carrier with a doctor blade gap of 0.8–1.2 mm. Drying at 60°C produces a green tape with 50.0–55.0 wt% ceramic solids, and binder burnout is conducted at a ramp of 0.5–1.0°C/min to 600°C with a 2 h hold, followed by sintering at 1,500–1,600°C. The terminal products include alumina electronic substrates, LTCC green sheets, and ceramic separator membranes. Compliance for these components is governed by IEC 60672-1 for ceramic insulating materials, ASTM C373-18 for water absorption in fired substrates, and Directive 2011/65/EU RoHS when the sintered substrate is incorporated into printed circuit assemblies. Process limits are narrow in the burnout step: heating rates above 2.0°C/min produce blistering and carbon residue that reduces sintered density below 3.90 g/cm³; therefore, multi-stage burnout profiles with air exchange above 6 volume changes/min are required. Published data for SX-II in this specific alumina tape-casting configuration is limited, and the binder burnout profile should be re-validated when the alumina Lot median particle size changes by more than 0.2 µm.
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Shuangxin SX-II PVA is a polyvinyl alcohol resin supplied as a free-flowing granular solid with the polymer identity CAS 9002-89-5. The model designation SX-II identifies the producer’s grade within a sequence of alcoholysis and viscosity variants, but published English-language technical data for this exact configuration is limited. Before plant-scale substitution, the batch-specific certificate of analysis should be obtained to confirm degree of hydrolysis, viscosity of a 4% aqueous solution at 20 °C, volatile matter, ash, and pH. In comparative screening the product is usually evaluated alongside conventional 1788, 1792, and 1799 polyvinyl alcohol resins because the SX-series performance boundary is set by dissolution behaviour and film mechanics rather than by a single nominal viscosity. The resin is shipped in 20 kg or 25 kg multi-wall bags with an inner polyethylene liner. Storage should be maintained at 10–35 °C and below 60% relative humidity; at higher RH, bulk handling can produce lumps that are difficult to disperse.
Polyvinyl alcohol is produced by polymerization of vinyl acetate followed by catalysed alcoholysis. The degree of hydrolysis is controlled by the molar ratio of methanol to polymer and the catalyst dose. For SX-II, the residual acetate content defines the polar balance of the polymer; if the lot-specific alcoholysis data fall in the partially hydrolysed range from 86 mol% to 89 mol%, cold-water dispersibility and cellulosic adhesion improve, while dry-film water resistance declines relative to fully hydrolysed resin. The product should therefore be specified as a grade for temporary films, warp sizing, paper surface conversion, and emulsion stabilisation rather than as a high-barrier moisture film.
Specification parameters are not reducible to a single viscosity value. Viscosity, measured on a 4% solids solution at 20 °C under JIS K6726:1994 or the corresponding GB/T 12010.1-2008 system, reflects molecular weight and degree of polymerization. Volatile matter and ash content influence clarity, odour, and block resistance in film and sizing applications. The following class-level table is provided for initial screening when the producer’s certificate of analysis has not yet been received; it represents comparable partially hydrolysed polyvinyl alcohol grades and does not replace lot-specific data.
| Parameter | Test method | Typical screening envelope for comparable partially hydrolysed PVA |
|---|---|---|
| Degree of hydrolysis | JIS K6726:1994 | 86.0–89.0 mol% |
| Viscosity of 4% solution at 20 °C | GB/T 12010.4-2010 | 20.0–30.0 mPa·s |
| Volatile matter | ISO 3251:2019 | ≤5.0% by mass |
| Ash content | ISO 3451-1:2019 | ≤0.5% by mass |
| pH of 4% solution | JIS K6726:1994 | 5.0–7.0 |
| Bulk density | ISO 60:1977 | 0.45–0.65 g/cm³ |
For a formulator replacing conventional 1799 or 1788 with SX-II, the decisive measurements are degree of hydrolysis, 4% solution viscosity, gel particle count, and interfacial adhesion to the intended substrate. Degree of hydrolysis below 90 mol% lowers the temperature required for full dissolution and increases cold-water swell, but it also decreases aqueous film water resistance after drying. A medium viscosity in the 20.0–30.0 mPa·s range provides greater film toughness than low-viscosity grades but reduces wetting and penetration into porous paper or warp yarns. In production-scale textile sizing trials, batch-to-batch hydrolysis drift greater than ±0.5 mol% has been observed to shift size box viscosity by 10–20% at equal solids, requiring real-time correction of the size recipe. That sensitivity is a primary reason the certificate of analysis must be matched to the specific lot rather than to a general product name.
