| HS Code | 156992 |
| Product Name | Shuangxin 20-88 PVA (PVA 088-35) |
| Cas Number | 9002-89-5 |
| Chemical Family | Polyvinyl alcohol |
| Degree Of Hydrolysis | 88 mol% (range 86.0-90.0 mol%) |
| Average Degree Of Polymerization | 2000 |
| Molecular Weight | ~88,000 g/mol |
| Viscosity 4 Solution 20 C | 35 mPa·s (range 30-40 mPa·s) |
| Volatile Content | ≤5.0% |
| Ash Content | ≤0.7% |
| Ph 4 Aqueous Solution | 5.0-7.0 |
| Bulk Density | 0.4-0.6 g/cm³ |
| Solubility | Soluble in hot water |
| Appearance | White granules |
As an accredited Shuangxin 20-88 PVA (PVA 088-35) factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Shuangxin 20-88 PVA (PVA 088-35) is supplied in 25 kg multi-layer paper bags with moisture barrier for safe storage. |
| Container Loading (20′ FCL) | 20′ FCL loading of Shuangxin 20-88 PVA (PVA 088-35): palletized bags, secured evenly, with proper ventilation and moisture protection for safe transport. |
| Shipping | Shuangxin 20-88 PVA (PVA 088-35) ships as a non-hazardous, water-soluble polymer powder. Pack in sealed, moisture-proof bags, then palletized and containerized. Keep dry, ventilated, and away from ignition sources. Avoid prolonged exposure to humidity to prevent clumping. Standard handling and transport conditions apply. |
| Storage | Store Shuangxin 20-88 PVA (PVA 088-35) in a cool, dry, well-ventilated area, away from direct sunlight, heat, and ignition sources. Keep the container tightly sealed to prevent moisture absorption. Avoid generating dust; use appropriate ventilation. Ensure incompatibility with oxidizing agents is observed. Maintain temperatures below 25°C for best stability. |
| Shelf Life | Shelf life is typically 2 years when stored in a cool, dry, sealed container away from moisture and sunlight. |
Shuangxin 20-88 PVA (PVA 088-35) is specified in downstream formulations where a partially hydrolysed poly(vinyl alcohol) of 86.0–89.0 mol% alcoholysis and a 4% aqueous solution viscosity of 35.0–45.0 mPa·s at 20°C is required. The residual acetate content produces lower crystallinity and a more open aqueous solution structure than fully hydrolysed PVA, which affects film formation, adhesive joint flexibility, and dissolution behaviour in the following industrial applications.
In recycled linerboard and fine paper manufacture, PVA 088-35 is prepared as a 4.0–8.0 wt% size-press solution and applied by rod-metering or film-transfer equipment at a wet film thickness of 6–12 µm. Compliance for direct food-contact paper and paperboard falls under FDA 21 CFR 176.170 and 176.180; surface-sized paper is verified by ISO 535 for Cobb water absorption, ISO 1924-3 for tensile strength, IGT pick-resistance testing, and TAPPI T 530 for sizing degree. The addition rate is expressed as dry pick-up: 0.4–1.2 g/m² per side for recycled linerboard and testliner, and 1.0–2.0 g/m² per side for fine paper and envelope base. The make-down system uses a 5–10 m³ jacketed vessel at 90–95°C with a high-shear Cowles disperser, followed by dilution to working concentration and filtration through 100–150 µm bag filters. On the coating line, rod-pressure and machine-speed interactions become critical above 900 m/min: edge misting and rod streaks have been observed when solution viscosity at 50°C exceeds 200–250 mPa·s on a Brookfield LV spindle, and the formulation is corrected by reducing solids to 6.0% or adding a nonionic ethoxylate wetting agent at 0.05–0.10% of solution mass. Finished paper grades include recycled linerboard, corrugating medium, folding carton board, food-contact bakery papers, and envelope base paper.
