| HS Code | 313108 |
| Material | polyvinyl alcohol (PVA) |
| Fiber Form | chopped filament |
| Nominal Length | 12 mm |
| Filament Diameter | 39 µm |
| Specific Gravity | 1.30 |
| Density | 1.30 g/cm³ |
| Tensile Strength | 1.6 GPa |
| Tensile Modulus | 40-43 GPa |
| Elongation At Break | 6.0-6.5% |
| Melting Point | about 230 °C |
| Moisture Regain | about 3% |
| Alkali Resistance | excellent |
| Acid Resistance | resistant to weak acids; susceptible to strong acids |
As an accredited Kuraray KURALON 1239-PVA Filament Fiber factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Kuraray KURALON 1239-PVA Filament Fiber is supplied in 1 kg water-soluble pouches, packaged as 20 kg per moisture-proof carton. |
| Container Loading (20′ FCL) | Kuraray KURALON 1239-PVA Filament Fiber is packed in sealed bales/cartons, palletized, and securely loaded into a 20′ FCL container. |
| Shipping | Kuraray KURALON 1239-PVA Filament Fiber ships as dry, wound spools or bales on pallets, wrapped in moisture-barrier film. Avoid humidity, punctures, and direct sunlight. Transport at ambient temperature in standard dry cargo containers or trucks. Ensure proper labeling and separation from incompatible materials. |
| Storage | Store KURALON™ 1239-PVA Filament Fiber in its original, unopened packaging in a cool, dry, well-ventilated area. Protect from moisture, rain, and high humidity, as PVA is water-soluble. Avoid direct sunlight, heat sources, and sharp objects. Keep away from ignition sources and incompatible chemicals. Maintain stable temperature and low humidity for optimal performance. |
| Shelf Life | Shelf life is indefinite under proper storage: keep dry, cool, and sheltered from direct sunlight and moisture. |
The conversion of KURALON 1239-PVA filament fiber into chopped reinforcement for engineered cementitious composite (ECC) places the interfacial bond between hydroxyl-rich fiber surfaces and cement hydration products at the centre of the processing window. In production-scale ECC, the filament is precision-cut to 6 mm or 12 mm and added to a high-shear pan or planetary mixer. The main process conflict is not dispersion alone, but the tendency of uncoated PVA filament to form a chemically bonded interfacial layer that exceeds the fiber tensile capacity. Fiber rupture then occurs at crack openings below 50 µm, suppressing multiple-crack development and limiting strain-hardening behaviour. An oiling treatment of 0.8–1.2 wt% is therefore specified on the fiber surface to reduce the chemical bond and promote pullout-dominated slip-hardening. A reference matrix for PVA filament ECC contains cement at 1.00, low-calcium fly ash at 1.20, silica sand at 0.80, and a water-to-cementitious-material ratio of 0.27. Polycarboxylate-based superplasticizer is added at 1.3 wt% of binder to achieve the required mini-slump flow before fiber addition. Chopped PVA filament is introduced at 2.0 vol%, which is generally the upper practical limit for pan-mixer dispersion; above this level, fiber balling becomes severe unless vacuum deaeration and slower addition rates are used. In a high-shear mixer with paddle speeds above 120 rpm, the fiber should be fed gradually over 30–60 s after the matrix reaches a homogeneous sheen. Slurry temperature is held below 40 °C to avoid accelerated stiffening. Mini-slump flow typically falls from 240 mm to 180 mm after fiber addition, and this drop is used as an indirect indicator of fiber distribution. Hardened composite performance is evaluated under ASTM C1609/C1609M-19 and, where applicable, JCI-DFRCC. Published ECC using PVA fibers reports direct tensile strain capacity in the range of 3–5%; however, published data for the specific 1239 filament in this exact matrix configuration is limited. On-line failure modes include fiber balling at addition above 2.0 vol%, premature fiber rupture after storage at RH above 60% without reconditioning, and air entrainment causing reduced compressive strength. Terminal components include bridge deck link slabs, dam repair overlays, seismic coupling beams, and sprayed repair liners.
