| HS Code | 786634 |
| Oxygen Permeability | 0.1 cc·mm/m²·day·atm |
| Ethylene Content | 32 mol% |
| Density | 1.19 g/cm³ |
| Melting Point | 183°C |
| Glass Transition Temp | 62°C |
| Tensile Strength | 70 MPa |
| Elongation At Break | 180% |
| Water Absorption | 6.8% |
| Haze | 1.5% |
| Melt Flow Rate | 3.5 g/10min |
| Chemical Resistance | Excellent resistance to oils, fats, and organic solvents |
| Food Safety Compliance | FDA approved for food contact |
As an accredited Special Modified EVOH factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Special Modified EVOH is supplied in 25 kg sealed multi-layer paper bags with moisture-proof polyethylene liner. |
| Container Loading (20′ FCL) | Special Modified EVOH shipped as 20′ FCL, palletized, moisture-protected, secured to prevent shifting, ensuring safe, contaminant-free transport. |
| Shipping | Special Modified EVOH ships in sealed, moisture-proof bags or drums to preserve purity and prevent contamination. Use clean, dry containers with proper ventilation. Avoid high heat and direct sunlight during transit. Label according to applicable chemical regulations and include handling documentation to ensure safe, compliant delivery. |
| Storage | Store Special Modified EVOH in sealed, moisture-proof containers in a cool, dry, well-ventilated area. Protect from direct sunlight, heat sources, and humidity to prevent degradation or caking. Keep away from oxidizing agents and incompatible materials. Maintain stable temperatures, avoid compression, and use first-in, first-out rotation to preserve quality within shelf life. |
| Shelf Life | Store in a cool, dry place away from sunlight; shelf life is 12 months from date of manufacture when unopened. |
Special modified EVOH resins entering high-barrier conversion are normally delivered with a moisture content below 0.3%; if storage humidity exceeds 60% RH, the pellets absorb surface water within 12 h and must be dried in a desiccant-air hopper dryer at 80 °C for 4 h, with a dew point of −40 °C, to restore a target moisture of 250 ppm. Melt temperature at the lip should remain between 210 °C and 230 °C; residence time above 230 °C beyond 20 min produces crosslinked gel defects, which appear as fisheyes in cast film and as dart impact failures in finished laminates. Screw geometry with an L/D of 28:1 and a compression ratio of 3.0:1 is preferred, and shutdown purging is carried out with a low-melt-index LDPE at 2 g/10 min to avoid carbonized residues.
Retort packaging produced with modified EVOH as a buried barrier layer must tolerate steam retort at 121 °C for 30 min without developing microcracks that allow oxygen ingress through the film web. The film construction for a transparent retort pouch typically places a 12 μm biaxially oriented polyester outer web against a 3 μm maleic anhydride-grafted polyolefin tie layer, a 5 μm modified EVOH core, a second 3 μm tie layer, and a 70 μm cast polypropylene sealant web; the modified EVOH accounts for 5.4% of total thickness, while the complete barrier portion including tie layers is 11.8%. This layer ratio is selected because the modified EVOH retains flex-crack resistance after steam retort, limiting Gelbo flex pinholes to fewer than 5 per 300 cm² after 50 cycles under ASTM F392, whereas unmodified EVOH grades may exceed 12 pinholes in the same test. Oxygen transmission rate after retort is controlled to below 0.5 cm³/(m²·day·atm) at 23 °C and 65% RH using ASTM D3985-17, and converters typically require a post-retort seal strength above 35 N/15 mm according to ASTM F88/F88M-21. Compliance for food contact falls under EU Regulation 10/2011 Annex I with an overall migration limit of 10 mg/dm², FDA 21 CFR 177.1360 for the olefin copolymer components, and China GB 9685-2016 for permitted additive usage; the modified grade must be covered by a supplier FCN and tested for specific migration of the compatibilizer at the intended retort temperature. Process conditions on a three-layer blown-film line require a dual-lip air ring with a die gap of 1.8–2.2 mm, a blow-up ratio of 2.0–2.4, and a frost line height of 350–450 mm; the EVOH extruder zone set points are held at 205 °C, 215 °C, 220 °C, and 225 °C from feed throat to adapter. Terminal products include transparent retort pouches for wet pet food, ready-to-eat rice, broth, and high-acid sauces.
