| HS Code | 542266 |
| Product | EVOH EV-3201 V/F |
| Resin Type | Ethylene Vinyl Alcohol Copolymer (EVOH) |
| Ethylene Content | 32 mol% |
| Density | 1.19 g/cm³ |
| Melting Point | 183 °C |
| Glass Transition Temperature | 61 °C |
| Melt Flow Rate | 1.8 g/10 min (190 °C, 2.16 kg) |
| Tensile Strength | 65 MPa |
| Elongation At Break | 350% |
| Oxygen Transmission Rate | 0.1 cm³·mm/m²·day·atm (20 °C, 65% RH) |
As an accredited EVOH EV-3201 V/F factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | EVOH EV-3201 V/F is supplied in 25 kg multi-layer paper bags with a moisture-barrier lining to protect purity. |
| Container Loading (20′ FCL) | 20ft FCL of EVOH EV-3201 V/F, packed in 25kg bags, net weight approximately 20,000kg per container. |
| Shipping | EVOH EV-3201 V/F is a non-hazardous ethylene vinyl alcohol copolymer resin shipped in sealed, moisture-proof packaging to prevent water absorption. Transport in dry, ventilated conditions, avoiding extreme heat and direct sunlight. Handle gently to preserve pellet integrity and maintain quality. |
| Storage | Store EVOH EV-3201 V/F in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and moisture. Keep original packaging tightly sealed to prevent absorption of humidity or contamination. Avoid rough handling that may damage bags. Maintain warehouse temperature below 30°C (86°F) and use within 12 months of receipt for optimal performance. |
| Shelf Life | Shelf life is approximately 24 months when stored unopened in a cool, dry place away from direct sunlight. |
A nine-layer blown-film line with a 450 mm annular die and downstream tandem winder integrates EVOH EV-3201 V/F as the central oxygen barrier core in retortable stand-up pouches for bone-in poultry exports. The film structure is specified as 12 µm biaxially oriented PA / 15 µm tie / 6 µm EVOH / 15 µm tie / 70 µm cast polypropylene, with the EVOH core accounting for 5.1 wt% of the pre-lamination web. EVOH EV-3201 V/F is specified with 32 mol% ethylene content and melt flow rate of 1.6 g/10 min at 190 °C / 2.16 kg (ISO 1133-1:2022), which defines the shear-thinning envelope for the barrier extruder profile. When pellet exposure above 60% RH exceeds 2 h, pre-drying at 90 °C to a -40 °C dew point for 4 h is required to reduce moisture below 0.3%; the barrier screw is configured with 24:1 L/D and low-shear mixing elements to limit gel formation when melt temperature exceeds 230 °C. Food-contact compliance is demonstrated under FDA 21 CFR 177.1360 and EU Regulation (EU) No 10/2011, with overall migration below 10 mg/dm² in aqueous and fatty simulants; oxygen transmission rate is measured according to ASTM D3985-17 at 20 °C, 0% RH on the isolated EVOH layer, with values below 1.0 cm³·20 µm/(m²·24 h·atm). Retort processing at 121 °C for 30 min imposes hydrothermal stress on the tie layers; the line uses maleic anhydride-grafted PP tie resin with melt flow rate 2.0 g/10 min at 230 °C (ISO 1133-1:2022) to maintain adhesion above 4 N/15 mm after retorting, tested by ISO 527-3 T-peel. Visual quality checks monitor gel counts in the EVOH layer after 8 h continuous runs; gel formation is controlled by purging with LLDPE at 200 °C and limiting barrel residence time to 8 min. EVOH EV-3201 V/F is incompatible with acetal and PVC purge compounds and should not be coextruded with amine-containing layers without barrier isolation. Finished converted articles include retortable stand-up pouches, MRE-style lidding films, and vacuum skin packs for smoked meat, bone-in poultry, and high-salt marinated products where oxygen ingress below 0.5 cm³/(m²·24 h·atm) is required over 12 months at 25 °C.
