| HS Code | 228584 |
| Polymer Name | Ethylene-Vinyl Acetate (EVA) Copolymer |
| Vinyl Acetate Content | 28 wt% |
| Melt Flow Index | 6 g/10 min (190°C/2.16 kg) |
| Density | 0.951 g/cm³ |
| Melting Point Dsc | 72 °C |
| Vicat Softening Point | 45 °C |
| Tensile Strength At Break | 14 MPa |
| Elongation At Break | 800% |
| Hardness | 85 Shore A |
| Brittleness Temperature | -70 °C |
| Ring And Ball Softening Point | 100 °C |
As an accredited Elvax 260 EVA Copolymer Resin,Footwear & Adhesives Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Elvax 260 EVA copolymer resin, footwear and adhesives grade, supplied as free-flowing pellets in 25 kg multiwall paper bags. |
| Container Loading (20′ FCL) | 20′ FCL: Elvax 260 EVA resin bags on pallets, securely stowed, protected from moisture/heat, for footwear and adhesives. |
| Shipping | Ship Elvax 260 EVA Copolymer Resin as non-hazardous polymer pellets in clean, dry containers. Avoid moisture, heat, and direct sunlight. Use covered transport to prevent contamination. Keep away from ignition sources and incompatible materials. Ensure proper labeling and documentation for safe, efficient delivery. |
| Storage | Store Elvax 260 in a cool, dry, well-ventilated area away from direct sunlight, heat, sparks, and open flames. Keep containers tightly sealed to prevent moisture absorption and contamination. Avoid high humidity and elevated temperatures, which can cause clumping or blocking of the resin. Maintain stable conditions and use within recommended shelf life. |
| Shelf Life | Shelf life is typically two years when stored in a cool, dry area, away from heat, moisture, and direct sunlight. |
Compounding of Elvax 260 for injection-molded footwear midsole foam is executed on co-rotating twin-screw extruders with L/D 40:1, segmented screw elements, atmospheric venting, and staged vacuum venting at -0.08 MPa to -0.09 MPa. The resin carries nominal 28 wt% vinyl acetate comonomer, melt mass-flow rate 6 g/10 min at 190 °C/2.16 kg per ISO 1133-1:2022, density 0.955 g/cm³ per ISO 1183-1:2019, and peak melting temperature near 73 °C by DSC per ISO 11357-3:2018. This vinyl acetate level suppresses polyethylene crystallinity sufficiently to allow uniform dissolution of decomposition gases before expansion, but processing temperatures above 200 °C cause deacetylation and acetic acid release, which nucleates uncontrolled cells and produces surface pitting on molded parts. In chemically expanded formulations, dicumyl peroxide is pre-dispersed into a small EVA carrier before addition to the main compounder; the one-minute half-life temperature of dicumyl peroxide at approximately 171 °C requires feed-zone barrel temperatures not to exceed 120 °C, otherwise scorch initiates in the screw root and raises torque. Azodicarbonamide blowing agent decomposes exothermically with onset between 200 °C and 210 °C, so the expansion stage must be thermally separated from the crosslinking stage by barrel profiling across the mid-zone and downstream injection. Mold temperature for midsole expansion is controlled between 170 °C and 180 °C, with clamp force set by projected cavity area and cavity pressure typically in the 40 MPa to 60 MPa range; multi-cavity athletic midsole tools often require 180 tonnes to 220 tonnes clamp force depending on gating and runner balance. If the blowing gas liberation rate exceeds vent capacity, trapped volatiles cause charred spots because residual acetic acid accelerates polymer degradation at the cavity surface. The expanded article is tested for hardness by ASTM D2240-21 Shore C or Asker C, foam density by ISO 845-2006, compression set by ASTM D395-18 after 24 h at 50 °C, and tensile properties by ASTM D638-22. At warehouse relative humidity above 70% and bag residence beyond 48 h, pre-drying at 60 °C for 4 h in a desiccant dryer with -40 °C dew point is imposed to prevent steam-induced voids; this is an operational boundary for humid tropical plants rather than a general requirement, because the base resin absorbs only limited moisture at ambient conditions. Mold corrosion from liberated acetic acid is managed with chrome-plated cavities and weak alkaline neutralization of vents; copper alloy or brass mold components are incompatible in this environment.
