| HS Code | 606261 |
| Vinyl Acetate Content | 18% |
| Melt Flow Rate 190 C 2 16 Kg | 2.5 g/10 min |
| Density | 0.940 g/cm³ |
| Tensile Strength At Break | 190 kg/cm² |
| Elongation At Break | 800% |
| Hardness Shore A | 88 |
| Vicat Softening Point | 60 °C |
| Melting Point | 85 °C |
| Brittleness Temperature | -70 °C |
| Volume Resistivity | >1.0E+15 Ω·cm |
| Dielectric Constant 1 Mhz | 2.6 |
| Water Absorption | <0.1% |
As an accredited Formosa Taisox EVA 7350M factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Formosa Taisox EVA 7350M is supplied in 25 kg moisture-proof paper bags, palletized for industrial handling and storage. |
| Container Loading (20′ FCL) | Formosa Taisox EVA 7350M is loaded into a 20-foot FCL container, securely stowed and braced for safe transport. |
| Shipping | Formosa Taisox EVA 7350M is shipped as solid EVA copolymer pellets in moisture-barrier bags, lined bags, or bulk containers. Keep dry and away from heat and direct sunlight. It is generally non-hazardous for transport; follow the SDS and local regulations. Use appropriate handling to prevent bag damage and spillage. |
| Storage | Store Formosa Taisox EVA 7350M in a cool, dry, well-ventilated area away from direct sunlight, heat, sparks, flames, and oxidizing agents. Keep original bags or containers closed, palletized, and off the floor to prevent moisture pickup. Avoid prolonged stacking and UV exposure. Maintain good housekeeping, do not smoke, use first-in, first-out stock rotation, and follow the SDS. |
| Shelf Life | Typically 24 months in cool, dry, ventilated storage in original unopened packaging, protected from direct sunlight and heat. |
Formosa Taisox EVA 7350M is metered as the base polymer in chemically crosslinked injection-moulded foam for athletic and comfort footwear components. The grade carries 18 wt% vinyl acetate, a melt index of 2.5 g/10 min at 190 °C under 2.16 kg load by ASTM D1238, and density of 0.939 g/cm³ by ASTM D1505. For crosslinked foam, the compound is built on 100 phr EVA 7350M with azodicarbonamide at 1.5–3.0 phr, dicumyl peroxide at 0.6–1.2 phr, zinc oxide at 1.0–2.0 phr, and stearic acid at 0.3–0.5 phr. These ratios are not fixed; a moving die rheometer trace at 175 °C and 1° arc is used to adjust peroxide loading until maximum torque falls between 0.8 N·m and 1.2 N·m for a 20 mm diameter specimen. Torque above 1.2 N·m is associated with over-crosslinking, hardness beyond Shore C 55, and tear-strength loss, while torque below 0.8 N·m produces a coarse cell structure and poor recovery. Compounding is performed on a co-rotating twin-screw extruder with L/D 32:1, feed zone 105 °C, and die zone 125 °C; the melt temperature must not exceed 130 °C to avoid premature azodicarbonamide decomposition. The pelletized compound is then injection-moulded on machines with shut-off nozzles and clamp force from 1,800 kN to 2,500 kN, using a low-compression metering screw with L/D 20:1 and compression ratio 1.8:1. Melt temperature is held within 170–180 °C, a band not wider than ±5 °C in multi-cavity production. Above 185 °C the blowing agent decomposes inside the barrel and generates surface pitting, sink marks, and inconsistent cell diameter. Below 165 °C the melt viscosity prevents complete cavity packing in thin midsole wings. Mould surface temperature is controlled at 18–30 °C for rapid skin formation and cycle-time reduction. Production-scale failure documentation includes gas entrapment at rib intersections when vent depth is under 0.02 mm and vent spacing exceeds 25 mm, plus post-demolding expansion when parts are removed before internal gas pressure equilibration. Finished foam components are tested for apparent density by ISO 845, tensile by ISO 1798, compression set by ASTM D395 Method B at 23 °C and 70 °C, and Shore C hardness by ISO 868. For EU footwear articles, the formulation must satisfy REACH Regulation EC 1907/2006 Annex XVII restrictions and SVHC screening under Article 33; no food-contact claim applies. Terminal parts are injection-moulded midsoles, sockliners, footbed cores, and lightweight outsole components for running, casual, and orthopedic footwear.
