| HS Code | 211698 |
| Oxygen Barrier Property | Excellent, low oxygen transmission rate |
| Chemical Resistance | Resistant to most agricultural chemicals, solvents, and oils |
| Solvent Barrier | High resistance to non-polar solvents |
| Mechanical Strength | Good tensile and impact strength |
| Thermal Stability | Stable during hot-fill and processing up to typical melt temperatures |
| Processability | Suitable for co-extrusion and multilayer blow molding |
| Moisture Sensitivity | Barrier properties decrease with increasing humidity; requires protective outer layers |
| Transparency | High clarity and gloss |
| Density | Typically 1.13–1.21 g/cm³ depending on ethylene content |
| Melting Point | Ranges approximately 165–185°C depending on grade |
| Adhesion To Polyolefins | Requires tie layer for bonding to PE or PP |
| Recyclability | Compatible with multilayer recycling streams when properly processed |
As an accredited EVOH for Agricultural Chemical Bottles factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | EVOH resin in 25 kg moisture-barrier bags, designed for durable agricultural chemical bottle blow molding. |
| Container Loading (20′ FCL) | EVOH for agricultural chemical bottles packed in moisture-proof bags, palletized, loaded into 20′ FCL dry container, securely stowed. |
| Shipping | EVOH for agricultural chemical bottles is shipped as non-hazardous resin pellets in sealed moisture-proof bags, then palletized and shrink-wrapped for stability. Ship via standard dry cargo containers or trucks in clean, dry conditions. Avoid excessive heat and direct sunlight. No special hazmat labeling required, but keep protected from moisture. |
| Storage | Store EVOH resin in a clean, dry, well-ventilated area, preferably below 30°C. Keep original packaging sealed to prevent moisture absorption, which degrades barrier properties. Avoid direct sunlight, heat sources, and contamination from dust or chemicals. Use within the manufacturer’s stated shelf life, rotating stock to ensure freshness for optimal bottle performance. |
| Shelf Life | Shelf life: 2 years from manufacture when stored unopened in a cool, dry place, protected from moisture and sunlight. |
Six-layer coextrusion blow moulding of a 1 L Boston round bottle for xylene-based emulsifiable concentrate formulations containing 50–60 wt% aromatic hydrocarbon solvents was evaluated on a 70 mm barrier-screw machine with 24:1 L/D, die head temperature 215 °C, and mould temperature 8 °C. The layer distribution was outer HDPE 38 wt%, regrind 22 wt%, maleic anhydride grafted polyolefin tie resin 2.5 wt%, EVOH 5.0 wt%, tie resin 2.5 wt%, inner HDPE 30 wt%. The EVOH layer containing 32 mol% ethylene produced a nominal barrier thickness of 58–62 µm in a 1.25 mm wall; melt flow rate was 1.7 g/10 min at 190 °C/2.16 kg per ISO 1133-1:2022. Oxygen transmission rate on flat wall sections conditioned at 23 °C/0% RH was 0.17–0.20 cm³/(m²·day·atm) per ASTM D3985-17. Pinch-off weld lines showed EVOH thinning to 11–16 µm; local oxygen transmission at those weld lines increased to 0.65–0.80 cm³/(m²·day·atm). The dominant production failure mode was moisture-induced hydrolytic gel formation in regrind containing EVOH threads; regrind moisture above 0.3 wt% produced star-burst defects at the pinch-off and caused intermittent bottle leak failures. Pre-drying of EVOH with desiccant air at 80 °C for 4 h to below 0.01 wt% moisture and limiting regrind to 22 wt% eliminated the defect on a 6-cavity shuttle line running at 1,100 bottles/h.
