| HS Code | 820820 |
| Product Name | Sinopec-SVW SS-4(L)-Low-Temperature Water Soluble PVA Fiber |
| Polymer | Polyvinyl alcohol (PVA) |
| Fiber Form | Cut staple fiber |
| Water Solubility Temperature | 40 deg C |
| Fineness | 1.56 dtex |
| Cut Length | 38 mm |
| Dry Breaking Tenacity | 4.0 cN/dtex |
| Breaking Elongation | 15-25% |
| Density | 1.31 g/cm3 |
| Moisture Regain | 4-5% |
| Appearance | White, clean, uniform fibers |
| Solubility Behavior | Readily dissolves in water at low temperature; stable in dry ambient conditions |
| Acid Alkali Resistance | Good resistance to acids, alkalis, and organic solvents |
| Biodegradability | Biodegradable and environmentally compatible |
As an accredited Sinopec-SVW SS-4(L)-Low-Temperature Water Soluble PVA Fiber factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Packaged in 20 kg woven bags with PE inner liners, moisture-proof and sealed for safe transport and storage. |
| Container Loading (20′ FCL) | 20′ FCL: Low-temperature water-soluble PVA fiber packed in cartons on pallets, securely stowed for safe sea transport. |
| Shipping | Ship as dry cargo in sealed, moisture-proof packaging to prevent premature dissolution. Store in a cool, dry, ventilated area away from water, humidity, and direct sunlight. Use standard chemical handling precautions, avoid dust exposure, and ensure secure labeling for transport. |
| Storage | Store in original sealed packaging in a cool, dry, well-ventilated area. Protect from moisture, rain, direct sunlight, and high temperatures. Since the fiber is water-soluble, ensure complete dryness. Keep away from open flames, heat sources, and oxidizing agents. Handle gently to prevent breakage. Proper storage preserves quality and shelf life. |
| Shelf Life | The shelf life is approximately 2 years when stored in a cool, dry place, protected from moisture and direct sunlight. |
Sinopec-SVW SS-4(L) low-temperature water soluble PVA fiber is carded on a 1.2 m carding/hydroentanglement line equipped with 120 µm orifice injectors operating at 80–120 bar; the fiber is processed as 100% furnish or blended with viscose at 20–40 wt% to produce a dissolvable embroidery backing. The low-temperature dissolution permits removal at 30–40°C in a tunnel washer within 60–90 s, leaving no thermoplastic residue on dark polyester or cotton substrates. A 30 g/m² web of 38 mm staple fiber with a linear density of 1.4 dtex typically shows a dry tensile strength of 18–25 N/50 mm when tested according to ISO 9073-3, with CD/MD ratios between 0.6 and 0.8. Embroidery machine speed is limited to 800–1000 spm on multi-head equipment because higher needle penetration rates generate localized fiber breakage and web pull-out. Conditioning before use at 65% RH and 20°C per ISO 139:2005 is required; moisture below 8% increases fly and web splitting. After embroidery, dissolution residue is checked by extracting a 100 mm × 100 mm sample in 2 L deionized water at 40°C for 10 minutes and measuring nephelometric turbidity; a limit of less than 5 NTU prevents visible deposits on thread surfaces. Direct steam calendering above 60°C before embroidery is not compatible with later removal because partially dissolved and redried PVA forms a film bond that resists washing. If thermal point bonding is required, bond surface temperature should remain at or below 60°C.
The wet-end chemistry of a Fourdrinier machine changes measurably when SS-4(L) is used as a binder fiber in specialty papers. Addition levels are 0.5–3.0 wt% of bone-dry furnish, replacing latex binder in saturated grades or wet-strength resin in tissue. Because the fiber dissolves during the drying phase, it forms a film at fiber-to-fiber junctions and raises dry tensile index without the two-sidedness caused by binder migration to the sheet surface. Blending requires a pulper stock temperature of 35°C or lower if the nominal dissolution onset is 40°C; headbox temperature must remain below 35°C to preserve fiber integrity until the dryer section. In handsheet testing per ISO 5269-2:2004, tensile index determined by ISO 1924-2:2008 increases linearly up to 2.0 wt% addition; beyond that level the effect plateaus as excess PVA film reduces bulk and air permeability. Freeness measured by ISO 5267-1:1999 shifts by 5–15 SR points depending on fiber length and addition level, so couch vacuum load and retention aid demand must be adjusted. In through-air drying tissue lines, a wet-line temperature above 40°C early in the drying curve can dissolve PVA prematurely and blind the TAD fabric with a clear film that resists standard alkaline cleaning. This failure mode is controlled by keeping the forming zone wet-line temperature at or below 40°C and delaying the high-temperature TAD profile until the web has reached 70–80% dryness. Batch-to-batch variance in dissolution onset is checked by dispersing 1.0 g of fiber in 100 mL deionized water at 40°C for 10 minutes; residue above 0.5 wt% is off-specification for wet-end addition because it produces undispersed fiber bundles in the sheet.
