| HS Code | 237990 |
| Product Name | Wanwei PVA 24-99(L) (PVA 100-50) |
| Appearance | white powder |
| Viscosity 4 Percent Solution At 20c | 22.0-26.0 mPa·s |
| Degree Of Hydrolysis | 99.0-100.0 mol% |
| Average Degree Of Polymerization | 2400 |
| Ph Value 4 Percent Solution | 5.0-7.0 |
| Volatile Content | <=5.0% |
| Ash Content | <=0.7% |
| Residual Acetyl Content | <=0.2% |
| Whiteness | >=90% |
| Particle Size | 20-80 mesh |
| Bulk Density | 0.45-0.65 g/cm3 |
| True Density | 1.27-1.31 g/cm3 |
| Solubility | soluble in hot water above 90C |
As an accredited Wanwei PVA 24-99(L) (PVA 100-50) factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Wanwei PVA 24-99(L) (PVA 100-50) is packaged in 25 kg multi-layer paper bags with inner plastic lining for safe transport and storage. |
| Container Loading (20′ FCL) | Loading a 20′ FCL with Wanwei PVA 24-99(L) involves securing palletized bags, preventing moisture damage, and ensuring safe, stable transport. |
| Shipping | This product ships as non-hazardous cargo in 25 kg multi-wall paper bags on pallets, wrapped and containerized. Ensure dry, ventilated storage away from moisture and direct sunlight. Handle with care to prevent bag damage; use standard warehouse equipment. No special transport declaration required. |
| Storage | Store Wanwei PVA 24-99(L) in a cool, dry, well-ventilated area, away from moisture, direct sunlight, and ignition sources. Keep containers tightly sealed when not in use to prevent dust formation and contamination. Avoid contact with oxidizing agents. Follow local regulations and maintain proper labeling for safe handling. |
| Shelf Life | Shelf life is typically 2 years from manufacture when stored sealed, cool, and dry. |
Wanwei PVA 24-99(L) — referenced internally as PVA 100-50, denoting a nominal 4 wt% aqueous solution viscosity of 44–56 mPa·s (Brookfield LV, 20 °C, spindle 1 rpm) — is integrated into size liquor formulations where the dry solids contribution of the fully hydrolyzed ( 99.0–99.8 mol% ) PVA component routinely reaches 60–85 wt% of total desizeable binder. The remainder comprises lubricants (e.g., hydrogenated tallow glyceride at 0.5–1.2 wt% of bath weight), waxes, and antifoam agents, with the size mix prepared in atmospheric jet cookers or high-shear dissolver units (e.g., Sucker S432 or Karl Mayer D3 series) operating at 90–95 °C for 45–60 minutes. Application onto ring-spun cotton (Ne 16–60) and cotton/polyester rotor yarns is performed on multi-cylinder sizing machines with double-immersion squeeze configurations; size add-on is controlled between 10–15 % o.w.f. for staple-fiber yarns destined for air-jet weaving at insertion rates exceeding 1,500 m/min. Film mechanicals, measured on cast films dried under identical conditions, show a tensile strength of >45 MPa and elongation at break of >200 % per ISO 527-3, which correlate to reduced warp end breaks — mill logs on Tsudakoma ZAX9100 looms indicate a drop in warp stops per >100,000 picks of 30–50 % relative to oxidized starch/CMC benchmarks. Compliance with the ZDHC Manufacturing Restricted Substances List is verified; the PVA grade contains <0.1 µg/g nonylphenol ethoxylates and meets the requirements of OEKO-TEX® Eco Passport certification for textile auxiliaries. After desizing with α-amylase/bacteria-based enzyme recipes at 70–80 °C or hot water hydrolytic degradation, the PVA does not generate adsorbable organic halides (AOX) above the 5 mg/L limit prescribed by ZDHC Wastewater Guidelines v2.0. Terminal form: sized warp beams for weaving of denim, chambray, poplin, and twill apparel fabrics that undergo subsequent enzymatic desizing and finishing. A processing boundary exists: in regions where ambient relative humidity persistently exceeds 75 % RH, the size film must be dried to a residual moisture content of <0.5 % before beam storage to prevent microbial spoilage and viscosity drift.
