| HS Code | 704901 |
| Product Name | Shuangxin 24-88 PVA (PVA 088-50) |
| Chemical Name | Polyvinyl Alcohol |
| Cas Number | 9002-89-5 |
| Appearance | White powder |
| Hydrolysis Degree | 86.0 - 89.0% |
| Viscosity 4 Solution 20 C | 20.0 - 30.0 mPa·s |
| Ph 4 Solution | 5.0 - 7.0 |
| Volatile Content | ≤ 5.0% |
| Ash Content | ≤ 0.5% |
| Average Degree Of Polymerization | ~500 |
| Molecular Weight | ~22,000 - 26,000 g/mol |
| Solubility | Soluble in water |
| Bulk Density | 0.4 - 0.6 g/cm³ |
| Particle Size | 80 - 120 mesh |
As an accredited Shuangxin 24-88 PVA (PVA 088-50) factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Shuangxin 24-88 PVA (PVA 088-50) is packaged in 25 kg multi-wall paper bags with PE liner for safe storage. |
| Container Loading (20′ FCL) | 20′ FCL container loaded with Shuangxin 24-88 PVA (PVA 088-50), packed in bags on pallets, secured safely for transport. |
| Shipping | Shuangxin 24-88 PVA (PVA 088-50) ships in sealed multi-layer paper/plastic bags on pallets, wrapped for protection. Transport in dry containers or covered trucks, keeping cargo away from moisture, rain, and sunlight. Store in a cool, ventilated area. Non-hazardous, but minimize dust exposure during handling. |
| Storage | Store in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Keep the container tightly sealed to prevent moisture absorption and contamination. Avoid contact with oxidizing agents. Maintain stable temperatures and moderate humidity. Use appropriate PPE when handling. Check for degradation or clumping before use. |
| Shelf Life | Shelf life is typically two years when stored in a cool, dry place away from moisture. |
The protective-colloid function in vinyl acetate-ethylene and vinyl acetate-acrylic copolymerization is governed by the 86.0–89.0 mol% alcoholysis range of Shuangxin 24-88 (PVA 088-50) combined with the 44–52 mPa·s apparent viscosity of a 4% aqueous solution at 20 °C measured by ISO 2555. Those two properties set the grafted PVAc segment solubility and the aqueous-phase shear stability during delayed monomer feeding. In standard jacketed stainless-steel reactor practice, the protective colloid is pre-dissolved in demineralized water at 80–90 °C under slow agitation to a 5–10% stock concentration before the initial reactor charge is assembled at 2–6 parts per hundred parts monomer on total vinyl acetate mass. At 3–4 phm, vinyl acetate-ethylene dispersions with 50–55% solids typically require coagulum below 0.1% when screened through a 150 µm filter, ethylene pressure is held at 2.0–6.0 MPa, and polymerization temperature is controlled at 70–75 °C. Below 2 phm, average particle diameter increases and kettle-wall fouling becomes measurable within a single campaign; above 6 phm, latex viscosity can exceed 4,000 mPa·s at 25 °C, limiting jacket heat transfer and requiring post-charge dilution to restore sufficient turbine agitator torque.
Compliance for adhesive and packaging end uses is screened against FDA 21 CFR 175.105 for indirect food-contact adhesives, while the polymer itself is managed under EU REACH as an exempt polymer and the vinyl acetate monomer supply remains subject to registration. Terminal products from this downstream track include D3 interior polyvinyl acetate wood adhesives tested to EN 204/205 D3, vinyl acetate-ethylene carpet-backing compounds, packaging laminating adhesives, and architectural joint compounds. Batch-to-batch viscosity drift in the reactor is commonly traced to incomplete dissolution of the PVA stock solution or to residual acetyl distribution in the grade, not to variation in the 44–52 mPa·s input specification. Borate-containing buffers must be excluded because polyvinyl alcohol undergoes reversible gelation with borate ions, which can destabilise the dispersion during letdown.
