Ateva 1821A Ethylene Vinyl Acetate Copolymer

Ateva 1821A is an ethylene vinyl acetate copolymer with nominal vinyl acetate content of 18 wt% and melt flow index of 2.0 g/10 min at 190°C/2.16 kg when tested according to ASTM D1238-20. Density at 23°C is approximately 0.94 g/cm³ under ISO 1183-1:2019. The following application tracks are limited to downstream routes with documented industrial formulation and conversion data; no speculative sectors are included.

How Does the 18 wt% Vinyl Acetate Fraction Shift Seal Initiation Temperatures in Coextruded Lidding Films?

In flexible packaging heat-seal layers, Ateva 1821A is blended or used neat as the sealing skin of multi-layer polyethylene structures. The formulation addition ratio falls into two standard configurations: 100 wt% Ateva 1821A as the sealant layer in cast and blown coextrusions, and 10–30 wt% Ateva 1821A added to linear low-density polyethylene in monolayer or core-modified films, with total EVA content in the finished web typically between 5 wt% and 25 wt%. Industry compliance is established under FDA 21 CFR 177.1350 for ethylene-vinyl acetate copolymers with vinyl acetate content not exceeding 50 wt%, and under EU Regulation (EU) No 10/2011 Annex I, where the specific migration limit for vinyl acetate is 12 mg/kg in food simulants. Downstream production on cast film lines uses melt temperatures of 190°C to 215°C, a chill roll temperature of 15°C to 25°C, and corona treatment at 38–42 mN/m for downstream ink or adhesive adhesion. On three-layer blown film lines, the EVA skin is coextruded with HDPE or LLDPE backwebs at a die gap of 1.8–2.5 mm, blow-up ratio of 2.0–2.5, and die temperature of 180–205°C. Seal initiation temperature, measured according to ASTM F2029, for this vinyl acetate level generally falls between 86°C and 98°C at 0.5 s dwell time and 0.35 N/mm² seal bar pressure; hot tack strength follows ASTM F1921. Terminal finished products include lidding films for fresh-cut produce, frozen vegetable pouches, bag-in-box liners for sauces and dairy creams, and tamper-evident dairy cup lids.

Processing grade Ateva 1821A in crosslinked footwear foam systems is formulated at 100 phr as the primary polymer, with azodicarbonamide at 2.5–4.0 phr, dicumyl peroxide at 0.6–1.0 phr, zinc oxide at 1.5–3.0 phr, stearic acid at 0.5–1.0 phr, and calcium carbonate at 15–35 phr when the target slab density is 0.08–0.25 g/cm³. The zinc oxide functions as an activator for blowing agent decomposition and as a mild crosslinking co-agent, while the stearic acid reduces filler-particle agglomeration during mixing. The downstream production sequence requires an internal mixer with ram pressure at 0.4–0.6 MPa and discharge temperature held at 105–115°C to avoid scorch; the batch is then formed on a two-roll mill with roll temperature 80–95°C and nip gap 0.5–2.0 mm. Compression moulding is conducted at 165–175°C for 7–12 min per 10 mm of final part thickness; during this step the decomposition of azodicarbonamide at approximately 200–210°C in the polymer melt is decoupled from the press set temperature because the exotherm and pressure regime create internal gas expansion only after sufficient melt elasticity develops. Process failure modes observed on production lines include premature cure before gas release, producing high-density boards with closed-cell collapse, and excessive blowing agent load above 4.0 phr creating split slabs or uncontrolled surface pinholes. Compliance for finished footwear components is assessed against REACH Annex XVII entries 51 and 52 for phthalate plasticisers in articles with prolonged skin contact, and producer-level restricted substance specifications aligned to California Proposition 65 where decomposition residues are contractually limited. Physical properties are checked under ISO 845 for density, ISO 868 or ASTM D2240 for hardness, and ASTM D395 Method B for compression set at 50°C for 6 h. Terminal finished product types include injection-moulded midsoles, die-cut insole boards, and compression-moulded forefoot support inserts.

Hot Melt Adhesive Compounding for Carton Sealing and Bookbinding

Adhesive formulators specify Ateva 1821A in rosin-free or low-rosin hot melt systems where the 18 wt% vinyl acetate content provides cohesive strength without the low-temperature brittleness of low-VA grades and without the melt instability of high-VA EVA grades. The addition ratio in standard packaging adhesives is 25–40 wt% Ateva 1821A, 35–50 wt% hydrocarbon tackifier, 20–35 wt% paraffin or microcrystalline wax, and 0.5–1.0 wt% hindered phenolic antioxidant. For bookbinding applications, the wax content is reduced to 15–25 wt% and the tackifier content is raised to 40–55 wt% to extend open time and improve page-pull adhesion. Compliance is governed by FDA 21 CFR 175.105 for adhesives used in food-contact packaging if the adhesive is separated from food by a functional barrier or has a negligible transfer, and by EU Regulation (EC) No 1935/2004 with good manufacturing practice under EC No 2023/2006 for materials intended as indirect food contact. Downstream compounding is performed in a jacketed sigma-blade mixer heated by oil at 150–180°C, mixed under low shear for 20–40 min, and deaerated under vacuum at 0.080–0.095 MPa to prevent bubble entrapment in the adhesive film. Application to finished packages uses slot-die or roller coaters at 165–185°C, with pump speeds adjusted to achieve coating thicknesses of 0.15–0.50 mm. Melt viscosity for a 30 wt% EVA, 40 wt% hydrocarbon tackifier, 30 wt% wax system is commonly measured under ASTM D3236 with a Brookfield Thermosel at 180°C; published data for this specific EVA grade in complete commercial formulations is limited, so converter-side viscosity and peel adhesion under ASTM D1876 must be verified on the production batch. Terminal finished products include corrugated case and carton sealing, tray erection, bookbinding, and magazine spine gluing.