In pharmaceutical lidding applications where push-through aluminum foil is replaced by transparent barrier films, modified EVOH is inserted as a buried layer between an oriented polyamide web and a peelable sealant. A common lamination for unit-dose blister lidding uses 25 μm oriented polyamide, 4 μm tie resin, 5 μm modified EVOH, 4 μm tie resin, and 18 μm ethylene-vinyl acetate-based sealant; the modified EVOH layer accounts for 8.9% of the total structure and is positioned below the printable polyamide to avoid direct contact with medication. The composite must meet USP 671 moisture vapor transmission limits for tight packaging and maintain oxygen barrier after folding, where pre-existing microcracks in standard EVOH cause a rapid increase in oxygen ingress when the lidding is bent around blister cavities. Compliance is assessed under EU 10/2011 overall migration 10 mg/dm², FDA 21 CFR 177.1360, and drug stability protocols such as ICH Q1A(R2); seal integrity is checked by ASTM F1929-15 dye penetration with no dye channel through the peelable seal, and oxygen transmission rate is measured on the total lamination according to ASTM D3985-17. Solventless lamination of the pharmaceutical webs operates with a coating weight of 1.8–2.2 g/m², a two-component polyurethane adhesive mixed at 100:60 by volume, a nip temperature of 65 °C, and a line speed of 120 m/min; the polyamide surface is corona-treated to a minimum surface energy of 42 mN/m. Finished goods include child-resistant calendar blister lidding, clinical trial overpacks, and transparent lidding for ampoules and vials.
| Requirement | Standard or regulation | Measured / specified condition |
|---|---|---|
| Oxygen transmission rate | ASTM D3985-17 | 23 °C, 0% RH; target <0.3 cm³/(m²·day·atm) |
| Moisture vapor transmission rate | ASTM F1249-20 | 38 °C, 90% RH; target <2.0 g/(m²·day) |
| Seal integrity | ASTM F1929-15 | No dye penetration through seal after 5 s vacuum |
| Overall migration | EU 10/2011 Annex I | <10 mg/dm² |
| Food/medical component compliance | FDA 21 CFR 177.1360 | Grade-specific FCN extractives limits |
Multilayer blow molding of automotive fuel tanks imposes a narrow viscosity-matching window because the modified EVOH layer must remain cohesive between high-density polyethylene skins and adhesive tie resins during parison inflation and pinch-off welding. A six-layer structure for a passenger car tank uses HDPE outer skin 3.4 mm, tie 0.08 mm, modified EVOH 0.12 mm, tie 0.08 mm, HDPE inner skin 2.6 mm, and regrind layer 1.4 mm; the EVOH layer represents 1.6% of total wall thickness but provides the primary hydrocarbon barrier in ethanol-containing fuels. The modified EVOH for fuel tanks is processed at 210–225 °C with a melt flow index between 3 g/10 min and 6 g/10 min at 210 °C/2.16 kg, while the HDPE skins run at 190–210 °C with a melt flow index of 0.25–0.35 g/10 min at 190 °C/21.6 kg. If the EVOH layer exceeds 220 °C for more than 15 min, gel formation increases and the barrier becomes brittle at low temperatures; if it drops below 205 °C, the layer thickness becomes non-uniform and sidewall oxygen ingress may exceed the design target. Permeation validation is performed using SAE J1737 hydrocarbon loss protocols with ASTM Reference Fuel C at 40 °C, with the tank exposed to 10% ethanol, 45% toluene, and 45% isooctane by volume; automotive evaporative emission requirements in CARB LEV III and EPA Tier 3 programs define the system-level leakage and permeation budgets. Process limitations include a maximum regrind loading of 15% in the outer HDPE skin, because heavily degraded EVOH particles in recycled material create interfacial voids that reduce bowl creep resistance under pressure cycles; the pinch-off zone is trimmed to avoid barrier delamination at the mold parting line. Terminal uses include blow-molded fuel tanks for passenger cars, all-terrain vehicles, marine fuel cells, and small-engine fuel containers requiring permeation resistance to oxygenated fuels.
For cosmetic tube sleeves produced on high-speed side-seam lines, modified EVOH is buried as the central oxygen barrier between low-density polyethylene skins. A typical coextruded tube sheet comprises outer LDPE at 220 μm, tie resin at 15 μm, modified EVOH at 30 μm, tie resin at 15 μm, and inner LDPE at 80 μm, giving a total thickness of 360 μm and an EVOH fraction of 8.3%. The high side-seam welding speed requires the modified EVOH to resist thinning and scorch at the seam edge; hot-air welders set at 380 °C with nip pressure 0.4 MPa produce continuous side seams at 80 m/min without visible barrier fracture. The extruder profile for the barrier layer is maintained at 195–210 °C, while the polyolefin skins run at 170–185 °C, and the resulting web is corona-treated to 42 mN/m prior to printing. Compliance follows EU 10/2011 for food contact, FDA 21 CFR 177.1360 for the olefin-containing components, and REACH Annex XVII restrictions for phthalates and heavy metals. Flavor and oxygen barrier retention in the side seam is evaluated by ASTM D3985-17 on seam sections and by aging the filled tube at 45 °C for 12 weeks with a limonene-containing model cream; oxygen transmission targets for the finished tube body are below 0.8 cm³/(m²·day·atm) at 23 °C, 65% RH. Terminal products include toothpaste tubes, cosmetic cream tubes, barrier overcap shrouds, and personal-care sample packs.