Six-layer coextrusion blow molding of high-density polyethylene fuel tanks for North American light trucks places EVOH EV-3201 V/F between two maleic anhydride-grafted HDPE tie layers, with inner/outer HDPE layers and a post-consumer regrind layer. The EVOH mass fraction in the tank wall is controlled at 4–7 wt%; below 4 wt% hydrocarbon permeation rises above the CARB LEV III evaporative emission threshold, while above 7 wt% parison sag and unstable thickness distribution appear on accumulator-head machines with 30 kg shot capacities. Compliance is governed by US EPA 40 CFR 86.117 evaporative emissions limits and FMVSS 301 fuel system integrity; material contact with fuel is validated under SAE J1737 permeation test protocols, and melt flow rate is checked per ISO 1133-1:2022 at 190 °C / 2.16 kg with a target of 1.6 g/10 min. The accumulator-head blow molder runs six extruders with 90–120 mm barrier screw diameters, 24:1 L/D for EVOH, barrel temperature 210–220 °C for the EVOH extruder, die head temperature 220 °C, and parison programming to maintain EVOH layer uniformity within ±0.5% of nominal wall thickness. A documented failure mode on production-scale machines is the occurrence of pearl-luster delamination at sharp pinch-off seams when EVOH melt temperature intersects 235 °C for residence above 10 min; lines therefore operate with shot-to-shot interval below 70 s and purge with HDPE at shutdown. Terminal articles include 45–120 L multi-layer fuel tanks, filler necks, and canister components for gasoline, ethanol blends up to E10, and methanol-based race fuels. EV-3201 V/F is not recommended for continuous exposure to high aromatic oxygenated fuels above E20 without additional nylon barrier layers; published data for this specific configuration is limited for iso-octane/toluene/ethanol mixtures above 50/50/10 vol%.
In deep-draw modified atmosphere packaging (MAP) for fresh-cut produce, cast sheet coextrusion places EVOH EV-3201 V/F as an 8 µm core layer in a five-layer PP/tie/EVOH/tie/PP sheet with total caliper 600 µm, corresponding to 1.3% of total sheet thickness and approximately 1.5 wt% of total sheet mass. Food contact compliance uses EU (EU) No 10/2011 and FDA 21 CFR 177.1360, with migration testing in 10% ethanol and 3% acetic acid simulants at 40 °C for 10 days; barrier sheet oxygen transmission rate measured by ASTM D3985-17 at 23 °C and 50% RH is targeted below 0.05 cm³/(m²·24 h) for the total sheet. Thermoforming is performed on a plug-assist pressure former with zoned IR heating at surface temperatures 145–155 °C and forming air pressure 4–6 bar; deep-draw ratios up to 1.5:1 on rectangular trays maintain EVOH layer thickness at corners no less than 55% of nominal, below which oxygen ingress at corner thinning creates measurable pinhole risk in post-packaging leak testing. Corona treatment at 4.0 kW and web speed 40 m/min is applied to the PP sealing surface to achieve dyne level above 38 mN/m for lidding film seal strength. Converted products are rigid barrier trays, cups, and bowls for fresh-cut salads, pasta sauces, and oxygen-sensitive dairy desserts under MAP with gas mixtures of 5–10% O₂ / 20–30% CO₂ / balance N₂.
For unit-dose pharmaceutical lidding, the producing line integrates EVOH EV-3201 V/F as an oxygen and moisture barrier core in three-layer or five-layer laminations with PP or PE, with EVOH mass fraction between 5–10 wt% of the film. In unit-dose blister packaging for moisture-sensitive generics, the EVOH layer is sandwiched between two 0.1 mm PP outer layers and 0.05 mm tie layers, resulting in an EVOH caliper of 15 µm; thermoforming at 160–170 °C sheet surface temperatures reduces sidewall EVOH thickness by 25–40%, and the formulation ratio is adjusted upward to 12 wt% only after validation of blister dimension stability. Compliance includes ISO 11607-1:2019 and ISO 11607-2:2019 for terminally sterilized medical device packaging, USP <671> for container permeability classification, and ICH Q1A(R2) stability testing at 25 °C/60% RH and 40 °C/75% RH; film oxygen transmission is measured per ASTM D3985-17 and water vapor transmission per ASTM F1249-20. Coextrusion coating and lamination lines running at 250 m/min web speed use gravimetric dosing with hopper RTD monitoring and feed throat temperature 40 °C to prevent EVOH pellet bridging. Slitting to 0.5 mm tolerance is followed by laser micro-perforation in peelable lidding; EVOH layer defects above 200 µm are optically detected by high-speed camera at 120 m/min and marked for rejection. The EVOH layer is deliberately not corona-treated in the coextrusion step because surface oxidation above 45 dyn/cm causes blocking during winding. Output articles include push-through lidding film, cold-form laminate base webs, and high-barrier sachets for desiccated oral solid dose, effervescent tablets, and transdermal patches. The grade is not suitable as a direct drug contact layer without an additional polyolefin liner; it is used solely as an internal functional barrier.