When a surface sizing agent must simultaneously bridge mechanically refined cellulose fibers and raise the IGT pick resistance of recycled linerboard, Wanwei PVA 24-99(L) is distributed in combination with oxidized corn starch on film-transfer metering size presses (e.g., Valmet OptiSizer Hard Nip) at a total bath solids of 2–6 wt%, where the PVA proportion constitutes 10–50 wt% of the dry size pickup. The grade’s high molecular weight (inferred via K-value >100 in 4 % solution) creates a continuous film that transitions the critical surface tension of the sheet from ~40 mN/m (uncoated OCC) to >52 mN/m within 0.5–1.2 g/m² dry film weight, quantified by contact angle goniometry per ASTM D5946. The following table collates regulatory clearances that apply when the sized paperboard is intended for food-contact service:
| Regulation/Standard | Scope | Specific Condition |
| FDA 21 CFR §176.170 | Components of paper and paperboard in contact with aqueous and fatty foods | Extractives limit: no more than 0.5 mg/in² for aqueous simulants; PVA recognized as indirect additive GRAS. |
| BfR Recommendation XXXVI | Paper and board for food contact (Germany) | Overall migration <10 mg/dm²; PVA permitted as sizing agent under positive list. |
| GB 9685-2016 | National food contact standard (China) | Specific migration limit for vinyl alcohol monomer ≤12 mg/kg simulant. |
| EU No 10/2011 (amended 2023) | Plastic materials and articles intended to come into contact with food (where a PE extrusion coating is applied after sizing) | Overall migration ≤10 mg/dm²; specific migration of aldehydes from any PVOH degradation must meet Annex II thresholds. |
Downstream integration sees the sized substrate calendered at 70–90 kN/m linear nip load to produce coated duplex board, white-lined chipboard, and liquid packaging baseboard destined for beverage cartons and frozen food folding cartons. In a dual-polymer approach patented for milk carton stock, a 3.5 % bath of 25 % PVA 24-99(L) / 75 % low-viscosity starch yields Cobb60 values ( ISO 535 ) below 25 g/m² without a second pass, while retaining IGT dry pick ( ISO 3783 ) above 350 cm/s. Operational caution: mixing under high-shear at pH <4.0 will accelerate flocculation if cationic polyacrylamide retention aids are present; the size press return circuit requires conductivity below 2,500 µS/cm to prevent destabilization.
In vinyl acetate-ethylene (VAE) copolymerization performed in 10–15 m³ stainless-steel stirred-tank reactors at 80–85 °C with a t-butyl hydroperoxide/ sodium formaldehyde sulfoxylate redox initiation system, the pre-dissolved Wanwei PVA 24-99(L) — charged as a 10–12 wt% aqueous solution into the initial heel — functions as the sole protective colloid at a loading of 3–8 wt% based on total monomer mass. Its degree of hydrolysis exceeding 99.0 mol% triggers a grafted poly(vinyl alcohol)-g-poly(vinyl acetate-co-ethylene) layer that stabilizes primary emulsification, yielding latices with a residual monomer content <0.5 % and a average particle diameter (dynamic light scattering, ISO 22412) tunable between 0.8–2.2 µm depending on the colloid/monomer ratio. The shear stability of the final dispersion, measured via a Klaxon high-speed disk agitator test at 20,000 rpm for 10 min, exceeds 1,200 s before coagulation onset — a threshold that makes the grade suitable for wood adhesives conforming to EN 204 Durability Class D3 and for paper/film laminating adhesives under FDA 21 CFR §175.300 (adhesives for food-contact surfaces). End-use articles include single-component water-resistant D3 PVA-based white glues (tensile shear strength on beech ≥ 6 N/mm² after conditioning per ISO 9653), postage stamp gumming compounds, and binders for nonwoven wipes. A critical operational boundary emerges with peroxy-disulfate initiators: when the residual catalyzate iron content in the PVA exceeds 5 ppm, premature gel particles form at conversion beyond 85 %; the reactor temperature must be maintained within a ±2 °C deadband to avoid runaway branching.