When modified EVOH is specified for soil fumigation film, the barrier layer must withstand concentrated methyl bromide under plastic film conditions while the outer polyethylene skins resist tearing on stony or mechanically cultivated ground. The film is usually cast as a five-layer structure: HDPE outer web 22 μm, tie resin 3 μm, modified EVOH 5 μm, tie resin 3 μm, and anti-drip EVA inner web 17 μm, totaling 50 μm; the EVOH barrier represents 10% of thickness. The conversion line runs at 45 m/min with a matte embossing calender at 55 °C, edge trim of 10 mm per side, and web tension controlled at 55 N/m; melt temperatures are held at 215 °C in the barrier extruder and 185 °C in the polyolefin extruders to prevent barrier layer degradation. Permeation is tested under ASTM D1434 with pure methyl bromide at 25 °C and 0% RH, and the target permeability coefficient for the finished laminate is below 1.0 × 10⁻¹⁰ cm³·cm/(cm²·s·cmHg); because methyl bromide use is restricted to quarantine and pre-shipment fumigation under the Montreal Protocol, film manufacturers must align label claims with national pesticide registration requirements and the relevant EPA fumigant management plan. Barrier loss occurs when the EVOH layer is scratched during field deployment or when dessicant packs are not placed over the film edge; therefore the structure is supplied as lay-flat tubing with a minimum inner width of 3 m to allow mechanical layering over raised beds. Terminal products include gas-retentive tarps for soil fumigation, controlled atmosphere commodity fumigation sheets, and silage cover films where restricted crop protection products require high gas impermeability.
Terminally sterilized barrier pouches made from modified EVOH laminates must not develop microcracks after ethylene oxide stripping at 55 °C and 65% RH, because oxygen ingress through flexural microcracks accelerates loss of sterility over the labelled shelf life. A common pouch structure uses 12 μm polyester outer web, 3 μm tie resin, 5 μm modified EVOH, 3 μm tie resin, and 50 μm cast polypropylene sealant; the EVOH layer is 6.8% of the total thickness and remains buried to prevent direct contact with the medical device. Pouch conversion is performed at a sealing temperature of 160 °C, dwell time 0.8 s, and jaw pressure 0.5 MPa; seal strength is checked to exceed 1.5 N/15 mm after sterilization. In ethylene oxide cycles, the laminate is preconditioned at 55 °C and 65% RH for 12 h before gas exposure, then aerated at 40 °C for 24 h; modified EVOH shows fewer Gelbo flex pinholes than standard grades after this cycle, with ASTM F392 results below 5 pinholes per 300 cm² after 50 cycles. Oxygen transmission rate after sterilization is measured by ASTM D3985-17 and is typically specified below 0.5 cm³/(m²·day·atm) at 23 °C, 50% RH; package integrity is validated under ISO 11607-1:2019 and ISO 11607-2:2019, with dye penetration testing per ASTM F1929-15 showing no seal channeling. Terminal products include sterile barrier pouches for single-use syringes, catheters, wound dressings, and surgical instrument sets.
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Special Modified EVOH is supplied under the model designation SM-EVOH-32 as a pelletized, high-barrier ethylene-vinyl alcohol copolymer with a nominal ethylene content of 32 mol% and a reactive modifier package intended to shift film-forming, adhesion, and flex-crack behaviour relative to unmodified EVOH grades. The modifier system comprises a carboxyl-functional compatibilizing resin and an inorganic slip/anti-block dispersion at a combined loading of 2.0–4.0 wt%, determined as ash content after 800 °C ignition under ISO 3451-1. The material is intended for coextruded barrier layers in polyethylene- and polypropylene-based flexible packaging, blow-moulded bottles, retortable sheet, and thermoformed containers where delamination or pinhole formation limits shelf-life performance. Because the modifier chemistry increases melt viscosity and lowers the onset temperature for thermal degradation, the grade is processed at a melt temperature of 195 °C–205 °C, approximately 10–20 °C lower than unmodified EVOH of equivalent ethylene content. Published data for this specific configuration are limited; the values presented in this document are manufacturer release specifications and independently measured values for analogous 32 mol% ethylene modified grades verified under ISO/IEC 17025 conditions.
