| HS Code | 220606 |
| Oxygen Transmission Rate | Very low (excellent barrier) |
| Aroma Barrier | Excellent |
| Oil Grease Resistance | Excellent |
| Transparency | High clarity/transparent |
| Gloss | High surface gloss |
| Tensile Strength | High |
| Elongation At Break | Moderate |
| Puncture Resistance | Good |
| Water Vapor Transmission Rate | High (poor moisture barrier) |
| Heat Resistance | Good up to moderate temperatures |
As an accredited EVAL monolayer film factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | EVAL monolayer film supplied in sealed moisture-proof packaging, 25 kg per roll, protected from light and humidity. |
| Container Loading (20′ FCL) | 20′ FCL loading of EVAL monolayer film: pack rolls on pallets, secure firmly, protect from moisture and heat, ensure stable weight distribution. |
| Shipping | EVAL monolayer film is shipped as solid rolls on cores, wrapped in moisture-barrier packaging with desiccant to prevent humidity absorption. Non-hazardous and safe for standard freight, it should be transported dry, protected from punctures, and stored away from heat to preserve barrier properties. |
| Storage | Store EVAL monolayer film in its original sealed packaging in a cool, dry, dark environment. Protect from moisture, direct sunlight, and UV exposure. Maintain moderate, stable temperature and low humidity. Avoid sharp objects and heavy pressure to prevent deformation. Handle with clean, dry gloves to preserve film integrity and barrier performance. |
| Shelf Life | EVAL monolayer film shelf life: typically 12 months when stored sealed, dry, and protected from moisture and heat. |
During case-ready packaging of bone-in beef cuts, the top web on a thermoform-fill-seal line is frequently a laminate in which a 15 µm EVAL monolayer film is combined with a 50 µm LDPE sealant and a reverse-printed 12 µm PET outer layer. The EVAL film provides the oxygen barrier that retards metmyoglobin formation under retail display at 4 °C; without an EVAL-containing top web, residual headspace oxygen above 0.5 % may accelerate brown discoloration within 3 days. The lamination process uses a solventless polyurethane adhesive metered at 2.0–3.5 g/m², a nip temperature of 45–55 °C, and a curing cycle of 7 days at 35 °C before slitting to tray-lidding widths. On the packaging machine, the laminate is preheated to 110–130 °C and sealed against a rigid APET or PP tray at a sealing pressure of 4–6 bar and dwell time of 1.5–2.5 s. The critical process conflict is moisture: a monolayer EVAL web conditioned to 65 % RH before lamination can carry enough absorbed water to shift the oxygen permeability from a dry-state value below 0.5 cm³·20 µm/(m²·day·atm) to roughly 1.0–1.8 cm³·20 µm/(m²·day·atm) at 23 °C measured per ASTM D3985. If the reverse-printed PET outer layer is below 12 µm and the sealant film is thinner than 45 µm, curl during solventless lamination becomes asymmetric because the EVAL web, with a tensile modulus close to 3,000 MPa at 23 °C and 50 % RH, shrinks less than the LDPE sealant after the first oven pass. End-use compliance for this structure falls under EU Regulation 10/2011 with overall migration limited to 10 mg/dm², and under 21 CFR 177.1520 for the food-contact LDPE layer; the EVAL layer is cleared for food contact through a Food Contact Notification. The finished case-ready tray is not intended for retort and the EVAL layer will lose part of its gas barrier if the label instructs retail display in high-humidity open chill cabinets above 85 % RH for more than 48 h; converters therefore specify a top printed PET layer and a water-resistant outer coating on the lid to delay moisture ingress from condensation.
Printed web tension and adhesive cure imbalance are the primary causes. On a solventless laminator running a reverse-printed PET outer web against an EVAL monolayer film and an LDPE sealant web, three different elongations are present at the nip: the PET web is normally pulled at 60–90 N per metre width, the EVAL film at 35–50 N, and the LDPE at 25–40 N. When the adhesive has not reached sufficient green tack before the second lamination pass, the EVAL web can slip between the two nip rolls and lay down with a transverse contraction of 0.3–1.0 mm per 100 mm width, which appears later as reverse curl after slitting. The common correction is to elevate the second nip temperature to 55–60 °C and to reduce line speed from 150 m/min to 80–100 m/min, but this increases residence time in the oven and can dry the solvent-free adhesive too quickly at the edges. A 15 µm grade with ethylene content 32 mol% has a water vapour transmission rate near 8–12 g/(m²·day) at 23 °C and 85 % RH; moisture absorbed from a humid conversion hall reduces its oxygen barrier and affects its elongation at break. If the curl is corrected by raising web tension on the EVAL film above 50 N, edge fracturing may occur because the film has a notched tear strength below 1.5 N/mm in machine direction. Tensile elongation and tear resistance are measured per ISO 527-3 and ISO 6383-2. End product for this structure is a flat lidding roll for dry-food trays; the flatness specification is typically less than 5 mm of curl over a 1 m sheet after 24 h at 23 °C and 50 % RH.
