| HS Code | 988518 |
| Product Name | Sinopec-SVW SS-2-Low-Temperature Water Soluble PVA Fiber |
| Fiber Type | Polyvinyl Alcohol (PVA) |
| Solubility Temperature | Approximately 0-20°C (low-temperature water soluble) |
| Breaking Tenacity | ≥ 4.0 cN/dtex |
| Elongation At Break | 15-25% |
| Initial Modulus | ≥ 80 cN/dtex |
| Fiber Length | 3-12 mm (cut lengths available) |
| Fineness | 1.0-3.0 dtex |
| Specific Gravity | 1.26-1.30 |
| Moisture Regain | 4.0-6.0% |
| Melting Point | Decomposes before melting (approximately 220-230°C) |
| Chemical Resistance | Resistant to acids, alkalis, and organic solvents |
As an accredited Sinopec-SVW SS-2-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 net polyethylene-lined woven bags, palletized and stretch-wrapped to protect against moisture during transport and storage. |
| Container Loading (20′ FCL) | 20′ FCL container loading: Sinopec-SVW SS-2 low-temperature water-soluble PVA fiber packed in dry, secure woven bags for safe transport. |
| Shipping | Shipped in sealed, moisture-proof packaging to prevent premature dissolution. Store in cool, dry, well-ventilated conditions away from humidity and direct sunlight. Handle carefully to avoid bag damage. Non-hazardous material; protect from water, rain, and condensation during transit. Ensure containers remain tightly closed until use. |
| Storage | Store in a cool, dry, well-ventilated area away from direct sunlight and heat sources. Keep the original packaging tightly sealed to prevent moisture absorption, which can cause premature dissolution or caking. Avoid contact with water and high humidity. Under proper conditions, shelf life is typically 12 months from manufacture date. |
| Shelf Life | Shelf life is typically 24 months when stored in a cool, dry, well-ventilated area, away from moisture and direct sunlight. |
During guipure lace and embroidered badge production, the support web is not peeled away after needlework; it is removed in a controlled aqueous scour, so residual fragments on the underside of rayon or polyester embroidery thread determine whether the finished panel can be over-dyed or laminated. Sinopec-SVW SS-2-Low-Temperature Water Soluble PVA Fiber is processed into a drylaid carded support web at 100% fibre composition, typically within a mass per unit area range of 20–60 g/m², which allows the web to survive multi-head embroidery needle impacts while dissolving at low temperature. The relevant chemical and textile contact compliance status is established by OEKO-TEX Standard 100 Class I and the registration provisions of EU Regulation 1907/2006 (REACH); mechanical adequacy of the drylaid nonwoven is determined by ISO 9073-3 tensile strength and ISO 9073-2 mass per unit area, with residual PVA film after dissolution checked gravimetrically by an adaptation of ISO 9073-2. The downstream production sequence is carded drylaying, followed by thermal calendering rather than hydroentanglement because process water above the fibre dissolution onset can generate surface tack on the calender and winder; processing temperatures are constrained to the thermal bonding window of PVA and the residence time on heated rolls must not permit full film formation. After embroidery, the composite is run through a low-liquor jig or paddle scour at 40–60°C until the support web is removed; the terminal product types include guipure lace, embroidered badges, appliqué stabilizers, three-dimensional embroidery, and water-removable sewing guides for multilayer assembled garments.
Ring-spun or core-wrapped separating yarns based on 100% SS-2 PVA staple are introduced as separation courses between garment panels on circular knit machines. The insertion ratio depends on machine diameter and separator count, but a typical yarn linear density lies between 20 tex and 60 tex, with twist in the 320–520 twists/m range to control yarn breakage at knitting needles without causing abrasion holes in adjacent cotton or polyamide courses. The yarn must satisfy textile-grade toxicological and restricted-substance requirements under OEKO-TEX Standard 100 Class I and should be assessed for dimensional stability of the residual garment using ISO 5077 after the dissolution wash; colour bleeding from dyed outer yarns onto the PVA separation line can be quantified by ISO 105-C06. In downstream processing, the PVA separation yarn is knitted into the tubular structure, the fabric is cut across the intended separation rows, and the pieces are loaded into a scour bath at 40–65°C; liquor ratio and mechanical movement determine removal rate. Process-control findings on production-scale paddle scours indicate that redeposition of dissolved PVA onto hydrophobic outer yarns occurs if the scour bath is not exchanged or if rinse water temperature falls below the dissolution point, leaving a stiff residue on collars and cuffs. Batch-to-batch variance in fibre spin finish can alter dissolution time and raise chemical oxygen demand in the drain liquor, so processors quantify incoming fibre finish and adjust scour exchange frequency rather than extending wash duration. Terminal product types include separated sock pairs, hosiery lines, seamless garment body panels, ribbed collars, cuffs, and divided panels for shapewear.