Surface sizing of kraft linerboard and coated folding boxboard with Shuangxin 24-88 requires the resin to be cooked separately at 90–95 °C for 30–60 min in a continuous jet cooker or thermosyphon kettle at 5–15% dry solids. When the cooked PVA is blended with oxidized starch in a dry-weight ratio of 1:4 to 1:1 and applied on a rod-metered size press, dry PVA pickup on sheet mass typically falls within 0.3–1.2%. Substitution beyond 50% of the starch component raises circulating size viscosity at 60 °C above 120 mPa·s, which narrows the metering rod working window and increases streak formation on the press roll. The production sequence runs from the size kitchen through 100–150 µm mesh screens, into the size press, and onward to after-drying sections with cylinder surface temperatures of 90–120 °C. The dried sheet is monitored by TAPPI T 530 for Hercules sizing and by ISO 535 for Cobb water absorption. Compliance for food-contact paper and board relies on FDA 21 CFR 176.170 and, for Chinese packaging supply chains, GB 9685-2016. Finished products include high-burst grocery bags, frozen food cartons, inkjet topcoats, and moisture-resistant corrugated medium.
In slasher sizing of high-count cotton and polyester-blended warp yarns, Shuangxin 24-88 is cooked in a jet cooker at 110–130 °C and held in the size box at 85–95 °C. The formula typically replaces 20–40% of starch solids with PVA solids, with total size solids between 8% and 12% depending on yarn count and weave density. Wet pickup on 40/1 Ne combed cotton after the squeeze roll is controlled at 90–110% on yarn mass, yielding a dry add-on of 8–12% by weight. The sized warp is dried over multi-cylinder cans at 120–140 °C cylinder surface temperature and passed through split rods before the take-up head. Weaving on air-jet looms shows that hairiness reduction is sensitive to size-box temperature; skinning below 90 °C transfers undissolved gel particles onto the warp sheet and increases loom stops. Sized yarn tensile retention is assessed by ISO 2062:2010 after conditioning at 65±2% relative humidity and 20±2 °C. Compliance screening for apparel supply chains includes REACH SVHC absence and OEKO-TEX Standard 100 residue limits for textile chemicals, with verification conducted on greige fabric after desizing rather than on the size film itself. Terminal products include tight-weave shirting, workwear fabrics, bed linen, and denim woven on high-speed air-jet looms.
Water-soluble film production from Shuangxin 24-88 starts with an aqueous solution at 15–25% dry solids, into which plasticizer is metered at 10–20 parts per hundred parts resin. Glycerol and sorbitol are applied as a plasticizer system at weight ratios from 3:1 to 5:1; sodium lauryl sulfate or nonionic wetting agents are introduced at 0.1–0.5 phr, and defoamer at 0.05–0.2 phr. The solution is degassed under vacuum of −0.06 to −0.09 MPa and cast through a slot die with a lip gap of 0.8–1.5 mm onto a chromium-plated steel belt. Drying zones are ramped from 80 °C to 110 °C over 20–40 min, and residual moisture in the finished film is held at 8–12% to prevent brittleness. At the 88 mol% hydrolysis level and 35–75 µm thickness, film dissolution in 20 °C water typically occurs within 60–180 s under gentle agitation, which supports unit-dose detergent encapsulation. For food-contact film, 21 CFR 177.1670 applies; for detergent packaging, ready biodegradability is evaluated by OECD 301B or ISO 14851. Terminal products include laundry detergent capsules, automatic dishwashing tablets, agrochemical water-soluble pouches, and transfer-print release film. Melt compounding on a twin-screw extruder with L/D 40:1 is possible, but published data for this specific configuration is limited; barrel temperatures above 180 °C risk acetaldehyde release from residual acetate groups.
Remoistenable gummed tape and envelope adhesive formulations use 24-88 as a secondary film former blended with dextrin at 10–20 dry parts PVA per 100 parts dextrin to raise adhesion to kraft paper and control curl. The coating is applied by reverse-roll or gravure coater at 3–5 g/m² dry adhesive mass, dried in a tunnel at 80–100 °C with relative humidity held at 30–40%, and wound without silicone release liner. Compliance for food packaging tapes is screened against FDA 21 CFR 175.105. Terminal forms are water-activated paper sealing tape, envelope flaps, and remoistenable label stock.