| Parameter | Reference method / equipment | Routine control range |
|---|---|---|
| Dissolution onset in deionized water | Thermal microscopy / internal COA method | 20–40°C |
| Dissolution time at 40°C | Dispersion of 1.0 g fiber in 100 mL water | ≤10 min |
| Fiber linear density | ISO 1973:2021 | 1.0–2.0 dtex |
| Tenacity at break | ISO 5079:2020 | ≥5.0 cN/dtex |
| Elongation at break | ISO 5079:2020 | 15–25% |
| Dissolution residue after 40°C wash | Filtration through 45 µm sieve | ≤0.5 wt% |
Preform manufacture for closed-mold resin infusion requires a binder fiber that holds dry reinforcement plies in shape and is either removed or tolerated by the matrix after cure. SS-4(L) can be needled or stitched into glass or carbon noncrimp fabrics at 2–6 wt% binder content; the low-temperature dissolution makes it suitable for washout tooling layers that must be dissolved after resin cure. Vacuum-assisted resin infusion with a 25°C epoxy system penetrates the preform without immediately dissolving the binder if the dwell time is short; however, amine-cured resin systems with bath alkalinity above pH 9 accelerate PVA swelling and gelation, creating a resin-rich boundary layer at the laminate interface. Laminates containing this fiber as a sacrificial core binder should be tested by ASTM D2584-18 for ignition loss and ASTM D3039-17 for tensile properties; interlaminar shear strength measured by ASTM D2344-16 may decrease if residual PVA film remains at ply interfaces. Washout of tooling preforms uses deionized water at 40–50°C delivered through a 4–6 bar spray manifold; full removal is verified by drying the laminate at 105°C to constant mass and comparing mass loss to the theoretical binder content. A process conflict arises with water-based mold release agents: if mold face temperatures exceed the dissolution point, PVA can dissolve inside 0.5 mm spray nozzles and block release agent application. Published data for this specific grade in laminated composite systems is limited; qualification panels tested under ASTM D3039-17 and ASTM D2344-16 are required before production use.
Because the dissolution temperature of SS-4(L) sits below the heat-setting range of many sheath polymers, the fiber is used as a sacrificial core in core-spun yarns for hollow and lightweight textile structures. On a ring-spinning frame, a 70:30 sheath-to-core ratio with cotton or wool as sheath and SS-4(L) as core is drafted at 30–40 Ne; the PVA core dissolves in a subsequent wet-finishing bath at 35–45°C, leaving an air-filled core cavity. Yarn tensile strength before dissolution, tested by ISO 2062:2009, is governed by the sheath fiber, but a tenacity loss of 5–15% is observed after core removal, depending on twist factor and yarn count. The critical bottleneck is traveler heat: spindle speeds above 12,000 rpm can raise traveler temperature locally above the dissolution point and produce tacky PVA residue on rings and travelers. Conditioning of the PVA fiber at 65% RH and 20°C per ISO 139:2005 is required before spinning; overdried fiber with moisture below 8% becomes brittle and generates fly. Hollow yarn fabrics are used in thermal underwear and filtration media where the core cavity reduces thermal conductivity and increases void volume. Reactive dyes used for cellulosic sheath fibers do not develop shade on PVA, but residual PVA in the dye bath can raise turbidity above 2 NTU, requiring a 40°C hot rinse before dyeing.
Specifications for temporary aquaculture containment mesh do not require long-term service life; a PVA filament net can be designed to dissolve after a defined immersion period. SS-4(L) filaments with a nominal linear density of 150 denier twisted into 2-ply netting are used where timed release of fish or bait is required. Knot breaking force is measured by ISO 1805:2006; a 0.5 mm monofilament knot in freshwater at 25°C typically loses 50% of its initial tensile strength within 2–8 hours depending on flow velocity. Dissolution in marine water is slower than in freshwater, and published data for SS-4(L) in natural water bodies is limited; tethered panel field trials are required before deployment. The operational boundary is strict: mesh handling must occur before immersion, because wet fiber loses dimensional stability and cannot be re-tensioned.