PVA 088-35 functions as an aqueous-phase protective colloid and particle-bound stabiliser in poly(vinyl acetate) homopolymer and vinyl acetate-ethylene copolymer emulsions for packaging and wood assembly. In a 5 m³ glass-lined batch reactor, an initial PVA charge of 3.0–6.0 phm is dissolved at 10–12% solids in demineralised water at 90°C, cooled to 60–70°C, and combined with 0.10–0.25 phm ammonium persulfate before a 3–4 h delayed vinyl acetate monomer feed. Below 3 phm, latex particles grow to median diameters above 1.8 µm, reactor wall fouling increases, and Brookfield viscosity at 20 rpm and 25°C can fall below 5 000 mPa·s, producing shelf instability. At 5.0–6.0 phm, median particle size typically narrows to 0.8–1.2 µm and final emulsion viscosity rises to 15 000–30 000 mPa·s on a Brookfield RV spindle 5. Compliance references are EN 204 and EN 205 for D3 wood adhesive classification, FDA 21 CFR 175.105 for incidental food-contact packaging adhesives, ISO 3251 for non-volatile content, and ISO 13741-1 for residual vinyl acetate monomer. The downstream process includes redox finishing with 0.03–0.08 phm tert-butyl hydroperoxide and sodium formaldehyde sulfoxylate, vacuum defoaming, pH adjustment to 4.5–5.5, and final packaging through 150–200 µm filters. Finished products include D3 PVAc wood glues, paper lamination adhesives, bookbinding emulsions, and repulpable packaging adhesives. Sodium borate post-addition is limited to 0.2–0.4% of wet emulsion mass because excess borate crosslinks residual alcohol groups and can produce irreversible gelation in this hydrolysis range.
A 10–15 m³ make-down vessel fitted with a bottom-entry turbine is used to pre-dissolve PVA 088-35 at 10–15% solids for corrugating and tube-winding adhesives before it is added to the carrier portion of a Stein Hall starch system. The grade can replace 15–35% of carrier starch solids and is incorporated at 2.0–4.0 wt% of finished adhesive mass at 22–28% total solids. Sodium hydroxide is dosed at 0.8–1.2% on starch solids and borax at 0.2–0.4% of finished adhesive mass; the PVA increases adhesive tack and wet strength on semi-porous recycled liners, verified by TAPPI T 811 edgewise compression testing of the finished board and ISO 3037 edgewise crush resistance. FDA 21 CFR 176.170 covers incidental food contact for corrugated packaging, and REACH registration covers the polymer and residual input substances. On the corrugator, the adhesive is applied at 52–58°C with a grooved roll coater and a compression time of 5–15 s at machine speeds of 200–350 m/min; insufficient PVA make-down into a fully dissolved solution leads to visible gel particles on the glue roll and bond-line lumps on board surfaces. The finished output includes double-wall and triple-wall corrugated board, spiral-wound paper tubes, angle boards, and honeycomb core edge fillers. When borax exceeds 0.5% of finished adhesive mass in the presence of PVA 088-35, viscosity can climb beyond 3 000 mPa·s at 55°C, causing pump cavitation and starved application at the glue station.
Warp sizing of ring-spun cotton and polyester/cotton blended yarns uses PVA 088-35 as the primary film-forming binder in size formulations at 6–12% solids, with a target size pick-up of 8–14% dry mass on the warp. The size box is maintained at 80–85°C, squeeze rollers are set to 12–18 kN/m linear pressure, and the section is dried through cylinder cans at 95–130°C before winding. Compliance for the finished fabric is assessed against OEKO-TEX Standard 100 Annex 4 limits for residual monomers and restricted additives, ZDHC MRSL Version 3.1 for size formulation inputs, and REACH Article 33 for intentionally released substances. The addition level is adjusted to yarn hairiness and count: 8.0–10.0% solids for carded cotton, 10.0–12.0% solids for combed cotton and polyester/cotton, and 2.0–4.0% polyacrylic ester size is co-formulated to reduce sloughing on high-speed looms. Weaving-room humidity is held between 65–75% RH because the 88 mol% hydrolysis film absorbs moisture and can become tacky above 80% RH, leading to locking at the reed and increased warp stops. Finished textile products include shirting, sheeting, workwear, and dyed or printed woven fabrics. Desizing requires hot-water or oxidative treatment; amylase enzymes alone do not remove this synthetic size, and residual PVA above 0.3% on mass of fibre, detected by iodine-boric acid staining, can reduce reactive dye uptake in subsequent finishing.
Ceramic tape casting of alumina and glass-ceramic substrates uses PVA 088-35 as a water-soluble temporary binder because the residual acetate groups plasticise the dried green sheet and improve punching flexibility. The slurry is compounded at 55–65% solids with 1.0–3.5 wt% PVA on dry ceramic powder, 0.5–1.0 wt% glycerol or PEG 400 plasticiser, and 0.1–0.5 wt% ammonium polyacrylate dispersant; the mixture is milled in a planetary mill for 12–18 h and deaired under 100–200 mbar vacuum. Green tapes are cast with a doctor-blade gap of 200–800 µm onto Mylar carrier film and dried at 60–80°C with laminar air velocity below 1.5 m/s; drying above 80°C forms a surface skin that entrains residual water and causes blisters during binder burnout. Compliance for finished substrates is tested to ASTM C1161-18 flexural strength and ISO 14644-1 Class 8 cleanroom limits for tape-handling rooms. The binder burnout schedule ramps at 0.5–1.0°C/min to 450–600°C in air, holding for 1–2 h to reduce carbon residue below 0.05%. Published data for this exact viscosity grade in submicron alumina tape casting is limited; the addition window is derived from alumina and LTCC tape-casting literature using PVA binders with 80–89 mol% hydrolysis. Finished product types include alumina substrates for thick-film circuits, glass-ceramic tapes for low-temperature co-fired ceramic modules, silicon nitride substrate tapes, and zirconia-based green sheets for planar oxygen sensors.