In rubber hose, V-belt, and conveyor belt carcass construction, the 1239-PVA filament cord is processed through a resorcinol-formaldehyde-latex (RFL) dipping line before calendering into uncured rubber sheet. The filament is first twisted to a first twist of 80–100 tpm and a second twist of 80–100 tpm in the opposite direction to balance torque and prevent snarling on the creel. RFL dip pickup is held between 2.5 wt% and 5.0 wt%. Below 2.5 wt%, adhesion to sulfur-cured rubber compounds becomes marginal under peel loading; above 5.0 wt%, the dried latex film forms a boundary layer that lowers mechanical interlock and increases hysteresis in the finished carcass. The RFL line drying zone operates at 120–140 °C, while the curing zone is maintained at 160–180 °C, with residence time between 60 s and 120 s per zone. Cord tension during dipping should not exceed 0.8 cN/dtex because thermal exposure combined with high tension produces fibrillar damage and reduces loop tenacity. Before entering the RFL bath, the filament moisture content is reduced to below 0.5 wt%; pre-drying at 60–80 °C is required when ambient RH exceeds 60%. Vulcanization of the reinforced rubber article is carried out at 145–160 °C for 20–40 min, depending on compound thickness and accelerator system. Adhesion is assessed by tensile peel or cord pull-out methods aligned to ISO 37:2017 and ASTM D412. After hot-air ageing per ISO 188:2011, adhesion retention at or above 80% is commonly used as the acceptance criterion for hydraulic hose cord. Production failure modes on RFL lines include centre-to-edge dip pickup variation caused by non-uniform tension, pre-cure of the latex layer in the first oven zone at temperatures above 150 °C, and cord breakage at guide-roll bearings when fiber moisture is high. The resulting carcass components are converted into hydraulic hoses, V-belts, and heat-resistant conveyor belts. Continuous PVA filament cord is not specified for prolonged exposure above 180 °C, where oxidative tensile strength loss becomes measurable.
Woven and warp-knitted geotextiles made from KURALON 1239-PVA filament are placed in contact with lime-stabilised soil, fresh concrete, or alkaline drainage media. The alkali resistance of PVA filament is a relevant design property where polyester and nylon would hydrolyse under sustained pH loading. Filaments are beamed to a rapier loom or warp-knitting machine; fabric mass per unit area is controlled to 180–350 g/m². Tensile strength is measured per ISO 10319:2015 and ASTM D4595-17. In a reinforced soil retaining wall, the geotextile is placed in layers with embedment ratio between 0.6 and 0.8 of wall height. Short-term characteristic tensile strength is reduced by creep deformation of the PVA yarn; creep evaluation per ISO 13431 is used to determine allowable design load. On production looms, the main processing bottleneck is filament stick-slip and static generation at RH below 40%, which produces broken ends and reed marks. Pre-conditioning the filament to 4–6% moisture regain improves weaving efficiency and reduces dust generation. Finished products are installed as basal reinforcement, slope facing wraps, and landfill drainage mats. Published data for 1239-PVA filament in this specific geosynthetic configuration is limited, and long-term creep curves should be generated on the actual fabric rather than extrapolated from polyester data.
For braided and twisted rope production, the PVA filament is processed on double-twist or braiding machines into 8-strand and 16-strand constructions. The braiding angle is maintained below 40° to preserve axial stiffness and limit sheath slippage under cyclic loading. Wet breaking strength retention of PVA filament ropes is generally above 80% when tested per ISO 2307:2019, supporting use in mooring lines, fishing nets, and aquaculture cage components. Knot slip resistance is evaluated by tying an overhand knot and comparing the knotted breaking load to the unknotted value; knotted strength below 55% indicates poor balance between sheath and core in braided constructions. Production-scale failure modes include core protrusion through the sheath when the braid cover is too tight, excess yarn breakage at the needle bed when filament moisture falls below 3%, and uneven take-up tension causing strand length variation. Twisted yarn is often sized with a water-insoluble size at 0.5–1.0 wt% to protect the filament during braiding; the size is scoured before use where non-industrial or food-contact certification is relevant. End uses include deep-sea fishing nets, aquaculture predator barriers, and industrial lifting slings.
