| HS Code | 563444 |
| Oxygen Barrier Property | Extremely high resistance to oxygen permeation |
| Tensile Strength | High tensile strength suitable for structural packaging films |
| Elongation At Break | Moderate elongation typically ranging from 200% to 400% |
| Melting Point | Approximately 165-185°C depending on ethylene content |
| Density | Typically 1.13-1.21 g/cm³ |
| Oxygen Transmission Rate | Very low, often below 0.1 cc·mm/m²·day·atm |
| Water Absorption | Relatively low water absorption under ambient conditions |
| Chemical Resistance | Resistant to oils, fats, organic solvents, and acids |
| Thermal Stability | Stable during typical heat processing and retort conditions |
| Transparency | Excellent optical clarity and gloss |
| Processability | Compatible with coextrusion and film casting processes |
| Food Contact Compliance | Suitable for food packaging applications under relevant regulations |
As an accredited Special Grade EVOH factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Special Grade EVOH is supplied in 25 kg moisture-proof, nitrogen-flushed laminated bags for safe storage and handling. |
| Container Loading (20′ FCL) | 20' FCL shipment of Special Grade EVOH, packed in sealed bags/pallets, secured to prevent moisture damage and shift during transit. |
| Shipping | Special Grade EVOH is shipped in moisture-proof, sealed bags or drums to prevent hygroscopic degradation. Transport should avoid open storage, high humidity, and direct sunlight. Keep containers dry and intact during handling. Standard chemical logistics with clean, ventilated vehicles is suitable; no special hazard placarding is typically required. |
| Storage | Store Special Grade EVOH in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and open flames. Keep the original container tightly sealed to prevent moisture absorption and contamination. Avoid exposure to high humidity, and maintain stable temperatures. Under proper conditions, shelf life is generally one year from manufacture date. |
| Shelf Life | Store in cool, dry conditions; typically stable for 24 months from manufacture when sealed in original packaging. |
Coextruded five-layer cast polypropylene film lines running at 120–180 m/min integrate a 3–6 µm EVOH core between two maleic anhydride-grafted polypropylene tie layers. The outer layers are a high-ethylene-content polypropylene random copolymer with a melt flow index of 8–12 g/10 min at 230 °C/2.16 kg per ISO 1133-1:2022. The special grade EVOH selected for this configuration contains 32 mol% ethylene and exhibits an oxygen transmission rate of 0.4–0.7 cm³/(m²·day·atm) at 23 °C and 0 % RH when tested on a 20 µm film per ASTM D3985-17. At 85 % RH the transmission rate rises to 1.8–2.6 cm³/(m²·day·atm), a humidity-dependent increase that constrains the minimum outer layer thickness and the placement of the EVOH core. The PP outer-layer extruders are single-screw machines with L/D 30:1; the EVOH extruder is a single-screw machine with L/D 24:1 and a compression ratio of 3:1. EVOH pellets are dried in a desiccant dryer with a dew point below −40 °C to residual moisture below 0.3 %. Failure to reach this threshold produces splay and microvoids in the cast film. When ambient relative humidity exceeds 60 %, dried EVOH pellets are conveyed in a closed loop with dry air at −40 °C dew point to prevent moisture regain above 0.3 % before the extruder throat. Melt temperature at the feedblock is held at 210–225 °C, and the die gap is set to 0.8–1.2 mm. Exposure above 240 °C for more than 15 min initiates gel formation and black specks in the EVOH layer, which then tear during orientation.
Tie layer coat weight is 3–5 g/m² per side, and interlayer adhesion measured by T-peel per ASTM F904-16 exceeds 2.5 N/15 mm. A melt pump upstream of the die reduces surging, and the feedblock is configured for layer distribution variation of ±2 %. The final coextruded film, total thickness 45–65 µm, is used for modified atmosphere packaging of processed meat and cheese; oxygen ingress below 0.5 cm³/(m²·day·atm) at 23 °C and 50 % RH per ASTM D3985-17 is the acceptance criterion for refrigerated shelf life. The EVOH layer is not used in direct contact with aqueous food; direct food contact is assigned to the polypropylene layer per FDA 21 CFR 177.1520 or Regulation (EU) No 10/2011, Annex I, Table 1, FCM substance No 448. If hot fill above 85 °C is required, the grade is reformulated to 44 mol% ethylene to limit post-fill barrier loss.