Dry-mix cementitious tile adhesives and gypsum wall putties use PVA 088-35 as a secondary water-retaining polymer at 0.3–1.0 wt% of the total powder formulation. A C1T tile adhesive formulation contains CEM I 52.5R cement, 0.1–0.5 mm silica sand, 0.3–0.5% cellulose ether, 1.5–3.0% redispersible polymer powder, and 0.3–1.0% PVA 088-35; the dry blend is mixed for 10–15 min in a twin-shaft paddle mixer to avoid localised PVA concentrations that form gelatinous lumps on water addition. Water demand is maintained at 24–26% of dry mix, and the polymer dissolves during the initial 3–5 min of mixing, increasing open time to 25–30 min and reducing slip on vertical ceramic facades. Compliance is assessed by EN 12004-2 for tensile adhesion after water immersion and heat ageing, with a minimum 0.5 N/mm² required for C1 classification, and EN 196-1 for compressive strength. GB 18583 covers free formaldehyde and VOC release in indoor adhesives where the dry-mix is sold as a ready-mixed or site-mixed adhesive. At loadings above 1.2 wt%, PVA 088-35 retards cement hydration and reduces 28-day compressive strength by more than 10% compared with the same formulation without PVA, and continuous water exposure at 23°C for 7 days can extract the non-crosslinked polymer and increase porosity. Finished products include C1T ceramic wall and floor tile adhesives, gypsum wall putty, cementitious skimming compounds, and non-structural repair mortars.
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Shuangxin 20-88 PVA, also designated PVA 088-35, is a partially hydrolyzed polyvinyl alcohol resin with a nominal alcoholysis degree of 87.0–89.0 mol% and a 4% aqueous solution viscosity at 20 °C of 35.0–42.0 mPa·s when tested according to GB/T 12010.3-2010. The resin is supplied as a white granular solid; typical certificate-of-analysis limits include volatile matter ≤5.0 %, ash ≤0.5 %, and pH 5.0–7.0 in a 4% solution. The 20-88 designation identifies a nominal degree of polymerization of 2000 and an alcoholysis level of approximately 88 mol%. The alternative PVA 088-35 code carries the same hydrolysis information; the 088 segment corresponds to the 88 mol% alcoholysis band, and the 35 segment corresponds to the 35.0–42.0 mPa·s viscosity specification. The grade occupies the medium-high viscosity position among partially hydrolyzed PVA resins. PVA 17-88 is typically specified at 20.0–28.0 mPa·s and PVA 24-88 at 44.0–52.0 mPa·s under the same 4 % solution conditions. Compared with fully hydrolyzed PVA 20-99, the 20-88 grade has a residual acetate content of approximately 11–13 mol%, which reduces crystallinity, lowers dissolution temperature, and yields films with higher elongation but lower water resistance. Compared with low-viscosity PVA 05-88, the 20-88 grade contributes greater film strength and higher solution viscosity at equivalent solids. The main downstream uses of 20-88 are textile warp sizing, paper surface sizing and coating co-binder, water-based adhesive compounding, and protective colloid in vinyl acetate and acrylic emulsion polymerization. The material functions as a film-forming, hydrogen-bonding polymer rather than as a thermosetting or reactive crosslinker.
Plant-scale dissolution of 20-88 is normally conducted by first forming a cold slurry, then heating under controlled shear. In a jacketed stainless-steel vessel, the powder is wetted into demineralized water at 20–30 °C using an anchor or pitched-blade impeller at 60–80 rpm. The dispersion is then heated to 90–95 °C and held for 30–60 min at 300–500 rpm. If the slurry is heated before complete particle wetting, a gelatinous skin forms on individual granules and retards water diffusion; this is the most common cause of undissolved fisheye defects in downstream coating and sizing lines. In a 5000 L vessel with a diameter-to-height ratio near 1:0.6, a heating ramp above 2 °C/min can produce a rubbery heel at the tank bottom. A high-shear rotor-stator mixer is often required to redisperse such a heel, which increases batch time and can shear-degrade the polymer if the local temperature exceeds 95 °C. A 10 % batch after dissolution should pass a 100 mesh screen with less than 5 g retained gel per 1000 L.
