Copolímero de acetato de vinilo de etileno ELVAX 3130

In hot-melt packaging assembly, ELVAX 3130 is compounded as the polymer backbone in formulations for case sealing, carton closing, and tray erection lines. The resin has a nominal vinyl acetate content of 13 wt% and a melt flow rate of 30 g/10 min at 190 °C/2.16 kg when determined according to ISO 1133-1:2022. The 13 wt% vinyl acetate content produces a controlled polarity that permits homogeneous mixing with hydrogenated C5 tackifiers and Fischer-Tropsch waxes, while the 30 g/10 min melt flow rate allows wet-out on fibreboard at low application pressures. On production equipment, the compound is typically processed through a gear-pump hot-melt unit at 150–170 °C and applied through a slot nozzle or bead nozzle; holding temperatures above 200 °C for more than 8 h promote deacetylation and viscosity drift. The viscosity of the finished adhesive is measured at 170 °C with a Brookfield Thermosel spindle per ASTM D3236; target values are formulation-dependent rather than fixed product specifications. Softening point is evaluated by ring-and-ball per ASTM E28, and bond performance is tested as a T-peel on treated corrugated board under ASTM D1876. The use of ELVAX 3130 at 32–40 wt% increases cohesive strength and improves heat resistance, but excessive polymer loading raises melt viscosity and reduces tack. Wax levels are adjusted in the 20–30 wt% range to control open time and set time; Fischer-Tropsch wax lowers viscosity and accelerates solidification, while a polar microcrystalline wax modifies low-temperature flexibility. The formulation conflict is between set time and adhesion: higher wax reduces open time but can dilute interfacial wetting, so wax type and level are matched to the specific converter line speed. Antioxidant addition at 0.2–0.5 wt% using a hindered phenol/phosphite package is standard to limit thermo-oxidative chain scission. In packaging lines running at 30–80 m/min, adhesive tanks under nitrogen blanket show lower char formation on hot surfaces and fewer nozzle plugging events than open tanks. Granular or pillow forms of the hot melt are preferred because ELVAX 3130 has limited pigment wetting capacity compared with higher-VA EVA grades.

How Does ELVAX 3130 Function as a Heat-Seal Layer on Aluminum Foil?

Solution-applied heat-seal coatings based on ELVAX 3130 are used on aluminium foil lids, coated paper, and flexible packaging where a peelable or weldable seam is required. The coating is prepared by dissolving the copolymer in a solvent blend such as toluene/MEK or ethyl acetate/cyclohexane at 20–35 wt% solids, then adding a compatible rosin ester or hydrocarbon resin to lower heat-seal initiation temperature. Direct gravure or reverse gravure coating equipment applies the solution at a dry coat weight of 3–6 g/m². Drying in multi-zone ovens must remove residual solvent to below 5 mg/m²; retained solvent contributes to odour and lowers heat-seal strength. The heat-seal initiation temperature of ELVAX 3130 is higher than that of higher-VA grades because the 13 wt% vinyl acetate content leaves a higher crystalline ethylene fraction. Typical sealing temperatures for foil lidding are 120–160 °C at dwell times of 0.3–1.0 s, depending on jaw temperature and coating weight. Peelable seals are achieved by partial fusion, while frangible seals require higher sealing energy. Heat-seal strength is tested per ASTM F88/F88M on 25.4 mm wide specimens; reported values vary with substrate and coating weight, so a single universal number is not technically meaningful. The coated foil must meet food-contact requirements under FDA 21 CFR 177.1350 for EVA copolymers, and the adhesive component of the laminate commonly falls under 21 CFR 175.105. In EU markets, the coating is assessed under EU 10/2011 for overall migration and vinyl acetate specific migration limit of 12 mg/kg. For low-gauge foil, the coating must also resist flex cracking; the low tensile modulus of ELVAX 3130 is relevant, but published data specific to 3–6 g/m² coatings on 20 µm foil are limited. Application lines usually maintain a solvent recovery or regenerative thermal oxidizer to control emissions, and the coating head is operated at 20–35 °C to maintain coating viscosity between 100–400 mPa·s depending on solids and solvent ratio.

