EVAtech EVA 130S/10 Copolímero de acetato de vinilo de etileno

Ethylene-vinyl acetate copolymer supplied under the designation EVAtech EVA 130S/10 belongs to the low-vinyl-acetate, high-flow segment of EVA thermoplastic resins. The grade descriptor is interpreted as a nominal vinyl acetate incorporation of 10 wt% and a nominal melt flow rate of 130 g/10 min determined under ISO 1133-1:2022 at 190 °C with a 2.16 kg load. The product is typically supplied as free-flowing pellets for compounding, injection moulding, and hot-melt formulation. Compared with EVA grades containing 18–33 wt% vinyl acetate, the 10 wt% comonomer level limits polar interaction while retaining polyethylene-like stiffness, a comparatively high melt fluidity, and reduced blocking tendency. Representative values for this composition class include a density of 0.925–0.930 g/cm³ under ISO 1183-1:2019, a melting peak of 94–98 °C under ISO 11357-3:2018, and a Vicat softening temperature of 58–64 °C under ISO 306:2022. Because lot-specific values vary with comonomer distribution, catalyst residues, and additive package, the stated data are indicative for an equivalent ethylene-vinyl acetate copolymer with 10 wt% vinyl acetate and 130 g/10 min nominal melt flow rate; they do not replace the certificate of analysis issued for a specific production lot.

Thermal Degradation Boundaries and Acetic Acid Release

Thermal processing of EVAtech EVA 130S/10 must respect the deacetylation threshold of the ethylene-vinyl acetate backbone. Degradation proceeds through chain scission and acetic acid elimination; the rate accelerates when the melt temperature exceeds 230 °C, and oxidative shear conditions can generate measurable acid release below the static thermogravimetric onset. On production-scale twin-screw compounding equipment with L/D 32:1 segmented screws, a barrel profile of 150/165/175/185/190/190 °C from feed throat to die has been reported for equivalent high-flow EVA grades. The melt temperature measured at the die by an immersion thermocouple should remain below 210 °C, and residence time above 190 °C should not exceed 4–5 min. Acetic acid generation reduces local melt pH and contributes to corrosion of nitrided barrel liners and nitrided screw surfaces. Thermogravimetric analysis under nitrogen at 10 K/min typically shows an onset of mass loss near 260 °C, but this is not a safe processing limit because shear heating and oxygen accelerate degradation before the static onset. Compounding lines should be purged with a low-melt-flow polyethylene before shutdown, and local exhaust ventilation is required to remove acetic acid vapour from the die area.

Processing Conditions in Twin-Screw and Injection-Moulding Lines

For hot-melt adhesive manufacture, EVAtech EVA 130S/10 is typically combined with tackifier resins and paraffin or microcrystalline waxes in a high-shear sigma-blade or planetary mixer at jacket temperatures of 150–180 °C. The high melt flow rate allows low application viscosity. In a formulation containing 30 wt% EVA, 40 wt% tackifier, and 30 wt% wax, Brookfield viscosity at 180 °C generally falls between 500 and 1500 mPa·s. Because the vinyl acetate content is only 10 wt%, adhesion to polar substrates such as glass, aluminium, and coated board is lower than that obtained with 28 wt% vinyl acetate grades; quantified T-peel data for EVAtech EVA 130S/10 are limited in the open literature, and formulation-specific peel testing under ASTM D1876 is required before specifying the product for a polar substrate assembly.

In injection moulding, the high melt flow rate can reduce fill pressure in thin-wall tools. Values reported for equivalent 130 g/10 min EVA grades on hydraulic injection machines with 80–120 t clamp force indicate melt temperatures of 190–210 °C, mould temperatures of 20–40 °C, and injection pressures of 50–80 MPa. The low melt strength of a 130 g/10 min resin makes packing pressure and gate geometry important for sink-mark control in thick sections; direct gating into thick sections is preferred over long pin gates. Screw recovery should use a low back pressure of 0.2–0.5 MPa to limit additional shear heating.

How Does 10 wt% Vinyl Acetate Alter Adhesion, Flexibility, and Barrier Character?

Vinyl acetate units disrupt polyethylene crystallinity. At 10 wt% incorporation, the crystalline fraction remains high enough to retain translucency, surface hardness, and free-flowing pellet behaviour; the polymer is neither a flexible encapsulant nor a pressure-sensitive adhesive base. Differential scanning calorimetry under ISO 11357-3:2018 shows a melting peak of 94–98 °C, whereas a 28 wt% vinyl acetate grade typically exhibits a melting peak below 75 °C and significantly lower Shore D hardness. The manufacturing consequence is that EVAtech EVA 130S/10 can be handled in conventional polyethylene pellet-handling equipment, does not block as readily as high-vinyl-acetate grades, and can be blended with low-density polyethylene without phase separation at typical compounding temperatures. Its water vapour transmission rate is closer to polyethylene than to high-vinyl-acetate EVA, and its oxygen barrier contribution is not sufficient for barrier-layer structures. Adhesion to polar substrates is reduced but not eliminated; the surface energy of the 10 wt% vinyl acetate copolymer is lower than that of a 28 wt% vinyl acetate grade, and corona or flame treatment may be required for lamination or coating adhesion.

Table 2 provides a representative comparative gradient across EVA grades. The values are drawn from public industrial literature for compositionally equivalent materials and are not lot-specific specifications.

Compliance status for food-contact use is governed by additive composition and migration testing rather than the base resin alone. EVAtech EVA 130S/10 as an ethylene-vinyl acetate copolymer can be evaluated under 21 CFR 177.1520 for olefin polymers in food-contact applications, provided the finished article meets the end-use limitations and additive restrictions of that regulation. European food-contact suitability is assessed under Commission Regulation (EU) No 10/2011, where overall migration for food-contact plastics is limited to 10 mg/dm². Electrical and electronic equipment relevance is addressed through RoHS Directive 2011/65/EU, but the base resin is outside the restricted-substance scope unless formulated with noncompliant additives or reused in a regulated component. REACH obligations under Regulation (EC) No 1907/2006 are substance-specific and generally addressed at monomer and additive level by the polymer manufacturer. Users must obtain a compliance statement for the specific lot and application because additives, catalyst residues, and processing aids are not captured by a generic polymer classification. No medical device claim is established under ISO 10993; biocompatibility is device-specific and must be assessed on the finished medical device.

If High-Vinyl-Acetate Encapsulant Grades Are Substituted, What Changes in Optical and Rheological Response?

Substituting EVAtech EVA 130S/10 for ethylene-vinyl acetate grades containing 28–33 wt% vinyl acetate is not a drop-in replacement. The 10 wt% vinyl acetate composition produces higher haze and lower optical transmittance than clear encapsulant grades, making it unsuitable for photovoltaic module encapsulation where optical clarity above 90 % transmittance is typically specified. High-vinyl-acetate grades also provide the flexibility and metal adhesion required in cable compounds and polar hot-melt systems; EVAtech EVA 130S/10 requires tackifier adjustments or surface treatment to approach equivalent polar adhesion. In profile extrusion, the lower vinyl acetate content can improve mar resistance and reduce blocking, but the high melt flow rate reduces melt strength and limits draw-down in profile and blown-film geometries. The substitution therefore shifts processing latitude: higher shear rates are acceptable, but lower melt tension and reduced polar interaction define the operational boundary. For applications requiring optical clarity, low-temperature flexibility, and high peel adhesion, the existing dataset does not support substitution.