For 500 mL trigger spray bottles filled with ready-to-use agricultural herbicide dilutions, the label panel wall thickness falls to 0.80–0.95 mm, compressing the six-layer structure to outer HDPE 40 wt%, regrind 20 wt%, tie resin 2.0 wt%, EVOH 4.0 wt%, tie resin 2.0 wt%, and inner HDPE 32 wt%; the EVOH layer target is 30–35 µm. This thin-wall geometry creates a process conflict: high shear raises the EVOH melt temperature toward 228–232 °C at a die head setting of 205 °C, while the 32 mol% ethylene grade shows gel formation above 235 °C and interfacial instability below 200 °C. The operating window is ±5 °C. Capillary rheometry at 100 s⁻¹ shows a HDPE-to-EVOH viscosity ratio near 0.6:1; layer waviness and break-up begin when the ratio exceeds 1.8:1. Oxygen transmission measured by ASTM D3985-17 at 23 °C/0% RH is 0.30–0.38 cm³/(m²·day·atm), rising to 2.1–2.9 cm³/(m²·day·atm) at 65% RH. A 25-point radial parison programmer with 0.1 mm wall resolution is required to maintain tie-layer continuity at the handle pinch-off. Drop testing under ISTA 3A with 10 kg top load produced no panel cracking at −20 °C when the inner HDPE layer stayed above 0.25 mm.
For a 2.5 L multilayer jug filled with a 250 g/L azoxystrobin aqueous suspension concentrate, the water-continuous formulation has pH 6.5–7.5, 1.8 wt% xanthan gum, and Brookfield viscosity 800–1,200 mPa·s at 20 rpm. The oxygen-sensitive active ingredient requires a 38 mol% ethylene EVOH layer at 3.5 wt% of total wall, producing 45–50 µm barrier thickness in a 1.40 mm nominal wall. Oxygen transmission at 23 °C/0% RH is 0.45–0.55 cm³/(m²·day·atm) per ASTM D3985-17, increasing to 1.8–2.4 cm³/(m²·day·atm) after 28 days at 40 °C/75% RH; the inner HDPE layer prevents direct liquid water contact with the EVOH core. Wet-ground particles with D50 2–4 µm do not chemically attack the polyolefin layers, but residual naphthalene sulfonate dispersant can reduce thermal stability of EVOH-containing regrind if regrind content exceeds 25 wt%. Extrusion control is set with die head temperature 215 °C ±5 °C; the barrier screw is purged with a high-MFR polyolefin before shutdown to avoid carbonized EVOH deposits on the die lip. The terminal bottle meets UN 3H1 packaging group III requirements for liquids with specific gravity not exceeding 1.2, and passes 1.2 m drop height on cap and base at 23 °C after filling with water to 95% capacity.
Concentrated glyphosate SL formulations containing 480 g/L isopropylamine salt, pH 4.8, and 10–12 wt% ethoxylated amine surfactant fall into a high-ionic-strength, low-solvent category that does not demand aromatic solvent barrier. The container uses a five-layer HDPE/tie/EVOH/tie/HDPE structure with 44 mol% ethylene EVOH at 2.5 wt%, achieving 30–35 µm barrier thickness in a 1.30 mm wall. The higher ethylene content is selected for moisture tolerance during ventilated warehouse storage at 35 °C/80% RH; oxygen transmission for the 44 mol% grade at 20 °C/85% RH is approximately 5–8 cm³·20 µm/(m²·day·atm) per ASTM D3985-17, which is sufficient for glyphosate but not for high-solvent emulsifiable concentrates. The inner HDPE layer has MFR 0.35 g/10 min at 190 °C/2.16 kg per ISO 1133-1:2022 to resist environmental stress cracking; specimens tested per ASTM D1693-21 Condition A in 10% nonylphenol ethoxylate at 50 °C exceed 100 h without failure. The lower melt strength of 44 mol% EVOH requires a reduced die gap of 1.2 mm and shorter parison swell time; die-lip drool appears after 45 min if die temperature exceeds 210 °C. Terminal 1 L and 5 L jugs pass 0.8 m side-drop impact at −10 °C and show no tie-layer delamination after 72 h fill storage at 54 °C.
