| HS Code | 978950 |
| Vinyl Acetate Content | 33% |
| Density | 0.955 g/cm³ |
| Melt Flow Rate 190 C 2 16kg | 3.0 g/10min |
| Melting Point Dsc | 62°C |
| Vicat Softening Temperature | 48°C |
| Tensile Strength | 12 MPa |
| Elongation At Break | 800% |
| Shore Hardness | 80 Shore A |
| Brittleness Temperature | -70°C |
| Crosslinkability | Peroxide-crosslinkable |
As an accredited EVAtech 140S/33C EVA Copolymer Compound,Crosslinkable Foam Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | EVAtech 140S/33C is supplied in 25 kg polyethylene bags, ensuring safe, moisture-protected delivery for foam processing. |
| Container Loading (20′ FCL) | Loaded in 20′ FCL, palletized and secured, well-ventilated, protected from moisture and heat for safe transport. |
| Shipping | EVAtech 140S/33C is shipped as solid pellets in heat-sealed moisture-resistant bags or bulk containers. Protect from direct sunlight, moisture, and mechanical damage. Store in a cool, dry warehouse. Transport in covered, clean vehicles to prevent contamination. Handle with standard industrial equipment; no special hazardous shipping requirements apply. |
| Storage | Store EVAtech 140S/33C in a cool, dry, well-ventilated area, away from direct sunlight, heat sources, and open flames. Keep containers tightly sealed to prevent moisture absorption and contamination. Maintain moderate temperatures, avoid stacking excessively, and use within the manufacturer’s stated shelf life. Ensure good housekeeping and proper labeling. |
| Shelf Life | Store in a cool, dry place away from direct sunlight. Shelf life is 12 months from production date. |
In two-roll mill compounding for expanded footwear midsole sheets, EVAtech 140S/33C is mixed with azodicarbonamide at 2.8–4.2 phr, dicumyl peroxide at 0.6–0.9 phr, zinc oxide at 0.8–1.2 phr, stearic acid at 0.4–0.6 phr, and calcium carbonate at 10–20 phr. Mixing on a 14 inch two-roll mill with friction ratio 1:1.25 is maintained at 105–115 °C for 10–15 min. The mixed sheet is calendered to 2.0–4.0 mm and transferred to a multi-platen compression press. Cure is performed at 155–165 °C under 10–15 MPa for 8–12 min. During cure, dicumyl peroxide decomposes and crosslinks the ethylene-vinyl acetate matrix while azodicarbonamide evolves nitrogen. The resulting closed-cell foam is die-cut into midsoles. Target density is 0.18–0.25 g/cm³. Shore C hardness is 45–55. Compression set remains below 30% after 24 h at 50 °C per ISO 815-1:2014. Export material compliance for branded footwear normally requires REACH Annex XVII screening and control of semicarbazide below 50 mg/kg in finished foam under certain EU brand RSLs. Published data for this specific compound configuration is limited; the starting ranges shown reflect common industrial starting points for crosslinkable EVA foam grades. A known production failure on multi-platen lines is backrind at mold parting lines when cure pressure is released before surface blow-off is complete. Another failure mode is cell collapse when roll-mixed batches are stored longer than 8 h before pressing due to moisture pickup on filler surfaces.