| Property | Nominal value | Test standard |
|---|---|---|
| Vinyl acetate content | 28 wt% | ASTM D5594-18 |
| Melt mass-flow rate | 6 g/10 min | ISO 1133-1:2022 |
| Density | 0.955 g/cm³ | ISO 1183-1:2019 |
| Peak melting temperature | 73 °C | ISO 11357-3:2018 |
Hot-melt packaging adhesives formulated with Elvax 260 are bounded by two simultaneous degradation pathways: acid-catalysed chain scission from deacetylation and oxidative chain scission from repeated heating under air. In side-arm or bottom-melt hot-melt tanks operated at 170 °C to 190 °C, a starting compound containing 25 wt% to 35 wt% Elvax 260, 35 wt% to 45 wt% hydrogenated C-9 hydrocarbon tackifier with softening point 95 °C to 110 °C, 15 wt% to 25 wt% Fischer-Tropsch wax with congealing point 70 °C to 85 °C, and 0.3 wt% to 0.8 wt% hindered phenolic primary antioxidant maintains viscosity stability within ±10% over an 8 h shift when measured by ASTM D3236-15. If tank temperature exceeds 200 °C for more than 2 h, acetic acid formation drops local melt pH and accelerates oxidation; apparent viscosity can increase by more than 30%, and char particles become visible on 200 µm slot-die filters. The 28 wt% vinyl acetate content promotes wetting on corona-treated low-density polyethylene, oriented polypropylene, and clay-coated board, but it lowers heat resistance in the final adhesive. Shear adhesion failure temperature determined by ASTM D4498-07 does not typically exceed 65 °C to 75 °C unless the formulation is crosslinked by moisture-curing silane-grafted EVA or blended with a low-acid polyolefin elastomer. Amine-functional adhesion promoters and epoxy functional co-resins are incompatible with EVA hot melts because the acetic acid evolved during processing reacts to form amide salts that block applicator nozzles. For low-temperature filling lines running at 4 °C to 10 °C, open time on clay-coated corrugated board may fall below 3 s, causing bond failure if compression is delayed; increasing tackifier softening point above 110 °C extends open time but reduces adhesion at refrigerator temperatures. Bond performance is measured by 180° peel test ASTM D903-98(2017) on laminated LDPE and clay-coated board, with values below 2 N/mm considered insufficient for high-speed case sealing. Gear-pump transfer at 1,200 rpm to 1,800 rpm with a 200 µm screen pack is maintained below 5,000 mPa·s apparent viscosity to avoid cavitation and stringing; exact viscosity depends on tackifier aromaticity, wax molecular weight distribution, and addition of 0.2 wt% to 0.4 wt% secondary phosphite stabilizer for color retention. Acid scavengers such as hydrotalcite at 0.1 wt% to 0.3 wt% can neutralize acetic acid, but may reduce adhesion to aluminum foil and are not universally applicable.
| Application boundary | Regulation / standard | Relevant condition |
|---|---|---|
| Food packaging hot-melt adhesive | FDA 21 CFR 175.105 | Indirect contact adhesive components |
| Ethylene-vinyl acetate copolymer food contact | FDA 21 CFR 177.1350 | Direct contact extraction limits |
| Footwear articles | REACH Annex XVII entry 51 | Restricted phthalates in additives |
| Electronics assembly tapes | RoHS 2011/65/EU | Pb, Cd, Hg, Cr(VI), PBB, PBDE screening |
Solution-cast pressure-sensitive transfer tapes based on Elvax 260 are prepared at 25 wt% to 35 wt% total solids in a 60:40 toluene/ethyl acetate solvent blend; the high vinyl acetate content requires high-shear dispersion at 1,000 rpm to 1,500 rpm because inadequate dispersion produces rosin ester domains that appear as gel particles in the dried film. The dried coat weight is controlled at 20 g/m² to 30 g/m² on a comma coater or slot-die coater, with drying tunnel zones staged at 60 °C, 70 °C, and 80 °C; temperatures above 85 °C induce blocking in the roll because the resin melting peak is near 73 °C. Loop tack per PSTC-16 and 180° peel adhesion per PSTC-101 on corona-treated low-density polyethylene are controlled by tackifier acid number and EVA/tackifier phase miscibility; if the tackifier is replaced with a low-polarity C-5 hydrocarbon resin, peel adhesion drops sharply. Shear holding power per PSTC-107 at 25 °C with a 1 kg load is limited by molecular weight and is not meaningfully improved by increasing vinyl acetate content alone; failure times on treated polypropylene may fall below 24 h unless a crosslinker is introduced. Solvent recovery must reduce residual solvent below 50 µg/m² by headspace gas chromatography, otherwise migration into adjacent food-contact layers or graphic films creates odor and compliance failures. The pressure-sensitive adhesive film is not inherently flame retardant; UL 94 V-0 is not achievable without intumescent fillers, which reduce tack and increase application viscosity. For electronics assembly tapes, the base EVA resin contains no Pb, Cd, Hg, Cr(VI), PBB, or PBDE, but formulated adhesive layers must be verified under RoHS 2011/65/EU because tackifier and mineral oil components can introduce unintended impurities.