In oil-based adjuvant concentrates containing 25–35 wt% alkoxylated tristyrylphenol phosphate and 20–30 wt% butanol/aromatic co-solvent, the six-layer bottle uses 27 mol% ethylene EVOH at 4.5 wt% to obtain the lowest solvent transmission among the commercial EVOH grades; barrier thickness is 55–60 µm in a 1.35 mm wall. Although the 27 mol% grade gives oxygen transmission of 0.12–0.16 cm³/(m²·day·atm) at 23 °C/0% RH per ASTM D3985-17, it is moisture-sensitive and must be encapsulated by tie layers to avoid direct contact with humid air during silo storage. Monolayer HDPE weight gain in 50:50 butanol/aromatic solvent at 40 °C for 28 days exceeds 8 wt%; the multilayer structure limits total package weight loss to below 0.3 wt% over 12 months in 4 °C storage. Published laboratory sorption data for EVOH in pure cyclic adjuvant solvents remain limited; field data from a 6-cavity reciprocating screw blow moulder show that maintaining melt pressure at 180–220 bar and using a 30:1 L/D barrier screw prevents layer displacement in the shoulder radius. Bottle panels show no stress whitening after 7 days of continuous product contact at 45 °C; drop testing at −5 °C from 1.2 m does not fracture the EVOH core.
Returnable 10 L multilayer jerricans for closed-loop pesticide distribution are washed with 60 °C sodium hydroxide solution at pH 12–13 for 120 s, followed by acid rinse at pH 3. The EVOH layer must survive 20 reuse cycles without blistering or delamination; this drives the selection of maleic anhydride grafted linear low-density polyethylene tie resin with density 0.922 g/cm³ and melt index 2.0 g/10 min at 190 °C/2.16 kg per ISO 1133-1:2022. Coextruded layer distribution is outer HDPE 35 wt%, regrind 25 wt%, tie resin 3.0 wt%, EVOH 4.0 wt%, tie resin 3.0 wt%, inner HDPE 30 wt%. Caustic washes hydrate the EVOH layer through the polyolefin over repeated cycles; oxygen barrier at 65% RH after 20 cycles falls from 1.5 cm³/(m²·day·atm) to 2.8–3.5 cm³/(m²·day·atm). The operational boundary is that caustic wash temperature must not exceed 65 °C, because tie-layer peel strength measured by T-peel per ASTM F88/F88M-21 drops below 4 N/15 mm after 70 °C wash exposure. The terminal jerrican is qualified under UN 3H1 for packaging group II liquids, and passes the internal pressure test of UN Model Regulations 6.1.5.3 after the fifth reuse cycle.
During seed treatment slurry packaging for insecticidal and fungicidal flowable concentrates containing 200–300 g/L tebuconazole or metalaxyl-M and 15–20 wt% red iron oxide pigment, the bottle requires barrier protection against both oxygen ingress and residual methanol from synthesis. The six-layer bottle uses 32 mol% EVOH at 4.0 wt%, but abrasive pigment reduces the practical regrind content to 12–15 wt% because iron oxide particles of 0.2–0.8 µm accelerate wear in the barrier screw and cause black specks in the parison. Extruder screw and barrel are specified with bimetallic coating and 0.5 mm root clearance at the feed zone; temperature profile is 180 °C, 195 °C, 205 °C, 210 °C from feed to die. Oxygen transmission on the shoulder panel is 0.35–0.43 cm³/(m²·day·atm) at 23 °C/0% RH per ASTM D3985-17; methanol permeation data for EVOH/methanol systems per ASTM F739-20 are limited. Terminal 500 mL and 1 L bottles are paired with polypropylene child-resistant closures tested to ISO 8317:2015 and induction-sealed with aluminium foil laminated liner, preventing EVOH contact with slurry at the neck bore.