| Application segment | DCP (phr) | ADC (phr) | Filler (phr) | Target density (kg/m³) | Typical hardness range |
|---|---|---|---|---|---|
| Footwear midsole | 0.6–0.9 | 2.8–4.2 | 10–20 | 180–250 | Shore C 45–55 |
| Sports mat core | 0.5–0.8 | 3.5–5.5 | 0–10 | 60–120 | Shore C 20–40 |
| Marine fendering | 1.0–1.3 | 2.0–3.0 | 5–15 | 200–350 | Shore C 55–70 |
| Orthotic footbed | 0.7–1.0 | 1.5–2.5 | 20–30 | 350–550 | Shore A 60–80 |
| Automotive NVH gasket | 0.6–0.9 | 2.0–3.0 | 0–5 | 80–150 | Shore C 25–40 |
| Insulation sleeve | 0.7–1.0 | 4.0–5.5 | 0.5–1.0 | 90–130 | Shore C 15–30 |
Closed-cell EVA foam for martial arts and gymnastics mat cores is processed as compression-molded buns. Final bun thickness after splitting is 20–50 mm. Expansion ratio is controlled by balancing azodicarbonamide loading between 3.5–5.5 phr and zinc oxide activation. Zinc stearate is kept below 1.0 phr to narrow the gas evolution exotherm. This reduces oversized cells. Press cure at 150–160 °C uses a two-stage pressure profile. Stage one applies 2–3 MPa during gas nucleation. Stage two applies 8–12 MPa during crosslink completion. This produces a uniform closed-cell structure with cell diameter 0.2–0.5 mm. After demolding, buns are conditioned at 70–80 °C for 4–6 h in a forced-air oven. Post-cure removes condensation water. Physical properties are measured under ASTM D3575-20 Suffix D for tensile strength and Suffix B for compression deflection at 25%. Rebound resilience is measured by ASTM D2632-15. Accepted ranges for general training mats are density 60–120 kg/m³, Shore C 20–40, and vertical rebound 30–45%. Impact attenuation for judo and taekwondo mats is assessed by drop-mass methods. Adhesion of embossed surface films requires corona treatment of the foam web to 42–48 mN/m surface energy before lamination with polyurethane or PVC wear layers. Thickness tolerance across a 1200 mm wide bun is commonly held to ±1.0 mm by horizontal splitting. Edge-to-center density mismatch is a known batch defect when press temperature gradients exceed ±5 °C.
Marine buoyancy and fendering components manufactured from EVAtech 140S/33C are compression-molded as billets or cylindrical fender cores. Outer diameters range from 100 mm to over 600 mm. The formulation shifts toward higher crosslink density and higher density. Dicumyl peroxide is loaded at 1.0–1.3 phr. Azodicarbonamide is loaded at 2.0–3.0 phr. Carbon black or mineral filler is added at 5–15 phr for UV stabilization. Cure time is extended to 15–20 min at 155–165 °C. Thick sections require thermal soak to achieve uniform gel fraction above 65% by xylene extraction. Closed-cell content is measured by ASTM D2856-94 air pycnometer. Values above 90% correspond to long-term water absorption below 5% by volume under ASTM D1056-14 soak protocols. The foam is cut into fender arcs, D-shaped profiles, and cylindrical collars. Bonding uses moisture-curing polyurethane adhesive. Bond strength measured by ASTM D429-14 Method B typically exceeds 0.5 MPa on peeled specimens. Saltwater exposure per ISO 1817:2015 for 7 days at 23 °C requires less than 3% volume swell. A known production bottleneck is porosity at the center of thick billets when press loading is too rapid. Preheating the preform to 100–110 °C before hot compression reduces this core under-cure defect.
After crosslinked sheet is skived to 4–6 mm gauge, thermoformable EVA foam blanks for foot orthoses are heated to 120–140 °C for 2–5 min in a convection oven. Heated blanks are vacuum formed over plaster or CNC-milled positive casts. The compound is formulated with azodicarbonamide at 1.5–2.5 phr and calcium carbonate at 20–30 phr. This produces a stiffer foam with density 0.35–0.55 g/cm³ and Shore A hardness 60–80. Crosslinking prevents melt collapse during heat forming. Gel fraction measured by ASTM D2765-16 is held above 60%. Compression set after 22 h at 50 °C according to ISO 815-1:2014 remains below 20% for functional posting density. Skin-contact compliance is assessed against REACH Annex XVII and brand RSL limits for residual peroxide byproducts, formamide, and heavy metals. No prolonged skin cytotoxicity test is required for adult footbeds under EU 2017/745 unless the product is marketed as a medical device. Process control at the thermoforming stage depends on sheet thickness uniformity. Tolerance of ±0.3 mm across 1000 mm sheet width prevents local thinning under the heel seat.