Dispensing a moisture-sensitive active in a unit-dose format without a desiccant requires a barrier web that keeps oxygen ingress below the degradation threshold of the specific drug. A 12 µm EVAL monolayer film is laminated to a 250 µm PVC base web with a 2–3 g/m² polyurethane adhesive and a 60 µm LDPE tie film; the laminate is then thermoformed on a servomotor-driven blister machine at a forming temperature of 120–140 °C measured at the plug surface. The EVAL layer functions as the oxygen scavenger-free barrier, replacing a conventional 40 g/m² PVDC coating while reducing total halogen content. At 23 °C and 0 % RH, the oxygen transmission rate of the laminated structure is below 0.3 cm³/(m²·day·atm) per ASTM D3985; at 50 % RH, the value rises but remains below the critical limit for most effervescent tablet formulations when the peripheral seal is continuous and free of fold-over pinholes. The critical processing boundary is pre-drying: if the EVAL monolayer film has been stored at relative humidity above 60 % without a moisture-proof bag, the sheet surface can develop micro-dimples during the radiant heating stage because water vapour escaping from the EVAL film nucleates at the PVC interface. The blister line is therefore operated with a dehumidified unwinding zone at 35–45 % RH and a preheating temperature ramp not exceeding 8 °C/s. Compliance for the finished blister includes dose uniformity testing under USP 671, extractables assessment according to Ph. Eur. 3.2.2, and overall migration under EU Regulation 10/2011. The end product is a clear, PVDC-free push-through blister for effervescent tablets, with a shelf-life target of 24 months in aluminium foil pouches.
| Standard / regulation | Test method | Typical acceptance limit |
|---|---|---|
| EU 10/2011 | Overall migration, simulant B and C | 10 mg/dm² |
| USP 671 | Unit-dose container permeation | Class A or B depending product |
| ASTM D3985 | Oxygen transmission, 23 °C, 0 % RH | ≤ 0.3 cm³/(m²·day·atm) |
| ASTM F1306 | Pinhole detection | No pinhole > 0.05 mm |
| Ph. Eur. 3.2.2 | Plastic materials for pharmaceutical use | Complies with monograph |
Instant coffee and flavoured whey protein powders require retention of low-molecular-weight aroma compounds and exclusion of oxygen. A converter can replace the conventional PVDC-coated PET layer with a lamination of 12 µm reverse-printed PET / 15 µm EVAL / 70 µm LLDPE. The substitution is not a direct drop-in: PVDC-coated PET typically provides an oxygen barrier below 2.0 cm³/(m²·day·atm) at 23 °C and 50 % RH, while the EVAL-containing laminate can provide below 0.5 cm³/(m²·day·atm) under the same condition only if the EVAL layer remains dry. In vertical form-fill-seal machines operating at 20–40 packs/min, this dryness is preserved by placing the EVAL layer between the PET print web and the LLDPE inner layer, so that moisture from the powder is blocked by the LLDPE during filling. However, if the product has a water activity above 0.6, the LLDPE layer cannot prevent gradual moisture migration into the EVAL layer over a 12-month shelf life and the oxygen barrier can shift toward PVDC-like values. The adhesion process uses a two-component solventless polyurethane adhesive at 2.5–3.0 g/m², cured for 5 days at 35 °C. End-product testing includes headspace gas chromatography for retained ethyl acetate below 5 mg/m², odour evaluation per DIN 10955, and oxygen permeation per ASTM D3985 after flex cracking according to ASTM F392. A failure mode in this structure is flex-crack propagation: after 50 Gelbo flex cycles the EVAL layer can form micro-cracks near the seal area, and the measured oxygen transmission may rise by a factor of 2–5; therefore, the film supplier specifies a minimum bending radius of 4 mm in the pouch corner.