The retort process imposes a saturated steam cycle at 121 °C for 30–45 min, and this thermal load plasticizes the amorphous phase of the EVOH core. A coextruded PP/tie/EVOH/tie/PP sheet is produced on a three-extruder line; main extruders have screw diameters of 90 mm, and the EVOH extruder is 30 mm with L/D 24:1. The polished roll stack is held at 20–30 °C to quench the sheet. EVOH layer thickness is 10–18 µm. The oxygen transmission rate before retort is 0.6–1.2 cm³/(m²·day·atm) at 23 °C and 50 % RH per ASTM D3985-17. After retort and cooling, the same film exhibits 3.5–5.5 cm³/(m²·day·atm), because absorbed water disrupts interchain hydrogen bonding that governs dry-state barrier performance. The EVOH grade is therefore selected with 44 mol% ethylene content. The melt temperature window for this grade is 210–215 °C, a ±5 K control band, because higher temperature accelerates gel formation and lower temperature produces layer non-uniformity. The food-contact polypropylene layer is covered under FDA 21 CFR 177.1520; the EVOH layer remains separated by the tie layer.
Thermoforming of the retort tray uses plug assist with a mold temperature of 110–130 °C. Plug assist depth is limited to avoid corner thinning below 60 % of nominal EVOH thickness; thinning below this threshold produces localized oxygen ingress at the tray corner. Delamination near the flange is observed when residual moisture in the EVOH exceeds 0.4 % before the retort ramp; therefore the sheet is stored in a humidity-controlled area at 20–30 % RH for 24–48 h before thermoforming. The tie layer is a maleic anhydride-grafted polypropylene with a melt flow index of 2.5–4.0 g/10 min; adhesion after retort is checked by a 90° peel test per ASTM D6862-11 and must remain above 2.0 N/15 mm.
Soil fumigation films produced on three-layer blown film lines use a 10–15 µm EVOH core between low-density polyethylene skins. The die gap is 1.8–2.2 mm, the blow-up ratio is 2.2–2.8, and the frost line height is 4–6 die diameters. The special grade EVOH is chosen for resistance to chloropicrin and 1,3-dichloropropene; permeation is measured per ASTM D1434 on flat film and is typically 2–5 g/(m²·day·bar) for chloropicrin. Sulfur-containing active chemistries can react with residual vinyl alcohol units and reduce barrier retention; published data for this specific configuration is limited. The EVOH layer is buried and not exposed to soil contact; the outer LDPE skin contains a UV stabilizer package at 0.15–0.30 wt%. Film gauge is 25–40 µm; the EVOH layer contributes no measurable impact on tear resistance as measured per ASTM D1922.
Used as a buried oxygen barrier in thermoformed sterile medical packaging, a 15–25 µm EVOH layer is coextruded between high-impact polystyrene and low-density polyethylene sealant layers. The sheet is produced at a thickness tolerance of ±5 % on a five-extruder line with a feedblock optimized for viscosity matching; the EVOH melt temperature is 205–215 °C. Thermoforming uses a pressure of 4–6 bar and a forming temperature of 120–140 °C. The EVOH layer is not in direct contact with devices. The sterile barrier system is validated per ISO 11607-1:2019 and ISO 11607-2:2019. Ethylene oxide sterilization leaves no detectable residue in the EVOH layer above 1 µg/g; gamma irradiation at 25–40 kGy can reduce oxygen barrier by 10–20 % due to chain scission in the amorphous fraction, though published data for this specific configuration is limited. The final tray is used for pre-filled syringes, orthopedic implants, and wound care products. Compliance with ISO 10993-5:2009 for cytotoxicity is addressed at the sealant layer. The oxygen transmission rate of the formed tray barrier at 23 °C and 50 % RH is below 0.5 cm³/(m²·day·atm) per ASTM D3985-17.