In halogen-free flame-retardant cable compounds, EVA 7350M functions as the polar, filler-accepting polymer phase in blends with linear low-density polyethylene or higher-vinyl-acetate EVA. A production-scale formulation may combine 25–40 wt% EVA 7350M of the total polymer fraction, 35–50 wt% LLDPE, and 15–25 wt% of a 28 wt% vinyl acetate EVA grade, with precipitated alumina trihydrate at 120–180 phr on total polymer, magnesium hydroxide at 20–40 phr, zinc borate at 5–10 phr, vinyl silane coupling agent at 0.5–1.5 phr, and hindered phenolic antioxidant at 0.3–0.8 phr. The compound is screened to IEC 60332-1-2 for vertical flame propagation on a single insulated wire, IEC 60754-1 and IEC 60754-2 for halogen acid gas evolution and pH/conductivity, and EN 50363-5 for low-voltage cable sheathing material limits. RoHS Directive 2011/65/EU and REACH Regulation EC 1907/2006 apply to the final cable article in the EU market. Production is executed in a co-rotating twin-screw extruder with L/D 40:1, atmospheric and vacuum venting, melt temperature 140–160 °C, and filler side-feeding after the polymer melting zone to control viscosity peaks. The resulting pellets are extruded onto copper or aluminium conductors through a crosshead wire coating line with a single-screw extruder of L/D 24:1–30:1, compression ratio 1.5:1, and melt temperature 130–160 °C. Processing above 180 °C is prohibited for ATH-filled compounds because alumina trihydrate releases water of crystallisation and creates internal porosity, diameter fluctuation, and spark-test failures. The main production bottleneck is screw torque at filler loadings above 160 phr; underwater pelletizing with die plate temperature 170–190 °C and high-speed cutting is used to prevent die-face build-up. Published data for EVA 7350M as the sole polymer phase in high-filler HFFR insulation is limited; industrial practice uses it as a co-polymer rather than the only polymer because its 18 wt% vinyl acetate content provides less filler wetting than 28–33 wt% EVA grades used for maximum alumina trihydrate acceptance. At filler loading above 160 phr, elongation at break may fall below the 125% minimum required by some cable specifications, and a higher-vinyl-acetate EVA or maleic anhydride-grafted compatibilizer is required. Terminal articles include low-voltage building wires, control cables, and signal cable sheathing for data centres, mass transit, and public buildings where halogen-free char and low smoke are specified.
Continuous crosslinked foam sheet operations use EVA 7350M as the primary resin because a melt index of 2.5 g/10 min is compatible with low-pressure flat die extrusion and the 18 wt% vinyl acetate content provides a balance between flexibility and static load recovery. The addition ratio for closed-cell sheet is commonly 100 phr EVA 7350M, low-density polyethylene 0–30 phr, azodicarbonamide blowing agent 8–15 phr, dicumyl peroxide 0.8–1.5 phr, calcium carbonate nucleating filler 10–20 phr, and naphthenic process oil 2–5 phr. The formulation is first dispersed on a two-roll mill with front roll 95–105 °C and rear roll 85–90 °C; the high compound viscosity at mill temperatures creates a tight bank and prevents powder loss. After blending, the sheet is extruded through a flat die using a single-screw extruder with L/D 20:1 and barrel temperatures 90–110 °C. The extruded web then passes through a continuous vulcanization tunnel at 190–210 °C with line speed 8–15 m/min. The critical control variable is density versus line speed: increasing line speed above 15 m/min reduces dwell time and produces a high-density skin with an uncured core, measured by split-tear inspection and ISO 845 apparent density. Finished sheet is specified under ASTM D3575 for closed-cell olefin foams; compression set is evaluated by ASTM D1056, tensile by ISO 1798, and cell count against reference panels. For EU market children’s mats, EN 71 Part 3 migration limits for heavy elements apply. Terminal products are sports mats, gym mats, anti-fatigue mats, gaskets, automotive interior padding, and packaging dunnage.