Across tea bag and single-serve beverage pod media manufacture, the wet-lay stock must remain dispersible in the headbox while delivering dry-strength adhesion after the drying section without collapsing the sheet pore structure. SS-2 is added as a water-soluble PVA fibre in dry furnish proportions from 3 wt% to 15 wt%; at these levels the fibre acts as a temporary structural binder during formation and subsequently as a thermoplastic bonding fibre during Yankee cylinder drying, while the cellulose or abaca backbone retains most of the filter sheet tensile load. For food-contact grades, compliance is set by FDA 21 CFR 176.170, EU Regulation 1935/2004, and BfR Recommendation XXXVI for paper and board in dry food contact; sheet physical properties are characterized by ISO 5269-2 handsheet preparation, ISO 1924-2 tensile strength, and ISO 5636-3 air permeance. The production process is wet-lay on an inclined wire or cylinder wire with cold whitewater maintained below the dissolution onset of the SS-2 fibre; after formation, the sheet is pressed and dried at 100–130°C, causing surface dissolution of the PVA fibre and bond formation at fibre intersections. A known process conflict is the accumulation of dissolved PVA in closed whitewater loops, which raises COD and can cause felt filling or drainage inhibition on the wire; mills therefore control fibre addition rate, furnish temperature, and whitewater exchange. Terminal products include tea bag outer wraps, coffee pod filter media, hot-and-cold filter papers, water-washable packaging tissue, and short-contact dry food contact liners.
Water-soluble PVA fibre can be constructed into nonwoven bags that enclose used linen, garments, or process wipes; the sealed bag is placed directly into an industrial washer where the fabric dissolves before the main disinfection cycle. SS-2 is used at 100% fibre composition in the nonwoven shell because any non-soluble structural layer would remain as foreign matter in the washer and contaminate the load. The fabric weight is commonly specified in the 30–60 g/m² range to balance handling tear strength on wet gloved hands against complete dissolution in the pre-wash stage; hot-melt seam positioning and ultrasonic lap seals are used for closure because adhesive films with lower water solubility can leave isolated fragments. A relevant compliance framework is EN 14065 for risk analysis and biocontamination control in textile processing, with processing durability of the outer laundry textiles assessed by ISO 15797; bag storage should remain below 60% RH and below the dissolution onset temperature to prevent tack and blocking on the storage shelf. The downstream production path is drylaid web formation, thermal calendering, roll slitting, and bag conversion by side-seal or bottom-seal ultrasonic welding; each lot must be sealed inside moisture-barrier packaging to prevent premature degradation. Terminal product types include contamination control laundry bags for hospital linen, isolation room laundry sacks, cleanroom wiper bags, and soluble packaging for chemical protective clothing that requires no manual sorting before washing.
In porous ceramics and inorganic membrane manufacturing, water-soluble PVA fibre can be dispersed into ceramic slips or pastes as a sacrificial pore former that is removed at low temperature before the main binder burnout and sintering steps; the fibre diameter and cut length determine the channel width and interconnectivity of the final porosity. Published data for the specific SS-2 configuration in this application are limited, but commercial trials typically begin at fibre loadings from 2 vol% to 15 vol% of the wet green body volume, adjusted by final pore size tolerance because oversupply above the percolation limit can reduce green strength to unacceptable levels. Relevant standards for the final porous body include ISO 15901-1 mercury intrusion porosimetry for pore size distribution, ASTM C20 apparent porosity, and ISO 13383-1 chemical analysis of ceramic raw materials; the green body itself must meet internal compaction and shrinkage specifications before firing. The production route is slurry mixing, tape casting or extrusion into green sheets or honeycomb monoliths, low-temperature drying, water leaching at 40–60°C to remove the SS-2 fibre, followed by thermal debinding and sintering. Process conflicts on production lines occur when leaching is conducted too rapidly, causing internal swelling and delamination of thin cast tapes; starch or microsphere pore formers may still be required if the ceramic drying profile exceeds the fibre dissolution window before the matrix develops sufficient green strength. Terminal product types include porous ceramic membrane supports, catalyst carrier honeycombs, diesel particulate filter substrates, solid oxide fuel cell anode support layers, and porous cermet components for fluid distribution.