| Test method | Condition | Observed result for six-layer HDPE/EVOH bottle |
|---|---|---|
| ASTM D3985-17 | Flat wall, 23 °C/0% RH | 0.17–0.55 cm³/(m²·day·atm) depending on EVOH ethylene content and layer thickness |
| ASTM F1249-20 | 37.8 °C/90% RH | 0.4–0.8 g/(m²·day) for 1.0–1.4 mm wall |
| ASTM D543-21 | Immersion in xylene/cyclohexanone 60:40, 40 °C, 28 days | Weight change <2.5 wt% |
| UN Model Regulations 6.1.5.3 | Internal pressure, packaging group II | No leakage or permanent deformation exceeding permitted limit |
| ISO 8317:2015 | Child-resistant closure cycle test | Closure passes child-panel and senior-use requirements |
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Ethylene-vinyl alcohol copolymer (EVOH) for agricultural chemical bottles is supplied as a pelletised barrier resin with ethylene contents from 27 mol% to 44 mol%, although blow-moulding grades for pesticide and agricultural chemical containers are usually specified between 27 mol% and 38 mol%. Resin designations commonly cited in supplier literature include Kuraray EVAL F171B, H171B, and L171B, corresponding to ethylene molar fractions of 32%, 38%, and 27%. Equivalent grades are supplied by other manufacturers under different designations and are selected using the same ethylene-content and melt-flow classification. Published melt flow rate values for the above grades fall between 1.6 g/10 min and 1.7 g/10 min at 190 °C under 2.16 kg per ISO 1133-1. Density is reported in the range of 1.12 g/cm³ to 1.19 g/cm³ by ISO 1183-1. Increasing ethylene content lowers the melting point from approximately 191 °C for 27 mol% ethylene to 158 °C for 44 mol% ethylene; the bottle-grade region balances polar solvent resistance, oxygen barrier, and melt processability. The resin is not used as a monolayer in agrochemical containers. It is coextruded as a discrete core layer within high-density polyethylene (HDPE) to suppress permeation of xylene, cyclohexanone, n-butanol, and ester solvents that degrade active ingredient stability and plasticise polyethylene. The EVOH layer also reduces oxygen ingress that can oxidise sulphur-containing or phosphorothioate active ingredients. Because the specific package configuration is application-dependent, the grade selection is made after chemical storage trials on the filled commercial formulation; published data for individual agricultural chemical products is limited.
Oxygen transmission rate is the primary resin QC metric, measured on cast film at 23 °C and 0% or 65% relative humidity by ASTM D3985. Typical published values for a 25 µm film of 27 mol% ethylene EVOH are 0.1–0.3 cm³/(m²·day·atm) at 20 °C/65% RH; the 38 mol% ethylene grade may reach 0.7–1.0 cm³/(m²·day·atm) under the same conditions. Whole-bottle oxygen transmission is measured separately by ASTM F1307, because film OTR values overstate the moisture effect and do not account for wall thickness distribution. Water vapour transmission is measured by ASTM F1249; EVOH is hydrophilic and its oxygen barrier declines when relative humidity exceeds 70%. Agricultural chemical formulations frequently contain xylene, cyclohexanone, n-butanol, or alkylphenol ethoxylates. Chemical resistance is evaluated by ASTM D543 immersion of composited sidewall specimens in the actual formulation, with acceptance criteria based on mass uptake, dimensional change, and loss of tensile strength after immersion at 40 °C for 28 days or shorter accelerated conditions. Mechanical integrity of the bottle is assessed by tensile tests per ISO 527-2 and flexural tests per ISO 178 on sidewall sections. Environmental stress cracking resistance of the complete bottle or sidewall is tested according to ASTM D1693 or ISO 22088 using a surfactant or actual formulation as the stress-cracking agent. UN packaging requirements apply when the agricultural chemical is classified as a hazardous liquid; performance tests include drop, leakproofness, and hydraulic pressure under UN Model Regulations Chapter 6.1.