Because EVA 7350M can release residual acetic acid at elevated processing temperatures, direct-gated cold-runner moulds are preferred over hot-runner systems in injection-moulded non-foamed elastomeric parts. The material is processed neat or in blends with LDPE at 10–30 wt% and EPDM at 5–15 wt%; EVA 7350M content remains 60–100 wt% of the polymer fraction depending on target hardness and flexural modulus. Components are moulded on reciprocating-screw injection machines with screw diameter 30–40 mm, L/D 20:1, compression ratio 2.0:1, and clamp force 600–1,200 kN. Melt temperature is controlled at 160–185 °C and mould temperature at 15–35 °C; shot size should not exceed 70% of maximum barrel capacity to avoid residence-time degradation. Pellets are pre-dried at 65 °C for 2 hours when ambient relative humidity exceeds 60%. Continuous service temperature is limited to 60 °C under load due to the low softening point and creep behavior of 18 wt% vinyl acetate EVA. Where articles contact food, the converter must verify formulation compliance with 21 CFR 177.1350 for ethylene-vinyl acetate copolymers and the extractive limitations therein; in the EU, Regulation EU 10/2011 on plastic materials intended for food contact requires migration testing. RoHS Directive 2011/65/EU applies to electrical and electronic auxiliary parts. Terminal products are anti-vibration pads, appliance feet, child-resistant closures, laboratory device bumpers, electronic device corner guards, and sports grip components.
| Standard/regulation | Test method or scope | Application relevance to EVA 7350M |
|---|---|---|
| ASTM D1238 | Melt index at 190 °C/2.16 kg | Incoming resin control |
| ASTM D1505 | Density gradient column | Resin density confirmation |
| ISO 845 | Apparent density of cellular plastics | Foam density control |
| ISO 1798 | Tensile strength and elongation of flexible cellular materials | Quality acceptance of EVA foam |
| ASTM D395 | Compression set under constant deflection | Footwear midsole recovery |
| ASTM D3575 | Closed-cell olefin foam test methods | Foam sheet specification |
| IEC 60332-1-2 | Vertical flame propagation for single insulated wire | Low-voltage cable insulation |
| IEC 60754-1 | Halogen acid gas measurement | Halogen-free cable sheath |
| IEC 60754-2 | pH and conductivity of evolved gases | Corrosivity control |
| EN 50363-5 | Sheathing materials for low-voltage cables | Material limit acceptance |
| 21 CFR 177.1350 | Ethylene-vinyl acetate copolymers in food-contact articles | Injection-moulded closures |
| REACH EC 1907/2006 | SVHC screening and Annex XVII restrictions | EU article compliance |
| RoHS 2011/65/EU | Restricted substances in electrical and electronic equipment | Cable and appliance auxiliary parts |
Rigid PVC compounds for exterior profiles and fittings incorporate Formosa Taisox EVA 7350M as a polymeric impact modifier at 5–15 phr on 100 phr PVC resin. The compound is dry-blended in a high-speed mixer to 110–120 °C, cooled to 40–50 °C, and extruded on a counter-rotating twin-screw extruder with L/D 27:1 and barrel temperatures from 160 °C to 185 °C. The EVA phase must remain dispersed as discrete domains within the PVC matrix; addition above 15 phr can reduce tensile modulus below 2,500 MPa and increase plate-out in the calibration die. The compatibility window is narrow, and paraffinic lubricants are limited to 0.2–0.5 phr to avoid surface migration. Finished profiles are tested for notched impact by ISO 179 or ASTM D256, tensile modulus by ASTM D638, and heat reversion by EN 479. EU Construction Products Regulation and REACH Regulation EC 1907/2006 apply; RoHS Directive 2011/65/EU applies when the profile is used in electrical conduit. Terminal products are window and door profiles, cable conduit, indoor furniture edge bands, and impact-modified pipe fittings.
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Formosa Taisox EVA 7350M is an ethylene-vinyl acetate copolymer with a vinyl acetate comonomer content of 26 wt% and a melt mass-flow rate of 2.5 g/10 min at 190 °C under 2.16 kg load, determined according to ASTM D1238 or ISO 1133-1:2022. The resin is specified with a density of 0.95 g/cm³ under ASTM D1505. This comonomer level locates the grade in the medium-to-high acetate portion of the Taisox EVA range, where statistical incorporation of acetate repeat units suppresses polyethylene crystallisation. The structural result is a material that displays lower tensile modulus and heat softening than lower-vinyl-acetate copolymers, while offering higher elongation at break, improved low-temperature flexibility as evidenced by ASTM D746 testing, and stronger interaction with polar substrates and additives. Typical downstream operations include blown film, cast film, injection-molded footwear components, profile extrusion, and chemically blown foam. The grade differs from lower-acetate EVA products in its reduced crystallinity and from higher-melt-index grades in its greater melt strength and more stable extruded bubble structure.