Six-layer fuel tank lines running accumulator-head blow molding machines with a shot weight of 30–50 kg and clamp force of 1500–2500 kN use a 60–100 µm EVOH layer, representing 1.5–2.5 % of total wall thickness. The layer structure is shown in the table below.
| Layer | Thickness percentage | Function |
|---|---|---|
| HDPE outer | 35–40 % | Impact and abrasion resistance |
| Regrind | 35–40 % | Cost recovery |
| Tie | 2–3 % | Adhesion |
| EVOH | 1.5–2.5 % | Hydrocarbon barrier |
| Tie | 2–3 % | Adhesion |
| HDPE inner | 10–15 % | Fuel contact |
Melt temperature at the accumulator head is 205–215 °C; parison programming of 100 points maintains EVOH layer continuity at the pinch-off and corner regions. In blow molding, EVOH layer thickness variation across the tank wall must not exceed ±15 %; localized thinning below 40 µm coincides with permeation spikes in sealed housing evaporative determination (SHED) testing. The finished tank is evaluated per 40 CFR Part 86 and CARB LEV III procedures. Adhesion between HDPE and tie layer is measured by 90° peel per ASTM D6862-11 and must remain above 1.5 N/15 mm after immersion in fuel containing 10 vol% ethanol at 40 °C for 500 h. Ethanol blends above E20 plasticize the EVOH amorphous phase; long-term permeation data for this specific configuration is limited.
Tandem extrusion coating lines apply a six-layer barrier structure to paperboard with a basis weight of 250–350 g/m². The outer polyolefin coat weight is 12–20 g/m², and the food-contact polyolefin coat weight is 20–30 g/m². The EVOH layer coat weight is 4–8 g/m², and each tie layer is 3–5 g/m². EVOH melt temperature is 220–240 °C, and the die gap is 0.5–0.8 mm. Line speed is 300–600 m/min, and draw resonance in the EVOH layer is controlled by adjusting the air gap to 15–25 cm. Paperboard pretreatment uses corona discharge of 2–5 kW and an ozone level of 2–4 g/h to improve tie layer anchorage. The oxygen transmission rate of the finished board is 0.1–0.3 cm³/(m²·day·atm) at 23 °C and 50 % RH per ASTM D3985-17.
Creasing and folding can generate microcracks in the EVOH layer; scoring depth is limited to 70 % of board thickness and crease width is set at 1.2–1.5 mm. The food-contact compliance of the EVOH layer is covered by FDA 21 CFR 177.1360 and Regulation (EU) No 10/2011, Annex I, Table 1, FCM substance No 448. The finished cartons are used for aseptic juice and dairy packaging; direct contact with high-acid liquids above pH 3.5 is limited to the polyethylene food-contact layer, not the EVOH. Amine-functional primers are avoided on EVOH-containing paperboard because amine-hydroxyl interactions may accelerate yellowing under retort; published data for this specific configuration is limited. If the line is stopped for more than 5 min, the EVOH layer in the die must be purged to prevent residence-time degradation; degraded EVOH releases acetic acid odor and creates fish-eyes in the coating.
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Special Grade EVOH, model designation SPG-EVOH-27, is an ethylene–vinyl alcohol random copolymer with an ethylene molar fraction of 27–29 mol% and a melt volume-flow rate of 2.0–4.0 g/10 min when measured at 190°C under 2.16 kg load in accordance with ISO 1133-1:2022. The product is intended for use as a continuous oxygen barrier lamina in coextruded polyolefin structures, including high-barrier rigid containers, thermoformed trays, flexible packaging films, and multilayer automotive fuel tanks. In dry-state oxygen permeation testing according to ASTM D3985, a 20 µm cast film exhibits an oxygen transmission rate of 0.02–0.05 cm³/(m²·day·atm) at 20°C and 0% RH; under 65% RH, the transmission rate increases to 0.8–2.0 cm³/(m²·day·atm) when conditioned at 20°C and tested per ASTM F1927. Compared with conventional 32 mol% EVOH grades, the lower ethylene fraction raises dry-state barrier performance and increases moisture sensitivity, which requires protected positioning between hydrophobic layers in final structures. The resin is not recommended for monolayer use because oxygen permeability becomes unstable when the layer is exposed directly to liquid water or condensing humidity.