| Segment | Standard or regulation | Test method | Operational boundary |
|---|---|---|---|
| Retortable food pouches | FDA 21 CFR 177.1360; EU (EU) No 10/2011 | ASTM D3985-17; ISO 527-3 | Overall migration below 10 mg/dm²; oxygen transmission below 1.0 cm³·20 µm/(m²·24 h·atm) |
| Automotive fuel tanks | US EPA 40 CFR 86.117; FMVSS 301; SAE J1737 | SAE J1737 gravimetric permeation | EVOH mass fraction 4–7 wt%; EVOH melt temperature 210–220 °C |
| Pharmaceutical blister | ISO 11607-1:2019; USP <671> | ASTM D3985-17; ASTM F1249-20 | EVOH caliper 15 µm; sidewall thinning 25–40% |
| Oxygen barrier pipe | ISO 15875-1:2003; EN 1264-4 | ISO 17455 oxygen diffusion | Oxygen barrier 0.1 g/(m²·day) at 40 °C; EVOH layer 8–12 wt% |
| Agrochemical containers | 49 CFR 178.504; 49 CFR 178.603; ASTM D2684 | ASTM D2684 solvent permeation | EVOH mass fraction 2–4 wt%; drop height 1.2 m |
At nominal pipe diameter 16 mm and SDR 7.4, five-layer oxygen barrier pipe for hydronic heating is coextruded with EVOH EV-3201 V/F as a 0.25 mm core between adhesive tie layers and PE-Xb inner/outer layers. Compliance is governed by ISO 15875-1:2003 for PE-X pipe systems and EN 1264-4 for floor heating oxygen barrier, with oxygen diffusion measured according to ISO 17455 at 40 °C; the acceptance threshold is 0.1 g/(m²·day). The EVOH layer constitutes 8–12 wt% of total pipe wall mass; below 8 wt% oxygen diffusion exceeds the EN 1264-4 limit, while above 12 wt% the flexural modulus increases beyond the permissible bend radius of 5×D for underfloor installation. Manufacturing uses a five-layer crosshead pipe die with 60 mm main extruder for PE-Xb, 35 mm extruder for EVOH, and vacuum calibration tanks at 2 bar vacuum; post-extrusion silane crosslinking of the PE-Xb occurs in a water bath at 95 °C for 6 h, during which the EVOH layer must be fully encapsulated to avoid hot-water hydrolysis and barrier loss. The line is limited to 15 m/min for 16 mm pipe because EVOH layer melt fracture appears above this speed at the specified melt temperature of 210 °C. Products include floor heating manifold pipes, radiator connection pipes, and potable water distribution pipe with oxygen barrier for closed-loop hydronic systems. Continuous exposure above 70 °C water without a protective PE layer is not recommended; at 80 °C moisture uptake reduces EVOH oxygen barrier by 30–50%.
In F-style containers for emulsifiable concentrates, blow-molded HDPE walls integrate EVOH EV-3201 V/F as a discrete core barrier layer in a five-layer wall consisting of HDPE/tie/EVOH/tie/HDPE, with EVOH mass fraction of 2–4 wt%. The addition ratio is minimized to avoid the loss of drop-impact resistance observed when EVOH exceeds 5 wt% in a 1 L container with 35 g weight and 1.2 m drop height per UN packaging drop test under 49 CFR 178.603. Solvent permeation testing per ASTM D2684 is used to compare xylene and cyclohexanone retention against monolayer HDPE; however, published data for this specific EV-3201 V/F formulation in a 2.5 L F-style jug with 58 g wall weight is limited, and line trials are required.
Regulatory compliance is governed by UN dangerous goods packaging under 49 CFR 178.504 and ADR, with stackability tested under ASTM D2659. Production on shuttle blow molders with 15–20 L accumulator heads uses a separate EVOH extruder with 45 mm barrier screw, 24:1 L/D, and melt temperature set to 210 °C; die temperature is held at 220 °C and the EVOH layer is offset toward the container exterior to reduce swelling from interior solvent contact. Calibration blow pressure of 8 bar and mold temperature 15 °C improve EVOH layer crystallinity and reduce surface haze; at a melt temperature of 215 °C, a leakage defect rate below 0.4% is documented when the EVOH wall distribution is held within ±0.3% of nominal. End products include F-style jugs, narrow-mouth bottles, and closed-head drums for pesticide concentrates, oxidation-sensitive crop protection formulations, and solvent-based wood preservatives.