Investment casting pattern waxes are modified with ELVAX 3130 at loadings of 2–5 wt% to raise hardness, reduce surface tack, and improve dimensional stability during shell building. The wax compound is blended in a jacketed kettle at 110–125 °C under low-shear agitation until the copolymer is fully dissolved into the paraffin or microcrystalline wax base. The high melt flow rate of ELVAX 3130 allows rapid dispersion without excessive viscosity increase, but adding more than 5 wt% can cause brittleness and poor pattern repair response. Needle penetration is tested per ASTM D5; the addition of ELVAX 3130 typically reduces penetration compared with unmodified wax, but the exact value depends on wax type and filler content. Congealing point can be measured by ASTM D938, and viscosity at filling temperature is evaluated with a rotational viscometer. On pattern injection equipment, the modified wax is usually injected at 0.5–1.5 MPa into aluminium dies at 20–25 °C. The presence of ELVAX 3130 reduces sink marks and improves edge definition, particularly in thick sections. However, ash content of the copolymer must be considered in high-integrity casting applications because residual ash can affect shell reactivity and metal cleanliness if pattern residuals remain. Published data for the specific high-temperature ash profile of ELVAX 3130 in investment casting formulations is limited; foundries therefore run thermogravimetric analysis per ASTM E1131 before production qualification.

Pigment Wetting and Filter Pressure in Polyolefin Masterbatch Carrier Resin

The high melt flow rate of ELVAX 3130 is exploited in polyolefin masterbatch carriers for colour concentrates, additive packages, and processing aids. The resin is fed into a co-rotating twin-screw extruder with an L/D ratio of 40:1 and a screw profile containing two or three kneading blocks. The low melt viscosity permits processing at 140–180 °C and reduces melt temperature rise in high-letdown formulations. Pigment loadings of 40–60 wt% are common for white titanium dioxide concentrates; carbon black and organic pigment formats operate at lower loadings depending on oil absorption and dispersive energy. The vinyl acetate component of 13 wt% improves pigment wetting relative to LDPE carrier resins, although it is less effective than EVA grades with 18–28 wt% vinyl acetate for highly polar organic pigments. Filter pressure tests are performed on a screen pack with 60/100/60 mesh combinations to monitor pigment dispersion; an increasing pressure per unit time indicates agglomeration. Dispersion is further evaluated by transmitted-light film inspection at 200× magnification and by blown-film gel counting. Melt flow rate after compounding is measured per ISO 1133-1:2022. Because ELVAX 3130 has narrow elastic melt behaviour at elevated shear rates, the final masterbatch is usually pelletized by die-face cutting rather than strand cooling. The carrier is let down at 2–5 wt% into polyethylene or polypropylene film and moulding applications. A limitation is that the crystalline ethylene backbone of ELVAX 3130 may leave visible gels if the concentrate is overheated above 220 °C or held in the extruder for extended residence time. Pre-drying is specified when storage relative humidity exceeds 60%, because surface moisture can cause hydrolytic degradation and acetic acid release at processing temperatures.

When Open Time Drops Below 5 Seconds in Footwear Lasting Lines

A temperature window of 150–170 °C is maintained in thermoplastic footwear lasting adhesives based on ELVAX 3130 for side lasting, toe lasting, and insole board bonding. The adhesive is applied by narrow-width nozzle in a zigzag or pearl pattern, and the upper material is pressed within a few seconds. When open time drops below 5 s, the adhesive may lose tack before mating, causing bond voids and quality rejection. Open time is influenced by wax type, tackifier softening point, and ambient line temperature. The low vinyl acetate content of ELVAX 3130 raises the crystalline melting point and produces a relatively fast set, which is useful for high-speed lines but requires tighter handling. Creep resistance is tested under a static load at 50 °C to simulate tropical storage; adhesive formulations with insufficient crystalline content fail at 24 h. Peel adhesion to leather, synthetic leather, and polyvinyl chloride is measured per ASTM D1876; the mode of failure and maximum load are recorded. The adhesive must also resist plasticizer migration from PVC uppers, which can soften EVA-rich formulations. In production, the hot melt is prepared by mixing ELVAX 3130 with a rosin ester tackifier and a low-viscosity paraffin or Fischer-Tropsch wax, with antioxidant stabilization at 0.3–0.5 wt%. Equipment used includes gear-pump application systems with 0.3–0.6 mm nozzle orifices and heated hoses no longer than 2 m to reduce thermal degradation. If the melt is held at 180 °C for longer than 16 h, viscosity can increase due to deacetylation; therefore tanks are refilled at low levels as practical and cleaned on a stated frequency. The low-temperature flexibility of the bond line is limited compared with ethylene-vinyl acetate grades containing 18–28 wt% vinyl acetate, which must be accommodated by formulation adjustments when the finished footwear will be exposed to −20 °C or below.