The oxygen-barrier performance of EVOH is controlled by water molecules that hydrogen-bond to the vinyl alcohol segments and plasticize the amorphous phase. For SM-EVOH-32, the oxygen transmission rate at 23 °C and 0 % RH is specified as ≤0.12 cm³·20 μm·m⁻²·day⁻¹·atm⁻¹ when measured on cast film by ASTM D3985 with a coulometric sensor. At 23 °C and 65 % RH, the OTR increases to 0.9–1.4 cm³·20 μm·m⁻²·day⁻¹·atm⁻¹, consistent with published barrier curves for 32 mol% ethylene EVOH. The modified grade retains a humidity-dependent barrier profile rather than eliminating it; therefore, it is not a substitute for aluminium foil or SiOx-coated films in applications requiring OTR below 0.1 cm³·m⁻²·day⁻¹·atm⁻¹ at 85 % RH.
Pre-drying is mandatory when ambient relative humidity exceeds 60 %. Residual pellet moisture above 0.05 wt%, determined by Karl Fischer titration at 180 °C per ISO 15512, produces bubble formation and local hydrolysis during extrusion. The specified drying protocol uses a desiccant dryer with −40 °C dew-point air and 4 h residence at 80 °C–90 °C. On production-scale coextrusion lines, failure to maintain dryer dew point below −30 °C causes visible shark-skin melt fracture at the die lip and a 0.5–1.0 log increase in oxygen permeation across the barrier layer.
In addition to barrier properties, the mechanical specification of SM-EVOH-32 determines its suitability for high-speed form-fill-seal lines. The melt volume-flow rate is 3.2 cm³/10 min at 190 °C and 2.16 kg load under ISO 1133-1:2022, with an expected batch-to-batch variation of ±0.4 cm³/10 min. Density is 1.17 g/cm³ at 23 °C under ISO 1183-1:2019. Tensile yield stress of injection-moulded ISO 527-2/1A specimens is 52 MPa at 23 °C, elongation at break is 14 %, and flexural modulus is 2100 MPa under ISO 178. These values are 8–12 % lower than unmodified EVOH of equivalent ethylene content due to the modifier phase; the reduction in stiffness is offset by a 20–30 % improvement in slow puncture resistance on 50 μm cast film when tested by ASTM F1306 with a 12.7 mm spherical probe.
Coextrusion of SM-EVOH-32 requires a barrier screw with a low compression ratio of 1.8:1–2.2:1 and a length-to-diameter ratio of 30:1–36:1. Production-scale cast film lines using 75 mm extruders report specific energy input of 0.18–0.22 kW·h/kg when the barrel temperature profile is set at 185/195/200/200/205 °C from feed throat to adapter. The melt pressure before the screen changer is typically 8–12 MPa at a screw speed of 45 min⁻¹, depending on die gap and throughput. Compared with unmodified EVOH, the modified grade exhibits 15–20 % lower melt pressure and a 5 °C wider die-lip stability window because the modifier reduces interfacial slip resistance at the tie-layer boundary.
The processing window is 195 °C–205 °C, equivalent to a tolerance of ±5 °C around the midpoint of 200 °C. At melt temperatures above 210 °C, thermal degradation of the vinyl alcohol segments proceeds by a first-order dehydration mechanism with an apparent activation energy of approximately 120 kJ/mol determined by isothermal thermogravimetric analysis at 200 °C, 210 °C, and 220 °C. At 220 °C, the melt flow rate increases by more than 30 % within 10 min, and the extruded web develops acetic acid odour and yellowing at the die lips. Below 185 °C, incomplete melting of the modifier phase produces unmelted gels of 50–200 μm in the cast film, which appear as specks in the final laminate. These gels cannot be removed by downstream melt filtration below 250 μm screen pack retention without increasing melt temperature.
Adhesion to maleic anhydride-grafted polypropylene tie layers is measured as peel strength on coextruded film. SM-EVOH-32 achieves 2.5–3.5 N/15 mm at 23 °C after 30 min conditioning under ASTM F904, compared with 1.2–1.8 N/15 mm for unmodified EVOH in the same PP/tie/EVOH/tie/PP structure. The improvement is attributed to covalent ester linkages formed between the carboxyl-functional modifier and residual anhydride groups in the tie layer. However, the same functionality makes the grade incompatible with amine-based anti-block concentrates, which accelerate crosslinking and generate die-lip plate-out within 20–30 min of continuous extrusion.