| Parameter | Test method | Typical value |
|---|---|---|
| Ethylene content | 13C NMR | 27–29 mol% |
| Melt volume-flow rate | ISO 1133-1:2022 | 2.0–4.0 g/10 min |
| Density | ISO 1183-1:2019 | 1.19–1.21 g/cm³ |
| Tensile strength at yield | ISO 527-3 | 55–65 MPa |
| Elongation at break | ISO 527-3 | 200–300% |
| Oxygen transmission rate, 20 µm film, 20°C, 0% RH | ASTM D3985 | 0.02–0.05 cm³/(m²·day·atm) |
| Oxygen transmission rate, 20 µm film, 20°C, 65% RH | ASTM F1927 | 0.8–2.0 cm³/(m²·day·atm) |
| Melting temperature | ISO 11357-3 | 186–192°C |
| Vicat softening temperature | ISO 306 | 168–176°C |
The melt viscosity is shear-thinning under typical coextrusion shear rates, and the material cannot be processed on equipment that lacks closed-loop barrel cooling below 170°C in the feed zone. Published data for this specific configuration is limited; therefore, pilot-scale verification on the target line is required when replacing a 32 mol% grade.
Water sorption is the dominant limiting variable for oxygen barrier retention. At external relative humidity above 60–70%, absorbed water molecules disrupt interchain hydroxyl hydrogen bonding, increase fractional free volume, and produce a non-linear rise in oxygen transmission. The effect is thermally activated; a barrier lamina in contact with a moist product or a condensing headspace can lose more than 90% of its dry-state oxygen barrier capacity within 7–14 days of storage when the surrounding polyolefin skins are thinner than 50 µm. Moisture ingress calculations based on ASTM E96 water vapour transmission data indicate that a polypropylene skin of 250–400 µm on each side delays internal RH at the EVOH layer beyond 60% for approximately 90–180 days under temperate-zone warehouse conditions. The test boundary is important because the specification value at 65% RH under ASTM F1927 is not a failure threshold; it is a conditioning point that must be interpreted in relation to the total wall thickness and the moisture sorption isotherm of the adjacent layers.
In rigid high-barrier containers produced by coextrusion blow molding, SPG-EVOH-27 is run as a buried layer between polypropylene skins with maleated polypropylene tie layers. Typical layer distribution is 8–12% EVOH, 3–5% tie resin on each side, and the balance polypropylene. The EVOH layer remains at 10–20 µm in finished sidewall sections. Accumulator-head blow molding machines with clamp force in the 30–50 t range and a programmed parison drop profile are used to maintain wall-thickness uniformity at pinch-off seams. If the EVOH layer thickness falls below 6 µm at the fold seam, oxygen transmission under ASTM D3985 rises above the package specification, and drop-impact testing per ASTM D2463-15 may show brittle failure from delamination. The material is not suitable for containers that require steam retorting above 121°C unless the barrier layer is fully shielded by polypropylene and the thermal load duration is validated on the finished package.
Automotive fuel system structures use SPG-EVOH-27 in six-layer high-density polyethylene tanks to meet evaporative emission limits under CARB LEV III and EPA 40 CFR Part 86 test procedures. In such constructions, the EVOH lamina is embedded between regrind layers and adhesive tie layers, with a typical nominal EVOH content of 2–4% of total wall thickness. The functional specification is not the resin oxygen transmission alone but the hydrocarbon permeation of the finished tank after pinch-off, welding, and thermal cycling. Published data for this specific configuration is limited; finished-tank hydrocarbon permeation must be validated under SAE J1737 or the applicable vehicle-level sealed housing evaporative determination procedure because seam thinning can concentrate permeation. Field failure analysis on production-scale multilayer blow molding lines identifies poor pinch-off adhesion, high regrind moisture, and localized melt stagnation as recurring causes of barrier lamina discontinuity in the weld zone. The lower ethylene fraction reduces equilibrium fuel swell compared with 44 mol% EVOH, but it also lowers melt drawability in deep cavities; tooling with divergent weld-line angles below 10° is preferred.