Technical ceramic powder processing uses Shuangxin 24-88 as a temporary binder and plasticizer precursor in alumina and zirconia injection-molding feedstocks. The resin is predissolved at 8–12% aqueous concentration and milled with ceramic powder at 1–5 wt% dry binder on powder mass in a ball mill at 40–60 rpm for 4–8 h. Slurry pH is maintained below 9.0; higher pH increases slurry viscosity and retards spray-dryer throughput. Spray-drying produces feedstock granules with apparent density of 1.1–1.3 g/cm³, which are injection molded at a barrel profile of 90–130 °C and mold temperature of 30–60 °C. Binder removal proceeds by solvent debinding in water or ethanol followed by thermal debinding from 250 °C to 500 °C at a ramp no faster than 0.5 °C/min; residual carbon after debinding is specified below 0.1 wt% before sintering. Published data for this specific configuration is limited, and each powder-binder combination requires thermal gravimetric verification to 800 °C. Sintered-part conformance is assessed by ISO 18754 for bulk density and apparent porosity. Terminal products include injection-molded alumina components, zirconia dental blanks, and technical ceramic green parts requiring green machining.
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Shuangxin 24-88 PVA, designated in the alternate manufacturer coding as PVA 088-50, is a partially hydrolyzed polyvinyl alcohol resin supplied as a white to pale-cream granular powder. The numerical suffix 24-88 denotes a nominal degree of polymerization of 2400 and a nominal alcoholysis degree of 88 mol%, placing the material in the medium-viscosity, partially hydrolyzed class of polyvinyl alcohol. In the 088-50 designation, the 088 component refers to the 88 mol% alcoholysis level, while the 50 component corresponds to the viscosity class associated with a 4% aqueous solution viscosity in the 44.0–50.0 mPa·s range at 20 °C when tested under equivalent conditions to JIS K6726 or GB/T 12010.2. The product is used as a temporary binder, film former, protective colloid, and sizing agent across papermaking, adhesive compounding, textile warp sizing, and emulsion polymerization. Unlike fully hydrolyzed PVA grades, the residual acetate groups in the 88 mol% hydrolysis structure limit crystallinity and allow dissolution at lower temperature while still supporting a continuous film after water evaporation. The material is commonly supplied in 20 kg or 25 kg multiwall paper sacks with an internal polyethylene liner; batch certificates typically report volatile matter, ash, pH, viscosity, and alcoholysis degree.
The dual designation is not a separate chemical composition but a shifted expression of the same grade on different producer or regional code systems. The first two digits 24 in the Chinese-style name indicate a nominal degree of polymerization of 2400, a value that correlates with a 4% aqueous solution viscosity in the 44.0–50.0 mPa·s band. The second two digits 88 indicate a nominal hydrolysis degree of 88 mol%, meaning the residual acetyl content is approximately 12 mol%. The 088-50 code recasts the same information: 088 is the mole percent alcoholysis expressed as 88, and 50 is the nominal upper viscosity value in mPa·s at 20 °C. The product should therefore not be confused with 088-20 or 088-30 codes, which correspond to lower-viscosity grades in the same hydrolysis class. Processors purchasing by viscosity should verify the exact lot viscosity because the viscosity class width can affect downstream metering pumps and film thickness control. In paper sizing and adhesive compounding, a viscosity shift from 44 mPa·s to 50 mPa·s at the same solids content changes the rheological response and may require pump speed adjustment rather than solids correction.
