| HS Code | 281963 |
| Product Name | Sinopec-SVW SS-4 Low-Temperature Water Soluble PVA Fiber |
| Fiber Type | Water-soluble polyvinyl alcohol staple fiber |
| Water Solubility Temperature | Approximately 40°C |
| Tensile Strength | 3.0–4.0 cN/dtex |
| Elongation At Break | 15–25% |
| Initial Modulus | 25–35 cN/dtex |
| Fineness | 1.5–2.0 dtex |
| Cut Length | 38–51 mm |
| Moisture Regain | ≤5% |
| Degree Of Polymerization | Around 500–600 |
| Alkali Resistance | Good resistance to weak acids and weak alkalis |
As an accredited Sinopec-SVW SS-4-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 double-layer moisture-proof woven bags, palletized and shrink-wrapped to protect against humidity during transport. |
| Container Loading (20′ FCL) | Sinopec-SVW SS-4 PVA fiber loaded in 20′ FCL: dry, moisture-proof packing, evenly stowed, secured for safe transit. |
| Shipping | Sinopec-SVW SS-4 Low-Temperature Water Soluble PVA Fiber ships in dry, moisture-proof packaging to prevent premature dissolution. Product remains stable under normal transport temperatures but must be shielded from rain, condensation, and high humidity. Use clean, dry containers or trucks; avoid compression damage and ensure proper ventilation during handling. |
| Storage | Store in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and open flames. Keep container sealed to protect against moisture, humidity, and contamination. Avoid stacking heavy loads or rough handling that could damage bales. Use FIFO rotation; recommended shelf life is typically 12 months under proper conditions. |
| Shelf Life | Shelf life is 12 months from production date when stored unopened in a cool, dry, well-ventilated area. |
When a wet-laid nonwoven is designed to disperse after discharge into municipal wastewater, the binder fiber controls whether the sheet survives converting abrasion yet releases mechanically after agitation in water. Sinopec-SVW SS-4 low-temperature water-soluble PVA fiber is introduced at 5 wt% to 15 wt% on dry furnish mass, with finished wipe substrate basis weight from 45 g/m² to 65 g/m² measured according to ISO 9073-1. The furnish pH is maintained at 6.5 to 7.5 because alkaline conditions above pH 9 accelerate surface hydrolysis of the partially hydrolyzed polyvinyl alcohol, while acidic conditions below pH 4 shift the solubility window and destabilize dispersion. The headbox stock temperature is held below 30°C to avoid premature dissolution of the fiber surface, which increases suction-box fouling and felt deposits. On an inclined wire wet-laid machine, vacuum dewatering is followed by a through-air dryer with supply temperature limited to 120°C to 135°C; exposure above 160°C creates heat-induced crystalline domains that reduce cold-water dispersibility and produce non-dispersible residues. Hydroentanglement consolidates the web at injector pressure of 60 bar to 90 bar using flat-jet strip orifices from 120 µm to 140 µm; this mechanical bonding step preserves flushability in a way that thermal bonding does not. Wet tensile strength measured by ISO 9073-3 is controlled between 1.2 N/5 cm and 2.0 N/5 cm in the machine direction for converting, while slosh-box disintegration according to INDA/EDANA GD4 is monitored in water at 20±2°C. The terminal flushable wipe is packed with a lotion containing 70% to 90% water by weight; packaging film must maintain a moisture vapour transmission rate below 2 g/m²/day at 38°C and 90% RH to prevent storage-induced pre-dissolution. Borate-based additives are excluded from the furnish because borate ions complex with PVA diol units and elevate the effective dissolution temperature beyond the cold-water target; the same restriction applies to casein-based coatings and starch crosslinkers that require boric acid.
