| HS Code | 257242 |
| Ethylene Content | 44 mol% |
| Density | 1.18 g/cm³ |
| Melt Flow Rate | 4.4 g/10 min (190°C, 2.16 kg) |
| Melting Point | 183 °C |
| Glass Transition Temperature | 62 °C |
| Tensile Strength At Break | 40 MPa |
| Elongation At Break | 300% |
| Tensile Modulus | 1.5 GPa |
| Oxygen Transmission Rate | 0.5 cm³·mm/(m²·day·atm) at 20°C, 65% RH |
| Water Absorption | 2.4% at 23°C, 50% RH |
As an accredited EVOH EVAL L171B factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | EVOH EVAL L171B is supplied in 25 kg sealed multi-layer paper bags, protected from moisture and contamination for safe handling and storage. |
| Container Loading (20′ FCL) | 20′ FCL loading of EVOH EVAL L171B: 25kg bags palletized, shrink-wrapped, and securely stowed in standard dry container. |
| Shipping | EVOH EVAL L171B ships as a non-hazardous ethylene vinyl alcohol copolymer resin in sealed moisture-proof packaging such as lined bags or drums. Protect from water/humidity, store below recommended temperature, and avoid direct sunlight. No dangerous goods designation; standard dry freight transportation is acceptable. |
| Storage | Store EVOH EVAL L171B in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and moisture. Keep original container tightly closed to prevent contamination and humidity absorption. Avoid stacking heavy loads on bags to prevent deformation. Use within recommended shelf life, protecting from physical damage and extreme temperature fluctuations. |
| Shelf Life | Shelf life is typically 2 years from production date if stored in original sealed packaging in a cool, dry place. |
Pre-drying of EVOH L171B pellets is the first control point in coextruded barrier film for modified-atmosphere food packaging. The grade has an ethylene content of 27 mol%, a melt mass-flow rate of 3.9 g/10 min at 190 °C/2.16 kg (ISO 1133-1), a density of 1.20 g/cm³ (ISO 1183-1), and a melting point by differential scanning calorimetry of 191 °C (ISO 11357-3). A residual moisture content above 0.1 wt% produces bubble nucleation at the melt lip and haze bands in thin layers. Hopper drying at 90–105 °C for 4–6 h is used when ambient relative humidity exceeds 60%. Dried pellets are conveyed with dry air at a dew point below -20 °C to keep moisture uptake below 0.05 wt% at the feed throat. The barrier layer is coextruded at 3–8 µm in a five-layer LDPE/tie/EVOH L171B/tie/LDPE or seven-layer LDPE/tie/EVOH L171B/tie/PA/tie/PE stack. Maleic anhydride grafted polyolefin tie resins are required for interfacial adhesion; acrylic acid grafted tie resins are not interchangeable when the sealing layer contains migratory slip additives. A barrier screw with L/D 24:1 to 30:1 and compression ratio 2.8–3.5 is used. On a cast film line, the EVOH extruder is set with barrel zones from 180 °C to 230 °C, melt temperature at 215 ± 5 °C, and die temperature at 220–235 °C. The tie resin melt temperature is held within 10 °C of the EVOH melt temperature to avoid interfacial viscosity mismatch. Residence time in the extruder and adapter is held below 20 min above 220 °C to avoid gel formation from thermally degraded EVOH. During shutdown, the EVOH extruder is purged with low-density polyethylene at 200–220 °C; PVC or PVdC remnants in the feedblock must be avoided because acid gases accelerate EVOH crosslinking. On production lines, the most frequent failure during start-up is EVOH layer waviness caused by insufficient tie-layer output during acceleration from 20 m/min to 60 m/min. Oxygen transmission rate is measured according to ASTM D3985 at 23 °C and 0% RH; water vapour transmission rate is measured according to ASTM F1249. The converted film is used for thermoformed barrier trays and lidding webs for processed meat, cheese, and pre-cooked poultry. Food-contact compliance is supported by FDA 21 CFR 177.1360 and EU Regulation 10/2011 with the understanding that individual national positive lists require final article testing.