In flexible packaging subjected to repeated mechanical stress, such as stand-up pouches for liquid detergents or retortable pet food laminates, barrier failure occurs through flexural fatigue of the EVOH layer rather than steady-state oxygen permeation. SM-EVOH-32 is specified for these applications because the modifier phase increases resistance to pinhole formation during Gelbo flex testing. On 100 μm cast coextruded structures with a 25 μm EVOH core, the number of pinholes after 1000 flex cycles under ASTM F392 is ≤3 holes/100 cm², whereas the unmodified 32 mol% EVOH control exhibits 10–18 holes/100 cm² under identical conditions. The flex-crack resistance is sensitive to EVOH layer thickness; below 10 μm, both modified and unmodified grades show rapid pinhole formation, and the specification should not be interpreted as eliminating the need for tie-layer stress analysis.
| Property | Test method | SM-EVOH-32 | Unmodified EVOH 32 mol% |
|---|---|---|---|
| Oxygen transmission rate, 23 °C, 0 % RH | ASTM D3985 | ≤0.12 cm³·20 μm·m⁻²·day⁻¹·atm⁻¹ | ≤0.12 cm³·20 μm·m⁻²·day⁻¹·atm⁻¹ |
| Oxygen transmission rate, 23 °C, 65 % RH | ASTM D3985 | 0.9–1.4 cm³·20 μm·m⁻²·day⁻¹·atm⁻¹ | 1.2–1.8 cm³·20 μm·m⁻²·day⁻¹·atm⁻¹ |
| Flexural modulus | ISO 178 | 2100 MPa | 2300 MPa |
| Peel strength, PP/tie/EVOH/tie/PP | ASTM F904 | 2.5–3.5 N/15 mm | 1.2–1.8 N/15 mm |
| Gelbo pinholes, 1000 flex cycles | ASTM F392 | ≤3 holes/100 cm² | 10–18 holes/100 cm² |
| Die swell ratio, 190 °C, 100 s⁻¹ | Capillary rheometry | 1.4–1.6 | 1.7–1.9 |
In thermoformed barrier containers for hot-fill sauces and retortable ready meals, the grade is used in a PP/tie/SM-EVOH-32/tie/PP sheet structure with EVOH thickness between 15 μm and 30 μm. The lower melt stiffness of the modified grade permits draw ratios of 1.5:1 in plug-assisted forming without layer thinning to below 8 μm, a critical failure threshold observed on production-scale forming lines. The forming temperature window is 140 °C–160 °C; below 135 °C, the sheet develops microcracks at the tie-layer interface, and above 165 °C, the EVOH layer adheres to the plug and causes machine stops.
Compared with alternative barrier materials, SM-EVOH-32 occupies a specific application window between unmodified EVOH and polyamide-MXD6. Oxygen barrier at 65 % RH is superior to oriented PA-MXD6 by a factor of 4–6, but inferior to PVDC at 85 % RH in applications where chlorine-free disposal constraints do not apply. Published side-by-side PVDC and EVOH laminate data under ISO 15105-2 indicate that the EVOH layer must be 2.5–3.0 times thicker than PVDC to achieve equivalent OTR at 80 % RH; however, EVOH offers lower density and does not release hydrogen chloride during incineration.
For packaging converters, regulatory compliance is verified by migration testing and substance screening. Under EU Regulation (EU) No 10/2011, overall migration from a 900 μm PP/tie/EVOH/tie/PP sheet at 40 °C for 10 days is ≤6 mg/dm² when tested by EN 1186-1:2002. Specific migration of ethylene glycol in 3 % acetic acid at 100 °C for 2 h is below the detection limit of 0.01 mg/kg under EN 13130-4. The grade is compliant with RoHS 2011/65/EU with respect to lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls, and polybrominated diphenyl ethers; total concentration of each restricted substance is below 0.1 wt%. REACH Regulation (EC) No 1907/2006 screening confirms substances of very high concern are below the 0.1 wt% threshold.
| Requirement | Test method or standard | Result |
|---|---|---|
| Overall migration, PP/tie/EVOH/tie/PP, aqueous simulant | EN 1186-1:2002 | ≤6 mg/dm² |
| Specific migration of ethylene glycol | EN 13130-4 | <0.01 mg/kg |
| SVHC content, REACH | Regulation (EC) No 1907/2006 | <0.1 wt% |
| RoHS restricted substances | Directive 2011/65/EU | <0.1 wt% |
