Copolímero de acetato de vinilo de etileno Ateva 2810A

Ateva 2810A Ethylene Vinyl Acetate Copolymer is a pelletized thermoplastic supplied for injection moulding and compounding where a balance of flexibility, melt flow, and polar adhesion is required. The product is identified by a vinyl acetate comonomer content of 28 wt% and a melt mass-flow rate of 10 g/10 min when measured at 190 °C under 2.16 kg according to ISO 1133-1:2022 and ASTM D1238-20. Representative density is 0.950 g/cm³ by ISO 1183-1:2019; the melting endotherm peak occurs at 73 °C by differential scanning calorimetry under ISO 11357-3. Shore A hardness is 80 by ISO 868:2003, tensile strength at break is 13 MPa with elongation at break of 800% by ISO 527-2, and Vicat softening temperature is 47 °C by ISO 306 A50. These representative values are taken from the manufacturer’s technical data sheet; lot-specific values are recorded on the certificate of analysis.

Compared with EVA grades of lower vinyl acetate content, the 28 wt% comonomer fraction reduces crystalline ordering and increases segmental mobility; compared with higher vinyl acetate grades, the copolymer retains measurable crystalline domains at service temperature and exhibits lower surface tack. The melt mass-flow rate of 10 g/10 min positions the product for thin-wall injection moulding, whereas grades with melt mass-flow rate below 4 g/10 min are typically selected when melt strength is required for blown film extrusion or foam expansion. The product differs from ethylene-rich copolymers in its higher solubility for polar additives and greater filler-wetting capability, which is exploited in compounding and masterbatch carrier resin applications.

How Does the 28 Wt% Vinyl Acetate Content Alter Rheological Behaviour?

In capillary rheometry using a die with L/D 30:1 at 190 °C, the shear-thinning response of Ateva 2810A is governed by the short-chain branching introduced by the vinyl acetate copolymerization. The apparent viscosity at shear rates above 100 s⁻¹ is low enough to permit filling of moulds with wall sections of 1.2–2.0 mm when the injection screw maintains a shot cushion of 3–5 mm. At melt temperatures above 210 °C, deacetylation becomes significant; the resulting acetic acid release can corrode unprotected tool steels and produce surface splay. Published data for the specific deacetylation onset of this grade by ISO 11358-1 is limited, but the practical upper melt temperature is constrained by acid generation rather than viscosity alone. The melt elasticity is lower than that of a 4 g/10 min grade of the same comonomer content; this reduces die swell but also reduces parison stability in blow moulding. A mould temperature of 20–40 °C is normally required to prevent sink marks at gate impingement zones.

Production-scale handling of Ateva 2810A does not require desiccant drying unless condensation has formed on the pellet surface. In a silo or vacuum unloading system, the resin temperature should be allowed to equilibrate to the production environment before conveying to avoid surface moisture adsorption; if the air dew point exceeds 15 °C, a hopper-dryer at 50 °C for 2 h is used before processing. On a co-rotating twin-screw extruder with screw diameter 25–40 mm, L/D ratio 36:1–48:1, and screw speeds of 200–400 min⁻¹, the polymer melts at a specific mechanical energy demand in the range of 0.18–0.25 kWh/kg. Overheating at the die plate is controlled by using breaker plates with 40–60 mesh screens; pressure fluctuations above 15% indicate filler agglomerates or melt-temperature variation and require a reduction in throughput or screw speed. Strand pelletizing is stable when the water-bath temperature is kept between 20 °C and 35 °C; lower temperatures induce surface stress cracking of the pellet, while higher temperatures cause strand sticking and pellet agglomeration.

Injection Moulding, Compounding, and Interlayer Adhesion in Multi-Material Tooling

For injection moulding, a general-purpose screw with compression ratio 2.5:1–3.0:1 and length-to-diameter ratio of 20:1–24:1 is sufficient; high-shear mixing elements are not normally required because the copolymer exhibits a low melt temperature and low viscosity. A back pressure of 5–15 bar and an injection speed of 30–80 cm³/s are typical starting conditions for parts with a flow length-to-wall-thickness ratio up to 250:1. The material should be processed with a cushion of 3–5 mm; insufficient cushion produces density variation and surface flow lines. Mould shrinkage measured on 4 mm plaques under ISO 294-4 is typically 1.0–1.5% in the flow direction and 0.8–1.2% across flow; the degree of anisotropy increases with higher injection speed and lower mould temperature. Parts ejected at surface temperatures above 35 °C may stick in cores with draw angles below 1°; release is improved with a mould surface finish of VDI 3400 texture class 24 or better and a silicone-free external release. If a hot-runner system is used, the manifold temperature should not exceed 200 °C and residence time should be limited to 5 min to suppress acetic acid formation.