| Test method | Property | Production control value |
|---|---|---|
| ISO 9073-1 | Basis weight of finished wipe substrate | 45–65 g/m² |
| ISO 9073-3 | Wet tensile strength, machine direction | 1.2–2.0 N/5 cm |
| INDA/EDANA GD4 | Slosh-box disintegration at 20±2°C | >95% fiber release after 30 min |
| ISO 9073-6 | Water absorbency of dry sheet | <10 s wicking time |
Water-soluble PVA nonwoven backing produced from SS-4 fiber is used in multi-head embroidery to support high-density stitching without leaving a permanent layer after cold-water removal. The dry-laid web is formed at basis weight 35 g/m² to 50 g/m² from staple fiber of linear density 1.5 dtex to 2.2 dtex and cut length 38 mm; low-pressure calendering is carried out at roll surface temperature not exceeding 80°C to avoid the crystallite growth that raises dissolution onset. Multi-head machines operating at 800 spm to 1,200 spm with dense satin-stitch areas above 3,500 stitches per 10 cm² require the backing to resist needle deflection and hold perforation geometry through 12 to 20 needle penetrations per square centimetre. After embroidery, the article is immersed in water at 20°C to 30°C with a water-to-fabric ratio above 20:1 and agitation at 10 rpm to 20 rpm; complete dissolution is observed within 60 seconds to 120 seconds provided the backing has not been exposed to dryer temperatures above 160°C during converting. Because SS-4 dissolves at low temperature, the final fabric does not require alkaline washing or enzyme treatments, which reduces the risk of dyed-embroidery colour bleeding. Storage is controlled below 60% RH, and the backing is supplied in sealed moisture-barrier film with desiccant units because moisture absorption above 8% to 10% moisture content causes surface tack and machine jamming. Residual formaldehyde is measured by ISO 14184-1, and the value must remain below 16 mg/kg for infant textile products under REACH Annex XVII restrictions for textile auxiliaries.
In specialty paper production, low-temperature water-soluble PVA fiber is applied as a temporary reinforcement component in wet-laid sheets that are later converted into high-porosity filter media, electrostatic paper, or battery separator substrates. The fiber is added at 1 wt% to 5 wt% of bone-dry furnish, after refining but before the fan pump, so that the low-solids stock passes through pressure screens without shortening the fiber. Furnish pH is held between 6.5 and 7.5, and the headbox temperature must remain below 30°C; if stock temperature rises above 35°C, surface dissolution begins in the white water loop, increasing dissolved solids and reducing vacuum dewatering at the forming table. In this configuration the PVA fiber remains intact through wet pressing at linear loads up to 120 kN/m, then partially solubilizes in the dryer section when the web temperature exceeds the dissolution threshold; the dissolved PVA acts as a film-forming binder at fiber-fiber junctions, generating wet and dry strength without the use of a permanent latex binder. Dryer can surface temperature is maintained between 105°C and 125°C for fine paper and between 120°C and 135°C for dense separator sheets; operation above 160°C is prohibited because it insolubilizes the PVA fraction and produces a brittle, closed-pore structure. The terminal battery separator paper is characterized by porosity above 40% and maximum pore size below 5 µm when measured by mercury intrusion porosimetry according to ISO 15901-1; the soluble PVA component is permitted to remain in the separator only if the electrolyte system is aqueous and does not contain borate ions. For wet-laid filter media, the final sheet is washed after drying to remove the PVA binder and open the pore network, then re-dried without exceeding 120°C. The addition rate must not exceed 5 wt% because excess dissolved PVA at the dryer surface increases draw tension and can cause sheet flutter on open draws.
| Process variable | Setpoint | Failure threshold |
|---|---|---|
| Headbox stock temperature | <30°C | Premature dissolution above 35°C |
| Furnish pH | 6.5–7.5 | pH > 9 accelerates hydrolysis |
| Dryer can surface temperature | 105–125°C | >160°C insolubilizes PVA via crystallite growth |
Closed-mould composite preforms require tackifying and interlayer materials that neither contaminate the resin matrix nor degrade after cure. SS-4 fiber, chopped to 6 mm to 12 mm, is opened and formed into a lightweight veil with areal density from 2 g/m² to 8 g/m² using a wet-laid or dry-laid process; the veil is inserted between dry carbon or glass plies to stabilize stack orientation during automated preforming. Preforming temperatures are kept below 140°C for contact times up to 30 minutes; above that thermal budget, PVA begins to dehydrate and crosslink, leaving a residue that is no longer fully extractable. After resin infusion and cure, the component is post-washed with water at 30°C to 40°C under low-pressure flow to dissolve the veil and create an interlaminar drainage channel; washout efficiency is evaluated by measuring void content according to ASTM D2734, and a void-volume increase above 1.0% indicates residual PVA or displaced fiber. The washout water must be free of borate and heavy-metal ions, and its pH is held below 8.0, because alkaline water above pH 10 can attack the PVA and produce low-molecular-weight residues that adsorb onto the cured epoxy surface. In vacuum-assisted resin transfer molding, the veil must not exceed 4 g/m² if the matrix is a low-viscosity epoxy with mixed viscosity below 300 mPa·s, because thicker veil layers restrict resin flow and create dry-spot defects at the interlaminar boundary. Published data for this specific configuration is limited; therefore, washout time and allowable veil areal density must be validated on the target preform tool before production release.