In six-layer HDPE/regrind/tie/EVOH/tie/HDPE fuel tank coextrusion, continuous parison stabilization is constrained by the melt-strength differential between high-molecular-weight HDPE and EVOH L171B. The EVOH layer is typically 2–3 wt% of the total wall cross-section, corresponding to 40–80 µm in a 4–6 mm parison wall. The accumulator head runs at 220–240 °C, while the EVOH melt temperature is kept at 210–230 °C. Above 240 °C, gel particles appear within 8–12 min of static residence time; below 205 °C, the EVOH layer fails to distribute uniformly and forms wavy transverse bands. The parison must remain above 150 °C at the pinch-off zone. Premature cooling below this threshold creates interlayer delamination at the tie/EVOH interface because recrystallization of the 27 mol% ethylene grade reduces surface wetting. At pinch-off, an EVOH layer thickness below 25 µm at the weld line creates a permeation short-circuit. Blow mold cooling is set to give a mold surface temperature of 15–25 °C. Flash regrind is incorporated into the HDPE skin at 30–50 wt%, but EVOH regrind is not fed directly into the skin because it forms unmelted gel domains. Leak testing after molding is performed at 30 kPa internal pressure. Emissions performance is validated on a sealed housing evaporative determination system under EPA 40 CFR Part 86 testing protocols; CARB LEV III limits are usually met only when the EVOH layer is continuous and not thinned below 30 µm at the tank corners. Methanol-containing fuels above 5 vol% require separate validation since polar solvent uptake in EVOH can cause local swelling and layer waviness. Published data for the specific interaction of L171B with high methanol fuel blends is limited; validation is required. End applications include automotive fuel tanks, generator fuel cells, and jerry cans for hydrocarbon fuels.
Thermoforming of PP/EVOH/PP sheet introduces a different failure mode: solid-state cracking of the EVOH layer during plug-assisted draw. The coextruded sheet is produced at 0.8–1.2 mm total thickness with the EVOH layer at 5–8% of total thickness. The sheet line uses a coextrusion feedblock with A/B/C/B/A distribution; rheology matching of EVOH and PP is achieved by selecting a PP skin grade with melt mass-flow rate of 1.5–3.0 g/10 min. The sheet die is set at 230–245 °C, and the chill roll temperature is 80–90 °C to delay PP crystallization and allow EVOH to remain above its brittle transition. The forming surface temperature of the sheet is 150 ± 5 °C. If the sheet drops below 140 °C during preheating, the EVOH layer cracks when draw ratios exceed 3:1; if the sheet exceeds 165 °C, the PP skins sag and the EVOH layer becomes exposed at the trim edge. Plug-assist speed is reduced to 150–250 mm/s for cup depths above 40 mm to prevent localized thinning of the barrier layer below 10 µm. Plug temperature is maintained at 110–130 °C. The formed containers are used for shelf-stable dairy desserts, single-serve fruit cups, and microwaveable ready-meal trays. Oxygen transmission of the formed container is correlated with the thinnest EVOH point at the corner, measured by destructive cross-section microscopy and ASTM D3985 on flat sheet before forming. Steam retorting above 121 °C is not recommended for this grade without a polyolefin moisture barrier in the structure because oxygen barrier drops rapidly above 80% RH inside the container. Food-contact compliance is supported by FDA 21 CFR 177.1360 and EU Regulation 10/2011.
Pharmaceutical blister base webs have historically relied on PVdC for oxygen and moisture protection, but EVOH L171B is used as a coextruded core in PVC/PE/EVOH/PE structures when halogen-free disposal is required. The EVOH layer is 15–25 µm in a 250–350 µm base web. The cast film line runs at 60–120 m/min with a water-bath quench at 40–60 °C. The EVOH melt temperature is held at 215–225 °C, and the die is maintained at 220–230 °C. A key limitation is that EVOH oxygen barrier is humidity-dependent; the base web must be stored at <35% RH after slitting or the oxygen transmission rate at the formed cavity rises. Forming cavity depth to base web thickness ratio is limited to 2.5:1 when the EVOH layer is 20 µm; exceeding this ratio thins the barrier layer at the cup corner below 8 µm. Preformed blisters are tested for water vapour transmission using USP <671> permeation methodology and for overall drug stability under ICH Q1A conditions. The structure is generally not a direct substitute for PVdC when moisture protection below 0.1 g/(m²·24 h) at 38 °C/90% RH is required from a thin web without an additional aluminium foil layer. Residual solvent content in the printed lidding foil is controlled to avoid swelling the EVOH layer at the seal edge. End packaging includes oral solid dose blisters for hygroscopic actives and effervescent tablets where the barrier layer is laminated between polyolefin skins to reduce moisture ingress.