Formulation adjustments for automotive interior gaskets, die-cut NVH pads, and sealing strips prioritize low fogging performance. Azodicarbonamide is reduced to 2.0–3.0 phr. Part of the zinc oxide accelerator is replaced with zinc bis(2-ethylhexanoate) at 0.3–0.5 phr. Press cure is run at 160–170 °C for 10–14 min. The resulting closed-cell foam has density 0.08–0.15 g/cm³ and Shore C hardness 25–40. The foam is slit and laminated to acrylic transfer adhesive or polyester film. It is then die-cut into sealing washers and damper pads. Fogging performance is measured by VDA 278:2011 thermal desorption. Total volatile condensable matter below 250 µg/g is a typical acceptance threshold. Semicarbazide is controlled below 10 µg/g for interior air quality programs. Flammability is certified to ISO 3795:1989 or FMVSS 302. Burn rate below 100 mm/min is required for thickness 3–13 mm. Thermal dimensional stability is checked after 24 h at 80 °C per ISO 2796:1986. Volume change below 5% is needed for clip-retained gaskets. Die-cutting edge collapse occurs when foam density falls below 0.06 g/cm³. Adhesive failure on low-energy EVA surfaces is reduced by corona treatment to 38–44 mN/m surface energy before lamination.
Thermal insulation sleeves made from crosslinked EVA foam sheets require a small, uniform cell population to reduce gaseous conduction while retaining flexibility for snap-on installation around piping. A typical formulation uses azodicarbonamide at 4.0–5.5 phr, dicumyl peroxide at 0.7–1.0 phr, and nucleating talc at 0.5–1.0 phr. Cell size is kept below 0.4 mm by pre-curing the compound at 130–140 °C for 3–5 min before final expansion at 160–170 °C. Thermal conductivity is measured by ASTM C518-21 heat flow meter or EN 14304:2015. Values of 0.038–0.045 W/(m·K) at mean temperature 25 °C are typical for EVA-based elastomeric foams with density 90–130 kg/m³. Water vapor transmission is assessed by ASTM E96-22 Procedure A. A permeance below 1.0 perm is required for pipe applications to limit under-insulation corrosion. Cut-to-length sleeves are notched and solvent-welded with a ketone-based adhesive. Lap shear strength after 72 h cure is above 0.3 MPa. Continuous service above 80 °C is not recommended because oxidative chain scission accelerates and compression creep becomes significant. For hot piping beyond this boundary, EPDM or NBR/PVC closed-cell insulation is substituted.
Competitive EVAtech 140S/33C EVA Copolymer Compound,Crosslinkable Foam Grade prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615380400285 or mail to sales2@liwei-chem.com.
We will respond to you as soon as possible.
Tel: +8615380400285
Email: sales2@liwei-chem.com
Flexible payment, competitive price, premium service - Inquire now!
EVAtech 140S/33C EVA Copolymer Compound, Crosslinkable Foam Grade is supplied as a pelletized ethylene-vinyl acetate compound formulated for peroxide-initiated crosslinking and chemical blowing-agent expansion. The grade designation identifies a high-vinyl acetate class with a nominal vinyl acetate content of 33% by mass, though published data for this exact commercial designation is limited. The numerical ranges in this document are therefore drawn from industrial compounding literature for high-VA crosslinkable EVA foam systems and should be revalidated on the target production line. The compound differs from lower-VA EVA compounds and non-crosslinkable ethylene copolymer foams primarily through reduced crystallinity, lower Shore hardness, and the formation of an insoluble gel network after cure. Components produced from this compound are commonly tested under ASTM D395-18, ASTM D638-14, ASTM D624-00, and ASTM D2240-15.