Transfer printing and water-soluble packaging share the requirement for a substrate that carries printed matter during handling and disappears during a controlled aqueous process. A 15–25 g/m² wet-laid or spunbond web of SS-4(L) is used as a temporary carrier for disperse-dye sublimation printing; dye transfer to the final fabric occurs at 180–210°C without fusing the PVA web if the dwell time remains below 30 s. Longer sublimation cycles above 30 s can partially dehydrate the PVA surface and form an insoluble skin, reducing redissolution speed. The carrier is removed in a cold rinse at 30°C, and residual PVA is checked by measuring total organic carbon in the rinse water, with a typical limit of less than 20 mg/L for closed-loop water reuse. For water-soluble packaging, a 25–50 g/m² film-like nonwoven is heat-sealed at 90–110°C with a jaw pressure of 2–4 bar to form pouches; seal strength tested by ASTM F88/F88M-21 should exceed 2 N/15 mm for safe handling, while the pouch must disintegrate within 60 s in 40°C water. The critical compliance point for export is EU Regulation 10/2011 on plastic materials in contact with food if the pouch contacts food; migration testing under OM2 conditions should be commissioned for the specific grade.
Competitive Sinopec-SVW SS-4(L)-Low-Temperature Water Soluble PVA Fiber prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615380400285 or mail to sales2@liwei-chem.com.
We will respond to you as soon as possible.
Tel: +8615380400285
Email: sales2@liwei-chem.com
Flexible payment, competitive price, premium service - Inquire now!
Sinopec-SVW SS-4(L)-Low-Temperature Water Soluble PVA Fiber is supplied by Sinopec Sichuan Vinylon Works as a polyvinyl alcohol staple fibre engineered for temporary binder and sacrificial reinforcement functions in low-temperature aqueous process environments. The model designation SS-4(L) identifies a low-temperature dissolution grade; the parenthetical L is the supplier’s marker for a dissolution onset below 40 °C in neutral deionised water under gentle mechanical agitation. Representative manufacturer-published values include a linear density of 1.5 dtex ± 0.2 dtex measured by ISO 1973:1995, cut lengths of 4 mm and 6 mm, dry tenacity not lower than 3.5 cN/dtex and elongation at break between 20 % and 30 % under ISO 5079:1995. The product is used in wet-laid nonwoven, papermaking, hydroentangled preform, textile sizing, and embroidery backing processes. All values are representative lot data, not specification limits; current batch certificates should be reviewed for the exact dissolution profile, residual acetyl content, and cut-length distribution.
The product is not a direct substitute for high-tenacity structural PVA fibre. Dry tenacity is lower because molecular orientation is deliberately reduced to permit low-energy dissolution. The grade should be specified only when cold-water removal or low-temperature binder activation is the controlling process variable.
Standard water-soluble PVA staple fibre typically requires process water at 60 °C to 95 °C to lose fibrous geometry, while SS-4(L) dissolves at or below 40 °C. The lower activation threshold is produced by a higher degree of hydrolysis and lower crystalline order; the supplier does not publish the full comonomer or thermal history. This difference reduces the wet-end energy required for binder activation but also removes the safety margin that higher-temperature grades provide against incidental heat. The fibre is therefore specified only when the downstream process can hold forming, pressing, and recirculation temperatures below 35 °C. In systems that can do so, SS-4(L) replaces starch or latex binders and avoids the need for steam-heated white water. The lower dry tenacity of ≥ 3.5 cN/dtex is a further differentiator: high-tenacity water-insensitive PVA fibre commonly reports 6–9 cN/dtex, so SS-4(L) is not a load-bearing reinforcement substitute.
| Property | Representative value | Test basis |
|---|---|---|
| Dissolution onset in neutral deionised water | ≤ 40 °C | Supplier internal method; no direct ISO equivalent |
| Linear density | 1.5 dtex ± 0.2 dtex | ISO 1973:1995 |
| Cut length | 4 mm, 6 mm | Supplier optical fibre-length method |
| Dry tenacity | ≥ 3.5 cN/dtex | ISO 5079:1995 |
| Elongation at break | 20 %–30 % | ISO 5079:1995 |
| As-shipped moisture content | ≤ 5.0 % | Supplier gravimetric method |
| Grade class | Nominal dissolution onset | Processing implication |
|---|---|---|
| SS-4(L) low-temperature | ≤ 40 °C | Cold wet-end processing; strict heat control required |
| Conventional SS-2 series | 60 °C–70 °C | Heated wet-end or dryer activation; wider ambient safety margin |
| High-temperature PVA grades | ≥ 90 °C | Delayed dissolution for hot drying or high-shear compounding |
The dissolution-onset test is supplier-specific because no ISO method fully captures the transition from intact staple to homogeneous solution under mill conditions. Users should request the internal method, stirring speed, and endpoint definition. Published data for exact current SS-2 series values should be confirmed against the Sinopec-SVW technical data sheet.
For drylaid preforms that are subsequently hydroentangled, SS-4(L) is blended with polyester or polypropylene staple at 5 wt% to 15 wt%. The fibre remains coherent during opening, carding, and pre-needling; dry frictional heating at needle densities above 800 punches/cm² may soften the fibre surface, though published data for this specific configuration is limited. Hydroentanglement at water pressures from 80 bar to 120 bar requires process water below 35 °C to avoid dissolved PVA accumulation in the recirculation loop. Jet strips should be inspected every 4 h during long runs because PVA surface gel can accumulate in nozzle tips and reduce jet impact force. Fabric breaking force is evaluated by ISO 9073-3 or ASTM D5035-11. This grade is limited to preforms in which final cold-water extraction is acceptable; residual surface dissolution can alter fabric hand and increase stiffness variability across the web.