In cast film and blown film coextrusion, SPG-EVOH-27 contributes to oxygen barrier in lidding films, stand-up pouches, and vacuum skin packaging. The material is not intended for very thin monolayer cast film; it is run as a buried layer of 4–6 µm in a total film of 50–90 µm. On a three-layer blown film line with die diameter 250–350 mm and die gap 1.8–2.5 mm, the EVOH skin is positioned between two polyolefin skins using a low-shear spiral mandrel die. Blow-up ratios are limited to 2.0–2.8; higher blow-up ratios orient the stiff 27 mol% EVOH layer and promote flex-crack defects. Laboratory flex-crack testing according to ASTM F392 shows that 27 mol% grades develop pinholes earlier than 44 mol% grades under repeated creasing, which restricts the product to moderate flex-crack applications. Gelbo test results are structure-dependent and must be evaluated on the finished laminate rather than on extrusions of the barrier resin alone.
Thermal degradation and crosslinking define the upper processing boundary. The vinyl alcohol sequences in 27 mol% EVOH are more heat-sensitive than those in 32 mol% and 44 mol% grades because the higher hydroxyl density accelerates intermolecular etherification and dehydroxylation above 230°C. Extrusion should be set with feed section temperatures of 170–180°C, compression section temperatures of 200–215°C, metering section temperatures of 210–225°C, and adapter/die temperatures of 220–230°C. Melt temperature measured with an immersion thermocouple at the die exit should remain at or below 230°C. At 240°C, residence times above 5 min produce visible yellowing and microgel formation; at 250°C, crosslinked particles appear within 90–120 s of stagnation. Screw configurations for the barrier layer should use a compression ratio of 2.5:1–3.5:1 and an L/D ratio of 24:1–30:1. High-shear mixing elements are not required and may raise melt temperature by 8–12°C through viscous dissipation, reducing the safe operating window.
Pre-drying is mandatory when pellet moisture exceeds 0.05%. A desiccant hopper dryer with a dew point below −40°C and an inlet air temperature of 80–90°C is recommended for 4–6 h. On production lines with a 60 mm barrier extruder, feed moisture above 0.08% has been associated with screw-wrap, melt pressure fluctuation, and splay in the barrier layer. The same material is incompatible with amine-based additives, high-moisture nylon regrind, and unvented barrels when the resin is held above 210°C for more than 20 min, because liberated acetic acid and reactive amine groups accelerate hydrolysis and gel formation. Purging after use should be performed with a low-melt-index polyethylene at 200–220°C; purging with polycarbonate or polybutylene terephthalate is not recommended because these resins require temperatures above the EVOH degradation threshold.
| Parameter | SPG-EVOH-27 | Conventional 32 mol% EVOH | High-ethylene 44 mol% EVOH |
|---|---|---|---|
| Ethylene content | 27–29 mol% | 32 mol% | 44 mol% |
| Oxygen transmission rate, 20 µm film, 20°C, 0% RH | 0.02–0.05 cm³/(m²·day·atm) | 0.06–0.15 cm³/(m²·day·atm) | 1.0–3.0 cm³/(m²·day·atm) |
| Oxygen transmission rate, 20 µm film, 20°C, 65% RH | 0.8–2.0 cm³/(m²·day·atm) | 0.6–1.5 cm³/(m²·day·atm) | 2.0–4.0 cm³/(m²·day·atm) |
| Moisture sensitivity onset | 60–70% RH | 70–80% RH | 80–90% RH |
| Melt processing window | 210–225°C | 210–230°C | 200–220°C |
| Flex-crack resistance | Lower | Moderate | Higher |
| Equilibrium fuel swell | Lower | Moderate | Higher |
The practical substitution envelope is narrow. SPG-EVOH-27 should be selected when dry-state oxygen barrier is the controlling package requirement and the EVOH layer is fully shielded from moisture by polyolefin skins of at least 150 µm per side. It should not replace 44 mol% EVOH in flexible packages that undergo repeated flexing at sub-zero temperatures, because flex-crack initiation occurs earlier under ASTM F392 and the stiffer lamina cannot follow strain recovery in the seal area. For high-moisture retort or hot-fill applications requiring barrier retention above 80% RH, a 32 mol% or 44 mol% grade is preferred unless the barrier layer is separated from the moisture source by a sufficiently thick regrind layer. No single oxygen barrier material satisfies dry-state barrier, moisture tolerance, flex-crack resistance, and thermoformability without a trade-off; the selection of SPG-EVOH-27 is therefore governed by the humidity duration curve of the packaged product and the barrier layer thickness distribution achievable on the available coextrusion equipment.
