| HS Code | 503815 |
| Polymer Type | Water-soluble ethylene-vinyl alcohol copolymer |
| Water Solubility | Fully soluble in water |
| Solubility Temperature | Typically 60°C to 90°C |
| Appearance | White translucent granules or powder |
| Film Formation | Forms clear, flexible films via casting or extrusion |
| Tensile Strength | 20–40 MPa depending on film formulation |
| Elongation At Break | 150–350% |
| Oxygen Barrier | Moderate to good under dry conditions |
| Chemical Resistance | Resistant to oils, fats, and aliphatic hydrocarbons |
| Biodegradability | Aerobically biodegradable in aqueous environments |
| Thermal Processing | Processable at approximately 160–210°C |
As an accredited Water Soluble EVOH factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Water Soluble EVOH is packaged in 25 kg moisture-proof polyethylene-lined kraft bags, sealed to ensure purity and safe, dry storage. |
| Container Loading (20′ FCL) | Water Soluble EVOH packed in 25kg bags on pallets, loaded into a 20′ FCL, secured and moisture-protected for safe transit. |
| Shipping | Water Soluble EVOH ships in sealed, moisture-proof bags or drums to prevent premature dissolution. Keep dry, cool, and away from direct sunlight. It is non-hazardous under normal transport conditions, but avoid excessive humidity. Standard freight and air shipments are acceptable with proper labeling and handling precautions. |
| Storage | Store Water Soluble EVOH in a sealed, original container in a cool, dry, well-ventilated area. Protect from moisture, high humidity, direct sunlight, and heat sources. Keep containers tightly closed when not in use to prevent caking or degradation. Avoid contact with oxidizing agents. Follow manufacturer’s shelf-life recommendations for optimal performance. |
| Shelf Life | Store unopened in a cool, dry place away from moisture. Shelf life is typically 12 months from manufacture. |
Compounding of water-soluble EVOH for unit-dose detergent film begins with a specialty grade characterized by a degree of hydrolysis above 98 mol% and an ethylene content below 20 mol%; this distinguishes the material from standard gas-barrier EVOH containing 27–44 mol% ethylene, which does not undergo complete aqueous dissolution at ambient temperature. Extrusion is performed on a single-screw extruder with an L/D ratio between 28:1 and 36:1 using a barrier screw and water-cooled feed throat, with barrel temperature zones profiled from 170 °C to 215 °C and a flat die lip gap of 0.6–0.9 mm. The melt is cast onto a polished chill roll maintained at 12–18 °C, after which inline orientation is limited to 1.3×–1.8× in the machine direction to avoid residual shrink that would distort pouch sealing. Film thickness is typically held at 40–75 µm; thickness variation above ±5 % creates non-uniform dissolution and can leave undissolved polymer fragments in the washing machine or dishwasher dispenser. Glycerol or a polyol plasticizer is incorporated at 5–12 phr to reduce film brittleness below 40 % RH; the plasticizer package must be selected to avoid interference with the detergent powder or liquid fill. The film is tested for tensile properties according to ASTM D882-18, with target elongation at break above 180 % in the machine direction and 120 % in the transverse direction after conditioning at 23 °C and 50 % RH. For compliance, the finished film falls under Regulation (EU) No 10/2011 when placed on the EU market as a packaging component with food-contact implications, with overall migration assessed by EN 1186-1 using aqueous simulant for 10 days at 40 °C; the limit is 10 mg/dm². In production, batch-to-batch viscosity drift is controlled by measuring the 4 wt% aqueous solution viscosity at 20 °C with a Brookfield viscometer; a drift above ±1.5 mPa·s from the reference lot indicates a hydrolysis or ethylene-sequence variability problem that will shift die pressure and final gauge.