When ELVAX 3130 is dispersed into oxidized bitumen for modified roofing membranes, the copolymer functions as a polymeric modifier that raises softening point and reduces flow at elevated roof surface temperatures. Mixing is performed in a high-shear rotor-stator mixer at 160–180 °C, with stirring maintained until the polymer phase is dispersed; typical polymer loading is 5–12 wt% of the compound. Low shear and insufficient mixing time produce phase separation, visible as a rough surface and reduced low-temperature flexibility. The softening point of the modified bitumen is measured per ASTM E28, penetration per ASTM D5, and viscosity at 135 °C per ASTM D4402. ELVAX 3130 has a low molecular weight compared with high-viscosity EVA grades, so its ability to build viscosity is limited; it is more suitable for compound viscosity adjustment and surface hardness than for elastomeric elongation. In torch-applied membranes, the modified mix must pass fire resistance and flexibility tests according to regional standards, but published data for ELVAX 3130 in this specific configuration is limited. The modification process is restricted by thermal stability: above 200 °C, the copolymer may release acetic acid, which accelerates bitumen ageing and can corrode uncoated mixer components. Temperature control and nitrogen blanketing are used on production vessels. The final compound is calendered or spread onto a reinforcement carrier; line speed is governed by the viscosity of the melt at calendering temperature, typically 120–140 °C. If polymer loading exceeds 12 wt%, the compound may become too viscous for spreading equipment and require higher temperatures, which then narrows the thermal safety margin. The formulation is therefore balanced by the torque limit of the mixer and the softening point target.

In Solvent-Based Sealant Formulation, Low Solution Viscosity Can Mask High-Temperature Creep

Solvent-borne EVA sealants formulated with ELVAX 3130 require a different rheological profile than hot-melt grades because the resin is dissolved in a solvent blend to produce a gap-filling compound with thixotropic additives. The 30 g/10 min melt flow rate corresponds to a low solution viscosity at 25–35 wt% solids, allowing the compound to be pumped and extruded through static mixers without excessive solvent dilution. A typical solvent system includes toluene, cyclohexane, and methyl ethyl ketone; the resin is dissolved under high-shear mixing at 40–50 °C to avoid solvent flash. Plasticizers such as diisodecyl phthalate or paraffinic process oils may be added at 5–15 phr to reduce modulus, while fumed silica at 1–3 wt% provides sag resistance. The compound is tested for slump under ASTM D2202, lap shear strength under ASTM D1002 on aluminium, and hardness under ASTM D2240. The low VA content of ELVAX 3130 limits high-temperature creep resistance; sealants exposed to sustained temperatures above 70 °C may undergo cohesive failure if plasticizer level is too high. Solvent release is a critical bottleneck: thick films dry by solvent evaporation, but the outer skin can trap solvent and reduce adhesion. Application is therefore limited to bond-line thicknesses below 3 mm, or the formulation uses a moisture-curing silane additive. The low molecular weight of ELVAX 3130 contributes to faster solvent release than higher-molecular-weight EVA grades. Volatile organic compound content is determined by ASTM D2369; product specifications require compliance with local industrial VOC rules. In production, solvent recovery and explosion-proof mixing are mandatory because the solvent blend has a flash point below 21 °C. The use of ELVAX 3130 in this application is not suitable for continuous immersion in aromatic hydrocarbons, because the vinyl acetate groups are prone to swelling and loss of mechanical strength. Published data for creep performance at 80 °C in this specific formulation type is limited, so end-users must qualify the compound on the actual substrate and gap geometry.