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Sinopec-SVW SS-2 is a low-temperature water-soluble poly(vinyl alcohol) staple fibre supplied as a sacrificial component for wet-laid nonwoven, papermaking, textile support, and porous ceramic applications. The grade is designed to dissolve in water at 20 °C to 40 °C, compared with the 60 °C to 90 °C water-temperature band typical of conventional hot-water PVA fibres. The fibre is commonly available at linear densities of 1.4 dtex and 2.0 dtex, with cut lengths of 4 mm, 6 mm, 8 mm, and 12 mm. Mechanical values reported by the manufacturer are indicative rather than batch release limits; lot-specific data should be obtained from the certificate of analysis.
The polymer is a partially hydrolysed poly(vinyl alcohol) with degree of hydrolysis and crystallite structure adjusted to give cold-water solubility while retaining enough fibre integrity for carding, opening, and high-shear wet dispersion. This balance is the principal technical distinction of the SS-2 grade within the Sinopec-SVW water-soluble PVA series. Because dissolution is the intended performance function, the fibre is not specified for permanent reinforcement or for long-term wet-service applications unless an insolubilisation step is separately qualified.
Dissolution proceeds by surface swelling, gel-layer formation, and polymer-chain disentanglement. The rate is not a single material constant; it depends on water temperature, fibre cut length, agitation, water hardness, and the presence of dissolved organic matter. Under static conditions in distilled water at 20 °C, a 1.0 g fibre charge in 100 mL water may require more than 30 min for complete visual disappearance. In a stirred vessel at 30 °C, the same charge can reach gravimetric residue below 0.5 % within 15 min, using the manufacturer’s internal method. That method is not defined in ISO or ASTM standards, and end users should repeat the test in process water before line qualification.
| Property | Indicative range | Method or condition |
|---|---|---|
| Water dissolution temperature | 20 °C to 40 °C | Manufacturer internal method; 1.0 g fibre in 100 mL stirred distilled water |
| Linear density | 1.4 dtex, 2.0 dtex | ISO 1973:2021 |
| Cut length | 4 mm, 6 mm, 8 mm, 12 mm | ISO 6989:1981 |
| Tenacity | ≥ 3.5 cN/dtex | ISO 5079:2020 |
| Elongation at break | 15 % to 25 % | ISO 5079:2020 |
| Dissolution residue | ≤ 0.5 % | Internal method; 30 °C, 15 min, stirred distilled water |
On a production carding line, fibre with cut length below 6 mm can produce higher fly and cylinder wrapping when relative humidity falls below 50 %. Conditioning at 20 °C and 65 % RH for 24 h before bale opening reduces static charge accumulation. If vapour-barrier packaging has been compromised at humidity above 60 %, surface tack can develop because the fibre begins to dissolve in adsorbed moisture. Pre-drying at 40 °C for 2 h in a forced-air dryer and reconditioning is the standard recovery procedure. These are operational limits observed on carding and wet-laid lines, not product specification limits.
Dissolution is mass-transfer-limited below 40 °C. The dissolved polymer forms a viscous boundary layer at the fibre surface, and agitation reduces that layer. In a stirred vessel equipped with a pitched-blade impeller at 500 min⁻¹, the internal method uses 1.0 g fibre in 100 mL distilled water at 30 °C; under these conditions, residue below 0.5 % is typically reached within 15 min. In continuous counterflow washers, residence time must be matched to water temperature and turbulence. An under-designed wash zone leaves PVA residue that can block pore openings, while over-agitation can disrupt low-density wet-laid webs before bonding. These are process-engineering limits, not intrinsic solubility limits.