Side-lasting and toe-lasting cements based on Elvax 260 are formulated as solvent-borne systems at 15 wt% to 25 wt% solids, in which the EVA provides cohesive strength while nitrile rubber or polyurethane segments supply initial tack. The cement is applied by roller coater or brush to leather or synthetic leather pre-roughened to a surface roughness of 25 µm to 35 µm Ra and dried for 30 s to 60 s at 60 °C to 70 °C before pressing at 0.3 MPa to 0.5 MPa for 10 s to 15 s. If open time exceeds 90 s at 25 °C and 60% relative humidity, skin-over of the adhesive film reduces wetting; if open time is below 15 s, retained solvent forms blisters when the upper is pressed against the EVA midsole. Untreated EVA midsole surface energy is commonly in the 30 mN/m to 34 mN/m range, while synthetic leather may present 36 mN/m to 42 mN/m; this mismatch reduces wetting, and corona or plasma treatment to 45 mN/m to 50 mN/m or a chlorinated polyolefin primer is required for reproducible bonds. Plasticizer migration from PVC or polyurethane synthetic leather causes peel strength loss over 7 days at 50 °C; a blend containing 10 wt% to 15 wt% of 33% acrylonitrile NBR improves plasticizer resistance by creating a dispersed elastomer phase. T-peel strength is measured by ASTM D1876-08(2023) on cotton canvas-reinforced EVA; fresh bonds may exceed 3.0 N/mm, but plasticized systems without NBR commonly fall below 2.0 N/mm after thermal ageing. Heat resistance is evaluated by static dead-load testing at 60 °C for 30 min with a 200 g load; creep beyond 5 mm is considered unacceptable for export footwear. Solvent emissions from footwear adhesive application are subject to EU Directive 2010/75/EU for installations above the relevant solvent consumption threshold. Chlorinated primers with acidic residues can accelerate deacetylation of the EVA segment if the primed surface is stored above 30 °C before cement application.
At regrind addition above 20 wt% of total batch weight, cell morphology in injection-molded midsole foam is controlled less by virgin Elvax 260 than by the particle size distribution and gel fraction of cured scrap. Regrind from crosslinked midsole trim typically carries gel fraction between 60% and 80% by xylene extraction at 120 °C for 8 h; crosslinked particles act as heterogeneous nucleation sites and increase cell density while simultaneously reducing expansion ratio because gas diffusion is interrupted by gel domains. Compound preparation uses a co-rotating twin-screw extruder with L/D 40:1, vacuum venting at -0.08 MPa, and a side feeder for regrind flake; volumetric feeders must hold ±0.5 wt% accuracy because differences in bulk density between virgin pellets and regrind flake cause segregation in central conveying. At 0 wt% regrind, die melt pressure at 180 °C may be 12 MPa to 14 MPa; at 30 wt% regrind, pressure rises to 16 MPa to 18 MPa, and if the screen pack is finer than 80 mesh, pressure can exceed 25 MPa and trigger machine shutdown. Physical properties decline non-linearly: at 20 wt% regrind, tensile strength per ASTM D638-22 may drop by 10% to 15%, while elongation at break may fall by 15% to 25% because crosslinked domains act as stress concentrators. The process limit for premium visible midsoles is therefore set at 10 wt% regrind; for non-visible insoles, up to 30 wt% may be tolerated, although published data for this specific Elvax 260 regrind configuration is limited. Volatile content in regrind must be kept below 1,500 µg/g by thermal desorption-GC/MS to prevent bubble defects, and melt mass-flow rate per ISO 1133-1:2022 must be checked after each 500 kg batch to detect viscosity drift from degraded crosslinked resin and low-molecular-weight species generated during repeated heat history.