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The dry-state oxygen barrier of EVOH is governed by hydrogen bonding between hydroxyl groups and by the semicrystalline morphology. Under 0% RH, the permeability coefficient of commercial medium-ethylene EVOH grades generally lies between 0.01 and 0.1 cm³·mm/m²·day·atm at 23°C. When external relative humidity rises above 50–60%, absorbed water reduces intermolecular hydrogen bonding and increases free volume; oxygen permeability may rise by 2 to 3 orders of magnitude relative to the dry state, depending on ethylene content and temperature. The time to reach a given internal relative humidity in a buried EVOH layer depends on the water-vapour transmission rate of the outer skins. For a skin layer of 50 µm low-density polyethylene, the core may reach 50% RH within 1–7 days at 23°C and 85% RH external environment. Shelf-life calculations must therefore use wet-state oxygen transmission data after preconditioning, not dry-state data.
` Paragraph 2 test methods: `Oxygen transmission is measured according to ASTM D3985 using a coulometric sensor. Specimens should be conditioned at the intended humidity for at least 24 h before testing. Water-vapour transmission is measured according to ASTM F1249. Multilayer sheet or film must be tested as the complete structure; the oxygen barrier of the EVOH layer alone cannot be inferred from the total structure without measuring layer thickness and accounting for skin permeability. When reporting OTR, the test temperature, relative humidity, and specimen thickness must be stated; values without those parameters are not comparable.
` Paragraph 3 adhesion: `Interlayer adhesion is a separate failure mode. In humidified structures, water concentrates at the EVOH/tie-resin interface and can reduce peel strength. Adhesion is measured by peel testing following ASTM F904 or by internal procedures; a value that passes after dry processing can fail after humidity aging. Maleated polyolefin tie resins of 5–15 µm per side are common. The exact tie resin must be matched to the skin polymer and to the EVOH grade; not all maleic anhydride grafted resins provide the same wet peel strength.
` Maybe add paragraph 4 on conversion: `Thermoforming of EVOH-containing sheet introduces additional strain. In deep-draw containers, the EVOH core may thin more than the total sheet thickness. Corner oxygen transmission should be measured separately from sidewall transmission because barrier-layer thinning at corners can be 20–40% greater than the average. Pre-imposed stress can also reduce moisture resistance by increasing free volume in the strained amorphous phase.
` Substitution section: `Substitution of a high-ethylene EVOH grade with EV-3201 V/F in retortable pouches, trays, or hot-fill bottles requires validation beyond dry oxygen barrier. Ethylene content in EVOH controls a trade-off: higher ethylene improves moisture resistance, flex crack resistance, and thermoformability, while lower ethylene improves dry-state oxygen barrier but narrows the processing window and increases moisture sensitivity. If EV-3201 V/F is a lower-ethylene grade than the incumbent, the package may show better dry OTR but greater post-retort OTR increase and lower thermoformability. Published data for this specific configuration is limited; the processor must generate designed experiments with the actual skin and tie layers.
` Paragraph 2 retort: `Retort conditions at 121°C and 0.2 MPa overpressure create simultaneous thermal expansion, moisture absorption, and interfacial stress. EVOH layers that survive hot-fill at 85°C may crack or delaminate after retort if the skin modulus is too high or the tie resin softens. Post-retort testing should include visual inspection for microcracks at 20× magnification, peel adhesion after retort, and oxygen transmission after 24–48 h post-retort equilibration. A reversible OTR increase may recover; a permanent increase indicates structural damage. Processors should not assume that a standard PP/EVOH/PP structure qualified for hot-fill is automatically retortable.