Concentrations above 15 wt% can form a stiff gel on cooling below 30 °C; even a 10 wt% solution may develop structure viscosity sufficient to reduce metering-pump efficiency when line hold times exceed 2 h. Solutions are therefore held at 60–80 °C in circulation lines. The viscosity of a 10 % solution at 90 °C is typically in the range of 200–400 mPa·s; at 25 °C it may exceed 2000 mPa·s depending on shear history and residual acetate distribution. The powder should be pre-dried at 60–70 °C for 2–4 h in a dehumidified hopper dryer when ambient relative humidity exceeds 60 %; otherwise surface moisture causes lumping in screw feeders and shifts the volatile matter result. In adhesive preparation, borax should not be added to a concentrated 20-88 solution without dilution and pH control. Borate-induced complexation with the 88 mol% hydrolysis structure can produce a rapid viscosity increase, particularly above 0.5 wt% borax based on total wet adhesive weight.
The pH of a 10 wt% solution is typically 5.0–7.0. Prolonged exposure to pH <2 or pH >10 at temperatures above 50 °C can hydrolyze or condense the polymer and reduce molecular weight. The recommended processing boundary for batch make-up is therefore pH 4–9 at 50–95 °C. For long-term storage of wet solution, a biocide may be required because the polymer itself is biodegradable by specific microorganisms, but the solution is not inherently preserved.
In water-jet weaving of polyester/cotton warps, 20-88 is formulated at 6–10 wt% of the sizing liquor together with oxidized starch and acrylic size. The size-box temperature is maintained at 85–90 °C, and the squeeze nip pressure is typically 12–18 kN/m. Relative to PVA 17-88, the higher viscosity of 20-88 increases size add-on at equivalent solids and machine speed, but can reduce penetration into high-twist yarns. For mill-scale control, the size liquor is often adjusted to 8–12 s on a Zahn cup No. 2 at 90 °C; when penetration problems appear on high-twist cotton blends, a portion of 20-88 is replaced with 17-88 to bring the value into the 6–10 s range. Size add-on is typically 10–14 % by yarn weight for medium-count polyester/cotton warps; below 8 % weaving abrasion resistance may fall, while above 16 % desizing costs and water consumption increase.
Desizing is conducted in hot water or enzyme desizing lines. Because 20-88 is not readily degraded by conventional starch enzymes, recovery by ultrafiltration is used where local chemical oxygen demand discharge limits are restrictive. Film strength data generated on cast films from a 10 % solution per ISO 527-3:2018 can be used for incoming lot comparison. Direct inter-plant comparison requires identical conditioning at 23 °C and 50 % RH; otherwise residual moisture changes the tensile modulus and elongation at break.
In vinyl acetate emulsion polymerization, 20-88 is used as a high-viscosity protective colloid at loadings commonly around 3–6 wt% based on total monomer. Substitution from 17-88 to 20-88 at equal colloid loading changes both the molecular weight fraction in the continuous phase and the diffusion resistance at the monomer-water interface. The expected practical result is a broader particle size distribution and a higher low-shear emulsion viscosity. Particle size is measured by dynamic light scattering per ISO 22412:2017 after each grade change; emulsion viscosity is controlled per ISO 2555:2018 at 25 °C using a Brookfield viscometer at 20 rpm. Published data for this specific Shuangxin grade in a single full-scale reactor configuration is limited; therefore, particle-size and grafting shifts should not be read across without pilot or production-scale verification.
During polymerization at 65–75 °C with ammonium persulfate initiator, the PVA chain can participate in grafting reactions with vinyl acetate. The 88 mol% hydrolysis level provides sufficient adjacent hydroxyl groups to induce strong hydrogen bonding with the growing poly(vinyl acetate) phase. The higher molecular weight of 20-88 relative to 17-88 gives a more continuous network in the continuous phase, which raises yield stress and low-shear viscosity. High-shear mixing at 1000–2000 rpm can reduce visible gel slugs, but air entrainment must be controlled because it can destabilize the emulsion.