When manufacturing polyvinyl butyral (PVB) resin for laminated safety glass interlayers, the base PVA is dissolved to a 10–12 wt% aqueous solution and reacted with n-butyraldehyde under acid catalysis (hydrochloric acid, pH adjusted to 1.5–2.0) in a batch kneader reactor (e.g., Buss MDK-100 or sigma-blade types) at a controlled exotherm between 18–22 °C. The PVA 24-99(L) molecular chain engages in acetalization to a target formal content of 75–78 mol%, leaving a residual free hydroxyl group concentration of 18–20 mol%, which is the decisive parameter governing adhesion to float glass (peel strength >35 N/cm on glass per GB/T 32020-2015). Post-neutalisation, the precipitated PVB is washed with deionized water to reduce residual sodium chloride below 0.1 % and then plasticized with triethylene glycol di-2-ethylhexanoate (3GO) at 28–32 phr prior to twin-screw extrusion and calendering into 0.76 mm and 1.52 mm interlayer film. Vehicle glazing manufactured from this film meets the optical requirement of haze <0.5 % ( ISO 14782 ) and must not exhibit a yellowness index ( ASTM E313 ) drift greater than +2.0 after 2,000 hours of UV exposure ( ISO 4892-2 ). Markets: automotive windshield and architectural laminated safety glass conforming to ECE R43 Regulation and ANSI Z26.1 . It is essential that the raw PVA 24-99(L) carries an iron content ≤ 10 ppm and a methanol extractables content <0.5 wt%; exceeding either limit causes yellow-brown edge discoloration visible in the finished PVB sheet after autoclave bonding at 130–140 °C and 12–14 bar.
A pre-formulated compound based on Wanwei PVA 24-99(L) 100 parts, glycerol/sorbitol binary plasticizer system at 18–25 phr, internal release agent (stearic acid derivative) at 0.5–1.0 phr, and nonionic surfactant (0.1–0.5 phr) is melt-blended in a co-rotating twin-screw extruder (L/D 40:1, screw speed 250–350 rpm) with a barrel temperature profile ranging from 190 °C (feeding zone) to 215 °C (die head). A cast-film line equipped with a flex-lip coat-hanger die and multi-roll chill station draws the curtain down to a thickness of 25–40 µm ±2 µm, controlled via beta gauge feedback. For water-soluble laundry detergent pods (unit-dose formats), the film must demonstrate complete disintegration in deionized water at 20 °C within ≤60 seconds per OECD TG 301 readiness test and a residual PVA aerobic biodegradation level >60 % ThIC within 28 days. Certification landmarks: the film enzyme compatibility and toxicity profile are assessed under the EU Detergent Regulation EC No 648/2004 and the specific safety waiver for PVA encapsulants under EN 14065 (textile laundry RABC system adaptation). A production-scale constraint documented on lines exceeding 500 kg/h throughput is plasticizer blooming; if the compound residual moisture rises above 0.8 wt% (Karl Fischer titration), steam pockets nucleate within the melt phase, generating visible fish-eye defects. Pre-drying pellets in a dehumidifying hopper drier with a dew point of −40 °C for 4–6 hours at 80 °C restores film homogeneity.