Papermaking and wet-laid nonwoven reinforcement require KURALON 1239-PVA filament to be precision-cut or fibrillated to 4–12 mm and dispersed into an aqueous cellulosic furnish at 5–20 wt% of total solids. The fiber is pretreated with an anionic dispersant at 0.1–0.3 wt% before addition to prevent rope-like agglomerates in the headbox. Sheet formation follows ISO 5269-2:2004, and dry tensile strength is measured per TAPPI T 494 om-22. Strength enhancement is observed at addition levels above 5 wt%, but drainage time increases measurably above 20 wt%. Terminal products include alkaline battery separator base paper, filtration media, and heat-sealable nonwoven preforms. Filament-grade PVA reduces the tendency of fines to migrate through forming wires compared with standard PVA staple, provided the cut length is kept above 4 mm; shorter cuts behave similarly to conventional staple.
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Kuraray KURALON 1239-PVA filament fiber is a continuous, solution-spun polyvinyl alcohol multifilament yarn supplied on cylindrical packages. The suffix 1239 is a commercial grade identifier; it is not a direct statement of linear density or filament count, and converter interpretations of the suffix as a denier/filament code should not replace the certificate of analysis. Public technical data for this exact configuration is limited. The product is assigned to the high-tenacity PVA filament class rather than to water-soluble PVA staple grades, on the basis of hot drawing and reduced hot-water solubility. Polyvinyl alcohol for high-tenacity filament is typically produced from polyvinyl acetate with a degree of hydrolysis above 99.0 mol%, wet-spun into a coagulating bath, hot-drawn, and heat-set. The resulting fiber has a high degree of crystallinity, which reduces cold-water solubility and raises tensile modulus relative to partially hydrolyzed PVA film or nonwoven forms. For incoming inspection, the lot-specific certificate should be obtained and checked for linear density, filament count, twist level, finish-on-yarn, tenacity, elongation at break, and initial modulus.
Fiber-level specification boundaries are summarized in Table 1. The values are representative of the high-tenacity PVA filament class and are not a substitute for lot-specific certification. The density of polyvinyl alcohol filament is typically between 1.26 g/cm³ and 1.30 g/cm³, which is below the density of E-glass and above that of polypropylene. Tensile testing of PVA multifilament yarn is performed with a gauge length of 250 mm or greater and a constant rate of extension of 300 mm/min; a pre-tension of 0.5 cN/dtex is applied to remove slack without introducing creep. Conditioning at 20±2°C and 65±4% RH for at least 24 h is required before testing because the hydrophilic surface absorbs water and changes tensile response. Failure under axial load is primarily fibrillar; low-humidity measurements may show elongation values 1–2 percentage points lower than conditioned values.
| Parameter | Typical range | Test method |
|---|---|---|
| Linear density | Lot-specific; grade suffix 1239 does not substitute for the certificate of analysis | ISO 2060:1994 / ASTM D1907-12 |
| Tenacity at break | 9.0–12.0 cN/dtex | ISO 2062:2009 / ASTM D2256-10(2015) |
| Elongation at break | 6.0–10.0% | ISO 2062:2009 / ASTM D2256-10(2015) |
| Initial modulus | 180–280 cN/dtex | ISO 2062:2009 / ASTM D2256-10(2015) |
| Density | 1.26–1.30 g/cm³ | ISO 1183-1:2019 / ASTM D3800-16 |
| Equilibrium moisture regain at 65% RH, 20°C | 3.0–5.0 wt% | ASTM D2654-22 |
The finish-on-yarn level is a critical incoming-inspection parameter because it determines dispersion in water-based cementitious systems and wet-out in epoxy or RFL dipping. When finish level is below 0.5 wt%, dry filament friction on steel guides increases and fuzz generation is observed on creels. When finish level is too high, matrix adhesion can be reduced. The acceptable range is lot-specific and should be confirmed by extraction using the method named on the certificate of analysis. Published data for the 1239 configuration is limited; processors should not transfer finish specifications from one PVA grade to another without confirmation.