In aqueous ceramic tape casting for multilayer ceramic capacitor (MLCC) green sheets, water-soluble EVOH is introduced as the primary binder at addition levels from 6 wt% to 12 wt% based on dry ceramic powder mass; the exact loading is adjusted to the specific surface area of the barium titanate powder, which generally falls between 2.5 m²/g and 5.5 m²/g. The binder is first dissolved in deionized water at 60–70 °C under low-shear stirring for 4 h to produce a 15–20 wt% stock solution, then blended with dispersant and plasticizer before ceramic powder addition. Ball milling is conducted in a high-alumina jar mill with 10 mm zirconia media at 45 rpm for 20–24 h; slurry viscosity after deaeration is typically adjusted to 2,500–4,000 mPa·s at 25 °C using a Brookfield RV spindle 4 at 20 rpm. Tape casting is performed on a continuous carrier film with a doctor blade gap of 0.35–0.65 mm, producing dried green sheets with thickness between 25 µm and 60 µm. The drying profile uses three zones: 35 °C, 45 °C, and 55 °C, with total residence time of 8–12 min; rapid surface skinning above 60 °C traps water and creates pinholes in the green tape. Binder burnout is the critical process step: a ramp rate of 0.3–0.8 °C/min to 600 °C with a 1–2 h dwell at the peak temperature removes the polymer while maintaining flatness and avoiding carbon residue. Residual ash after burnout is measured according to ISO 3451-1:2019; levels above 0.05 wt% in the fired ceramic indicate insufficient oxygen flow or excessive binder content. The terminal product is a dimensionally stable green sheet used in nickel-electrode MLCC stacks; water-soluble EVOH is selected because it is removed more cleanly than acrylic latex binders and produces fewer organic volatile residues during the early burnout stage.
| Application segment | Normative reference | Testing condition | Typical control limit |
|---|---|---|---|
| Unit-dose detergent film | Regulation (EU) No 10/2011 | EN 1186-1, aqueous simulant, 10 days at 40 °C | Overall migration ≤ 10 mg/dm² |
| Repulpable paper coating | FDA 21 CFR 176.170 | Water and heptane extraction procedures | No exceedance of specified extractives fraction |
| Ceramic green tape binder burnout | ISO 3451-1:2019 | 600 °C muffle furnace, controlled air flow | Residual ash ≤ 0.05 wt% |
| Textile warp sizing | ISO 2062:2009 | Yarn tensile testing before and after desizing | Strength retention > 90 % after desizing |
Water-soluble EVOH is applied to kraft paperboard as an aqueous barrier coating in which solubility in water is exploited for repulping, while the dry film provides oxygen and grease resistance. The coating solution is prepared at 10–20 wt% solids by dissolving the resin in water at 75–85 °C, then cooling to 40–50 °C for application. Application equipment is typically a reverse gravure or air-knife coater running at 150–300 m/min; the dry coat weight is maintained between 3 g/m² and 8 g/m². Drying uses infrared preheat followed by air-flotation dryers at 90–110 °C, with web temperature held below 70 °C to avoid moisture-driven blistering of the coating. Oxygen transmission rate is measured by ASTM D3985-17 at 23 °C and 50 % RH; under these conditions the coated board exhibits a reduction in oxygen transmission of roughly 90 % relative to uncoated board at the same basis weight, although published data for water-soluble EVOH coatings on unbleached kraft are limited and must be verified on the target furnish. Grease resistance is assessed using TAPPI T559 cm-12; the coated sheet should survive 30 min without visible staining under the specified kit ratings. The key limitation is that the dry film loses barrier function at relative humidity above 70 %, because moisture plasticization of vinyl alcohol sequences increases oxygen permeability; therefore the technology is not specified for high-humidity retort conditions or direct liquid contact. Repulpability is checked by laboratory defibering according to TAPPI/ANSI T 205 sp-18; coated board must disintegrate within 20 min and leave no visible thermoplastic agglomerates on a 0.15 mm slotted screen. For food-contact use, the coating must comply with FDA 21 CFR 176.170 for paper and paperboard components in contact with aqueous and fatty foods; extraction testing is performed under the referenced conditions for water and heptane.