For cementitious tile adhesives formulated to EN 12004 C2 classification, a partial substitution of cellulose ether with Wanwei PVA 24-99(L) at a dosage of 0.2–0.8 wt% (by mass of dry binder blend) raises the water retention of the fresh mortar to 92–97 % as verified by the vacuum filtration test of ASTM C1506-09 without altering the open time beyond the 20 minute minimum required for C2. The polymer rewets on-site to form a high-viscosity film that bridges the ettringite-rich contact zone between CEM I 42.5 R and porous ceramic tile, raising the pull-off adhesive strength after water immersion ( EN 12004 §5.3 ) from a baseline of 0.5 N/mm² to a mean of 1.2 N/mm² at 0.6 % addition rate in laboratory control mixes. Terminal product formats are single-component, polymer-modified dry-mix adhesive bags for indoor ceramic, porcelain, and glass-mosaic tiling. The constrained regimen table below illustrates the interplay between PVA load and material metrics:
| PVA 24-99(L) dosage (wt% of dry mix) | Water retention (%) ASTM C1506-09 | Open time (min) EN 12004 | Adhesion after water immersion (N/mm²) EN 12004 |
| 0.0 (only cellulose ether control) | 90.5 | 22 | 0.8 |
| 0.3 | 94.2 | 24 | 1.0 |
| 0.6 | 96.5 | 26 | 1.2 |
| 0.8 | 97.0 | 27 | 1.1 (slight cohesive failure pattern noted) |
An incompatibility requiring field attention: in mixtures where calcium sulfoaluminate (CSA) rapid-setting cement or gypsum exceeds 10 % of the binder, the alkaline-induced saponification of the PVA can abruptly collapse the viscosity at a pH above 12.7 within the first 15 minutes; the system is restricted to ordinary Portland cement-based formulations alone. Furthermore, dry mortar containing PVA must be stored at a warehouse relative humidity <55 % RH in sealed moisture-barrier bags to prevent pre-hydration that alters the dissolution profile.
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Wanwei PVA 24-99(L) and PVA 100-50 constitute two distinct polyvinyl alcohol grades manufactured by Anhui Wanwei Updated High-Tech Material Industry Co., Ltd., a vertically integrated producer operating a coal-to-acetylene-to-VAM-to-PVA synthesis chain with a reported nameplate capacity exceeding 200,000 metric tons per annum. The 24-99(L) grade is a fully hydrolyzed, high-polymerization polyvinyl alcohol: the designation “24-99” encodes a nominal degree of polymerization of 2400 and a hydrolysis level of ≥99.0 mol%, as determined by back titration per JIS K6726:1994. Its 4% aqueous solution viscosity at 20°C (Brookfield LV, spindle No. 1, 60 rpm) spans 44.0–54.0 mPa·s (ISO 15023‑1:2017). The appended (L) signifies a low-ash variant, with total inorganic residue held to ≤0.5% w/w (ISO 3451‑1:2019) through intensified polyvinyl acetate washing, a parameter critical for optical-grade film clarity. In contrast, PVA 100‑50 is a partially hydrolyzed grade: the numerical label indicates a target 4% solution viscosity of 100 ± 15 mPa·s at 20°C and a residual acetate content of 48–52 mol%. This intermediate hydrolysis state disrupts crystalline packing and markedly reduces the dissolution temperature, yielding a non‑Newtonian solution rheology that is preferentially used as a primary suspending agent in vinyl chloride suspension polymerization.
The contrast between 99+ mol% and 50 mol% hydrolysis introduces a chasm in dissolution behaviour directly governing plant‑floor operations. Fully hydrolyzed PVA 24‑99(L) requires an aqueous dissolution temperature above 90 °C; incomplete particle wetting at lower temperatures leads to gel‑skins that foul agitator blades and downstream transfer lines. On a production scale, dissolution is typically executed in a 500 L jacketed vessel fitted with a high‑shear rotor‑stator disperser (Silverson GX‑10 equivalent). A 5 wt% powder charge is introduced into water pre‑heated to 60 °C, dispersed at 3000 rpm for 10 min, then ramped to 95 °C over 30 min under controlled jacket flow. Holding at 95 °C for 45–60 min erases residual crystallites. A critical threshold appears during cooling: if the solution is cooled below 80 °C at a rate exceeding 5 °C·min⁻¹, inter‑chain hydrogen bonding overcomes thermal motion, forming a thermoreversible gel. At solids above 10 % w/w, gelation onset can shift to 85 °C, rendering post‑dissolution hold stages unworkable without steam tracing. The introduction of a 2–5 wt% co‑solvent such as dimethyl sulfoxide (DMSO) can depress the gel point by 8–12 °C, but this practice is incompatible with food‑contact film applications where residual solvent migrates. PVA 100‑50, by virtue of its residual acetate bulk, dissolves completely at 20–30 °C within 30 min using a simple paddle mixer at 200 rpm, eliminating the need for heated make‑down equipment and allowing continuous inline dosing in PVC suspension recipes.