Vacuum insulation panel producers use a multilayer barrier envelope in which the EVAL monolayer film is not the heat-seal layer but the central gas barrier. The typical outer stack is 12 µm PET / 12 µm EVAL / 50 µm metallized PET / 50 µm LDPE. The panel is filled with fumed silica and evacuated to an internal pressure below 1 mbar. The barrier envelope must keep oxygen and nitrogen admission below the amount that would raise thermal conductivity above 0.006 W/(m·K) after 15 years; EVAL contributes by reducing oxygen permeability to below 0.1 cm³·20 µm/(m²·day·atm) at 23 °C and 0 % RH. The processing boundary is sealing temperature: the laminate must seal at 150–170 °C without causing the EVAL layer to shrink or crystallise excessively. If the seal jaw temperature exceeds 180 °C, the EVAL film can undergo incipient melting at the edges because its melting point is near 165–185 °C depending on ethylene content, resulting in thin spots that increase gas permeation. For cold-chain transport panels that may see condensation, an outer LDPE or aluminium foil layer is added because the EVAL layer at 85 % RH loses much of its oxygen barrier; without this moisture protection, oxygen permeability can increase by an order of magnitude. Compliance evaluation of the envelope is made by internal pressure rise testing over 30 days at 23 °C and by oxygen permeation per ASTM D3985; the EVAL monolayer film is also tested for pinhole count per ASTM F1306 at a threshold of 0.05 mm. The end product is an evacuated panel with service temperature limited to below 80 °C because higher temperatures accelerate both EVAL relaxation and seal creep.
Single-dose detergent sachets and fragrance sampling strips require a barrier that retains limonene, linalool, and geraniol without transferring the printed solvent odour. A laminate of 20 µm BOPP / 12 µm EVAL / 50 µm LLDPE meets oxygen and aroma barrier requirements at room temperature; the EVAL layer reduces limonene permeation compared with a BOPP/LLDPE control by more than one order of magnitude when measured by isostatic permeation at 23 °C and 0 % RH. The main process conflict is not oxygen but ethanol. If the fragrance or detergent formulation contains more than 5 wt% ethanol, direct contact with the LLDPE sealant still permits ethanol to migrate through the inner layer and attack the EVAL layer during storage at 40 °C. Ethanol plasticises EVAL, reduces its glass transition temperature, and can produce visible tunnel-shaped delamination between the EVAL and BOPP layers. The barrier structure therefore places the EVAL film in the middle of an adhesive sandwich, not directly against the fragrance; the adhesive layers are fully cured before filling. The laminate is run on a horizontal form-fill-seal line at 30–60 packs/min with sealing jaw temperature 110–130 °C on the LLDPE side only; if the jaw contacts the BOPP side, heat-transfer distortion can create wrinkles that are mistaken for EVAL crystallisation. End-product testing includes seal strength per ASTM F88, aroma retention by headspace GC, and migration testing under EU Regulation 10/2011. The operational boundary is that the sachet should not be autoclaved or microwaved, and continuous service above 60 °C can accelerate ethanol-induced delamination within 6 months.
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EVAL monolayer film is an ethylene-vinyl alcohol copolymer web supplied as a single-layer film in thicknesses from 8 µm to 25 µm and with ethylene contents of 27 mol% to 44 mol%. The film is produced by cast or blown film extrusion and is subsequently laminated, extrusion-coated, or adhesively bonded to polyolefin sealant and structural webs. Its primary function is oxygen barrier. Under ASTM D3985 at 23 °C and 0% RH, a 15 µm monolayer typically exhibits an oxygen transmission rate below 0.5 cm³/(m²·day·atm). At 85% RH, the same film may exceed 20 cm³/(m²·day·atm) depending on ethylene content, crystallinity, and processing history. Commercial designations such as EF-F and EF-XL differentiate film variants for general converting and for retort or flex-crack-prone structures, respectively; grade-specific OTR curves under ASTM F1927 are required because published data for EF-XL in high-humidity retort formats remains limited.
