Soarnol ET3803RB

During cast sheet coextrusion of five-layer PP/tie/Soarnol ET3803RB/tie/PP structures, the narrowest processing window occurs at the feedblock and the transition from the barrier polymer to the polypropylene skins. The 38 mol% ethylene grade is selected over a 32 mol% grade because its melt viscosity at 210–230°C lies closer to that of impact-modified PP copolymers, reducing interfacial instability across a 900 mm wide coat-hanger die. On a 75 mm single-screw extruder with L/D 30:1 and a barrier screw, the EVOH melt stream is maintained at 210–225°C, while the PP skins run at 230–245°C; die temperature is held at 220–230°C. If the die lip temperature exceeds 240°C for more than 15 min, gel particles derived from vinyl alcohol sequences form and produce visible specks in transparent PP trays. The EVOH layer is typically 15–30 μm within a total sheet thickness of 450–900 μm, corresponding to 3–6 wt% of total structure, depending on PP density and regrind content. The structure complies with EU Regulation (EU) No 10/2011 and FDA 21 CFR 177.1360 for food contact, provided migration testing under 10/2011 Annex V confirms overall migration below 10 mg/dm².

Thermoformed terminal products include modified-atmosphere packaging trays for fresh red meat, case-ready poultry, and steamed ready meals, where an oxygen transmission rate target below 1.0 cm³/(m²·day·atm) at 23°C/50% RH is specified per ASTM D3985. Because Soarnol ET3803RB loses oxygen barrier sharply above 70% RH, the PP skins must remain intact; cracking of the outer PP layer in freezer applications exposes the barrier layer to condensation, which can raise oxygen ingress by a factor of 2–3 and cause delamination at the tie-layer interface. Published data for this specific configuration is limited; the table above reflects representative literature values for EVOH with 38 mol% ethylene content rather than a grade-specific dataset.

What Happens to the Oxygen Barrier After a 121°C Retort Cycle?

The oxygen transmission rate of a PET 12 μm/ink/adhesive/EVOH 12 μm/CPP 70 μm laminate after a 121°C retort cycle is governed by moisture uptake in the EVOH layer and partial crystallization recovery during cooling. Soarnol ET3803RB constitutes approximately 8–12% of total laminate thickness and is protected from direct moisture contact by the outer PET and inner CPP layers. The barrier web is produced by first coextruding a blown PE/tie/EVOH/tie/PE film, then adhesive-laminating the barrier web to biaxially oriented PET using a two-component polyurethane adhesive at a dry coat weight of 2.5–3.5 g/m². Retort processing at 121°C/30 min with an F0 value of 3.0 plasticizes the EVOH layer through water permeation from the packaged food; this creates a temporary loss of oxygen barrier that is measured only after reconditioning.

Post-retort oxygen transmission is measured at 23°C/50% RH after 72 h conditioning according to ASTM D3985; typical values for a 12 μm EVOH layer are 2–5 times higher than pre-retort values due to residual moisture, but the layer recovers as moisture desorbs through the polyolefin sides. Terminal pouches include 180–250 g stand-up pouches for ready-to-eat rice, fish, sauces, and wet pet food. Compliance with FDA 21 CFR Part 113 for low-acid canned foods requires no seal failure or visual barrier layer disruption after 121°C/30 min processing; EU Regulation (EU) No 10/2011 applies to overall migration. Published data for this exact film configuration is limited; the cited values represent industrial targets rather than graded data for Soarnol ET3803RB alone.

On multi-layer accumulator blow moulding lines for plastic fuel tanks, Soarnol ET3803RB is embedded as a continuous hydrocarbon barrier between regrind HDPE layers in a six-layer wall structure: HDPE/regrind/tie/EVOH/tie/HDPE. The 38 mol% ethylene grade is preferred over lower-ethylene grades because the higher ethylene content improves layer uniformity under parison sagging and pinch-off deformation at shot weights up to 5 kg. The barrier layer is extruded at 210–220°C through a dedicated 45 mm single-screw extruder, while HDPE layers run at 220–240°C; total wall thickness ranges from 5 mm to 8 mm, with the EVOH layer at 30–70 μm, representing 1.5–3.0 wt% of the total shot weight. Regrind content up to 35 wt% is encapsulated between virgin HDPE skins to maintain barrier continuity and prevent direct fuel contact with EVOH.

Permeation testing according to EPA 40 CFR Part 86 and CARB EVAP procedures is used to verify diurnal hydrocarbon emission limits; a continuous EVOH layer with intact tie layers is required to achieve certification. Failure at the pinch-off weld line creates a permeation leak path that can exceed the 1.5 g/m²/day reference limit used in some tank wall specifications; therefore parison programming must maintain barrier layer coverage across the entire tank half shell. Pre-drying of Soarnol ET3803RB to below 0.1 wt% moisture is mandatory, because residual moisture causes hydrolysis at the tie-layer interface and pinholes in the barrier under fuel exposure. Terminal products include multi-layer plastic fuel tanks for compact SUVs, hybrid vehicles, and small off-road equipment. Published data for this specific grade in full-scale tank certification is limited because final permeation is strongly affected by die gap distribution and pinch-off geometry.

