LG EVA 15006 Copolímero de acetato de vinilo de etileno

Among the ethylene-vinyl acetate copolymers supplied by LG Chem, grade 15006 is identified by a nominal vinyl acetate monomer content of 15 wt% and a melt flow rate target of 6.0 g/10 min determined at 190 °C under 2.16 kg load according to ISO 1133-1:2022. The product is supplied as a pelletised thermoplastic resin under the model name LG EVA 15006 Ethylene Vinyl Acetate Copolymer. The comonomer is incorporated into the ethylene backbone through high-pressure polymerisation, which reduces crystalline organisation and introduces polar ester functionality along the chain. The resulting material exhibits a density of approximately 0.938 g/cm³ when measured per ISO 1183-1:2019, a tensile strength at break near 11 MPa per ISO 527-2:2012, and a Vicat softening point around 64 °C under the ISO 306:2022 A50 condition. These values are indicative and should be confirmed against the current manufacturer technical data summary for the relevant production lot.

What Distinguishes 15 wt% Vinyl Acetate From Surrounding Ethylene Copolymer Grades?

The principal differentiating variables are comonomer content and melt flow index. At 15 wt% vinyl acetate, the copolymer retains sufficient ethylene crystallinity to provide form stability at ambient temperature while introducing enough polar ester groups to increase filler wetting, surface adhesion and low-temperature flexibility relative to low-density polyethylene. Differential scanning calorimetry according to ISO 11357-3:2018 typically places the main melting peak near 82 °C, below the 105–115 °C range observed for LDPE homopolymers. Copolymers with lower vinyl acetate contents in the 5–9 wt% range exhibit higher crystallinity, higher melting peak temperatures and lower polar adhesion. Grades with higher vinyl acetate contents in the 18–28 wt% range show lower flexural modulus, higher tack, lower heat resistance and stronger adhesion to polar substrates. The 6.0 g/10 min flow also separates the 15006 grade from high-melt-index EVA grades used in low-viscosity hot melt application and from very low-melt-index grades used where high melt strength is required during blown film or foam expansion.

Melt processing of LG EVA 15006 is generally conducted in single-screw extruders, co-rotating twin-screw compounders or injection moulding machines with barrel temperatures maintained between 160 °C and 210 °C. The exact profile depends on shear rate, residence time and screw geometry. Extended operation above 230 °C accelerates thermally driven deacetylation, releasing acetic acid and causing corrosion risk in unhardened screw, barrel and die steel. When the resin has been stored at relative humidity above 60%, pre-drying at 60–70 °C for 2–4 h in a desiccant dryer is recommended where surface appearance or melt homogeneity is critical. The compressible melt and moderate shear viscosity require temperature profiling that avoids both unmelting in the feed zone and excessive energy input in the metering zone.

Indicative property data for the as-supplied pellet are summarised below. Test values are influenced by sample preparation, moulding history and conditioning; they are not a specification.

If Peroxide Decomposition and Blowing Agent Gas Evolution Are Thermally Mismatched

When crosslinked foam is produced from the 15006 grade, dicumyl peroxide is commonly used as the curing agent and azodicarbonamide as the blowing agent. The peroxide decomposes thermally over a temperature range that can be described by half-life values of approximately 10 h at 115 °C, 1 h at 135 °C and 1 min at 170 °C. Azodicarbonamide decomposition ordinarily begins above 195 °C, but activation via zinc oxide, zinc stearate or urea-based kickers can lower the effective gas-release window to 150–170 °C. If the peroxide cure and blowing gas release are mismatched, gas escapes before sufficient network formation or the crosslinked matrix restricts cell growth, producing coarse, collapsed or over-dense foam. In compression moulding practice, the compounded EVA gum sheet is first homogenised on a two-roll mill at 90–110 °C, then cured and expanded in a hydraulic press at 150–170 °C under 5–15 MPa for 10–20 min depending on sheet thickness. Final foam density and compression set are commonly evaluated by ASTM D3574-17 Test A or ISO 3386-1:2015. Published data for this specific formulation is limited; pilot-scale trials are required to fix the cure-to-blow ratio and demoulding cycle for a given part geometry.

Because 15 wt% vinyl acetate supplies ester dipoles to the polymer chain, the 15006 grade is used in halogen-free cable sheathing, mineral-filled compounds and semi-conductive screen compounds where carbon black or magnesium hydroxide must be dispersed. In co-rotating twin-screw extrusion, a machine with an L/D ratio of 40:1 and a side-stuffer for filler addition is typical. Melt temperatures are generally held between 180 °C and 210 °C, while filler loadings can range from 120 phr to 180 phr for aluminium trihydroxide or magnesium hydroxide in flame-retardant systems. The polar ester comonomer reduces filler-matrix interfacial failure compared with LDPE homopolymer of similar melt flow, which is relevant when elongation at break and tensile strength are measured on dumbbell specimens according to IEC 60811-501 or ISO 527-2:2012. The formulation should not be processed above 220 °C for extended residence times because deacetylation releases acetic acid and increases the risk of corrosion in unhardened downstream equipment.

Melt Flow Index Alone Does Not Determine Hot Melt Suitability

In hot melt adhesive trials, the 6.0 g/10 min melt flow index is not the only variable controlling wet-out, set speed and cohesive strength. Formulation with tackifying resins, waxes and stabilisers modifies the final viscosity and open time. The 15006 grade can be considered for extrusion lamination, profile wrapping and block adhesive systems where higher melt strength and firmer set than a typical 28 wt% vinyl acetate hot melt base are required. In comparison, EVA grades containing 18–28 wt% vinyl acetate are commonly selected for low-temperature flexibility and aggressive adhesion to polar films, but they generally exhibit lower heat resistance and higher surface tack. The 15 wt% comonomer content of the 15006 grade yields a stiffer adhesive film with reduced low-temperature tack and better retention of peel strength at elevated temperature. Formulation viscosity should be determined with a Brookfield Thermosel at 180 °C according to ASTM D3236-15; peel adhesion should be evaluated in the final laminate geometry using ASTM D1876-08.

Regulatory verification for a base EVA resin must be separated from the compliance of the final converted article. The ethylene-vinyl acetate copolymer is referenced under 21 CFR 177.1350 for food-contact applications when the vinyl acetate level and extractables satisfy the conditions of that section. Under Regulation (EU) No 10/2011, the final article must meet the overall migration limit of 10 mg/dm² and any specific migration limit applicable to unreacted vinyl acetate monomer. The neat as-supplied pellets are generally expected to meet the restricted substance requirements of RoHS Directive 2011/65/EU, Annex II, but the final compound can be altered by coloured concentrates, flame retardants, fillers or processing aids. A REACH Candidate List declaration under Regulation (EC) No 1907/2006, Article 33 should be obtained from the supplier for each packaging date.

Injection moulding and profile extrusion with the 15006 grade require altered temperature profiles relative to low-density polyethylene because of the lower crystallisation plateau and reduced melt temperature. Barrel zones are often set 10–20 °C lower than for an LDPE of equivalent melt flow, while mould temperature is held between 20 °C and 40 °C for rapid skin formation. The solidification behaviour is governed by the crystallisation exotherm measured under controlled cooling by ISO 11357-7:2022; cooling rate, mould geometry and hold pressure determine final part dimensions and warpage. The mid-range flow of 6.0 g/10 min allows the material to fill moderate-flow-length injection moulds without the excessive melt instability observed in very high-melt-index EVA grades, while still providing sufficient melt strength for profile extrusion and sheet operations. Processors should verify actual shrinkage on the specific tooling because published data for this specific configuration is limited and is strongly affected by part thickness, gate size and packing time.