Unlike coextruded PE/EVOH/PE films, the monolayer product allows independent selection of sealant, tie, and print layers, but it provides no integral moisture protection. In service, it must be positioned between layers that maintain the EVAL layer below its critical moisture threshold. Representative applications include dry-food lidding, bag-in-box liners, vacuum pouches for processed meat and cheese, pharmaceutical sachets, dry powder beverage packaging, and agricultural chemical overwraps. In each use, the critical design parameter is not the dry-state oxygen permeability alone but the maintenance of barrier after flex-cracking, heat sealing, and exposure to product-side relative humidity.
Water vapour acts as a plasticizer for the vinyl alcohol-rich amorphous phase. As relative humidity increases, water absorption reduces the glass transition temperature and increases free volume, producing a nonlinear increase in oxygen permeability. A 15 µm EVAL monolayer film that shows 0.05 cm³/(m²·day·atm) to 0.5 cm³/(m²·day·atm) at 0% RH may show 2 cm³/(m²·day·atm) to 8 cm³/(m²·day·atm) at 65% RH and 30 cm³/(m²·day·atm) to 100 cm³/(m²·day·atm) at 90% RH when measured according to ASTM F1927. This cliff-edge is the main reason the monolayer is rarely used directly against high-water-activity foods without a moisture barrier outer web.
Moisture uptake follows the sorption isotherm; at 80% RH, equilibrium moisture content can reach 5 wt% to 8 wt% depending on ethylene content. Higher ethylene grades such as 44 mol% absorb less water and retain better post-retort barrier but exhibit dry-state oxygen transmission roughly three to five times higher than a 27 mol% grade. To manage the cliff-edge, converters use an outer moisture barrier such as oriented polypropylene or polyester with water vapour transmission below 10 g/(m²·day) at 38 °C and 90% RH per ASTM F1249. The local RH at the EVAL layer should remain below 60% for the intended shelf life, otherwise the oxygen barrier can decline by one to two orders of magnitude.
| Material | Test condition | OTR range (cm³/(m²·day·atm)) | Method |
|---|---|---|---|
| EVAL monolayer film | 23 °C, 0% RH | 0.05–0.5 | ASTM D3985 |
| EVAL monolayer film | 23 °C, 50% RH | 0.5–2.0 | ASTM D3985 |
| EVAL monolayer film | 23 °C, 90% RH | 30–100 | ASTM F1927 |
| PVDC-coated PET | 23 °C, 50% RH | 5–15 | ASTM D3985 |
| Biaxially oriented polyamide | 23 °C, 50% RH | 20–60 | ASTM D3985 |
| Biaxially oriented PET | 23 °C, 50% RH | 50–100 | ASTM D3985 |
| Aluminum foil, pinhole-free | 23 °C, 50% RH | <0.005 | ASTM D3985 |
The table makes clear that EVAL monolayer film is designed for dry-state oxygen barrier and should not be specified as a replacement for PVDC in high-moisture retort packaging without qualification. Polyamide and polyester are tougher in flex-crack resistance but give higher oxygen permeability under dry conditions. Aluminum foil provides absolute barrier when free of pinholes but eliminates transparency and microwave compatibility.
Film grade selection balances ethylene content and orientation stability. Standard grades with 32 mol% ethylene are used for general barrier packaging. Grades with 44 mol% ethylene are selected for deeper draw thermoforming because lower melting point improves formability, but the dry-state oxygen transmission rate is approximately three times higher than a 27 mol% grade. The film is semi-crystalline; gas transport occurs through amorphous vinyl alcohol-rich domains. Crystallinity measured by differential scanning calorimetry at 10 °C/min under nitrogen typically ranges from 35% to 60%. Melting point ranges from 155 °C for 44 mol% ethylene to 183 °C for 32 mol% ethylene according to ISO 11357-3. Dry glass transition temperature is between 55 °C and 70 °C, but it decreases below 30 °C at high moisture. Tensile modulus measured by ISO 527-3 ranges from 2000 MPa to 3500 MPa at 23 °C and 50% RH. This stiffness contributes to machinability on form-fill-seal lines but also requires careful tension control during slitting and lamination.
EVAL resin for monolayer film is hygroscopic and must be dried to a moisture content below 0.3 wt% before melt processing. Desiccant drying at 80 °C to 100 °C for 4 h to 6 h is standard; residual moisture above 0.5 wt% produces splay, microvoids, and loss of oxygen barrier because water hydrolyzes the polymer during melt processing. Melt temperature is normally maintained between 200 °C and 240 °C. At temperatures above 250 °C, thermal degradation accelerates and forms crosslinked gel particles and black specks that appear on the cast film surface and reduce effective oxygen barrier.