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Elvax 260 EVA Copolymer Resin, Footwear & Adhesives Grade, is an ethylene-vinyl acetate copolymer supplied as free-flowing pellets for footwear compounding and hot-melt adhesive systems. The resin contains 28 wt% vinyl acetate comonomer determined by Fourier transform infrared spectroscopy in accordance with ASTM D5594-18a, exhibits a melt mass-flow rate of 6.0 g/10 min at 190 °C under a 2.16 kg load using ISO 1133-1:2022, and has a density of 0.955 g/cm³ at 23 °C according to ISO 1183-1:2019. Differential scanning calorimetry under ISO 11357-3:2018 places the main crystalline melting endotherm near 73 °C, with the 28 wt% vinyl acetate fraction reducing ethylene crystallinity sufficiently to produce a flexible, low-modulus copolymer rather than a rigid polyethylene. The grade is differentiated from other Elvax resins principally by molecular weight and melt rheology; it carries the same 28 wt% vinyl acetate content as Elvax 240 and Elvax 265 but has a lower melt flow rate than Elvax 240 and a higher melt flow rate than Elvax 265.
Vinyl acetate content controls the degree of crystalline order, the concentration of polar acetate sites, and the low-temperature flexibility of the copolymer. Compared with 15 wt% or 18 wt% vinyl acetate grades such as Elvax 550 and Elvax 460, the 28 wt% vinyl acetate in Elvax 260 depresses the melting point, lowers the heat of fusion, and reduces Shore hardness. These changes allow the resin to function in footwear midsoles where repeated flex cycles and sub-zero impact conditions require flexibility retention without plasticizer migration. In adhesive formulations, the higher vinyl acetate content shifts solubility characteristics toward rosin ester and polar tackifier systems, whereas lower-vinyl-acetate grades require higher loadings of paraffinic or microcrystalline wax to achieve a comparable cohesive-adhesive balance. Published data for specific rosin ester compatibility maps with Elvax 260 is limited.
Moving upward to 40 wt% vinyl acetate changes the profile again. Elvax 40W has a melt mass-flow rate of 52 g/10 min under the same test condition, which is far lower in viscosity than Elvax 260. While the higher vinyl acetate content increases room-temperature tack and specific adhesion to polar films, it reduces heat resistance and static load-bearing capacity. Elvax 260 is therefore specified in hot-melt adhesives that require higher melt viscosity, improved cohesive strength, or better heat resistance than a 40 wt% vinyl acetate grade can provide.
The distinctions among the 28 wt% vinyl acetate family are primarily molecular weight differences reflected in melt mass-flow rate. Elvax 210 flows at 400 g/10 min, Elvax 240 at 43 g/10 min, Elvax 260 at 6.0 g/10 min, and Elvax 265 at 3.0 g/10 min under ISO 1133-1:2022. The higher melt viscosity of Elvax 260 relative to Elvax 240 provides greater melt elongation and higher green strength in hot-melt adhesives, but it also restricts flow into narrow die gaps and low-pressure injection molds. Compared with Elvax 265, Elvax 260 offers a practical reduction in viscosity while preserving most of the cohesive strength benefit; the choice between the two grades usually depends on the viscosity limit of the coating head or the injection press.