In extrusion lamination for oral-care laminate tubes, the adhesiveless substrate stack commonly loads EVOH L171B at 5–10% of the sleeve wall thickness. The sleeve is produced on a multilayer blow molding die at 220–240 °C and a blow-up ratio of 1.5–2.2. The EVOH layer is 20–40 µm, and the total wall thickness is 300–400 µm. The extruder processing window is narrow because the tube line speed varies from 20 m/min during start-up to 80 m/min at steady state. Melt temperature is fixed at 215 ± 5 °C; variation beyond this range produces optical gel defects in the EVOH layer that are visible after flexographic printing on the outer PE skin. Hot air sealing for the tube side seam runs at 350–450 °C; seal pressure is 0.3–0.6 MPa for 1.0–1.5 s. The tube is pressure-tested at 0.05–0.15 MPa for side-seam integrity and dropped from 1.2 m at -20 °C to detect brittle failure. Barrier performance is specified by total oxygen ingress through the sealed empty tube over 12 months at 25 °C/50% RH. End products include toothpaste tubes, cosmetic lotion tubes, and barrier sleeves for hair colourant pastes. Packaging compliance falls under EU Cosmetics Regulation 1223/2009 for product compatibility, while the plastic layers may require migration testing to EU Regulation 10/2011 when the formulation contains food-grade aroma compounds.
Low-pH condiment stand-up pouches require barrier layer integrity through repeated flexing at the gusset crease. The lamination structure is typically BOPET 12 µm/adhesive/EVOH L171B 12–15 µm/LDPE 60–100 µm. The EVOH film is produced by blown film coextrusion with a die temperature of 220–235 °C and a blow-up ratio of 2.0–2.5. The film is subsequently corona treated to 42–46 mN/m before lamination. Lamination nip temperature is 70–85 °C with web tension of 100–200 N/m. Flex-crack resistance is evaluated using ASTM F392 Gelbo testing with 500 cycles at 25 °C; a barrier loss above 10% after flexing indicates that the EVOH layer must be thickened or separated from the external BOPET by a softer tie layer. The pouch is filled with hot-fill condiment at 85–90 °C. The EVOH layer must not be in direct contact with acetic acid above 4% concentration because acid-catalysed hydrolysis at the exposed edge can propagate delamination. The terminal product is used for ketchup, soy sauce, vinegar-based marinades, and cooking sauce refill packs. Oxygen transmission testing is performed after filling on flat panel sections cut from the pouch sidewall according to ASTM D3985; the specification is generally below 0.01 cm³/(pouch·24 h·atm) at 23 °C/50% RH for a 500 mL pack.
| Downstream segment | Compliance or performance standard | Test method designation |
|---|---|---|
| MAP processed meat/cheese film | Food contact, oxygen and water vapour barrier | FDA 21 CFR 177.1360, EU Regulation 10/2011, ASTM D3985, ASTM F1249 |
| HDPE/EVOH fuel tank | Evaporative emission | EPA 40 CFR Part 86, CARB LEV III, sealed housing evaporative determination |
| PP/EVOH/PP rigid containers | Food contact, barrier retention after forming | FDA 21 CFR 177.1360, ASTM D3985 |
| Pharmaceutical blister base web | Drug packaging permeation | USP <671>, ICH Q1A |
| Oral-care laminate tubes | Cosmetic packaging compatibility | EU Cosmetics Regulation 1223/2009 |
| Condiment stand-up pouch | Flex crack, oxygen barrier, acid resistance | ASTM F392, ASTM D3985 |
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EVAL L171B is a fully saponified ethylene-vinyl alcohol copolymer containing approximately 27 mol% ethylene. This ethylene content places the grade at the high-barrier, high-moisture-sensitivity end of the EVAL product range. The resin is supplied as cylindrical pellets and is specified for oxygen-barrier layers in coextruded multilayer packaging, thermoformed sheet, and blow-moulded rigid containers. Melt flow rate under ISO 1133-1:2022 is 3.9 g/10 min at 190°C and 2.16 kg; density under ISO 1183-1 is 1.20 g/cm³; melting point under ISO 11357-3 is 191°C. Oxygen transmission rate on a 20 μm film at 20°C and 0% RH is approximately 0.4 cm³·20 μm·m⁻²·day⁻¹·atm⁻¹ under ASTM D3985. Compared with higher-ethylene EVAL grades such as H171B, L171B provides lower dry-gas permeability but exhibits a sharper loss of barrier at elevated relative humidity. The product is therefore placed in architectures where oxygen ingress is the primary spoilage vector and moisture can be controlled by external polyolefin or polyester layers. This introduction is not a substitute for grade-specific datasheets; processing conditions must be validated on the target line.