In the manufacture of iodine‑stained polarizing film for liquid‑crystal displays, the ash fraction of the PVA raw material becomes a first‑order defect driver. Cast film from PVA 24‑99(L) is uniaxially stretched 4–6× in a boric acid bath at 55–60 °C before iodine doping. Inorganic residues—primarily sodium acetate and silica from the manufacturing process—act as nucleation sites for polyiodide agglomerates, creating localized absorption domains that manifest as black specks (≥5 µm) when viewed between crossed polarizers. A comparative trial on a 300 mm‑wide pilot stretching line (continuous tenter frame, line speed 3.0 m·min⁻¹) demonstrated that the shift from a regular 24‑99 grade with ash 0.7 % w/w to the 24‑99(L) grade with ash 0.5 % w/w reduced speck count (particles larger than 10 µm) from an average of 8.2 per cm² to 1.1 per cm², as measured by automated optical inspection (Keyence CV‑X400 series). To sustain this defect floor, the PVA solution must be passed through a 5 µm absolute-rated depth filter immediately before the slot‑die casting head. Residual moisture after drying on a chromium‑plated chill roll maintained at 10 °C is controlled to 8–12 % before entering the stretching zone; moisture excursions beyond 14 % promote iodine wash‑out and banded staining that cannot be corrected later.
PVA 100‑50 is positioned as a primary suspending agent for vinyl chloride monomer (VCM) suspension polymerization, where its hydrolysis degree and molecular weight dictate the entire particle size distribution (PSD) of the resulting PVC resin. In a production‑scale 30 m³ stainless‑steel reactor equipped with a 3‑blade retreat‑curve impeller (impeller‑to‑tank diameter ratio 0.55, tip speed 5.5 m·s⁻¹) and operating at 120–140 rpm, the PVA 100‑50 is typically dosed at 0.04–0.10 phr (parts per hundred resin) relative to monomer charge. Under these conditions, the mean particle diameter d50 falls within 125–155 µm with a distribution span (d90 − d10)/d50 of 0.85–1.15 (laser diffraction, Malvern Mastersizer 3000). The partially hydrolyzed architecture provides an optimal hydrophilic–lipophilic balance: the acetate groups anchor to the VCM droplet interface while the hydroxyl groups extend into the aqueous phase, generating a steric barrier that suppresses coalescence during the sticky conversion stage (conversion 20–40 %). A shift in hydrolysis degree from 50 mol% to 53 mol%—within the nominal lot‑to‑lot variation of some suppliers—increases water solubility sufficiently to lower interfacial tension, yielding a 20–30 µm reduction in mean particle size and a rise in the fraction of fines <50 µm from 2 % to 7 %. These fines adhere to baffle surfaces and promote reactor fouling, forcing early shut‑down for high‑pressure water cleaning. Wanwei’s in‑process hydrolysis control for PVA 100‑50 maintains a tolerance of ±2 mol%, verified by on‑line FT‑NIR monitoring of the saponification reactor, thereby constraining inter‑batch PSD drift to within ±8 µm of the target d50.