Viscosity control is equally process-critical. During size preparation, the resin is pre-slurried in water at 18–30 °C before steam injection raises the temperature to 85–95 °C. Direct dry addition into hot water produces gelatinous lumps and “fisheye” defects that survive downstream finishing. Complete dissolution in a low-shear vertical tank may require 30–60 min at 85 °C; a high-shear dissolver can shorten the cycle but may introduce molecular weight reduction if impeller tip speed exceeds 12–15 m/s for extended periods. After dissolution, the solution is filtered through an 80–100 mesh screen to remove residual gel particles. For film casting or size press use, a gel particle count above 5–10 particles per 100 cm² generally indicates an incomplete cook or contaminated batch.
In paper surface sizing, the resin is used as an aqueous film former at size press solids of 2–8% by mass. The partially hydrolysed character, if confirmed for SX-II, improves wet-out and adhesion to cellulosic fibre while producing a continuous film that reduces surface dust and roughness. Surface strength is commonly evaluated by IGT pick test or wax pick equivalents; the formulation is adjusted by adding starch, styrene-acrylate co-binders, and optical brighteners. SX-II should not be blended with strongly cationic additives without jar testing because residual acetate and ash can interact with cationic demand and alter first-pass retention.
In textile warp sizing, the solution is applied on high-speed slashers or size boxes at 300–600 m/min. A formulation containing 5–15 phr PVA on dry starch is typical for polyester/cotton blends, but the exact substitution ratio depends on yarn count, weaving speed, and shed humidity. The dried film must remain flexible enough to withstand repeated cyclic flexure on loom harnesses but hard enough to resist abrasion. Film tensile properties for partially hydrolysed PVA of this class, measured according to ASTM D638-14, typically fall between 25 MPa and 45 MPa tensile strength and 200–350% elongation at break. These values are lower than fully hydrolysed 1799 film, which usually exhibits 40–70 MPa tensile strength and 100–200% elongation. The difference explains why SX-II is preferred where lower crystallinity and easier desizing are more valuable than maximum film toughness.
Process control becomes most demanding when the difference between complete dissolution and thermal degradation is compressed. In a partially hydrolysed grade intended for low-temperature preparation, complete dissolution may begin at 70 °C and finish at 85 °C; the operating window is therefore approximately 15 °C, but the safe upper limit before shear-induced or thermal degradation is commonly set at 95 °C. If the steam supply overshoots to 100 °C during hold time, solution viscosity can decrease irreversibly and the dried film may lose 10–30% of tensile strength. Conversely, dropping the temperature below 70 °C leaves undissolved cores that appear as microgels in the size box and increase yarn hairiness at the loom. The practical control band is therefore often narrower than the thermodynamic solubility limit, and plant engineers typically specify a jacket temperature of 85±5 °C with a recirculation loop designed for 0.3–0.6 turnovers per minute.
From a comparative standpoint, SX-II differs from fully hydrolysed 1799 primarily in the concentration of residual acetate groups and the resulting steric disruption of crystallites. The higher residual acetate content in partially hydrolysed grades reduces melting point and heat of fusion, broadens the melt processing window, and permits water dissolution at lower temperatures. However, the same structural feature lowers dry-film water resistance and increases oxygen transmission rate. For gas-barrier packaging where low oxygen permeation is critical, fully hydrolysed PVA or ethylene-vinyl alcohol copolymer is generally selected instead. SX-II should therefore be positioned as a hydrophilic surface-active resin for cellulosic adhesion, temporary protective films, sizing, and emulsion stabilisation rather than as a high-barrier shrink film.