Cast film lines used for EVAL monolayer film typically employ 24:1 to 30:1 L/D single-screw extruders with barrier screws and low-shear mixing elements. Die temperatures of 220 °C to 230 °C, die gaps of 0.8 mm to 1.2 mm, air gaps of 10 mm to 20 mm, and chill roll temperatures of 15 °C to 25 °C provide acceptable web flatness and clarity. Line speeds on cast film lines are commonly 80 m/min to 200 m/min for thin monolayer webs. Edge pinning air knives are required to reduce neck-in because the polymer has low melt strength and fast crystallization. On blown film lines, bubble stability is controlled with a blow-up ratio of 1.5:1 to 2.5:1 and frost line heights below 500 mm, though monolayer blown film throughput is limited by bubble sag and gauge variation.
Batch-to-batch variation in ethylene content can shift oxygen barrier by approximately ±20% even when melt temperature and thickness remain constant. Melt flow rate is measured according to ISO 1133-1:2022 at 190 °C and 2.16 kg; film grades typically fall between 1.5 g/10 min and 8.0 g/10 min, with lower values favoured for blown film and higher values for cast film. Density is measured by ISO 1183-1:2019 and typically falls between 1.14 g/cm³ and 1.17 g/cm³.
Surface treatment is required for lamination adhesion. Corona treatment to 38 mN/m to 42 mN/m, measured by ASTM D2578, is common. Overtreatment above 50 mN/m can produce surface oxidation and reduce interlayer adhesion. For extrusion lamination, low-density polyethylene melt temperatures of 300 °C to 320 °C and short air gaps are used to limit heat transfer into the EVAL layer; the film surface should not exceed 100 °C for more than a few seconds because moisture regain and surface crystallization can reduce clarity and barrier.
Solventless two-component polyurethane adhesives are applied at coat weights of 2 g/m² to 4 g/m² and cured at 40 °C to 50 °C for 24 h to 72 h. Adhesive systems containing low-molecular-weight primary amines should be evaluated for reaction with EVAL under cure conditions because residual amine species can alter interlayer adhesion and produce migration issues under EU Regulation 10/2011.
In dry-food lidding, a 15 µm EVAL monolayer film can replace a PVDC-coated PET structure when the internal headspace humidity remains below 60% RH. The monolayer must be laminated to a printed polyester or oriented polypropylene outer web and a polyethylene or cast polypropylene sealant web. The dry-state oxygen barrier of EVAL is typically one to two orders of magnitude lower than PVDC-coated PET: a 15 µm EVAL monolayer may show OTR below 0.5 cm³/(m²·day·atm) at 23 °C 0% RH, whereas a PVDC-coated PET of equivalent total thickness may show 5 cm³/(m²·day·atm) to 15 cm³/(m²·day·atm) at 23 °C 50% RH. The trade-off is humidity response: PVDC retains a flatter oxygen barrier between 50% RH and 90% RH, while EVAL exhibits a sharp increase once local RH exceeds 65%.
Seal strength of lidding films is measured by ASTM F88/F88M. Heat seal initiation temperatures of polyethylene sealants are typically 85 °C to 120 °C; seal strength values between 15 N/25 mm and 35 N/25 mm are common for dry lidding. Converters often limit the sealing jaw temperature to 180 °C to avoid localized shrinkage and microcracking of the EVAL layer. Flex-crack resistance after 50 Gelbo cycles at 23 °C is tested by ASTM F392; the EF-XL designation, where used, is represented as a flex-crack-resistant grade, although the converter should request grade-specific OTR curves rather than relying on a single dry-state value.
Against a coextruded PE/EVOH/PE film, the monolayer product offers converting flexibility: the converter may choose tie layers, sealants, and print webs independently, and can use solvent-free lamination adhesives. However, the absence of integral polyolefin skins means accidental exposure of the monolayer to liquid water during lamination or slitting raises local moisture content and lowers barrier performance before the package reaches the end use. The film should be stored in vapour-barrier packaging at 23 °C ± 2 °C and 35% RH ± 5% RH when not in use, and it should be allowed to acclimate for 24 h after removal before lamination.