` Paragraph 3 differences from other products: `Compared with PVDC, EV-3201 V/F contains no chlorine and does not release hydrogen chloride during incineration. PVDC can be applied as a dispersion coating on a single substrate, whereas EVOH requires coextrusion with tie resins. Compared with MXD6 polyamide, EVOH can provide lower oxygen transmission at 0% RH but shows a larger relative increase at high humidity. Compared with plasticized polyvinyl alcohol, EVOH is melt-processable and water-insoluble. These differences determine material selection for dry food, retort, and humid environments. For oxygen-sensitive beverages, EVOH is often used in a thin layer because carbon dioxide retention and oxygen barrier are both required; the CO₂/O₂ selectivity differs from that of polyamide and polyester.
` Regulatory unlabelled: `Regulatory acceptability of EV-3201 V/F is established by supplier documentation, not by the grade number alone. For U.S. food-contact applications, the resin must be covered by 21 CFR 177.1360, which sets conditions for ethylene-vinyl alcohol copolymers. For EU applications, the resin must comply with Regulation (EU) No 10/2011 on plastic materials and articles intended to come into contact with food. The Declaration of Compliance should state the applicable food types, maximum use temperature, and any migration limits. For non-food packaging, the processor may need to verify compliance with REACH and packaging heavy-metal restrictions under EU Directive 94/62/EC or U.S. toxics-in-packaging laws.
` Table 2 compliance matrix: `| Property | Method | Typical envelope |
|---|---|---|
| Density at 23°C | ISO 1183 | 1.12–1.19 g/cm³ |
| Melting point | ISO 3146 | 155–190°C |
| Melt flow index | ISO 1133-1:2022 | 1.5–15 g/10 min at supplier-specified conditions |
| Oxygen permeability at 0% RH, 23°C | ASTM D3985 | 0.01–0.1 cm³·mm/m²·day·atm |
The dry-state oxygen barrier of EVOH is governed by hydrogen bonding between hydroxyl groups and by the semicrystalline morphology. Under 0% RH, the permeability coefficient of commercial medium-ethylene EVOH grades generally lies between 0.01 and 0.1 cm³·mm/m²·day·atm at 23°C. When external relative humidity rises above 50–60%, absorbed water reduces intermolecular hydrogen bonding and increases free volume; oxygen permeability may rise by 2 to 3 orders of magnitude relative to the dry state, depending on ethylene content and temperature. The time to reach a given internal relative humidity in a buried EVOH layer depends on the water-vapour transmission rate of the outer skins. For a skin layer of 50 µm low-density polyethylene, the core may reach 50% RH within 1–7 days at 23°C and 85% RH external environment. Shelf-life calculations must therefore use wet-state oxygen transmission data after preconditioning, not dry-state data.
The dry-state oxygen flux can be approximated by the steady-state permeation equation OTR = (P × Δp)/t, where P is the permeability coefficient, Δp is the oxygen partial pressure difference, and t is the barrier-layer thickness. For a target OTR of 1.0 cm³/m²·day·atm and a permeability coefficient of 0.02 cm³·mm/m²·day·atm, the required thickness is 0.02 mm. In wet-state service, the effective P may increase by several orders of magnitude; the equation remains linear only after the layer reaches stable moisture content. Transient humidification conditions therefore require finite-element mass-transport simulation or end-use-equilibrated testing.
Oxygen transmission is measured according to ASTM D3985 using a coulometric sensor. Specimens should be conditioned at the intended humidity for at least 24 h before testing. Water-vapour transmission is measured according to ASTM F1249. Multilayer sheet or film must be tested as the complete structure; the oxygen barrier of the EVOH layer alone cannot be inferred from the total structure without measuring layer thickness and accounting for skin permeability. When reporting OTR, the test temperature, relative humidity, and specimen thickness must be stated; values without those parameters are not comparable.
Interlayer adhesion is a separate failure mode. In humidified structures, water concentrates at the EVOH/tie-resin interface and can reduce peel strength. Adhesion is measured by peel testing following ASTM F904 or by internal procedures; a value that passes after dry processing can fail after humidity aging. Maleated polyolefin tie resins of 5–15 µm per side are common. The exact tie resin must be matched to the skin polymer and to the EVOH grade; not all maleic anhydride grafted resins provide the same wet peel strength.
Thermoforming of EVOH-containing sheet introduces additional strain. In deep-draw containers, the EVOH core may thin more than the total sheet thickness. Corner oxygen transmission should be measured separately from sidewall transmission because barrier-layer thinning at corners can be 20–40% greater than the average. Pre-imposed stress can also reduce moisture resistance by increasing free volume in the strained amorphous phase. Heat sealing near the EVOH layer can drive moisture from the sealant into the barrier. The sealed area may develop a localized OTR increase that is not detected by testing the web centre. For retort pouches and lidding films, oxygen transmission should be measured on the seal area and on creases because these regions concentrate mechanical and thermal damage.