In vacuum-infused thermoset composite production, the continuous filament is converted into unidirectional tapes or woven fabrics on low-tension winders and rapier looms. The yarn should be unwound at a tension below 5% of the certified break load to avoid filamentation; ceramic guides and polished alumina tensioners are preferred over steel because the dry PVA yarn is sensitive to surface abrasion. Pre-drying is required when equilibrium moisture content exceeds 2.0 wt%. Vacuum drying at 60°C for 4–8 h reduces water to below 0.5 wt% prior to layup. Infusion is commonly run with low-viscosity epoxy at 25–35°C, but amine-catalyzed room-temperature systems present a process risk: tertiary amine accelerators raise exotherm and can create hydrothermal aging conditions at the fiber–matrix interface. Cure schedules should be confirmed by differential scanning calorimetry at 10°C/min; peak temperatures above 90°C require a post-cure aging program because published data for KURALON 1239-PVA filament in amine-rich matrices is limited.
On a production-scale pultrusion die of 1.5 m heated length operating at a pull speed of 0.3 m/min, processors report fuzz generation and broken filaments at the die entry when unwinding tension is set too high or when feed rollers have worn chrome surfaces. Reducing the pre-tension and replacing steel guides with polished alumina eliminated the fuzz buildup in those trials. The observation is not universal, but it indicates that continuous PVA filament processes best under controlled low-tension transport and clean ceramic contact surfaces. For pultruded profiles, short-beam shear testing according to ASTM D2344-16 and transverse tensile testing according to ASTM D638-14 or ISO 527-5:2021 are used to confirm matrix translation before serial production.
In cement-bonded boards and strain-hardening cementitious composites, the filament is chopped to 6–12 mm and dosed at 2.0–3.0 vol%. The substitution is driven by the alkali stability of polyvinyl alcohol in portland cement pore fluid at pH above 12.5. Unlike E-glass, which loses tensile strength in alkaline environments unless protected by zirconia-rich sizing, PVA filament retains its load-bearing capacity under the same exposure. However, the fiber–matrix bond in cementitious systems can become excessively strong when the matrix contains high silica fume or metakaolin; under ASTM C1609-19 flexural testing, an overly high chemical bond reduces deflection-hardening because fibers rupture rather than pull out. The critical engineering variable is not filament tenacity alone but the ratio of chemical bond to frictional bond, which is adjusted by fly ash content, water-to-binder ratio, and surface size. Published data for the 1239 configuration in this application is limited, but the broader PVA filament class has been documented in micromechanical studies of engineered cementitious composites.
Chopped filament is metered into the pan mixer after the superplasticizer has dispersed. Addition before water can cause hydrophilic fibers to absorb water and form lumps. This failure mode is observed when the water-to-binder ratio is below 0.25 and when fiber volume fraction exceeds 3.0 vol% in conventional mixing; above this threshold, workability loss and fiber balling require a high-shear mixer or vacuum mixing. In engineered cementitious composites, the PVA filament–cement interface is described by a chemical debonding stress and a frictional slip stress. Reported values in peer-reviewed PVA–mortar pullout studies are often in the range of 1.0–3.0 MPa for chemical debonding and 0.5–1.5 MPa for frictional slip, depending on fiber diameter and matrix composition. These values are matrix-specific and should not be used for design without direct measurement. The fresh-state matrix is usually controlled by a flow table test under ASTM C230/C230M-21 and a compressive strength program under ASTM C109/C109M-21 to separate fiber-related changes from cement paste variations.