| Property | Test method | Typical value |
|---|---|---|
| Ethylene content | internal saponification assay | 27 mol% |
| Melt flow rate at 190°C, 2.16 kg | ISO 1133-1:2022 | 3.9 g/10 min |
| Density | ISO 1183-1 | 1.20 g/cm³ |
| Melting point | ISO 11357-3 | 191°C |
| Oxygen transmission rate, 20 μm film, 20°C, 0% RH | ASTM D3985 | 0.4 cm³·20 μm·m⁻²·day⁻¹·atm⁻¹ |
The oxygen barrier of EVOH arises from hydrogen-bonded crystalline domains that reduce free volume and impede oxygen diffusion. In L171B, the 27 mol% ethylene content yields a high hydroxyl-group density, which increases crystallinity and dry-gas barrier but also creates a more hydrophilic amorphous phase. At external relative humidity above 60%, water molecules diffuse into the EVOH layer and disrupt interchain hydrogen bonding, increasing segmental mobility and oxygen permeability. The increase is nonlinear: published oxygen transmission data for EVOH grades indicate a 3 to 6 fold rise between 0% and 65% relative humidity at 20°C. In practical multilayer structures, polyolefin skins and anhydride-modified tie layers reduce moisture ingress, but edge absorption and long-term storage at high humidity can produce localized barrier loss. For retort conditions at 121°C and 100% RH, published data for L171B in specific laminate configurations is limited; final structures require validation by ASTM F2622 or ISO 15105-2 at specified temperature and humidity.
Oxygen permeation in EVOH follows a solution-diffusion mechanism. The low permeability of L171B at low humidity is dominated by high crystallinity and low free volume in the amorphous phase; the ethylene sequences provide some chain mobility but do not substantially reduce hydrogen bonding. Water molecules act as plasticizing penetrants and weaken interchain hydrogen bonds. This plasticization reduces the glass transition of the water-saturated amorphous phase, although the crystalline regions remain impermeable until melting. The result is that oxygen flux increases mainly through the amorphous regions. In a coextruded film, this effect is not uniform: the EVOH layer adjacent to the inner tie layer may be at lower local relative humidity than the layer adjacent to the outer tie layer, producing an asymmetric barrier profile across the thickness. The 0.4 cm³·20 μm·m⁻²·day⁻¹·atm⁻¹ value at 0% RH corresponds to a permeability coefficient of 0.008 cm³·mm·m⁻²·day⁻¹·atm⁻¹ when normalized to 1 mm thickness. For a 5 μm EVOH layer at 0% RH, the calculated oxygen transmission rate is approximately 1.6 cm³·m⁻²·day⁻¹·atm⁻¹. At 65% RH, the same layer may transmit between 4.8 and 9.6 cm³·m⁻²·day⁻¹·atm⁻¹ if moisture protection is absent. Layer thickness variations of ±10% therefore produce roughly proportional oxygen transmission variations because oxygen flux is inversely proportional to thickness.
Before extrusion, L171B pellets are dried in desiccant dryers at 80°C for 4–6 h to reduce moisture below 0.1%. Residual moisture above this threshold hydrolyzes the polymer during melting, generating acetic acid and producing viscosity shifts that lead to screw surging and gel formation on single-screw extruders with L/D ratios below 30:1. On production cast-film and sheet lines, barrel temperature profiles are set from 180°C at the feed zone to 220°C at the metering zone, with melt temperature held between 220°C and 230°C. Residence times above 240°C accelerate thermal degradation, producing crosslinked gels and black specks. The screw is purged with low-density polyethylene before shutdown; halogenated purging compounds are not used because acid release promotes discoloration. On 45 mm single-screw extruders with 30:1 L/D barrier screws, screw speeds above 100 rpm may generate excessive shear heating. Gear pumps between screw and die reduce pressure fluctuations and layer thickness variation in coextrusion.