The vinyl acetate content in EVAtech 140S/33C places it between standard 28% VA foam grades and softer 40% VA polymer blends. At 33% VA, polyethylene crystallinity is suppressed enough to produce expanded Shore A values in the 35–55 range at foamed densities of 0.20–0.35 g/cm³. An 18% VA EVA foam at equivalent density commonly measures 60–75 Shore A. The higher polar monomer fraction improves wetting of calcium carbonate and silicate fillers, permits higher filler loadings before tensile strength loss becomes unacceptable, and increases adhesion to polar solvent-borne inks and adhesives. The main penalty is moisture uptake; pellets exposed to ambient relative humidity above 60% require drying before compounding. Compared with a non-crosslinkable EVA foam, the crosslinkable formulation develops 40–70% gel by solvent extraction under ASTM D2765-16 and reduces compression set after 22 h at 70°C under 25% deflection. This makes the 33C grade appropriate for seals, footwear components, and gaskets where recovery after compression is specified, not for disposable low-density packaging foam where lower-cost non-crosslinkable polyolefin would be sufficient.
Differential scanning calorimetry under ISO 11357-3:2018 on high-VA EVA typically shows a broad crystalline melting endotherm from 40°C to 80°C, with the main peak near 60–70°C. Lower-VA grades such as 18% VA retain a distinct polyethylene-like melting endotherm above 85°C. This difference lowers the preform softening temperature in the mold and means the 33C grade requires shorter air-venting time before full press pressure is applied. The glass transition of EVA remains below -20°C, so low-temperature flexibility is retained after crosslinking and expansion. The same polar structure that improves filler wetting also increases dispersion viscosity when high-surface-area carbon black is added; formulations with carbon black above 5 phr should be screened for peroxide adsorption before scale-up.
On a corotating twin-screw extruder with L/D 44–52, the compound is mixed in barrel zones at 90–120°C. Melt temperature is held below 130°C when dicumyl peroxide is present. Pre-drying at 60–70°C for 2–4 h is required when storage relative humidity exceeds 60%; residual moisture causes surface porosity and variable blowing-agent dispersion. Side stuffing of fillers is preferred over single-pass high-shear kneading because frictional heat can push the melt into the peroxide scorch zone before the azodicarbonamide masterbatch is distributed uniformly. Formulations containing fillers with pH below 4.5 should be avoided, because acidic surfaces consume peroxide radicals and depress final gel content. For color-critical footwear products, titanium dioxide and organic pigments are added through a separate masterbatch at the feed throat to minimize color streaks.
Melt flow rate for high-VA crosslinkable EVA foam grades is usually 2–6 g/10 min at 190°C/2.16 kg when tested to ISO 1133-1:2022. A melt flow rate below 2 g/10 min increases torque in reverse kneading blocks and can require barrel settings at the upper end of the 90–120°C window; a melt flow rate above 6 g/10 min may produce pellet cutting instability and lower melt pressure control. Dicumyl peroxide half-life data from organic peroxide suppliers place the one-hour half-life near 132°C. This establishes a practical melt-temperature ceiling of 120–130°C for compounding operations; if the melt remains above that ceiling for more than 60 s, localized scorch forms microgel particles that later appear as fish-eye defects in the expanded sheet. Compounding therefore uses low-shear screw profiles with distributive mixing elements and downstream melt thermocouples positioned before the pelletizer die. The die head zone is set at 100–120°C to avoid strand breakage while keeping residence time below 45 s.
Extruder barrel liners should be checked for wear at the kneading-block transition zone because high-VA EVA compounds are less abrasive than glass-filled polyamide but more shear-sensitive than polyethylene. If the melt temperature exceeds 130°C during a production run, the batch should be downgraded for scrap or sample evaluation rather than fed to the pellet silo, because scorched pellets cannot be re-melted without retaining fish-eye defects. For twin-screw lines with a gear pump before the pelletizer, the pump inlet pressure should be maintained above 10 bar to prevent cavitation at the lower melt viscosity generated by the VA fraction.
After pelletization, the compound is converted into closed-cell foam sheet in a hydraulic compression press or a continuous oven system. In compression molding, a pre-weighed preform is heated at 150–170°C under mold pressure sufficient to suppress premature gas expansion. The platen temperature should be controlled to ±2°C across the working area. If cure temperature falls below 150°C, gel development remains under 40% and compression set rises above 40% under ASTM D395-18 Method B. If cure temperature exceeds 170°C or hold time exceeds 12 min for a 10 mm preform, gas migration and cell coalescence produce a coarse internal structure and possible surface collapse. The mold opening step must release pressure rapidly enough to nucleate cells uniformly but not so fast that the parting-line skin tears. Production-scale observation on hydraulic presses indicates that platen temperature spreads greater than ±2°C create measurable sheet density variation; presses with validated PID controllers and heated platens are recommended for the 33C grade.