| Grade | Vinyl acetate content (wt%) | Melt mass-flow rate (g/10 min, 190 °C/2.16 kg) | Processing distinction |
|---|---|---|---|
| Elvax 210 | 28 | 400 | Low-viscosity spray and high-speed extrusion coating |
| Elvax 240 | 28 | 43 | Intermediate flow; general hot-melt and foam use |
| Elvax 260 | 28 | 6.0 | High-viscosity slot-die coating and footwear foam |
| Elvax 265 | 28 | 3.0 | Highest molecular weight; high cohesive strength |
| Elvax 40W | 40 | 52 | High tack; polar adhesion; reduced heat resistance |
In footwear midsole manufacturing, Elvax 260 is typically combined with ethylene-octene elastomer, calcium carbonate, zinc oxide, dicumyl peroxide, and azodicarbonamide in a tangential internal mixer. The ram pressure is maintained between 0.5 MPa and 0.6 MPa, and the dump temperature is held between 105 °C and 115 °C to prevent premature peroxide decomposition. The mixed batch is then sheeted on a two-roll mill at a front-roll surface temperature near 90 °C, granulated, and injection-molded or compression-molded at 170–185 °C. For compression molding, the press cycle is commonly matched to the half-life of dicumyl peroxide at the selected temperature; at 170 °C, the half-life is approximately 1 min, so cure times between 6 min and 10 min are used depending on mold thickness. The blowing agent decomposes after the EVA network has developed sufficient melt strength; if the mold temperature overshoots the decomposition plateau by more than 5 °C, cell coalescence and part shrinkage occur before the crosslinked matrix can stabilize the foam structure.
Crosslinking of the expanded compound is governed by peroxide decomposition kinetics rather than vulcanization chemistry because the ethylene-vinyl acetate copolymer has no unsaturated backbone. Gel content after extraction in toluene at 110 °C for 6 h is typically controlled between 55% and 75% in production midsoles; values below 50% are associated with compression set failures under ASTM D395-18 method B, while values above 80% can embrittle the foam and reduce elongation at break. The expansion ratio is adjusted by the azodicarbonamide loading and the pre-cure compound viscosity. Elvax 260 with its 6.0 g/10 min melt flow rate produces a higher-viscosity cell wall than Elvax 240, which can reduce drainage and improve cell size uniformity, but it may require a 3–5 °C increase in mold temperature to maintain the same expansion ratio in low-pressure presses. Published data for the relationship between gel content and Asker C hardness in Elvax 260-specific formulations is limited, so process settings are typically established by pilot molding.
Elvax 260 exhibits pseudoplastic flow and a broad molecular weight distribution that produces high shear sensitivity during compounding. In twin-screw extruders with length-to-diameter ratios of 40:1 or greater, the resin is frequently fed downstream of the primary kneading block so that its residence time at melt temperature remains below 2 min. Screw speeds above 300 min⁻¹ can raise the melt temperature above 200 °C by viscous dissipation; at this point, viscosity drops and the metering zone can become starved unless the feed rate is increased. The processing window is bounded by the crystalline melting endotherm near 73 °C on the low side and by the onset of deacetylation and oxidative chain scission near 220 °C on the high side. Deacetylation releases acetic acid, and without adequate venting the acid can corrode downstream dies and calender rolls.
In injection molding with clamp forces between 1,200 kN and 10,000 kN, the nozzle temperature is normally set between 180 °C and 200 °C. Mold temperatures below 30 °C tend to increase skin orientation and reduce knit-line strength in solid EVA components, while mold temperatures above 55 °C can trigger localized pre-decomposition of the blowing agent in foam formulations. Incoming resin should be screened by melt mass-flow rate under ISO 1133-1:2022; a batch-to-batch drift of ±0.5 g/10 min is sufficient to change fill pressure and shot weight in multi-cavity tools, particularly when the flow length-to-thickness ratio exceeds 150:1.
In hot-melt slot-die coating lines, substitution of Elvax 260 for a lower-viscosity EVA such as Elvax 240 requires either a higher set point or a reduction in line speed. The resin is heated in a reservoir at 160–180 °C; hold times should remain below 8 h unless a nitrogen blanket is applied, because prolonged exposure to air at these temperatures causes viscosity drift and char formation on heated surfaces. The higher melt strength of Elvax 260 reduces edge beading on polyester film and improves die-lip cleanliness during high-speed coating, but it also reduces penetration into porous substrates such as corrugated board unless the substrate is preheated or the nip pressure is increased. Spiral-spray and slot-die systems require a Brookfield Thermosel viscosity at 180 °C that matches the pumping capacity; published data for specific machine configurations is limited, so pilot trials are used to establish the optimum set point and die gap.
