Ateva 1811 EVA Copolymer Resin,18% VA,1.6 MI,Wire & Cable Grade (LSZH)

Ateva 1811 ethylene-vinyl acetate copolymer resin is supplied as a pelletized low-smoke zero-halogen wire and cable feedstock with a specified vinyl acetate content of 18 wt% and a melt index of 1.6 g/10 min determined at 190 °C under a 2.16 kg load in accordance with ISO 1133-1 / ASTM D1238. Typical density is 0.940 g/cm³ by ISO 1183-1 / ASTM D1505. The grade is positioned for extrusion jacketing and insulation compounds in which the finished cable must satisfy halogen acid gas release, smoke density, and flame spread criteria under IEC 60754, IEC 61034, and IEC 60332. The combination of polar comonomer content and moderately low melt viscosity places the product between slower-flowing high-molecular-weight EVA grades and higher-index, thin-wall extrusion resins.

The acetate comonomer at 18 wt% reduces ethylene sequence length and overall crystallinity relative to low-density polyethylene. Differential scanning calorimetry by ISO 11357-3 / ASTM D3418 typically returns a peak melting endotherm near 86 °C. The reduction in crystallinity lowers flexural modulus and increases filler-loading capacity, which is critical for LSZH compounds containing aluminum trihydroxide or magnesium hydroxide at loadings from 150 phr to 180 phr. Polar acetate groups interact with the hydroxyl surfaces of metal hydrates, reducing gross particle agglomeration during mixing. The acetate group is thermally labile above approximately 210 °C and degrades by deacetylation above approximately 230 °C, releasing acetic acid. This boundary constrains both compounding and cable extrusion temperatures.

How Does the 18 wt% Vinyl Acetate Content Influence Low-Smoke Zero-Halogen Chemistry?

Low-smoke zero-halogen performance is a property of the finished compound rather than the base resin. In a representative formulation, Ateva 1811 is compounded with 150–180 phr of surface-treated aluminum trihydroxide and often 10–30 phr of magnesium hydroxide to broaden the endothermic decomposition range. Aluminum trihydroxide evolves water from approximately 180 °C to 230 °C; magnesium hydroxide decomposes from 300 °C to 340 °C. The released water dilutes combustible gases and cools the flame zone. Smoke obscuration is evaluated on the finished cable by IEC 61034-2:2019, while halogen acid gas content is assessed by IEC 60754-1:2011 and aqueous effluent pH and conductivity by IEC 60754-2:2019. Published oxygen index values for EVA/aluminum trihydroxide systems in ISO 4589-2 testing frequently fall between 30 and 38, though published data for Ateva 1811-specific configurations is limited.

Compared with ethylene homopolymer matrices, the 18 wt% vinyl acetate level improves mineral filler wetting without the pellet-blocking tack that can characterize EVA grades in the 25–28 wt% vinyl acetate range. This difference is relevant in sheet-fed compounding operations where higher-VA resins may require cooled pneumatic conveying and chilled pellet storage. Ateva 1811 retains sufficient polarity for metal hydrate dispersion while remaining a free-flowing pellet under normal warehousing conditions below 50 °C.

On single-screw extrusion lines with L/D ratios from 24:1 to 30:1, barrel temperatures are commonly profiled from 130 °C at the feed throat to 190 °C at the metering section, with a die temperature near 180 °C. The 1.6 g/10 min melt index is high enough to reduce head pressure in thin-wall cable jackets but low enough to retain melt strength for tube-on or pressure extrusion. In heavily filled compounds, melt temperature measured at the die should not exceed 210 °C, and the resin must remain below 230 °C to limit acetic acid formation. Pre-drying of fresh pellets is generally unnecessary, but material stored above 80 % relative humidity or exposed to cold-shock condensation should be dried at 60–70 °C for 2–4 h before compounding.

When a Melt Index of 1.6 g/10 min Is Selected over Lower-Index and Higher-VA Grades

Compared with a 0.7 g/10 min EVA grade at the same 18 wt% vinyl acetate content, Ateva 1811 develops lower melt pressure and requires less torque at a given screw speed. This permits higher line speeds on crosshead cable lines but can reduce melt strength for very thick jackets, where sag may be controlled by drawing or by blending with 5–20 wt% of a lower-index EVA. Relative to higher-index grades in the 2.5–3.0 g/10 min range, Ateva 1811 retains a longer relaxation time, improving melt extensibility in crosshead tooling and reducing die-lip build-up. Relative to EVA grades containing 25–28 wt% vinyl acetate, the 18 wt% comonomer content provides lower tack and better pellet handling, while still imparting sufficient polarity for metal hydrate wetting.