Compared with a low-viscosity 1788 resin, the SX-II grade is expected to offer a different degree of polymerization and therefore a different balance of film strength and solution viscosity at constant solids. If the certificate of analysis shows a viscosity of 20.0–30.0 mPa·s, the resin is a medium-viscosity grade and will produce stronger films than a 10.0–15.0 mPa·s low-viscosity grade at the same solids. In emulsion polymerization, the medium-viscosity protective colloid can improve particle size stability and reduce coagulum in vinyl acetate-ethylene systems, but high solution viscosity may limit heat transfer if the dose exceeds 6 wt% of total monomer. Below 2 wt% of total monomer, the protective colloid layer may be insufficient, leading to poor latex stability and visible grit formation.
In water-based paper and packaging adhesives, SX-II can be formulated with starch, dextrin, or plasticizer at 10–30% solids. A partially hydrolysed PVA solution provides wet tack and re-wettability; borax or boric acid addition of 0.5–2.0 wt% on PVA solids is used to build viscosity and green strength. The response is nonlinear: a small borax increase can raise Brookfield viscosity from 2,000 mPa·s to more than 20,000 mPa·s, producing a gel that cannot be pumped through standard rotary lobe pumps without losing cohesion. Consequently, borax addition in production is controlled gravimetrically and not by dry-volume batching. The final adhesive must be checked for wet tack, open time, pH, and residue on stainless steel applicator rolls. Long open times can be achieved by adding 5–15 phr of a compatible humectant such as glycerol; however, this also reduces film shear strength after drying.
The physical structure of the dried film is determined by hydrogen bond density between hydroxyl groups and residual acetate groups. In a fully hydrolysed resin, the regular arrangement of hydroxyl groups permits tight crystalline domains, producing film with higher modulus and lower moisture uptake. In a partially hydrolysed resin, randomly distributed acetate groups interrupt that regularity, increasing free volume and reducing the temperature required for water penetration. The property changes are not linear; hydrolysis degrees below 86 mol% can produce excessive water sensitivity and blocking, while hydrolysis degrees above 92 mol% rapidly approach the higher crystallinity and dissolution temperature of 1799. The practical boundary for cold-water dispersible sizing and adhesives is therefore usually between 86 mol% and 90 mol%.
The interaction with gelling agents is another differentiation point. Borax and certain boric acid compounds can crosslink PVA through reversible didiol–borate complexes, increasing tack and build. This behaviour is used in water-based adhesives, but it creates a cliff-edge: borax addition of 0.5–2.0 wt% on PVA solids can raise Brookfield viscosity by several hundred percent; above that range, the mixture may form an elastic gel that is difficult to coat or pump. Trial work with borates should be run at 25 °C and controlled pH 7.0–8.5, because acidic pH and high calcium hardness can accelerate insoluble complex formation. Amine-containing additives should be screened for pH drift; although PVA itself is stable in mildly alkaline conditions, buffering capacity is limited. Thermal exposure above 200 °C in melt processing can eliminate water and form conjugated double bonds, producing yellowing and a drop in adhesive performance.
Incoming quality checks should include sieve residue on 40 mesh and 80 mesh screens, bulk density, and solution haze. Batch-to-batch variation in ash content above 0.5% can produce visible specks in cast film and reduce film clarity; haze measurement under ISO 14782:1999 can be used for transparent grades. When the resin is used in a twin-screw compounding line, pre-drying at 80–90 °C for 2–4 h in a dehumidified dryer with dew point no higher than -30 °C is recommended when ambient relative humidity exceeds 60%. The extruder L/D ratio should be 28:1–44:1 with a barrel profile that does not exceed 200 °C at the melt zone, depending on plasticizer content. High-shear dispersion of fillers into PVA solutions should be designed around a tip speed of 10–15 m/s to balance dispersion and shear thinning.
When SX-II is used as a protective colloid or surfactant-like stabiliser, the solution surface tension typically falls in the 45–55 mN/m range for comparable partially hydrolysed PVA at 20 °C. This lowers interfacial tension enough to stabilise emulsions but does not produce the same micellar behaviour as low-molecular-weight surfactants. Foam generation is influenced by stirring intensity and alcoholysis degree; defoaming additives or vacuum deaeration may be required in high-speed paper coating operations. The final performance is therefore a composite of hydrolysis degree, viscosity, ash profile, preparation temperature, and downstream pH rather than a single product parameter.