The barrier action originates from intermolecular hydrogen bonding in the EVOH phase. The pendant hydroxyl groups reduce free-volume diffusion of non-polar and moderately polar permeants; dry EVOH has oxygen permeability 1–3 orders of magnitude lower than high-density polyethylene. When water or strongly polar solvents occupy the hydroxyl sites, the barrier structure swells and the diffusion coefficient rises. This moisture sensitivity is why EVOH is placed as a core layer rather than exposed as a surface. It also explains why low-ethylene grades are preferred for aromatic solvents but are more sensitive to high-humidity storage than high-ethylene grades. The barrier function is a physical diffusion barrier, not a chemical scavenger for pesticide active ingredients.
Table 1 lists typical published values for three standard EVAL grades used in barrier layers. Values are not lot-specific specifications and must be verified against supplier certificates of analysis.
| Grade | Ethylene content (mol%) | Melt flow rate (g/10 min at 190 °C/2.16 kg) | Typical OTR at 20 °C/65% RH (cm³/(m²·day·atm)) | Processing note |
|---|---|---|---|---|
| EVAL L171B | 27 | 1.6 | 0.1–0.3 | Highest O₂ barrier; higher melt viscosity |
| EVAL F171B | 32 | 1.6 | 0.3–0.5 | Balanced barrier and processability |
| EVAL H171B | 38 | 1.7 | 0.7–1.0 | Broader moisture tolerance; softer barrier |
Agricultural chemical product classes impose different barrier demands. Emulsifiable concentrates containing 10–50% aromatic hydrocarbon carriers such as xylene or C9–C10 aromatics impose severe solvent permeation loads on HDPE and require EVOH layers with higher barrier output, typically 27 mol% or 32 mol% ethylene. Suspension concentrates and aqueous microemulsions often present lower solvent swelling but generate headspace oxygen and water vapour conditions that alter the hydrated state of EVOH. For water-based products, the oxygen barrier requirement is less critical, but the same EVOH structure may be retained to minimise tooling changes and maintain common bottle performance. Oil-based and ultra-low-volume formulations require the most stringent barrier validation because the active ingredient is present at high concentration and small permeant losses are proportionally larger. In such cases, gravimetric solvent loss from sealed bottles is monitored at 40 °C for 28 days, and acceptance limits are derived from regulatory storage stability data rather than generic film OTR values.
Post-mould fluorination of HDPE bottles modifies the surface polyethylene to create a barrier of 5–20 µm depth, but the treated layer can be damaged by surface abrasion or flexure during transport. Coextruded EVOH places a continuous core layer within the bottle wall. Under ASTM D543 immersion testing with xylene or cyclohexanone at 40 °C, unfilled HDPE exhibits measurable mass uptake within 7 days, whereas an EVOH-containing sidewall suppresses solvent permeation by one to two orders of magnitude depending on layer thickness and formulation; published data for specific agricultural emulsifiable concentrates is limited. Because the EVOH layer is buried, its barrier is not removed by surface contact, and bottle drop performance is dominated by the HDPE skins. Polyamide is an alternative barrier resin; PA6 provides lower oxygen barrier per unit thickness than EVOH at low humidity and is more water sensitive. PET has high aromatic solvent resistance but is less common in opaque HDPE agricultural bottles because it requires different bottle-making infrastructure. EVOH is specified where the combination of low oxygen transmission, solvent resistance, and compatibility with existing HDPE extrusion blow-moulding lines is required.
On continuous five-layer coextrusion blow-moulding lines, the EVOH core is conveyed through a dedicated barrier-layer extruder with 25:1 to 30:1 L/D and a low-compression barrier screw. Melt temperature at the die is held between 210 °C and 230 °C; excursions above 245 °C generate gel particles and localised layer-thickness variation that appear as fish-eye defects in the bottle wall. The HDPE skins are processed at 190–220 °C and maleic anhydride-grafted polyethylene tie layers at 200–220 °C. Layer thickness in 0.5 L to 5 L bottles typically places EVOH between 25 µm and 75 µm, with tie layers of 25 µm to 50 µm. The EVOH stream is pre-dried at 80–90 °C for 4–6 h when ambient relative humidity exceeds 60%; moisture content above 0.05% causes splay and micro-voiding at the adhesive interface. Layer distribution is monitored by bottle cross-section microscopy because non-uniform EVOH thickness reduces barrier performance and creates stress concentration. Continued operation with insufficient purging after EVOH accumulation in the die head causes carbonised black specks and delamination. Shutdown and purge procedures use low-density polyethylene to displace EVOH from the die head and adapter.