High-density polyester and nylon filament warps are sized with water-soluble EVOH in a slasher line to prevent filamentation and to reduce warp breaks under high-speed water-jet or air-jet loom conditions. The size liquor is prepared at 6–9 wt% solids in a cooking kettle at 60–70 °C, then transferred to the size box of a single-end or multi-end slasher with temperature held at 55–65 °C. Squeeze roll pressure is set to 2–4 bar, and size add-on is controlled to 8–12 wt% on dry yarn mass for polyester filament deniers from 75 den to 150 den; add-on below 6 wt% causes filamentation and warp breaks above 0.5 breaks per 100 m during weaving, while add-on above 14 wt% creates flaking deposits on reed and heald. Yarn tensile strength after sizing is measured according to ISO 2062:2009; a further loss of more than 10 % after desizing indicates that the size film has penetrated too deeply into the yarn bundle and damaged the fiber surface. The size is removed by washing at 40–50 °C with 0.5–1.0 g/L nonionic surfactant in a continuous open-width washer; residual size on the fabric may be assessed by the ISO 14184-1:2011 formaldehyde method only as a control for external contamination, since water-soluble EVOH releases no formaldehyde and the method is used to detect auxiliary residues. The principal processing limitation is viscosity instability below 50 °C; the solution thickens and produces uneven pick-up on edge yarns. Above 75 °C, surface evaporation forms a skin in the size box that transfers to the warp as small gel particles. The terminal output is a woven synthetic filament fabric for outdoor or filtration applications in which the sizing polymer must be completely removed before dyeing or coating to avoid shade variation and adhesion failure.
In laminating adhesives and flexographic ink primers, water-soluble EVOH is processed as a high-solids aqueous binder in which the dry film is repulpable but the wet formulation must remain shear-stable during roller transfer. The resin is dissolved at 15–25 wt% solids in a jacketed vessel at 80 °C with low-shear propeller agitation, cooled to 30 °C, and diluted with deionized water to a final viscosity appropriate to the application equipment. For paper-to-paper lamination, the adhesive is applied by roller coater at 2–5 g/m² dry coating weight and bonded under nip pressure between 3 bar and 5 bar; heat activation at 110–130 °C is required to develop full fiber-tearing bond strength at production speeds above 150 m/min. Peel adhesion after conditioning at 23 °C and 50 % RH is evaluated according to ASTM D1876-08 on 25 mm strips, with typical values between 1.5 N and 3.5 N per 25 mm width for 5 g/m² dry coating on kraft. The formulation requires 0.2–0.5 wt% of a silicone-free defoamer because silicone transfer to the printed surface reduces ink adhesion. High-shear stability is checked with a rotor-stator mixer at 5 000 rpm for 15 min; a viscosity increase above 20 % indicates shear-induced aggregation or crosslinking. The adhesive is incompatible with borate ions and certain amine-based additives, which cause rapid gelation through polyol complexation and can plug roller transfer surfaces. The terminal products are repulpable paper laminates and printed cartons with no thermoplastic screen rejects when recycled under standard pulping conditions.
Temporary machine embroidery backing and water-transfer release film represent a lower technical intensity application. Water-soluble EVOH film at 35–50 µm is laser-cut to hoop dimensions and placed under tension before stitching; the film must remain tear-resistant at high stitch density, then disperse within 90 s in cold rinse water without leaving residue on the substrate. The critical control is film thickness; below 35 µm penetration by the needle causes premature rupture, while above 50 µm the residual film may not dissolve fully in cold water. This application does not require the barrier or ceramic-binder performance described in other segments, so it is confined to a single operational consideration: dissolution rate and residue absence after cold-water washing.
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Water Soluble EVOH is a partially crystalline ethylene-vinyl alcohol copolymer in which reduced ethylene incorporation shifts solubility behaviour from the water-insensitive barrier domain of standard EVOH toward hot-water-removable performance. The resin is specified in supplier documents by ethylene content, melt mass-flow rate, density, and dissolution onset temperature. A representative water-soluble grade carries a specification of 20–24 mol% ethylene, 3.0–6.0 g/10 min melt mass-flow rate at 210 °C/2.16 kg under ISO 1133-1:2022, and density 1.16–1.19 g/cm³ under ISO 1183-1:2019. Dissolution in agitated deionized water typically begins between 68 °C and 84 °C; complete dissolution of a 50 µm cast film occurs within 8–15 min at 80 °C. Because the material is hygroscopic and thermally sensitive, the certificate of analysis also reports moisture content below 0.3 wt% and residual sodium acetate below 100 mg/kg. Published data for this specific configuration is limited, and these ranges are representative rather than universal specification limits.