In cable jacketing, the grade is used where the compounder requires a single resin that can accept high mineral loading while pumping through a 60 mm single-screw extruder at commercial output. Thin-wall data-cable jackets extruded at line speeds of 200–600 m/min generally favor the 1.6 g/10 min flow; thicker-wall power-cable sheathing may require blending with a 0.7 g/10 min EVA or high-density polyethylene to prevent draw-down and wall-thickness eccentricity. In comparison with linear low-density polyethylene, which can accept only limited aluminum trihydroxide before tensile elongation deteriorates, Ateva 1811 maintains elongational capacity at filler loadings above 150 phr. Ethylene-butyl acrylate copolymers of similar comonomer content may offer a higher thermal ceiling, but EVA generally provides higher tensile strength at equivalent filler loading and is more readily available in LSZH compound supply chains.

Thermal and Rheological Boundary Conditions in Commercial Cable Extrusion

Deacetylation of the acetate group is the limiting kinetic event. At melt temperatures above 230 °C, the rate of acetic acid elimination becomes consequential, leading to corrosive condensate on the downstream calibrator, die lip, and vacuum pump. Extruder screws and barrels should be constructed from nitrided or bimetallic surfaces for extended campaigns. The recommended melt temperature window for Ateva 1811 in mineral-filled LSZH formulations is 150–210 °C. At the lower end, unmelted pellets create dispersion defects; at the upper end, yellowing and odor increase. The processing window is therefore suitable for conventional single-screw cable jackets but not for high-temperature engineering resin conditions.

In twin-screw compounding with a co-rotating 40:1 L/D extruder, aluminum trihydroxide is typically side-fed after polymer melting to avoid excessive abrasion on the first kneading blocks. Specific energy input rises as filler loading increases from 120 phr to 180 phr; screw speed is often trimmed to keep compound melt temperature below 200 °C. Surface-treated aluminum trihydroxide with a median particle size of 1–2 µm is preferred for tensile-elongation retention. The filler-polymer interface dominates low-temperature elongation. When tensile elongation at break drops below 150 % on finished insulation, dispersion quality or additive selection is typically the cause rather than the base resin.

Batch-to-batch variance of the base resin is monitored by melt index and vinyl acetate content. Variations in melt index outside ±0.3 g/10 min can alter head pressure and cable concentricity. Variations in vinyl acetate content outside ±1 wt% may shift filler wetting and low-temperature brittleness. These limits reflect typical cable compounder incoming inspection criteria and should be confirmed against the supplier certificate of analysis.

Low-temperature flexibility is assessed by IEC 60811-506 cold bend and cold elongation tests on finished cables. Because Ateva 1811 has a peak melting temperature near 86 °C and a Vicat softening point near 75 °C, it retains flexibility in heavily filled compounds at low temperatures when the compound is not under stress. For applications requiring formal cold bend certification at −40 °C, compounders often blend EVA with polyolefin elastomers to pass cold wind and bending tests. The base resin itself is not usually the limiting factor; mineral filler loading above 150 phr can increase low-temperature modulus and should be assessed by ISO 527-2 / ASTM D638 at the specified service temperature.

LSZH qualification cannot be certified on Ateva 1811 alone. The resin contains no halogenated comonomer and is supplied without halogenated flame retardants, but halogen exclusion depends on the total formulation and any recycled material. Compliance with IEC 60754-1:2011 and IEC 60754-2:2019 is evaluated on the extruded cable compound. Smoke density is assessed by IEC 61034-2:2019 on a 3 m cube; flame spread is evaluated by IEC 60332-1-2:2015 for single cables. Supplier documentation for Ateva 1811 typically includes a RoHS statement confirming that lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls, and polybrominated diphenyl ethers are not intentionally added. REACH review of the safety data sheet remains necessary because the polymer may contain process residues.

For shipboard and rail cable jackets, processors typically pre-dry filled compounds, not the neat resin, at 70–80 °C for 4 h to remove surface moisture from aluminum trihydroxide. The resin should be kept away from direct sunlight and stored below 50 °C to prevent pellet blocking. When the product is used in foamed insulation or as a coupling-layer tie resin, higher-VA grades are often preferred for adhesion; Ateva 1811 is therefore specified for the jacket rather than the conductor adhesion layer. In thick-wall low-voltage power cable, a blend of 70–80 wt% Ateva 1811 with 20–30 wt% lower-index EVA or high-density polyethylene is used to control melt sag. The material is not designed for continuous exposure to hot mineral oil or to concentrated oxidizing acids.