Representative property values, not specification limits, are listed below.
| Property | Typical value | Test method |
|---|---|---|
| Vinyl acetate content | 26 wt% | Internal FTIR |
| Melt flow index | 2.5 g/10 min | ASTM D1238, 190 °C/2.16 kg |
| Density | 0.95 g/cm³ | ASTM D1505 / ISO 1183-1 |
| Tensile strength at break | 17 MPa | ASTM D638 / ISO 527-2 |
| Elongation at break | 800% | ASTM D638 / ISO 527-2 |
| Shore A hardness | 85 | ASTM D2240 / ISO 48-4 |
| Vicat softening temperature | 64 °C | ASTM D1525 / ISO 306 |
On a single-screw blown-film extruder with barrier screw geometry and an L/D ratio of 24:1 to 28:1, processing temperatures are commonly profiled from 160 °C at the hopper zone to 190–200 °C at the die. A melt temperature above 215 °C can initiate acetic acid evolution from deacetylation, resulting in bubble instability, surface roughness, and corrosion of downstream metal surfaces. The die gap is typically set between 0.8 mm and 1.5 mm for tubular film, with blow-up ratios maintained at 2.0:1 to 3.0:1 to balance machine-direction and transverse-direction tensile properties. If the line is stopped for more than 15 min, the barrel should be purged with a more thermally stable polyolefin to prevent carbonyl-containing residue from accumulating in the adapter, screen changer, and die lips.
Drying is not mandatory for resin stored in sealed, dry containers. When storage occurs at relative humidity above 60% or when condensation is visible, pre-drying at 55–60 °C for 2–4 h in a desiccant or circulating-air dryer removes surface moisture that otherwise produces film marks, melt voids, and uneven foam cell nucleation. The material is incompatible with strong oxidizers, concentrated mineral acids, and prolonged exposure to high shear at temperatures above 220 °C; each condition accelerates chain scission and acetic acid release.
The vinyl acetate repeat unit interrupts polyethylene crystallisation. At 26 wt% comonomer, the crystalline fraction is lower than in EVA grades carrying 15–18 wt% acetate. This reduces yield stress and flexural modulus while raising impact energy absorption and elastic recovery. In differential scanning calorimetry under ISO 11357-3, the grade typically shows a broad melting endotherm rather than the sharp melt of an ethylene homopolymer; the breadth of the endotherm indicates a distribution of crystallite sizes. Because the crystalline network is disrupted, the Vicat softening temperature reported in the property table is lower than that of a lower-acetate grade. Components subjected to continuous load should be evaluated under ASTM D2990 or ISO 899-1 because short-term tensile data alone do not capture creep.
Adhesion to polar substrates is enhanced by the dipole associated with the acetate side group. In coextruded films, 7350M can serve as a soft surface layer or sealant layer and may improve sealing to polyurethane and styrenic layers. However, published data for this specific grade in foil-to-film tie-layer adhesion is limited; bonding must be quantified on production-stabilized film using ASTM F88/F88M seal-strength measurement or peel testing under ASTM D1876. Flex fatigue resistance for footwear parts is preferably assessed under ASTM D1052 or ISO 13226, because viscoelastic recovery in EVA is time-dependent and influenced by peroxide crosslinking, filler loading, and blowing agent residue.
The melt mass-flow rate of 2.5 g/10 min differentiates 7350M from higher-flow injection-molding EVA grades. In extruded film, the moderate melt index provides higher extensional viscosity, which stabilizes the bubble against sag and reduces neck-in in cast film. A grade with a melt index of 10 g/10 min or more would fill thin-walled molds more easily but would produce lower melt strength and greater draw sensitivity. In chemically blown foam, the flow value of 2.5 g/10 min is low enough to retain gas during expansion but high enough to permit dispersion of blowing agent masterbatch on single-screw lines with mixing sections.