Oxygen Barrier Pipe Extrusion for Closed-Loop Hydronic Circuits

Multi-layer pipe extrusion for hydronic heating demands a continuous EVOH oxygen barrier to prevent dissolved oxygen ingress into water circulating through PEX or PE-RT pipes. In a 16 mm outside-diameter pipe with a 2.0 mm wall, Soarnol ET3803RB is coextruded as an intermediate layer of 60–100 μm between two tie layers and an outer PE layer; this corresponds to 5–7% of total wall thickness. The EVOH extruder is operated at 210–225°C with a barrier screw, while the polyolefin extruders run at 200–240°C; the multi-layer die is held at 220°C to prevent thermal degradation. Vacuum calibration is applied immediately after the die to maintain layer concentricity; deviations greater than ±10% in EVOH layer thickness produce localized oxygen diffusion paths.

Oxygen diffusion is tested according to ISO 17455 and DIN 4726, with a typical limit of 0.10 g/(m³·d) at 40°C for oxygen barrier pipes used in closed-loop heating. The outer PE layer is not optional; direct exposure of EVOH to humid ambient air at 60% RH reduces the oxygen barrier by a factor of 2–3, and contact with chlorinated water above 2 mg/L free chlorine may accelerate hydrolysis. Terminal products include underfloor heating manifolds, radiator connection pipes, and chilled ceiling systems. Start-up that exceeds 230°C melt temperature during barrel filling produces localized gels that tear at the die lip; the line should be purged with LDPE before and after EVOH processing to limit residence time to less than 20 min.

In tube laminating and side-seam welding lines, Soarnol ET3803RB is supplied as a coextruded PE/tie/EVOH/tie/PE film for lamination to a printed outer film and an internal sealant layer. The EVOH layer is typically 12–15 μm in a total laminated wall of 250–320 μm, representing 4–6 wt% of the tube body. The side seam is formed by high-frequency or hot-air welding; the EVOH layer is recessed 1.0–1.5 mm from the weld edge to prevent exposure and delamination at the seam. Shoulder and head injection moulding is carried out at 180–220°C, and the tube body must withstand 2.5 bar burst pressure without layer separation.

Pharmacopoeial requirements for plastic containers include Ph. Eur. 3.2.2 and USP 671, while ICH Q1A stability testing may require oxygen barrier verification for oxidation-prone formulations. The oxygen transmission rate of the finished tube is tested by ASTM D3985; values below 0.5 cm³/(m²·day·atm) are typically targeted for retinol and benzoyl peroxide products. In high-humidity filling areas above 60% RH, pre-drying and immediate processing are required because EVOH moisture sorption can reduce barrier performance before the tube is sealed. Terminal products include 15–50 mL tubes for retinol creams, benzoyl peroxide formulations, hydrocortisone ointments, and fluoride gels. Published data for this specific tube configuration is limited because final barrier is affected by side-seam geometry and head assembly welding.

When EVOH Replaces Foil in Paperboard Barrier Board for Aseptic Shelf-Stable Cartons

Extrusion coating of liquid packaging board with a three-layer polyolefin/EVOH/polyolefin structure is evaluated when converters require a foil-free barrier for extended shelf life but not multi-year ambient stability. Soarnol ET3803RB is deposited at 6–10 g/m², approximately 5–8 μm, between two LDPE layers on a board of 300–350 g/m², using a 1.6 m wide extrusion coating line with three extruders. The EVOH stream is held at 210–230°C, while the LDPE streams run at 300–320°C; the coextrusion feedblock and die must be designed to prevent EVOH from contacting the die lip at LDPE temperatures, which would cause degradation streaks. Line speed of 300–400 m/min requires a draw-down ratio that does not tear the EVOH layer; thickness monitoring is performed with an infrared gauge after the chill roll.

Barrier board is converted into gable-top cartons for extended-shelf-life milk, juice, and liquid dairy products. Oxygen barrier after creasing and folding is verified per ASTM D3985 on flat board before cup forming; the EVOH layer must survive transverse crease lines without microcracking. EU Regulation (EU) No 10/2011 and FDA 21 CFR 176.170 govern food contact compliance; no aluminum foil is present, so light-sensitive nutrients require additional pigmented PE or board layers. Compared with foil-bearing aseptic cartons, the oxygen transmission rate is several orders of magnitude higher; therefore these structures are limited to products with ambient shelf life below 6 months. Published data for this specific configuration is limited because barrier performance is strongly dependent on crease geometry and board moisture content.

In coextrusion blow moulding of monolayer HDPE bottles converted to six-layer oxygen barrier containers, Soarnol ET3803RB is placed between tie layers in a HDPE/tie/EVOH/tie/HDPE structure for sauces, dressings, and edible oils. The EVOH layer is 10–20 μm within a total wall of 0.8–1.2 mm, corresponding to 3–5 wt% of the bottle. The barrier extruder runs at 210–225°C, while the HDPE layers are processed at 220–240°C; continuous coextrusion rotary blow moulding machines with 6 stations are used for high-volume production, and 15–25% of in-line regrind is reincorporated into the outer layers. The hot-fill temperature is limited to 85°C because above that the EVOH layer softens and can distort during cooling.

Food contact compliance is established under EU Regulation (EU) No 10/2011 and FDA 21 CFR 177.1360; oxygen barrier performance is measured by ASTM D3985 on panel sections cut from the sidewall and referenced to the total bottle area. Terminal bottles include 250 mL–1 L containers for ketchup, mayonnaise, barbecue sauce, edible oil, and salad dressings. Direct exposure of the EVOH layer at the weld pinch-off line causes delamination; therefore the parison weld must be trimmed or contained within the outer HDPE layers. Published data for this specific grade in rotary blow moulding is limited because final barrier depends on parison programming and part geometry.