The primary difference is dissolution temperature. SS-2 removes in lukewarm water, avoiding thermal exposure that can shrink wool, polyamide, or bicomponent webs. The reduction in dissolution temperature is achieved by reducing crystalline order, which also lowers tensile strength. The fibre is therefore specified for sacrificial removal rather than permanent structural reinforcement. In hydroentanglement processes, SS-2 can survive the bonding step only if water temperature at the jet strips remains below 30 °C; prolonged exposure above 35 °C causes surface dissolution, lint accumulation, and web weakening before the intended washing stage. Published data for this specific configuration is limited; the stated boundary is derived from production-scale equipment behaviour on hydroentanglement lines using PVA staple.
| Parameter | SS-2 low-temperature | Conventional hot-water PVA | Non-water-soluble PVA fibre |
|---|---|---|---|
| Dissolution in water | 20 °C to 40 °C | 60 °C to 90 °C | Insoluble under normal process temperatures |
| Tenacity | ≥ 3.5 cN/dtex | ≥ 5.0 cN/dtex | ≥ 6.0 cN/dtex |
| Elongation at break | 15 % to 25 % | 10 % to 20 % | 15 % to 25 % |
| Storage humidity tolerance | Barrier packaging required | Moderate; less surface tack | High; not water-sensitive |
| Application role | Sacrificial removal at low temperature | Temporary support requiring hot-water removal | Permanent reinforcement |
| Wet-processing water limit before removal | ≤ 25 °C for stock preparation | ≤ 50 °C for stock preparation | No practical limit |
Compared with non-water-soluble PVA fibre, SS-2 is unsuitable for cement reinforcement or other wet-service applications unless a subsequent insolubilisation step is validated. The dissolution property is the performance function; residual strength in the finished matrix is not a design expectation. In addition, the low-temperature grade has a narrower storage and processing window than hot-water grades. Humidity uptake and premature dissolution are the main batch-to-batch variance sources observed on production lines, not fibre tensile strength. Compliance under REACH Regulation (EC) No 1907/2006 and, where indirect food-contact use is claimed, FDA 21 CFR 177.1670 or EU 10/2011 should be verified with the supplier because the fibre grade designation alone does not constitute a food-contact clearance.
In textile support yarns, the low-temperature dissolution threshold allows PVA removal from wool or polyamide panels without exposing them to the 60 °C water that hot-water PVA grades require. The fibre is typically used as a singles or ply component in temporary stitching yarns and is removed in a scour bath at 25 °C to 30 °C with mild mechanical agitation. The removal step should be validated against the dimensional stability standard applicable to the garment, such as ISO 6330:2012 for washing procedure selection, rather than by assuming that dissolution alone guarantees dimensional stability.
In papermaking and filter media, 4 mm SS-2 is metered into the pulp furnish at 2 wt% to 5 wt% of dry solids. After sheet formation and couch pressing, the PVA is dissolved in a wash zone at 30 °C to 40 °C, creating controlled pore volume. The resulting sheet is tested for air permeance according to ISO 5636-3:2013 and for burst strength according to ISO 2758:2014. Pore size changes depend on fibre length and furnish composition; no single numerical value should be treated as a product constant.
In porous ceramic tape casting, SS-2 cut to 4 mm is added to an alumina slurry at 5 vol% to 10 vol% of solids. After drying, the fibre is removed in a water bath at 30 °C before binder burnout. The resulting pore channels can be examined by mercury intrusion porosimetry, but specific pore-size distributions depend on particle packing and fibre dispersion. Published data for this specific configuration is limited; the ceramic application should be qualified by capillary flow porometry after the full binder-removal cycle.
SS-2 is added at 3 wt% to 12 wt% of dry furnish in wet-laid nonwoven lines producing filtration media and battery separator substrates. Stock temperature is maintained below 25 °C before forming to avoid premature dissolution. After hydroentanglement, the PVA is removed in a counterflow wash section at 30 °C to 40 °C. Washing efficiency is measured gravimetrically by drying samples at 105 °C and comparing mass before and after extraction. Iodine-boric acid staining can indicate residual PVA, but quantitative release should use an extraction method agreed between fibre supplier and converter. The main process conflict at production scale is the need to keep the forming section cold enough to prevent premature fibre loss while providing enough wash energy for complete removal.
Water containing borate ions or strongly alkaline conditions above pH 9 can form gel complexes on the fibre surface, increasing dissolution time and leaving insoluble surface residues. Hardness levels above 250 mg/L as calcium carbonate may reduce dissolution rate through ionic screening and should be evaluated with jar tests before line trials. Because water solubility is an intentional property, SS-2 is not suitable for permanent reinforcement or for any long-term wet-service application unless an insolubilisation treatment is qualified. Selection is based on lot-specific certificates of analysis and process-specific dissolution trials.
