ExxonMobil EVA 2026FL. CC EVA resina de copolímero, 26% VA, 2 MI, grau de filme

ExxonMobil EVA 2026FL.CC is an ethylene-vinyl acetate copolymer resin specified as a film grade with a nominal vinyl acetate content of 26 wt% and a melt index of 2.0 g/10 min when determined by ISO 1133-1:2022 at 190 °C under a 2.16 kg load. The identifier “FL” denotes film extrusion; the “CC” suffix distinguishes a cast-film variant within the manufacturer’s film portfolio. The exact slip and antiblock additive package should be confirmed from the manufacturer’s certificate of analysis, because the grade code alone does not define the additive formulation.

A density of approximately 0.95 g/cm³ is representative for a 26 wt% VA copolymer. The resin is used in monolayer and coextruded cast films, frozen-food sealant webs, cereal liners, and heat-seal layers in barrier laminates. The elevated vinyl acetate concentration suppresses polyethylene crystallinity and shifts the resin toward lower stiffness, lower sealing temperature, and greater low-temperature flexibility compared with lower-VA film resins. These same changes increase surface tack and reduce the maximum continuous service temperature.

How Does 26 wt% Vinyl Acetate Shift Seal Initiation and Hot Tack?

Increasing the vinyl acetate concentration from 18 wt% to 26 wt% reduces the number and length of crystallizable ethylene sequences. The result is a lower and broader melting endotherm, a lower peak melting temperature, and a shift in seal initiation temperature toward lower set points when evaluated under ASTM F1921-12. The hot-tack window widens on vertical form-fill-seal equipment because the resin retains tack while the seal is still under load; however, the absolute window is dependent on film gauge, dwell time, and seal-bar pressure. Production lines running cast films typically set seal-bar temperatures lower by 10–15 °C compared with 18 wt% VA films, but published data for this specific configuration is limited and each line must verify the seal window statistically.

Adhesion to polar substrates is improved because the acetate group raises the surface energy of the film. In stretch-film lamination, the resin layer develops cohesive peel and surface cling without high levels of migratory tackifier, although the final formulation depends on the CC additive package and adjacent layers. The higher VA content also increases low-temperature flexibility, allowing the film to survive sub-ambient folding and impact without cracking. Compared with a 28 wt% VA film grade, EVA 2026FL.CC has a higher degree of residual crystallinity and therefore improved blocking resistance, better dimensional stability during roll storage, and lower surface tack. Its seal initiation temperature is slightly higher than that of a 28 wt% VA resin, which can be advantageous when the package must withstand warm ambient temperatures without seal creep.

In cast-film extrusion, the resin is processed on single-screw extruders with L/D 24:1–30:1. A moderate compression screw with a mixing section is used because high-shear screw designs can generate excessive melt temperature and accelerate acetoxy-acid elimination. Barrel temperatures are profiled from 150 °C near the feed section to 210 °C at the metering zone, with adapter and die temperatures held below 230 °C. At melt temperatures above 230 °C, the comonomer begins to release acetic acid through thermal decomposition; this produces amber discoloration, carbonized gel defects, and corrosive species that can attack unplated screw and barrel surfaces. Consequently, production lines use chrome-plated or nitrided metallurgy, purge with LDPE during start-up and shutdown, and minimize residence time during die changes.

The melt curtain is pinned to a chill roll maintained at 10–25 °C to quench the film and limit haze development. Inadequate pinning or improper chill-roll temperature can increase surface defects and edge neck-in. Higher VA grades have a greater tendency to adhere to the chill roll; release aids or controlled roll temperature are necessary to prevent wrap-arounds. Winder tension is set lower than that for LLDPE because the film has lower tensile modulus and is more sensitive to tension-induced gauge variation.

Draw resonance amplitude and edge neck-in are process conflicts at higher line speeds. The resin’s low extensional strain hardening relative to LLDPE reduces the stable draw ratio; draw resonance appears as periodic thickness bands if the draw ratio exceeds the critical value. On production cast lines, the air gap is reduced and the chill-roll speed is balanced to keep the draw ratio below the critical value. Edge encapsulation in coextruded structures can occur if the sealant layer viscosity is lower than that of the substrate layer at the die lip; die temperature adjustment and melt pipe design are used to minimize layer distortion. If blown-film conversion is attempted, bubble stability is inferior to that of LLDPE of the same melt index, and a lower melt temperature with a modest blow-up ratio is required. Published data for this specific configuration is limited.

When Lower-VA Sealant Resins Are Replaced by 2026FL.CC in Coextruded Film

Substitution of an 18 wt% VA sealant with 2026FL.CC in a multilayer cast film changes the mechanical response of the total structure. Tensile stress at yield and secant modulus measured under ASTM D882-18 decrease, while elongation at break and puncture resistance increase. The sealant layer becomes the low-modulus component in the laminate; if the sealant thickness remains constant, the overall machine-direction stiffness of the web decreases, requiring adjustment of tension zones, slitting blades, and registration control. Higher VA also increases blocking tendency, so roll pressure and storage temperature must be controlled after slitting. In three-layer barrier laminates, the EVA sealant layer is run as a discrete skin layer, typically at 10–20% of total thickness; it is separated from metal foil or PET layers by appropriate tie layers to avoid lamination defects.

The comparative profile in Table 1 is directional because film data depend on gauge, quench rate, and additive package. For critical applications, the converter should derive film properties from pilot-line samples under standardized conditions, not from nominal resin data.

Compliance Verification and Material Handling Boundaries

For food-contact use in the United States, EVA copolymers are listed under FDA 21 CFR 177.1350, which specifies extractive limitations and end-use conditions. In the European Union, the finished package must comply with Commission Regulation (EU) No 10/2011 Annex I; overall migration into food simulants is limited to 10 mg/dm², and vinyl acetate monomer is subject to a specific migration limit. The migration kinetics in polymer matrices are temperature and time dependent; hot-fill or long-shelf-life conditions require diffusion modeling or migration testing using EN 1186 methods. For medical packaging, the sealant film is validated as part of a sterile barrier system under ISO 11607-1:2019.

The resin should be stored in sealed containers below 40 °C and below 60% relative humidity. If exposed to high humidity, surface moisture can create splay or bubbles in cast film; pre-drying at 60 °C for 4 h in a dehumidified-air dryer may be required. The resin should not be stored in direct sunlight or near oxidizers.

In frozen-food packaging, the resin is used as the sealant skin in coextruded structures over LLDPE or EVA tie layers. The low-temperature seal response reduces seal-bar dwell time and allows packaging at line speeds typical of vertical form-fill-seal machines. The sealant layer thickness should be maintained within the validated range because seal integrity decreases if the layer is thinned below the minimum specified for the packaging line. In medical film applications, the resin is converted into flexible pouches or lidding; the final film must pass peel strength, microbial barrier, and visual inspection per the applicable medical packaging specification.