In halogen-free flame-retardant cable sheathing, Ateva 1821A functions as the polar polymer matrix for high loadings of mineral flame retardants. The formulation addition ratio is 100 phr EVA, 100–160 phr aluminium hydroxide, 10–40 phr magnesium dihydroxide, 1.0–2.0 phr vinyl silane coupling agent, 0.5–1.5 phr dicumyl peroxide, and 0.5–1.0 phr antioxidant. The aluminium hydroxide and magnesium dihydroxide loadings are balanced to maintain limiting oxygen index above 30 % O₂ under ISO 4589-2 while avoiding the torque and pressure limits of the compounding line. Production is carried out on a co-rotating twin-screw extruder with L/D 44:1, screw speed 200–350 rpm, and barrel temperature profile 120/135/145/155/165/170/175/180°C; the melt temperature at the die is maintained at 185–200°C. Processing above 220°C is avoided because the vinyl acetate segment can release acetic acid and cause localised polymer degradation. Aluminium hydroxide requires pre-drying at 70°C for 4 h when moisture content exceeds 0.3 wt%; otherwise steam generated at 180°C or higher creates foamed extrudate and pellet porosity. The compounded pellets are then converted in a single-screw extruder to produce cable sheathing, with crosslinking either in the barrel or in a downstream continuous vulcanisation line. Terminal finished product types include sheathing for control cables, building wiring with halogen-free specifications, and industrial power cable jackets where low-smoke and low-acid emission characteristics are contractually required.

When Pelletized EVA Serves as a Carrier in High-Pigment-Load Masterbatch Compounds

Because Ateva 1821A retains sufficient melt elasticity at low shear and remains pellet-stable at storage temperatures up to 40°C, it is specified as a carrier in pigment and additive masterbatches for polyolefin films and injection moulded articles. The formulation addition ratio in colour masterbatches splits into 50–70 wt% Ateva 1821A carrier, 20–40 wt% organic or inorganic pigment, 5–15 wt% dispersant wax, and 0.5–1.0 wt% antioxidant. The vinyl acetate content modifies pigment wetting during kneading; unlike nonpolar LDPE carriers, the 18 wt% VA segment reduces agglomerate persistence when the pigment has a polar surface treatment, but wax addition is still required to wet high-surface-area carbon black grades above 150 m²/g. Masterbatches intended for food contact packaging are checked against EU Regulation (EU) No 10/2011 for overall migration limits of 10 mg/dm² or 60 mg/kg depending on the article geometry, and against FDA 21 CFR 178.3297 for colourants used in polymers for food contact when the masterbatch is used in US-compliant articles. Downstream production is performed on a co-rotating twin-screw extruder with L/D 36:1 to 44:1, barrel temperature profile 130/150/170/185/200/210°C, screw profile containing two or three kneading blocks, and specific energy input of 0.15–0.25 kWh/kg. The melt is filtered through a screen pack with mesh size 50–100 µm and pelletised through a strand bath at 25–35°C; high pigment loadings may require underwater die-face pelletising to prevent strand breakage. Terminal finished products include colour masterbatch pellets for polyethylene film, blow moulded containers, closures, and injection moulded household goods.

Beneath vehicle carpet systems, Ateva 1821A is the base polymer in crosslinked acoustic and vibration dampening sheets, formulated at 100 phr with 20–30 phr low-density polyethylene, 30–50 phr calcium carbonate, 1.5–3.0 phr azodicarbonamide, 0.6–1.2 phr dicumyl peroxide, and 1.0–2.0 phr zinc oxide. The filler loading is raised to 50 phr only where part thickness exceeds 4 mm and where the thermoforming geometry does not include sharp radii below 2 mm; at higher filler levels the sheet can crack during deep-draw forming. Production starts in an internal mixer with discharge temperature 105–125°C, followed by a single-screw extruder feeding a slot die to create a pre-foam sheet of 2–6 mm thickness. Expansion and crosslinking occur in a horizontal hot air or infrared oven at 190–210°C with residence time 4–8 min, yielding a closed-cell foam sheet with expansion ratio between 8:1 and 15:1 and density 0.060–0.150 g/cm³. The sheet is then thermoformed into contours under vacuum at 110–140°C. Finished parts are evaluated for flammability under ISO 3795 or FMVSS 302 with burn rate requirements below 100 mm/min for vehicle interior materials; volatile organic compound and fogging behaviour is tested under VDA 278, with producer-specific limits for total VOC and condensable fractions. Because the 18 wt% VA content yields higher stiffness than 28 wt% VA foam grades, this formulation is preferred for dash silencer substrates but carries reduced low-temperature extensibility below -20°C; cold climate installation therefore requires validation against the automobile manufacturer’s low-temperature tensile requirements under ASTM D638 or equivalent OEM specification. Terminal finished product types include carpet underlay pads, dash insulator sheets, and boot floor vibration damping layers.