Wet-laid nonwoven manufacturing uses SS-4(L) as a partial or complete binder fibre at 2 wt% to 20 wt% on dry furnish. The fibre disperses in water at 0.1 % to 0.5 % consistency without surfactant pre-treatment when dispersion temperature is kept at 20–30 °C. A stock temperature above 40 °C initiates surface gelation and raises white-water viscosity. After sheet formation, binder activation is carried out at 60–90 °C for 30–120 s in the drying section; the resulting tensile index is measured by ISO 1924-2 and water absorption by ISO 535. Dryer activation at 70–80 °C for 60 s is typical for lightweight sheets at 20–40 g/m² basis weight; heavier sheets require longer dwell. The dryer profile should include a gradual ramp rather than a rapid shock to avoid binder migration to the sheet surface. The principal process conflict is recirculated white water: if tray water approaches 40 °C, dissolved PVA raises Brookfield viscosity and increases wire contamination. At 5 wt% dissolved PVA in water at 25 °C, viscosity can exceed 50 mPa·s, causing sheet defects and press-section picking.
Excess process heat is the primary boundary condition for SS-4(L). Headbox temperatures should be held at 25–30 °C on twin-wire formers; vacuum pump heat and drying-hood blow-back can add 5–10 °C to the white-water loop, pushing the system toward the 40 °C dissolution threshold. If dissolved PVA accumulates, the wet-web tensile index decreases and felt cleaning frequency increases. Storage is a second boundary: the fibre should be kept in sealed moisture-barrier packaging at ≤ 30 °C and relative humidity below 60 %. Exposure to RH above 60 % for more than 24 h can produce tacky fibre surfaces and clumping in bale openers. Pre-drying may be required at 40–50 °C for 2 h before use, but drying air must remain below 50 °C to avoid premature fibre gelling. Conditioning for physical property verification should follow ISO 291 atmosphere A or B. Warehouse management should follow first-in-first-out inventory because aged fibre may show a widening dissolution temperature distribution if the moisture barrier is compromised.
Controlled addition of sodium tetraborate or boric acid retards the dissolution of SS-4(L) through didiol complexation with the 1,3-hydroxyl groups of PVA. This mechanism is used to retain temporary strength during intermediate processing and then remove the fibre by cold-water washing. A borate concentration of 0.1 wt% to 0.5 wt% on fibre weight shifts the observed dissolution onset upward by 15–30 °C, depending on pH and calcium hardness. The treatment bath should be maintained between pH 8.5 and 9.5; below pH 8.0 complexation is weak, and above pH 10.0 fibre surface swelling becomes excessive. Bath pH is measured by ISO 10523. Uncontrolled borate carryover from other additives can cause gel specks in wet-laid sheet and should be monitored through white-water total organic carbon and sludge dewatering tests. Published data for this specific configuration is limited, so mill trials should include worst-case pH and temperature excursions.
In textile sizing and embroidery backings, SS-4(L) functions as a temporary strength carrier that is removed in a cold-water scour at 20–30 °C. Warp sizing formulas containing 10–20 g/L of the fibre or its dissolved PVA can be removed without enzymatic desizing, reducing chemical oxygen demand compared with starch or acrylate sizes. Conventional textile PVA sizes require scour baths at 80–95 °C; the low-temperature grade therefore reduces energy input but yields a lower film strength. High-speed weaving above 800 m/min or abrasive warp yarns may require a secondary reinforcing polymer, because the dry film strength of the low-temperature grade is below that of high-tenacity PVA size films. Slash room humidity should be controlled below 60 % to prevent tack development on sized yarns.
White-water and effluent treatment from SS-4(L) processing must account for dissolved PVA as a soluble organic fraction. Dissolved PVA is poorly removed by conventional chemical coagulation unless aluminium sulfate or polyaluminium chloride is applied; membrane bioreactor degradation is possible, but kinetic data are site-specific. The dissolved PVA contributes to chemical oxygen demand and can increase foaming in activated sludge. Published data for this specific configuration is limited, and discharge permits should be reviewed before large-scale substitution.
Compliance documentation should include a current REACH registration and a supplier safety data sheet. The product is not classified as dangerous under CLP Annex I, but the supplier SDS must be checked for any national variations. Food-contact use is not automatic; verification under EU 10/2011 migration testing or a relevant national food-contact regulation is required. No medical implant use should be assumed, and no USP Class VI data is supplied for this fibre grade.