| Property | Typical value or range | Test basis |
|---|---|---|
| Alcoholysis degree | 86.0–89.0 mol% | JIS K6726-aligned titration |
| 4% aqueous solution viscosity | 44.0–50.0 mPa·s | Brookfield rotational viscometer, 20 °C |
| Volatile matter | ≤5.0 % | JIS K6726 |
| Ash content as Na₂O | ≤0.5 % | JIS K6726 |
| pH of 4% solution | 5.0–7.0 | JIS K6726 |
| Nominal degree of polymerization | 2400 | Calculated from viscosity data |
For aqueous solution preparation, the dissolution sequence has a greater effect on final solution quality than the average particle size. The powder is first dispersed in process water at 20–30 °C under low-shear agitation; direct addition to water above 50 °C without dispersion creates gel-coated lumps that require extended high-shear rework. A common production configuration is a jacketed stainless steel dissolving vessel with bottom-mounted turbine agitator and an external recirculation loop through a lobe pump. The slurry is mixed for 15–20 min before steam is applied to the jacket, and the temperature is raised to 90–95 °C at a controlled rate of approximately 1.0–1.5 °C/min. The solution is held at temperature for 30–60 min until the last visible gel particles disappear. Because PVA solutions are non-Newtonian, the apparent viscosity measured at 20 rpm differs from that at 100 rpm; certificates of analysis require a defined spindle and speed. In plant practice, batch-to-batch viscosity drift above 50 mPa·s is often traced to inadequate moisture correction of the weighed powder or to evaporation during the hold period. Solids should be checked by gravimetric drying in a forced-air oven at 105 °C for 3 h or by refractive index correlation calibrated against the same grade. Prolonged heating above 95 °C may advance hydrolysis and yellow the solution; therefore, temperature excursions above 98 °C are generally avoided.
In water-based adhesive formulation, Shuangxin 24-88 PVA is used as a base resin or co-binder in paper tube winding, carton sealing, and remoistenable adhesive systems. The 88 mol% hydrolysis level leaves sufficient hydroxyl groups for sodium tetraborate or boric acid complexation while retaining enough residual acetate to reduce the critical dissolution temperature. Formulators commonly prepare a 15–20 wt% aqueous solution and then add plasticizer such as glycerol at 2–5 wt% of the dry resin to reduce embrittlement. In paper surface sizing, the solution is applied at the size press at 0.5–3.0 wt% solids depending on the substrate and machine speed. The film strength of 24-88 is higher than that of 17-88 at comparable solids because the higher degree of polymerization increases chain entanglement, as reflected in comparative tensile tests under ISO 527-3 or equivalent GB/T 1040.3 methods. However, the higher viscosity also reduces penetration into dense paperboard; for low-porosity grades, a lower-viscosity PVA such as 17-88 is substituted or the application temperature is raised to 60–70 °C. The powder is compatible with neutral and alkaline papermaking additives but not with strong oxidizing agents.
When used as a protective colloid in vinyl acetate-ethylene (VAE) emulsion polymerization, the molecular weight distribution and hydrolysis degree of 24-88 influence particle size, viscosity, and coagulum formation. The resin is usually pre-dissolved to 10–15 wt% in demineralized water and charged to the reactor before initiator addition. The residual acetate groups promote interfacial activity, while the long 2400 DP backbone provides steric stabilization. In comparison with 17-88, the 24-88 colloid yields coarser particles and higher emulsion viscosity at equal solids because the longer chains create larger hydrodynamic volume in the aqueous phase. Reactor operators have reported that undissolved gel particles from incomplete colloid dissolution act as seed points for coagulum on the agitator and baffles; this failure mode is reduced by filtering the colloid solution through a 100-mesh stainless steel screen before charging. During polymerization, the viscosity of the emulsion can pass through a maximum at 35–55% monomer conversion if the colloid concentration is above 4 phr; this is a process conflict that requires staged initiator addition and jacket cooling. Published data for this specific Shuangxin grade in high-pressure VAE autoclaves is limited; general behavior is inferred from equivalent 24-88 grades tested under JIS K6726 and GB/T 12010.2.