Hot-melt adhesives based on Elvax 260 are formulated with rosin ester or hydrogenated hydrocarbon tackifiers and a wax phase. EVA content in packaging hot-melt adhesives typically ranges from 25 wt% to 35 wt% of the total formulation. The 28 wt% vinyl acetate content shifts the solubility parameter toward rosin esters; when the tackifier-to-EVA ratio exceeds 1.5:1, the glass transition temperature rises and the open time shortens. If the wax phase is increased above 30 wt%, low-temperature adhesion to coated board can fall below the performance limit of the package; formulations are therefore adjusted by differential scanning calorimetry and peel testing under ASTM D1876-08 for flexible laminates or ASTM F88/F88M for heat seals. Elvax 260 contributes higher cohesive strength than Elvax 240 in these formulations, but its higher melt viscosity can reduce machine throughput in gear-pump-fed lines by 5–15% when the pump is operating near its maximum discharge pressure.
When the adhesive is used for case and carton sealing, the compression-to-set time is machine-dependent and can be below 0.5 s on high-speed packaging lines. Because no single ASTM method fully captures the dynamic cooling profile of a packaging line, evaluations are typically performed on a pilot-scale line with actual board stock and adhesive nozzle geometry. Substituting Elvax 260 for Elvax 240 can extend the required compression time if the board stock is uncoated; however, the resulting bond often shows higher creep resistance under static shear. Published creep data for this specific Elvax 260 configuration is limited, and each packaging line requires its own qualification run to establish the maximum acceptable line speed.
Storage stability is affected by pellet blocking in hot climates. The resin should be kept in sealed packaging at temperatures below 40 °C and protected from direct sunlight. If the moisture content of the pellets exceeds 0.1% by mass, pre-drying in a desiccant dryer at 60 °C for 4 h is recommended before processing. Elvax 260 should not be combined with amine-based additives that can catalyze ester cleavage at processing temperatures above 200 °C, and it should not be exposed to ketones, esters, or highly aromatic solvents during cleaning or purging. Compliance with specific food-contact applications must be confirmed under the relevant regulation; many ethylene-vinyl acetate copolymers with the specified vinyl acetate content may be used in adhesives according to FDA 21 CFR 175.105 when the adhesive is separated from the food by a functional barrier, but the final adhesive system must be tested for extractives under the intended conditions of use.
Compared with Elvax 360 and Elvax 460, which contain 25 wt% and 18 wt% vinyl acetate respectively and have melt mass-flow rates near 2 g/10 min and 2.5 g/10 min, Elvax 260 provides lower hardness and greater low-temperature flexibility but lower creep resistance. In footwear, this means the resin is used in midsoles, sockliners, and flexible outsole components rather than rigid shell soles or high-abrasion outsole compounds. When higher hardness and abrasion resistance are required, the formulation is shifted to lower-vinyl-acetate EVA or blended with high-density polyethylene and styrene-butadiene rubber. The exact blend ratio is determined by the Asker C hardness specification and the abrasion loss measured under DIN 53516:2018-1; published data for Elvax 260 blends with high-density polyethylene is limited.
Incoming material release testing should include melt mass-flow rate, density, and vinyl acetate content because these three measurements are sufficient to detect lot-to-lot drift in composition and molecular weight. A sample that fails the ISO 1133-1:2022 melt flow specification by more than ±0.5 g/10 min can indicate unintended grade substitution or pellet contamination. Fourier transform infrared spectroscopy under ASTM D5594-18a identifies the vinyl acetate content by the carbonyl absorption near 1740 cm⁻¹; the absorbance ratio against the methylene band near 1465 cm⁻¹ is calibrated against known standards. Differential scanning calorimetry provides the melting endotherm and heat of fusion; a shift in peak melting temperature above 75 °C may indicate contamination with low-vinyl-acetate resin, while a high-temperature exotherm starting below 200 °C may indicate oxidative degradation or a foreign additive package. Each incoming lot is typically released for footwear or adhesive compounding only after these measurements fall within the specified control limits.