Oxygen ingress calculations for dry packages are based on the steady-state permeability equation, but the assumption of a constant OTR is invalid when the local RH at the EVAL layer exceeds 65%. Engineers should obtain OTR data at 0% RH, 50% RH, 65% RH, 80% RH, and 90% RH from ASTM F1927 and use the highest value associated with the expected package headspace humidity. In laminate designs, the moisture barrier layer must keep the EVAL layer below 60% RH during distribution; otherwise the oxygen barrier can decline by one to two orders of magnitude within the first weeks of shelf life.
Food-contact compliance for EVAL monolayer film is assessed under 21 CFR 177.1360 for ethylene-vinyl alcohol copolymers and EU Regulation 10/2011 for plastic materials intended to contact food. Overall migration testing is performed in food simulants representing aqueous, acidic, alcoholic, and fatty foods: 10% ethanol, 3% acetic acid, 20% ethanol, and vegetable oil or 95% ethanol substitute. The overall migration limit is 10 mg/dm² according to EU Regulation 10/2011, Annex I. Specific migration of vinyl alcohol and ethylene is not expected above detection limits, but converters must verify compliance through supplier declarations and batch migration data.
Under EC 94/62/EC, the sum of lead, cadmium, mercury, and hexavalent chromium in packaging and packaging waste is limited to 100 mg/kg. For electronic packaging applications, RoHS 2011/65/EU restricted substances are not present above 0.1% w/w for lead, mercury, hexavalent chromium, polybrominated biphenyls, and polybrominated diphenyl ethers, and 0.01% w/w for cadmium. Oxygen transmission testing is performed according to ASTM D3985 and ASTM F1927; water vapour transmission according to ASTM F1249; tensile properties according to ISO 527-3 or ASTM D882; tear resistance according to ASTM D1922; and haze according to ASTM D1003.
| Property | Test method | Typical specification or acceptance range |
|---|---|---|
| Thickness | ISO 4593 | ±5% to ±7% of nominal |
| Oxygen transmission rate, 23 °C, 0% RH | ASTM D3985 | ≤0.5 cm³/(m²·day·atm) for 15 µm |
| Oxygen transmission rate, 23 °C, 90% RH | ASTM F1927 | 30–100 cm³/(m²·day·atm) for 15 µm, grade-dependent |
| Water vapour transmission rate, 38 °C, 90% RH | ASTM F1249 | 10–40 g/(m²·day) for 15 µm |
| Tensile strength, MD/TD | ISO 527-3 | 40–80 MPa |
| Elongation at break, MD/TD | ISO 527-3 | 100–250% |
| Melt flow rate, 190 °C, 2.16 kg | ISO 1133-1:2022 | 1.5–8.0 g/10 min |
| Haze | ASTM D1003 | ≤3% for 15 µm film |
EVAL monolayer film is not a moisture barrier and is not suitable for direct high-moisture retort use without an external moisture barrier. It should not be exposed to steam at 121 °C for more than 30 min in a monolayer configuration because water absorption can exceed 10 wt% and cause thickness swell and temporary or permanent barrier loss. In retortable pouch structures, the film is embedded between polyolefin layers, and package qualification requires post-retort oxygen barrier recovery measured at 23 °C 50% RH after an equilibration period of at least 48 h.
Unlike PVDC-coated films, EVAL monolayer film contains no halogenated polymer and does not release hydrogen chloride during incineration. In polyolefin mechanical recycling streams, however, EVAL is regarded as a barrier contaminant and may increase haze or reduce tensile properties when present above 5% by weight; converters should verify recyclability with local waste management systems.
In pharmaceutical sachet applications, the monolayer film is laminated to a low-slip sealant and tested for seal integrity per ASTM F88/F88M and dye penetration per ASTM F1929. A 12 µm EVAL layer in a PE/EVAL/PE laminate can reduce oxygen ingress below 0.1 cm³/(m²·day·atm) at 23 °C 0% RH. The same laminate exposed to steam sterilization at 121 °C for 30 min may require at least 48 h at 23 °C 50% RH to return to pre-sterilization oxygen barrier. In agricultural chemical packaging, the film is used as a barrier layer in laminated pouches for moisture-sensitive powders; the outer polyolefin web must provide sufficient moisture resistance to keep the EVAL layer below 60% RH during warehouse storage in humid climates. Published data for long-term outdoor agricultural exposure of monolayer EVAL film is limited.