Cast films of 24-88 can be produced from aqueous solution at 10–20 wt% solids using a doctor blade or air-knife coating. The resultant film is transparent, flexible, and sensitive to ambient humidity. At 50% relative humidity and 23 °C, the equilibrium moisture content of an 88 mol% hydrolyzed PVA film is higher than that of a 99 mol% hydrolyzed grade because the residual acetate groups reduce the density of interchain hydrogen bonds. For applications requiring temporary water solubility, such as detergent unit-dose film or laundry bag film, the 88 mol% hydrolysis level supports dissolution at 20–40 °C, whereas fully hydrolyzed 24-99 film requires temperatures above 60 °C and often splits or persists as undissolved flakes. Plasticizer exudation is a limiting failure mode: glycerol additions above 5 wt% may bloom to the film surface after storage at 30 °C and 70% relative humidity, changing the coefficient of friction. Film tensile properties are strongly dependent on plasticizer content and conditioning; reported values for similar 24-88 grades under ISO 527-3 frequently fall within 40–60 MPa tensile strength and 150–300% elongation. For use in water-soluble packaging, pre-drying of the resin to ≤0.5% volatile matter is recommended before thermoplastic processing because residual moisture can create bubbles and foaming at the die.
Selection among PVA grades is governed by the interaction of degree of polymerization and hydrolysis degree. 17-88 is a lower-viscosity partially hydrolyzed grade with a nominal 1700 DP; it dissolves more quickly and yields lower solution viscosity at equivalent solids, but its film strength is lower. 26-88 is a higher-viscosity partially hydrolyzed grade with a nominal 2600 DP; it is selected when high cohesive strength and aggressive gap-filling are required, but it demands longer dissolution times and can overload size-press pump circuits. 24-99 is a fully hydrolyzed grade with a nominal 2400 DP and 99 mol% hydrolysis; it is more water resistant after drying, has a higher crystalline melting region, and requires dissolution temperatures above 85 °C, making it unsuitable for cold-water-soluble film and low-temperature adhesive processes. Shuangxin 24-88 therefore occupies an intermediate position: lower cold-water solubility than 17-88, higher film strength than 17-88, easier dissolution than 26-88, and lower water resistance than 24-99. These differences are not merely viscosity adjustments; the hydrolysis degree changes the number of residual acetyl groups and thus the compatibility with plasticizers, crosslinking agents, and hydrophobic substrates.
| Grade | Nominal DP | Hydrolysis class | 4% viscosity class at 20 °C | Processing characteristic |
|---|---|---|---|---|
| Shuangxin 24-88 / PVA 088-50 | 2400 | 86.0–89.0 mol% | 44.0–50.0 mPa·s | Medium viscosity, cold-water dispersible |
| 17-88 | 1700 | 86.0–89.0 mol% | 20.0–26.0 mPa·s | Lower viscosity, faster dissolution |
| 26-88 | 2600 | 86.0–89.0 mol% | 55.0–65.0 mPa·s | Higher viscosity, slower dissolution |
| 24-99 | 2400 | >99.0 mol% | 44.0–50.0 mPa·s | Requires hot-water dissolution, higher water resistance |
Under high-humidity storage conditions, the powder takes up moisture and flows less predictably through screw feeders and weigh hoppers. The resin is hygroscopic; bulk storage silos should be closed-loop conditioned with dry air at 20–25 °C and ≤60% relative humidity. Opened bags should be resealed or consumed within a defined campaign because moisture gain above 5% can shift the apparent viscosity before dissolution and reduce the accuracy of gravimetric feeding. The powder is not classified as hazardous under EU CLP or UN GHS for transport; dust handling should comply with general respiratory protection thresholds such as 3 mg/m³ for dust not otherwise classified. From a regulatory perspective, polyvinyl alcohol may be exempt from REACH registration as a polymer under Article 2(9), provided the monomer is registered and the polymer meets the exemption criteria; users must confirm the specific import or manufacturing status. For indirect food-contact adhesives, users should verify compliance with 21 CFR 175.105 and applicable migration limits rather than relying on the base resin alone. The product should be stored away from strong oxidizers, strong acids, and open flame because organic polymer dust can form exploitable dust clouds in air.