In healthcare linen handling, water-soluble laundry bags allow contaminated linen to be loaded directly into commercial washing machines without opening the bag, reducing staff exposure. SS-4 fiber is incorporated as a reinforcing staple in a PVA film or nonwoven bag structure at 4 wt% to 8 wt% on total dry mass; the staple length is kept below 6 mm to avoid visible fiber protrusion through the film. The bag is converted by impulse sealing or ultrasonic welding at a jaw temperature of 180°C to 220°C for film edges, while the seal area is kept below 3 mm wide to minimize the heat-affected zone that could insolubilize the polymer. In the washing machine, the bag must release between 40°C and 60°C during the pre-wash or main wash; SS-4's low-temperature solubility is exploited by programming a cold-water break cycle at 30°C for the first 3 minutes, which dissolves the bag before the thermal disinfection stage. If the hospital laundry uses ozone or chlorine-based oxidants, the PVA bag may degrade exothermically and generate foam; therefore, the bag is specified only for wash programmes without hypochlorite dosing. Tensile tear resistance of the reinforced film is measured according to ASTM D1922, and a minimum Elmendorf tear value of 400 g is typically required for handling full linen loads above 15 kg. The final product is certified for skin contact under ISO 10993-5 cytotoxicity testing when used in clinical settings, although the material is not intended for direct wound contact. Storage must remain below 50% RH and below 25°C; bags that have absorbed more than 10% moisture by mass should not be placed into the washing machine because film blocking can prevent opening and leave residual PVA on washed linen.
Immersed in natural watercourses, water-soluble PVA fiber mesh releases bait or aquaculture treatment agents only after the knitting structure loses tensile integrity. The mesh is produced from SS-4 staple spun into yarn with linear density 60 denier to 120 denier, then warp-knitted at gauge E12 to E20 with a mesh opening between 2 mm and 6 mm. The knittability of low-temperature PVA fiber is highly sensitive to humidity; the yarn is conditioned to 12% to 15% moisture content before knitting to reduce static and yarn breakage, but moisture above 20% causes surface dissolution and needle gumming. Dissolution rate in river or lake water follows a temperature-dependent profile: at 20°C, a 50 g/m² mesh dissolves completely within 90 seconds to 180 seconds, whereas at 8°C dissolution time extends beyond 5 minutes, which makes the product unsuitable for rapid-release coldwater deployment unless a lower-melt soluble grade is used. The mesh must be sealed by pressure welding at 90°C to 110°C, not by adhesive, because solvent-based adhesives leave carbonyl residues after dissolution. Because the product enters natural waters, the fiber must demonstrate ready biodegradability under OECD 301B and must not generate insoluble microplastic particles after complete dissolution. Storage in sealed bags below 30°C is required; exposure to direct sunlight for more than 48 hours causes yellowing and an increase in insoluble gel content.
Competitive Sinopec-SVW SS-4-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-Low-Temperature Water Soluble PVA Fiber is a low-temperature water-soluble polyvinyl alcohol fiber supplied as cut staple for wet-laid nonwovens, papermaking furnish, and temporary textile scaffolding. The grade designation SS-4 identifies a polymer morphology engineered for aqueous dissolution at lower process temperatures than conventional hot-water PVA staple, although batch-specific dissolution onset must be confirmed against the manufacturer certificate of analysis. The fiber is based on polyvinyl alcohol, CAS 9002-89-5, with controlled residual acetyl content and lower crystallinity than standard PVA grades. Published quantitative dissolution profiles for SS-4 in finished nonwoven constructions remain limited; the product should be qualified on production-scale equipment using the intended fabric basis weight, water temperature, and mechanical agitation.
Class-level physical properties for low-temperature water-soluble PVA staple are characterized by linear density in the range 1.0–2.2 dtex, tenacity of 3.5–6.0 cN/dtex, and elongation at break of 15–30% when tested under ISO 1973:2021 and ISO 5079:2020. These ranges represent the general product class; SS-4-specific values for cut length, finish, and dissolution temperature require certificate-of-analysis review. Cut lengths commonly supplied for wet-laid applications are 4–12 mm, while textile temporary scaffolds may use 38–51 mm. Batch-to-batch variability in dissolution onset can arise from minor shifts in acetyl content and heat treatment; incoming inspection should include dissolution verification rather than relying solely on grade name.