Bond strength between EVOH and HDPE relies on maleic anhydride-grafted polyethylene tie layers. Adhesion is checked by bottle sidewall peel resistance according to ASTM F904 or by microscopic inspection after flexural cracking; delamination indicates insufficient tie-layer thickness, moisture in the EVOH stream, or die-head temperature mismatch. Tie-layer thickness below 25 µm can produce intermittent adhesion failure, while thickness above 50 µm increases head pressure and can distort layer distribution. In five-layer configurations, the regrind layer should be placed between the outer HDPE and the tie layer; EVOH content in the regrind stream is limited to avoid phase-separated gel accumulation. The middle regrind layer may be absent in smaller bottles to reduce wall thickness variation. Layer distribution in blow-moulded bottles is affected by die design, parison programming, and melt strength differences between HDPE and EVOH; at the pinch-off and handle regions the EVOH layer thins and must be verified by microscopy. Published layer-distribution data for agricultural bottle-specific tooling is limited; start-up qualification therefore includes full cross-sections at multiple positions.
Chemical incompatibility boundaries exist for polar aprotic solvents. Concentrated N,N-dimethylformamide, N-methyl-2-pyrrolidone, and certain chlorinated solvents can plasticise EVOH and reduce interlayer adhesion; EVOH is not recommended above the concentration limits stated in the supplier chemical resistance table. The resin also loses oxygen barrier when the bottle is stored at external relative humidity above 70% for extended periods, although the HDPE skins and tie layers slow moisture ingress. EVOH is not a structural layer; mechanical strength is governed by the HDPE phase. The use of EVOH in agricultural chemical bottles does not eliminate closed-loop compatibility testing with the commercial formulation. The package must be tested for weight loss, sidewall deformation, discoloration, and active ingredient degradation under the intended storage period and climatic zone. Published data for EVOH contact with commercial pesticide emulsifiable concentrates is limited; therefore, generic solvent surrogate data cannot replace formulation-specific evaluation.
Table 2 assembles the standards most frequently applied to EVOH-containing agrochemical barrier structures.
| Function | Test standard | Measurement or requirement |
|---|---|---|
| Resin melt flow | ISO 1133-1 | 1.6–1.7 g/10 min at 190 °C/2.16 kg |
| Film oxygen transmission | ASTM D3985 | 0.1–1.0 cm³/(m²·day·atm) for 25 µm film at 20 °C/65% RH |
| Whole-bottle oxygen transmission | ASTM F1307 | As specified by product owner; lower than film OTR due to HDPE encapsulation |
| Chemical immersion | ASTM D543 | Formulation-specific mass uptake and tensile retention after 40 °C immersion |
| Water vapour transmission | ASTM F1249 | Evaluate only for moisture-sensitive formulations or high-humidity storage |
| Environmental stress cracking | ASTM D1693 / ISO 22088 | No crack development after test with relevant stress-cracking agent |
Validation of an EVOH-containing bottle for a new agricultural chemical formulation begins with the supplier chemical resistance table, followed by pilot bottle production at three melt temperatures within the 210–230 °C window and cross-sectional microscopy at the pinch-off, sidewall, and base. Bottle barrier qualification proceeds with whole-bottle oxygen transmission per ASTM F1307 and formulation-specific immersion per ASTM D543. When the filled product is classified as a dangerous good, the closure and bottle assembly is subjected to the drop, leakproofness, and hydraulic pressure tests of UN Model Regulations Chapter 6.1. Layer-thickness specifications, tie-layer adhesion, and regrind limits are not adjustable without repeating these tests because the bottle wall is a single coextruded structure rather than a monolayer material.