| Parameter | PVA 17-88 | Shuangxin 20-88 (PVA 088-35) | PVA 24-88 |
|---|---|---|---|
| 4% solution viscosity at 20 °C | 20.0–28.0 mPa·s | 35.0–42.0 mPa·s | 44.0–52.0 mPa·s |
| Alcoholysis degree | 87.0–89.0 mol% | 87.0–89.0 mol% | 86.0–89.0 mol% |
| Volatile matter | ≤5.0 % | ≤5.0 % | ≤5.0 % |
| Ash | ≤0.5 % | ≤0.5 % | ≤0.5 % |
| Solution behaviour | lower viscosity, faster penetration | medium-high viscosity, film strength | high viscosity, slower dissolution |
In starch-based adhesive compounding, 20-88 is added as a pre-dissolved 10–15 wt% solution to reach 2–5 wt% PVA on dry starch. The high viscosity of 20-88 can raise final adhesive viscosity above 3000 mPa·s at 25 °C if the addition level is not reduced relative to 17-88. Borax addition is limited to 0.3–0.5 wt% of total wet adhesive; above that range, borate crosslinking with the partially hydrolyzed PVA can cause gelation and transfer-roll streaking. Compared with 24-88, the 20-88 grade dissolves more readily at typical adhesive cook temperatures of 80–90 °C and gives lower final viscosity at equal solids. Paper-to-paper lap shear adhesion can be screened per GB/T 7124-2008, but lot-specific published data for this configuration is limited.
In surface sizing at the size press, 20-88 is typically applied at 0.5–2.0 % solution concentration, alone or with oxidized starch, to maintain a size-press working viscosity of 20–100 mPa·s at 50–60 °C. The higher viscosity of 20-88 relative to 17-88 means that a lower PVA-to-starch replacement ratio is used when the size press is limited by viscosity rather than by total solids. Pick-up control on blade or rod metering systems should be verified by ISO 535:2014 Cobb measurements after each grade change. Printing-grade targets are typically in the 25–50 g/m² range, but the grade itself does not define an absolute Cobb limit; base-sheet porosity and size-press solids dominate the result.
As a co-binder in paper coatings, 20-88 raises water retention and dry pick strength, but it increases high-shear viscosity at blade coater speeds above 1200 m/min. In formulations containing more than 0.5 parts PVA per 100 parts dry pigment, streak defects can appear if blade pressure is not adjusted and coating colour temperature is below 40 °C. The practical upper limit depends on blade geometry, base sheet absorbency, and coating colour solids; published data for this specific grade in single blade-coater configurations is limited. In corrugating adhesives, addition of 1–2 wt% 20-88 on total adhesive solids raises dry bond strength; wet strength remains inferior to fully hydrolyzed PVA 20-99 or chemically crosslinked systems.
In cast-film applications, 20-88 films are produced by solution casting or melt extrusion with plasticizers. A 10 % solution cast onto a chrome-plated drum at 80–85 °C surface temperature gives a dry film thickness of 30–60 µm depending on line speed. Plasticizer addition of 5–15 phr glycerol or polyethylene glycol is used to reduce brittleness; without plasticizer, film conditioned at 23 °C and 50 % RH commonly falls in the range of 30–45 MPa tensile strength and 150–250 % elongation at break when tested per ISO 527-3:2018. Lot-specific values for Shuangxin 20-88 should be confirmed by the same method because residual moisture and acetate distribution influence the result. The film remains water-soluble after drying; this differentiates 20-88 from fully hydrolyzed grades that require higher temperature to redissolve and from crosslinked barrier coatings that are insoluble. Migration of low molecular weight fractions from PVA films into food simulants is evaluated under EU 10/2011 or 21 CFR 177.1670 where applicable.
Incoming lots should be released against the manufacturer certificate of analysis and verified by the following test methods. Viscosity is determined on a 4 % aqueous solution at 20 °C using GB/T 12010.3-2010; volatile matter is measured by oven drying per GB/T 12010.4-2010; ash is determined by muffle furnace ignition per GB/T 12010.5-2010. Alcoholysis degree is verified by saponification titration or an equivalent calibrated method; typical acceptance limits are 87.0–89.0 mol%. The pH is measured on a 4 % solution with a calibrated glass electrode.
| Property | Method | Typical acceptance limit |
|---|---|---|
| Viscosity, 4% solution at 20 °C | GB/T 12010.3-2010 | 35.0–42.0 mPa·s |
| Alcoholysis degree | saponification titration / supplier method | 87.0–89.0 mol% |
| Volatile matter | GB/T 12010.4-2010 | ≤5.0 % |
| Ash | GB/T 12010.5-2010 | ≤0.5 % |
| pH, 4% solution | glass electrode method | 5.0–7.0 |
Sampling requires a composite from at least 3 points in the lot after homogenization. Moisture uptake during QC handling must be avoided because water absorption above 5 % alters flow properties and can shift measured ash and volatile matter. For food-contact paper sizing or paperboard applications, the final formulated article must be evaluated under 21 CFR 176.170 or 21 CFR 175.300 as applicable; the resin grade alone does not confer compliance.