Substitution of a high-ethylene EVOH grade with EV-3201 V/F in retortable pouches, trays, or hot-fill bottles requires validation beyond dry oxygen barrier. Ethylene content in EVOH controls a trade-off: higher ethylene improves moisture resistance, flex crack resistance, and thermoformability, while lower ethylene improves dry-state oxygen barrier but narrows the processing window and increases moisture sensitivity. If EV-3201 V/F is a lower-ethylene grade than the incumbent, the package may show better dry OTR but greater post-retort OTR increase and lower thermoformability. Published data for this specific configuration is limited; the processor must generate designed experiments with the actual skin and tie layers.
Retort conditions at 121°C and 0.2 MPa overpressure create simultaneous thermal expansion, moisture absorption, and interfacial stress. EVOH layers that survive hot-fill at 85°C may crack or delaminate after retort if the skin modulus is too high or the tie resin softens. Post-retort testing should include visual inspection for microcracks at 20× magnification, peel adhesion after retort, and oxygen transmission after 24–48 h post-retort equilibration. A reversible OTR increase may recover; a permanent increase indicates structural damage. Processors should not assume that a standard PP/EVOH/PP structure qualified for hot-fill is automatically retortable.
Compared with PVDC, EV-3201 V/F contains no chlorine and does not release hydrogen chloride during incineration. PVDC can be applied as a dispersion coating on a single substrate, whereas EVOH requires coextrusion with tie resins. Compared with MXD6 polyamide, EVOH can provide lower oxygen transmission at 0% RH but shows a larger relative increase at high humidity. Compared with plasticized polyvinyl alcohol, EVOH is melt-processable and water-insoluble. These differences determine material selection for dry food, retort, and humid environments. For oxygen-sensitive beverages, EVOH is often used in a thin layer because carbon dioxide retention and oxygen barrier are both required; the CO₂/O₂ selectivity differs from that of polyamide and polyester.
Regulatory acceptability of EV-3201 V/F is established by supplier documentation, not by the grade number alone. For U.S. food-contact applications, the resin must be covered by 21 CFR 177.1360, which sets conditions for ethylene-vinyl alcohol copolymers. For EU applications, the resin must comply with Regulation (EU) No 10/2011 on plastic materials and articles intended to come into contact with food. The Declaration of Compliance should state the applicable food types, maximum use temperature, and any migration limits. For non-food packaging, the processor may need to verify compliance with REACH and packaging heavy-metal restrictions under EU Directive 94/62/EC or U.S. toxics-in-packaging laws.
| Reference | Area | Required evidence |
|---|---|---|
| 21 CFR 177.1360 | U.S. food-contact use | Supplier compliance letter, migration data |
| Regulation (EU) No 10/2011 | EU food-contact plastics | Declaration of Compliance, overall migration |
| REACH | European chemical registration | Registration number or downstream user obligations |
| ASTM D3985 | Oxygen transmission rate | Test report at specified RH and temperature |
| ASTM F1249 | Water-vapour transmission rate | Test report with specimen thickness |
In-line regrind of edge trim is limited by the concentration of EVOH in the polyolefin skin layer. Because EVOH is incompatible with polyethylene and polypropylene, regrind above 5–10 wt% can produce visible gels and delamination. Regrind should be used only in the skin or tie layer, never in the EVOH core. Additives such as low-molecular-weight amines, some organic acids, and metal carboxylates may interact with hydroxyl groups and should not be added to the EVOH layer without supplier approval. If colour concentrates are required, they must be selected from EVOH-compatible carriers to avoid compromising layer continuity. The same restriction applies to slip and antiblock additives; they should be incorporated in the skin layers rather than the barrier core.
Unopened EV-3201 V/F should be stored in a dry area below 40°C. High warehouse temperatures may accelerate moisture absorption if the packaging is damaged. The shelf life of unopened EVOH is typically supplier-specified; after opening, the resin should be consumed within 24 h or resealed under nitrogen. Partially used bags that remain in humid air cannot be re-dried indefinitely because repeated drying cycles may alter pellet surface and increase fines. Fines can cause feed-bridging and barrier-thickness defects.