Residual fiber count after dissolution is governed by water temperature, water exchange rate, web density, and residence time, not by the fiber solubility grade alone. In a suction drum washer, water viscosity at 20 °C is approximately 1.0 mPa·s, while at 40 °C it declines to approximately 0.65 mPa·s; this difference can reduce convective penetration through dense nonwoven webs. If basis weight exceeds 80 g/m², interstitial water velocity often becomes the limiting factor because dissolved polyvinyl alcohol must be transported from the fiber surface through the void structure. Production-scale observation shows that shower temperature alone is insufficient when total water exchange is below 3–5 L/kg of fabric; published data for SS-4 in this configuration is limited. Open-width pad-steam ranges and rotary drum thickeners require different dwell-time profiles because mechanical nip pressure and web support alter retained water.
For low-temperature PVA staple, dissolution is surface-area-limited when water exchange is sufficient. The fiber diameter is typically 12–20 µm for 1.0–2.2 dtex PVA; smaller fibers dissolve faster because the diffusion path length is shorter. Wet-laid nonwovens containing high surface area furnish may therefore exhibit faster PVA removal than carded webs of the same basis weight. If the fiber is embedded between hydrophobic synthetic fibers, local water penetration can be hindered, leaving discontinuous PVA residues at junctions; mechanical agitation, nonionic surfactant addition, or extended immersion can improve removal. Published data for SS-4 in hydrophobic fiber blends is limited; laboratory extraction data should be generated at the intended blend ratio and web density.
Quantitative evaluation should follow a gravimetric extraction procedure in deionized water at the intended process temperature, followed by oven drying at 105 °C and reporting as mass loss. No harmonized ISO method currently exists for polyvinyl alcohol sacrificial fiber content in nonwovens; therefore, the internal method must define agitation rate, water-to-fabric ratio, extraction vessel geometry, and endpoint criterion. Without such controls, residual fiber measurements may differ between laboratories by more than the specification limit for low-temperature grades.
Wet-laid nonwoven production employs SS-4 as a sacrificial pore former, with addition levels typically adjusted between 5 wt% and 20 wt% based on target pore diameter and sheet tensile retention after dissolution. In furnish preparation, the staple is dispersed with cellulosic or synthetic fibers in a hydrapulper; because low-temperature grades soften or partially swell at lower temperatures, the pulper water temperature must remain below the specified dissolution onset. Process control should include online turbidity monitoring of white water to detect premature fiber dissolution during stock circulation. Retention aids and cationic wet-strength resins can modify fiber surface charge and dissolution behavior; jar testing under production shear conditions is required before full-scale use. After sheet formation, the fiber is removed in a low-temperature extractor or on the papermachine wire section if the stock temperature can be controlled. Published data for SS-4 addition in specific furnish formulations is limited; pilot trials on the target papermachine are the only reliable qualification route.
Replacing a hot-water PVA fiber with a low-temperature grade alters the energy balance and the processing window. Because water heating represents a significant fraction of wet-laid line energy input, the SS-4 grade permits lower extractor temperatures, but the lower temperature reduces polymer chain mobility and can increase residence time. Comparative class data are summarized below. The values are class-typical ranges assembled from publicly available literature and should not replace the manufacturer certificate of analysis for SS-4.
| Parameter | Sinopec-SVW SS-4 low-temperature grade | Conventional hot-water PVA fiber | Non-water-soluble high-tenacity PVA fiber | Test method |
|---|---|---|---|---|
| Nominal dissolution onset in water | below 40 °C; exact value CoA-dependent | 60–90 °C | insoluble under standard textile wash conditions | internal stirring dissolution test |
| Linear density | 1.0–2.2 dtex class range | 1.0–2.2 dtex class range | 0.9–2.2 dtex class range | ISO 1973:2021 |
| Tenacity | 3.5–6.0 cN/dtex class range | 3.5–7.0 cN/dtex class range | 10–15 cN/dtex class range | ISO 5079:2020 |
| Elongation at break | 15–30% class range | 15–30% class range | 6–10% class range | ISO 5079:2020 |
| Typical processing water temperature | 20–40 °C | 60–90 °C | not applicable | line qualification |
Relative to hot-water PVA fiber, SS-4 shifts the process risk from thermal damage to premature dissolution during stock circulation and drying. The lower temperature requirement permits use with heat-sensitive polyolefin or bicomponent binder fibers that shrink above 65 °C. However, the same sensitivity narrows the safe dryer temperature window; dryer cans and through-air dryers must be profiled so the web temperature remains below the dissolution onset until the intended extraction step. Production-scale suction drum washers with countercurrent water flow can maintain inventory levels; batch machines with static water often show slower PVA removal because local dissolved polymer concentration rises and suppresses further dissolution.