When Ateva 2810A Replaces an 18 Wt% Vinyl Acetate Grade in Flexible Applications

The substitution of Ateva 2810A for an 18 wt% vinyl acetate grade alters low-temperature flexibility, tensile modulus, and interfacial adhesion. The lower crystallinity of the 28 wt% comonomer resin reduces the storage modulus at −20 °C as measured by dynamic mechanical analysis under ISO 6721-6; the material also retains flexibility where the 18 wt% grade may show brittle crack formation in notched impact testing. However, tensile strength and creep resistance are lower, and the part may require increased wall thickness if the same mechanical load is applied. The higher vinyl acetate content increases the solubility parameter of the polymer; adhesion to polar substrates such as epoxy-based primers, alkyd coatings, or polyamide inserts is typically improved, although adhesive bond strength is system-specific. In footwear midsoles, the influence of vinyl acetate content on foam density and rebound is greater than the influence of melt flow index; therefore, a switch from an 18 wt% grade to Ateva 2810A should be accompanied by a re-evaluation of blowing-agent loading and cure temperature. Published data for the specific combination of Ateva 2810A with azodicarbonamide-based chemical blowing agents is limited; preliminary differential scanning calorimetry and capillary rheometry trials are required to define the optimum foaming temperature window. In halogen-free flame-retardant compounds, the higher vinyl acetate content improves filler dispersion of aluminium trihydrate and magnesium hydroxide, but the resulting compound has a lower heat deflection temperature under load and a narrower extrusion window.

For solvent-borne lamination and wire-and-cable compounding, the influence of vinyl acetate monomer distribution becomes critical. In lamination, the peel strength of Ateva 2810A films bonded to polyurethane adhesives is controlled by adhesive type, film corona treatment, and lamination temperature; no universal value can be assigned. In semiconductive compounds, volume resistivity below 100 Ω·cm is attainable only with high-structure carbon black grades and sufficient twin-screw dispersive mixing; the base resin contributes to carbon black dispersion but does not independently guarantee conductivity. In masterbatch carrier applications, the melt mass-flow rate of 10 g/10 min allows a let-down ratio of 20:1–50:1 for low-viscosity polyolefins, but the vinyl acetate content can limit compatibility with polypropylene and high-density polyethylene; co-extrusion or co-injection moulding with incompatible layers requires a tie resin.

Regulatory and Food-Contact Status Is Determined by the Finished Article

Compliance with food-contact regulations for Ateva 2810A is not automatically conveyed by the polymer type; the converter must verify the finished article under the relevant end-use conditions. The base resin can be assessed against FDA 21 CFR 177.1350 for ethylene-vinyl acetate copolymers and against European Commission Regulation (EU) 10/2011 for plastic materials intended for food contact. The specific migration limit applicable to vinyl acetate monomer under (EU) 10/2011 is 12 mg/kg. The product is manufactured without phthalate plasticizers, bisphenol A, or heavy-metal-based pigments. For articles sold in the European Union, REACH registration is the responsibility of the importer or resin producer; for electrical and electronic equipment, RoHS Directive 2011/65/EU Annex II substances are not intentionally introduced. The product should not be combined with amine-based additives where prolonged high-temperature service may generate coloured condensation products; this is an operational boundary, not a regulatory prohibition. Users should request a dual declaration from the resin supplier if the final part is intended for repeated food contact or medical packaging; the base pellet alone does not provide a finished-article compliance statement.

Operational boundaries are defined by acetic acid release at excessive melt temperature, condensation-driven moisture pickup on cold pellets, and the lower melt strength relative to grades with melt mass-flow rate below 4 g/10 min. The copolymer is not suitable for prolonged service above 60 °C under continuous load without crosslinking or structural support, because creep deformation increases with vinyl acetate content. When stored at temperatures below 30 °C in dry conditions, the pellet remains processable for extended periods; however, lot-to-lot melt flow index variation should be checked against ISO 1133-1:2022 before high-speed automated moulding campaigns.