The primary structural difference is ethylene mole fraction. Standard barrier grades occupy the 27–44 mol% ethylene range, where crystallite size and intermolecular hydrogen bonding are balanced to prevent water dissolution while maintaining oxygen barrier. Water-soluble EVOH reduces ethylene content to approximately 18–24 mol%; the higher vinyl alcohol fraction increases hydroxyl density and water uptake, and the copolymer becomes soluble in heated water. Unlike polyvinyl alcohol, the ethylene segments in water-soluble EVOH lower the melting point relative to fully hydrolysed PVOH and allow pelletized melt processing without plasticizer. Oxygen permeation, however, is compromised: dry-film oxygen transmission for a 25 µm water-soluble grade is reported in the range of 2.0–8.0 cm³/m²·day·atm at 23 °C and 0 % RH, roughly one to two orders of magnitude higher than a 25 µm standard EVOH barrier film. Water-soluble EVOH is therefore not indicated for permanent gas-barrier service; it is selected when the layer must be removed after an intermediate manufacturing step.
| Property | Water-Soluble EVOH | Standard Barrier EVOH | PVOH |
|---|---|---|---|
| Ethylene content | 18–24 mol% | 27–44 mol% | 0 mol% |
| Melt mass-flow rate at 210 °C/2.16 kg | 3.0–6.0 g/10 min | 1.0–15 g/10 min | not applicable; thermal degradation before melt |
| Dissolution in agitated water | 68–84 °C onset; complete at 80–95 °C | insoluble | 20–40 °C for cold-water grades |
| Tensile strength at break | 35–55 MPa under ASTM D638-22 | 50–70 MPa | 40–80 MPa |
| Oxygen transmission at 0 % RH, 25 µm | 2.0–8.0 cm³/m²·day·atm | 0.01–0.10 cm³/m²·day·atm | 0.5–2.0 cm³/m²·day·atm |
That solubility differential drives specific processing conditions. On a 25:1 L/D single-screw extruder with a 45 mm diameter screw, barrel temperatures from rear to front are typically 185/200/215/220 °C, with a melt temperature not exceeding 230 °C. Residence time at melt temperature is limited to 4–6 min; longer residence produces acetic acid odour, black specks, and melt fracture. Field observations from coextrusion trials indicate that pellet moisture above 0.35 wt% generates surface bubbles at wet-layer thicknesses above 150 µm, while pellet moisture below 0.15 wt% permits cast-film production down to 20 µm. Pre-drying in a desiccant dryer at 80 °C for 4 h with a -40 °C dew-point air supply is the minimum starting condition; if ambient relative humidity exceeds 60 %, hopper purge with dry air is required.
Rheological behaviour of water-soluble EVOH is shear-thinning and strongly temperature-activated. Apparent viscosity at 210 °C and 100 s⁻¹ is commonly reported between 800 and 1500 Pa·s; at 1000 s⁻¹ the apparent viscosity falls to 200–400 Pa·s. This response permits coextrusion as a thin core layer with polyolefin skins but also imposes limits on draw resonance. High-molecular-weight grades used for blow-moulded sacrificial preforms require a melt temperature of 215 ± 5 °C; deviation below 210 °C increases head pressure above 18 MPa on a 50 mm grooved-barrel extruder, while deviation above 225 °C initiates gel formation within 3 min. Dissolution after melt processing is not simply a solubility event; it is controlled by water temperature, flow velocity at the layer surface, and part geometry. In agitated water at 80 °C, a 2 mm sacrificial fin dissolves at an average linear rate of 0.4–0.8 mm/min; in static water at the same temperature, dissolution time can increase by a factor of 4 to 6. For blind channels with an aspect ratio above 5:1, complete dissolution is not ensured, and design rules should incorporate a minimum channel diameter of 3 mm or forced circulation through the part.