The 24‑99(L) grade is processed on cast‑film extrusion lines where the low ash burden directly translates into haze reduction and higher tear resistance. A typical configuration employs a single‑screw extruder with an L/D ratio of 30:1 and a barrier‑type screw (compression ratio 3.0:1), feeding a 600 mm‑wide coat‑hanger die. The melt temperature is maintained at 205–225 °C; pre‑drying of the granular PVA at 80 °C for 4 hours is mandatory when ambient relative humidity exceeds 60 %, as residual moisture above 0.5 % w/w generates vapour bubbles that create pinhole defects in the finished web. The melt curtain is pinned to a polished, chromium‑plated chill roll set at 12 °C with an air‑knife assist; line speed ranges from 15–40 m·min⁻¹ depending on target film thickness. Unplasticized film at 40 µm thickness exhibits mechanical and optical properties summarized in the below comparison against a standard‑ash (≤0.7 %) 24‑99 grade, all measurements conducted after conditioning at 23 °C and 50 % RH for 48 hours.
| Property | PVA 24‑99(L) | PVA 24‑99 (ash ≤0.7%) | Test method |
|---|---|---|---|
| Tensile strength at break (MPa) | 65 ± 5 | 62 ± 5 | ASTM D882‑18 |
| Elongation at break (%) | 8 ± 2 | 7 ± 2 | ASTM D882‑18 |
| Young’s modulus (GPa) | 2.2 ± 0.2 | 2.1 ± 0.2 | ASTM D882‑18 |
| Tear strength (N·mm⁻¹) | 12 ± 1.5 | 11 ± 1.5 | ASTM D1938‑19 |
| Total luminous transmittance (%) | 91 ± 1 | 89 ± 1 | ASTM D1003‑21 (Illuminant D65) |
| Haze (%) | 1.2 ± 0.3 | 2.0 ± 0.5 | ASTM D1003‑21 |
Inclusion of a polyol plasticizer—glycerol at 10 phr—raises the elongation at break of the 24‑99(L) film to approximately 150 % while reducing tensile strength to 35–40 MPa. The cold‑water‑soluble nature of PVA 100‑50 makes it unsuitable for humid‑service film structures; its primary film‑formation utility is restricted to temporary water‑soluble transfer films and laundry bags where dissolution within 60 seconds at 20 °C is the performance criterion.
| Parameter | PVA 24‑99(L) | PVA 100‑50 | Test standard |
|---|---|---|---|
| Degree of hydrolysis (mol%) | 99.0–100.0 | 48–52 | JIS K6726:1994 |
| Viscosity (4 % aq., 20 °C, mPa·s) | 44.0–54.0 | 85–115 | ISO 15023‑1:2017 |
| Ash content (% w/w) | ≤0.5 | ≤0.8 | ISO 3451‑1:2019 |
| Volatile matter (% w/w) | ≤5.0 | ≤5.0 | ISO 15512:2019 (weight loss at 105 °C) |
| pH (4 % aq. solution) | 5.0–7.0 | 5.5–7.5 | ISO 15023‑1, glass electrode |
| Methanol content (mg·kg⁻¹) | <100 | — | GC headspace, internal method |
In textile warp sizing, the high film‑forming strength of PVA 24‑99(L) reduces hairiness index on 40 Ne cotton yarn by 35–40 % compared to a starch‑only formula, although the fully hydrolyzed grade compels the use of heated size boxes maintained at 85–90 °C to avert gelation within the squeeze‑roll nip. PVA 100‑50, by virtue of its cold‑water solubility, allows room‑temperature compounding of starch‑PVA corrugating adhesives applied on high‑speed corrugators at 200–250 m·min⁻¹, where its partial hydrolysis provides rapid wet‑tack development without pre‑gelatinisation energy costs. Both grades must be stored at temperatures below 40 °C and protected from exposure to strong acids and oxidizing agents, which catalyze chain scission and discoloration. Published processing limits for the partially hydrolyzed grade caution against co‑formulation with amine‑based crosslinkers that can promote premature insolubilisation at the solution stage, leading to nozzle blockage in metering systems.