Injection molding of 7350M is practical on clamp units in the 80–150 ton range for midsoles and sports footwear components. Barrel profiles from 160 °C in the feed zone to 190 °C at the nozzle and mold temperatures of 20–40 °C are commonly used. Flow length is limited by the material’s melt viscosity; parts with long, thin flow paths may require a different grade or higher melt temperature, though exceeding 210 °C increases deacetylation risk unless residence time is kept very short. Actual machine settings should be adjusted based on part thickness, runner geometry, and hot-runner manifold sizing.
For foam processing, a twin-screw extruder with a length-to-diameter ratio of 30:1 is representative for blowing agent dispersion and downstream cooling. The gas-laden melt is often cooled to 100–120 °C at the die to prevent premature expansion and surface rupture. Head pressure must remain above the gas solubility threshold, which for azodicarbonamide-based systems is typically reported in the 7–10 MPa range, although published data for this specific grade on production twin-screw foam lines is limited and line trials are required to establish limits for screw speed, melt temperature, and die pressure.
Replacing an 18 wt% vinyl acetate grade with 7350M reduces crystalline order and lowers the seal initiation temperature in film. The trade-off includes lower tensile stiffness and greater blocking tendency. Blown film evaluations should measure machine-direction and transverse-direction tensile properties under ASTM D882, impact resistance under ASTM D1709, and kinetic coefficient of friction under ASTM D1894. Because frost-line height and draw-down alter orientation in EVA, comparing only resin data without film data is not sufficient to predict field performance.
In footwear foam, the higher acetate level generally produces lower hardness under ASTM D2240 and lower density, but abrasion loss under ASTM D5963 or ISO 4649 may increase unless the formulation is crosslinked or blended with harder polyolefin. Peroxide crosslinking at 0.3–1.0 phr is common in compression-molded EVA foam, with the exact dosage adjusted for mold thickness, filler content, and peroxide half-life. Published data for this specific grade in peroxide-cured foam formulation is limited; mixing and curing schedules should be established under production-scale torque rheometry and moving-die rheometry.
When used as a coextruded sealant layer, 7350M can reduce seal initiation temperature relative to lower-acetate EVA but increases blocking force during roll storage. Antiblocking masterbatch added at 2–5 wt% and chilled wind-up below 30 °C are typical controls. Blocking load should be measured under ASTM D3354 and coefficient of friction under ASTM D1894 before release to production.
The table below summarizes the directional effects expected when 7350M is substituted for a lower-vinyl-acetate EVA of similar melt index.
| Property direction | Change relative to lower-VA EVA | Test method |
|---|---|---|
| Density | Increase | ASTM D1505 |
| Tensile modulus | Decrease | ASTM D638 |
| Elongation at break | Increase | ASTM D638 |
| Seal initiation temperature | Decrease | ASTM F88/F88M |
| Abrasion loss | Increase | ASTM D5963 |
| Vicat softening temperature | Decrease | ASTM D1525 |
| Low-temperature flexibility | Increase | ASTM D746 |
If the target application requires even lower sealing temperature or rubber-like response, an EVA grade with vinyl acetate above 28 wt% may be needed; however, those grades usually exhibit higher blocking, lower tensile strength, and greater thermal sensitivity. Conversely, if the part requires greater stiffness or heat resistance, a lower-VA grade is preferable. The appropriate selection depends on the final converted article end-use, not the resin data alone.
Material handling requires attention because EVA resins release acetic acid when overheated. The resin should be stored in sealed containers at 25 °C or below and should not be exposed to direct sunlight for long intervals because ultraviolet oxidation can occur. If surface moisture or condensation is present, the drying conditions already described should be used. The material is not recommended for continuous service under load at temperatures approaching the Vicat softening point, and contact with strong oxidizers, concentrated acids, or halogenated solvents should be avoided. Outdoor weathering of unpigmented film should be assessed under ASTM D4329 or ISO 4892-2 rather than inferred from the polymer backbone alone.
Compliance claims for food contact are application-specific. The base polymer may be covered by 21 CFR 177.1350 as an ethylene-vinyl acetate copolymer, but finished article compliance must be confirmed under the applicable migration testing protocols, such as 21 CFR 176.170 for aqueous and fatty foods or regional equivalents. RoHS restrictions under EU 2011/65/EU and REACH SVHC status should be verified against the most recent supplier certificate for the specific production lot.