Water-soluble EVOH is used as a temporary support material in additive manufacturing, as a fugitive core in laminated composite forming, and as a protective interlayer in abrasive waterjet cutting of delicate surfaces, where the polymer is dissolved after the machining operation. In additive manufacturing, twin-screw compounded filaments with a diameter of 1.75 ± 0.05 mm are extruded through a 0.4 mm nozzle at 185–210 °C, with the build chamber maintained at 45–55 °C to reduce warpage. The material bonds adequately to acrylonitrile-butadiene-styrene and polylactic acid raft interfaces but should not be used with nylon substrates at chamber temperatures above 70 °C because differential crystallization stresses can delaminate the support and print layers. After printing, immersion in stationary warm water at 75 °C for 30 min removes a 5 mm thick support shell; ultrasonic agitation reduces the cycle to 10–15 min. These parameters are derived from machine-specific field runs, not from a universal standard, and must be revalidated for each part geometry.
Water-soluble EVOH pellets are substantially more moisture-sensitive than standard barrier EVOH. At 23 °C and 50 % RH, the equilibrium moisture content is typically 4.0–6.0 wt%; above 60 % RH, it approaches 8.0 wt%. Processing with moisture above 0.3 wt% degrades the melt through hydrolytic chain scission, visible as foam at the die lip, specks in transparent film, and a reduction in dissolution temperature because of reduced molecular weight. Converters using open hoppers in humid plants have observed batch-to-batch viscosity drift of 15–20 %, traced to variable pellet moisture. The reliable countermeasure is not simply longer drying; it is dry-air conveying, hopper inerting with -40 °C dew-point air, and feed-throat cooling to prevent condensation. Regrind addition is limited to 10 wt%; higher regrind levels increase black speck density and shorten run time by 20–30 min before die-lip deposits require cleaning.
Additive selection is restricted. Amine-based stabilizers and alkanolamine slip additives accelerate yellowing and gel formation; calcium stearate is preferred for internal lubrication at 0.05–0.15 wt%. Water-soluble EVOH is incompatible with petroleum-based tackifiers and low-molecular-weight ester plasticizers, which plasticize the amorphous phase and lower the dissolution onset below 55 °C, potentially causing premature failure in warm rinse baths. In coextrusion, polyamide tie layers that require processing above 240 °C are unsuitable; polyethylene-based tie resins processed at 200–220 °C are preferred. Layer composition should be verified through Fourier-transform infrared spectroscopy against a certified reference spectrum because visual inspection cannot detect interlayer migration of low-molecular-weight fractions.
Regulatory compliance is documented against Regulation (EU) No 10/2011; migration testing is performed under EN 1186-specific contact conditions. The resin is supported by a declaration of compliance stating overall migration below 10 mg/dm² for aqueous and acidic food simulants. Under FDA 21 CFR §177.1360, the copolymer is covered for food-contact use as an ethylene-vinyl alcohol copolymer, provided extractive and residual monomer limits in the relevant subchapter are met. REACH and RoHS declarations are also available.
| Regulatory/Test Area | Standard or Criterion | Typical Requirement |
|---|---|---|
| Melt mass-flow rate | ISO 1133-1:2022 | 3.0–6.0 g/10 min |
| Density | ISO 1183-1:2019 | 1.16–1.19 g/cm³ |
| Tensile properties | ASTM D638-22 | 35–55 MPa at break |
| Food-contact migration | Regulation (EU) No 10/2011 | overall migration <10 mg/dm² |
| Food-contact resin status | FDA 21 CFR §177.1360 | conformance to extractive limits |
| REACH SVHC | EC No 1907/2006 | no SVHC above 0.1 wt% |
For a blow-moulded air intake duct with a water-soluble EVOH core, a 60 mm accumulator-head extruder processes the core at 205 °C melt temperature and 10 MPa head pressure. The core is coextruded between two polyethylene layers at a total wall thickness of 3 mm and a core thickness of 0.5 mm. After cooling, the duct is immersed in a 85 °C agitated water tank with a flow rate of 0.2 m/s across the core openings; the fugitive layer is removed in 45–60 min. The polyethylene surfaces retain their surface finish, provided the water pH is maintained between 6.5 and 8.5; alkaline pH above 9.0 accelerates dissolution but can etch the skin layer. Weekly sampling of the wash water for total organic carbon and pH is recommended to prevent contaminant buildup and ensure consistent dissolution kinetics.