On a rubber hose calendering line, KURALON 1239-PVA filament yarn is unwound under controlled tension, passed through an RFL dip bath, and heat-set in ovens between 150°C and 200°C. The dip pickup is maintained between 3.0% and 6.0% by weight to promote adhesion to NBR, SBR, or natural rubber compounds without sacrificing yarn flexibility. A high-tenacity PVA filament with elongation at break below 10% is selected over PET when lower elongation under burst load and better modulus retention in hot air up to 120°C are required. The product should not be exposed to acidic curing systems below pH 4.0 or to strong oxidizing acids; PVA is chemically resistant to oils, aliphatic solvents, and dilute alkalis, but hydrolytic degradation can occur in concentrated mineral acids at elevated temperature. Continuous use above 120°C in oxidative environments should be avoided in the absence of long-term aging data.
Storage of the yarn at relative humidity above 60% increases equilibrium moisture regain toward the upper end of the 3.0–5.0 wt% range. Pre-drying is required before RFL dipping if the yarn moisture exceeds 2.0 wt%, because residual water can reduce dip pickup uniformity and create steam pinholes in the heat-set coating. Packages should be stored at 10–30°C and protected from UV radiation and condensation; plastic film overwrap should remain intact until the creel is loaded. On a high-speed creel, static charge can develop when the filament is overdried below 1.0 wt% moisture, which increases yarn breaks at the traversing guides; conditioning to 4.0 wt% moisture before warping is a practical control measure.
The difference between KURALON 1239-PVA filament fiber and other PVA and synthetic reinforcements is most visible in three areas: fiber continuity, surface chemistry, and failure mode in alkaline or aqueous service. Continuous filament provides higher packing density and longitudinal load transfer than staple PVA of similar linear density because the number of free fiber ends in the reinforcement is reduced. The surface is hydroxyl-rich and hydrophilic, which improves wet-out by water-based dispersion and epoxy systems, but also requires moisture control during storage. Water-soluble PVA grades are designed to dissolve at defined temperatures and are not equivalent to high-tenacity filament grades; the high-tenacity PVA filament is hot-drawn and is not intended for use as a sacrificial pore former unless solubility is confirmed by the supplier. Published data for this specific configuration is limited, and solubility should be verified with the mill certificate if the fiber is being considered for temporary support or textile sizing removal.
Table 2 presents a comparative envelope for fiber selection. The values are representative fiber-class data from supplier technical bulletins and standardized textile testing; they are not a substitute for lot-specific data. The selection of KURALON 1239-PVA filament over PET or glass typically occurs when the composite matrix is hydrophilic, when alkaline durability is required without the cost and density of aramid, or when lower elongation and higher modulus than commodity polyester are required in a rubber or hose carcass.
| Fiber type | Tenacity (cN/dtex) | Modulus (cN/dtex) | Elongation at break (%) | Density (g/cm³) | Alkali resistance in portland cement |
|---|---|---|---|---|---|
| KURALON 1239-PVA filament, high-tenacity class | 9.0–12.0 | 180–280 | 6.0–10.0 | 1.26–1.30 | High; no protective sizing required |
| PET high-tenacity filament | 7.0–9.0 | 100–140 | 12–20 | 1.38–1.40 | Moderate; hydrolytic degradation at pH > 12 |
| E-glass fiber | 12.0–14.0 | 280–310 | 4.5–4.9 | 2.54–2.60 | Poor unless alkali-resistant grade |
| Para-aramid filament | 19.0–27.0 | 550–900 | 2.4–4.0 | 1.44 | High, but UV and fibrillation limits require barrier sizing |
In knitted or braided industrial fabrics for filtration support and abrasion-resistant sleeves, the filament is processed on flat-bed knitting machines with needle gauges selected to avoid filament splitting. The yarn is waxed or over-sprayed to maintain a coefficient of friction below 0.25 on steel needles; surface speed is kept below 400 m/min because higher speeds generate frictional heat and may damage the finish. Fabric converters report better stitch clarity when the yarn is conditioned to 4.0 wt% moisture and when creel tension is maintained below 3% of the yarn break load. These processing conditions are not a substitute for line trials, but they define the operating boundary for high-speed conversion of the filament.