Typical flexible film structures place L171B between two polyolefin skins using anhydride-modified polyolefin tie resins. In a 50–90 μm film, the EVOH layer is 3–5 μm and each tie layer is 8–15 μm. For thermoformed trays with total sheet thickness of 750–1000 μm, the EVOH layer may be 25–50 μm. The tie layers must melt at temperatures close to the EVOH layer and must provide sufficient adhesion after forming. Coextrusion adhesion is measured by ASTM F904; values above 2 N/15 mm are typical for newly extruded film, with reductions to 1–1.5 N/15 mm after boiling or retort. Barrier performance depends on the EVOH layer remaining continuous; neck-in and layer thickness variation in dies with width-to-gap ratios above 30:1 can reduce the effective oxygen barrier by more than the nominal layer thickness would predict.
Tie resins are typically maleic anhydride-grafted polyolefins with melt flow rates between 1.0 and 3.0 g/10 min at 190°C. The tie layer must be coextruded at a melt temperature within ±10°C of the EVOH layer to avoid interfacial instabilities. Adhesion is tested after 24 h conditioning by ASTM F904; typical peel values above 2 N/15 mm indicate cohesive failure in the polyolefin, not adhesive failure at the EVOH interface. After pasteurization at 95°C or retort at 121°C, peel values commonly decrease to 1–1.5 N/15 mm but must remain above 0.8 N/15 mm to prevent delamination in distribution. The EVOH layer must be encapsulated; exposed edges can absorb moisture during storage, causing local barrier loss in thermoformed containers.
In flexible meat and cheese packaging, L171B is coextruded between polyethylene layers at total thicknesses of 50–90 μm; the EVOH layer is typically 3–5 μm. The structure is converted on blown-film lines with annular dies of 100–250 mm diameter and blow-up ratios of 2.0–2.5. Oxygen ingress is controlled below 1.0 cm³·m⁻²·day⁻¹·atm⁻¹ depending on EVOH layer thickness, with measurement under 23°C and 50% RH per ASTM D3985. Water vapor transmission remains governed by the polyolefin layers and is measured under ASTM F1249. On blown-film lines, die temperatures of 220–230°C are used to avoid unsteady bubble shape. Published data for L171B in specific thicknesses is available from resin supplier technical bulletins; final barrier values must be measured on the actual film structure because layer thickness variation and processing history change permeability.
Substitution of L171B for H171B changes the ethylene content from 38 mol% to 27 mol%. The dry oxygen barrier improves, but the melting point increases by approximately 16°C, from 175°C to 191°C. Melt temperature settings must therefore be raised by 10–15°C, and the thermal stability window narrows because degradation accelerates above 240°C. In thermoforming, L171B requires higher sheet temperatures for uniform draw, which can increase polypropylene skin sag and change plug-assist timing. In retort trays, the higher barrier of L171B is offset by greater moisture sensitivity at cut edges and corners after trimming. Published data comparing L171B and H171B in identical retort laminates is limited; therefore, replacing the barrier resin requires pilot-scale retort trials to verify oxygen barrier and adhesion under the intended time–temperature profile.
Compared with PVDC, L171B has lower oxygen permeability at 0% RH but requires encapsulation; PVDC can be used as a monolayer coating and retains barrier at high humidity. Compared with PA6, L171B provides roughly 50-fold lower oxygen permeability at 0% RH but lower flex-crack resistance. Compared with EVA, L171B is a barrier resin; EVA has no significant oxygen barrier and is used as a sealant or tie component.
| Barrier material | Typical O2TR at 20°C, 0% RH (cm³·20 μm·m⁻²·day⁻¹·atm⁻¹) | Response to 65% RH |
|---|---|---|
| EVAL L171B | 0.4 | increases by 3–6× |
| PVDC copolymer | 0.6–1.5 | low change |
| PA6 | 20–40 | moderate change |
| EVA | >500 | low change |
L171B is not used as a monolayer food-contact layer; its function is as an internal barrier layer separated by tie resins and polyolefins. Regulatory references for food-contact use include 21 CFR 177.1360 and EU Regulation (EU) 10/2011, but responsibility for migration testing rests with the finished-article manufacturer. The resin should not be combined with halogenated polymers such as PVDC or PVC during coextrusion because acid degradation products catalyze EVOH color formation. Pellets should be stored in sealed containers at ambient temperature below 30°C and relative humidity below 60%; opened bags should be dried before use. Published data for high-humidity industrial applications above 85% RH is limited.