In embroidery base fabrics, the fiber functions as a temporary matrix that is removed after stitching to leave dimensional stability during the embroidery operation. Low-temperature solubility is advantageous when the base fabric includes elastomeric yarns or heat-set polyester that would lose structure at conventional 60–90 °C wash temperatures. The fabric is typically needle-punched or chemically bonded, and the PVA staple may be blended with cellulosic fibers at ratios determined by the required handling stiffness. Removal after embroidery uses a cold-water rinse or a gentle drum washer below 40 °C; residual PVA is assessed by stiffness loss and gravimetric mass loss. Published data for SS-4 in embroidery base constructions is limited; production trials should evaluate stitching speed, needle penetration, and wash-off completeness.
Papermaking furnishes use water-soluble PVA fiber to create temporary wet strength or as a binder for specialty papers; low-temperature grades are evaluated where wet pressing and drying temperatures cannot complete solubilization. The key process conflict is that low-temperature solubility can reduce fiber integrity during stock preparation if pulper water temperature exceeds the onset; cold-water pulpers operating at 15–20 °C are required. Retention in the sheet before the drying section depends on fiber length and stiffness; if the fiber partially swells, it may collapse and reduce void volume. Freeness and retention should be monitored according to ISO 5267-1 and a dynamic drainage analyzer because low-temperature PVA fiber can alter fines retention and sheet porosity.
On a fourdrinier papermachine, the low dissolution temperature of SS-4 can create a conflict during wet pressing if the felt water temperature rises above the grade onset. Press section water is often recycled; its temperature may exceed 40 °C in closed water loops, causing premature PVA dissolution and sheet defects. This failure mode is observed as sticky deposits on press felts and reduced sheet release. Mill experience with hot-water PVA grades does not transfer directly; low-temperature SS-4 requires press section water temperature control, felt conditioning with non-dissolving surfactants, and possibly split loop water management. Published data for SS-4 in closed-loop papermachine systems is limited; a machine trial with felt life monitoring is necessary.
Compared with non-water-soluble high-tenacity PVA fiber used for concrete reinforcement, SS-4 has significantly lower tenacity and is not a load-bearing reinforcement. Data sheets for standard high-tenacity PVA fiber specify tenacity above 10 cN/dtex, while SS-4 class ranges remain below 6.0 cN/dtex; that tenacity gap defines the application boundary. Compared with hot-water PVA grades, the low-temperature product allows scouring energy reduction but introduces stricter stock preparation temperature control. Compared with starch or polyvinyl acetate binder fibers, the fiber form provides structural support during wet-lay and leaves a defined cylindrical pore after dissolution.
Thermal history during drying modifies dissolution onset irreversibly. If PVA fiber is exposed to dryer temperatures above the glass transition or prolonged annealing, crystallinity increases and low-temperature solubility can be lost. This failure mode is recognized in low-temperature PVA fiber processing: a through-air dryer profile that overheats the web before the extraction step can shift the fiber from low-temperature soluble to partially insoluble, leaving residues on downstream rolls. Water-soluble PVA fiber is hygroscopic; storage above 65% RH can cause surface tack and clumping, especially in humid seasons. Pre-drying at 40–50 °C for 2–4 h may be required before web opening if bags have been exposed to moisture. Avoid combination with borate-based additives, such as borax or boric acid, because the diol units in PVA form reversible crosslinks that raise the dissolution temperature; avoid strong oxidizing agents, concentrated acids, and cationic polymers that can precipitate the water-soluble PVA interface. Incompatibility with aluminum sulfate at acidic pH is also reported in papermaking systems, where alum can reduce PVA solubility by forming complexes; jar testing is required before alum addition to PVA-containing furnish.
Regulatory inquiries should confirm the manufacturer’s REACH registration for the specific grade; RoHS Directive 2011/65/EU does not directly apply to PVA fiber unless incorporated into electrical equipment. Food-contact use requires separate review of polymer status and fiber finish under 21 CFR. These regulatory instruments do not replace the need for batch-level technical data from the manufacturer.