For multilayered foam sheet, coextruded or laminated skins are applied before molding, and the crosslinkable core layer must be matched to the skin rheology to prevent interlayer delamination at the foam-skinned interface. The die temperature for skin-core coextrusion should not exceed the peroxide scorch ceiling of 130°C. In continuous oven curing, the residence time and zonal air temperature must be tuned so that the surface cures before the core expands; otherwise the sheet exhibits a collapsed center and densified surfaces.
Differential scanning calorimetry of azodicarbonamide-modified EVA systems typically shows a blowing-agent decomposition exotherm with an onset near 200–210°C, while dicumyl peroxide cure exotherm onset is significantly lower. In a mold set at 150–170°C, ADC decomposition is delayed by heat transfer from the platen surface; gas evolution therefore peaks later in the cycle. At mold temperatures above 175°C, gas pressure rises before the gel network is sufficiently developed, causing cell rupture and irregular cell size distributions. At mold temperatures below 155°C, ADC conversion remains incomplete within normal 8–12 min residence times; residual blowing agent can produce surface blisters during post-cure trimming or heat-setting. The practical operating window is therefore narrow. A variation of ±5°C around the optimized mold temperature is sufficient to shift foam density by more than 0.05 g/cm³ in some formulations, according to supplier technical data. Crosslinking coagents such as triallyl cyanurate or trimethylolpropane trimethacrylate are used in some formulations to widen this window by increasing crosslink density without raising cure temperature.
The concentration of dicumyl peroxide and azodicarbonamide must be matched to the VA content because the vinyl acetate comonomer affects both radical crosslinking and gas solubility. A formulation designed for a 28% VA EVA will not transfer directly to the 33C grade without adjusting the peroxide level, as the higher VA fraction can increase the tendency toward polar byproduct formation and may require a slightly higher co-agent loading to reach the same gel content. Pilot trials should use thermocouple-instrumented preforms to record the centerline temperature lag; when the centerline is more than 8°C below the platen temperature at 50% of cycle time, the mold heating system or preform thickness should be modified rather than extending cycle time alone.
Applications for this crosslinkable foam grade are those requiring a closed-cell, low-density elastic material with Shore A below 55 and limited compression set after thermal aging. Footwear midsole and sockliner processors use the 33C grade because it can be molded, skived, and die-cut without excessive edge tearing. Gasket and seal fabricators specify the compound when ASTM D395-18 Method B compression set must remain below 35% after 22 h at 70°C with 25% static deflection. Thermal insulation and packaging components use the compound where the continuous service temperature does not exceed 80°C, as high-VA EVA can embrittle after long-term oxidative aging. For flame-retardant orders, halogen-free packages using magnesium hydroxide or aluminum trihydrate are added, but these fillers raise density and require rebalancing of the peroxide and blowing-agent levels. Compared with metallocene polyethylene foam, EVAtech 140S/33C gives lower hardness at equal density and better adhesion to polar inks, but it has higher moisture absorption and a lower maximum service temperature. Compared with PVC/NBR foam, it avoids plasticizer migration but offers lower inherent flame resistance and may require additional fire-retardant additives to satisfy IEC 60695-2-12 glow-wire testing at 650°C.
| Property | Test method | Typical range | Operational note |
| Vinyl acetate content | Internal FTIR/TGA | 33% nominal | Confirm per lot certificate of analysis |
| Melt flow rate | ISO 1133-1:2022 | 2–6 g/10 min | At 190°C/2.16 kg |
| Foamed density | ISO 845:2009 | 0.20–0.35 g/cm³ | Depends on ADC dosage and mold temperature |
| Hardness | ASTM D2240-15 | 35–55 Shore A | At expanded density range |
| Gel content after cure | ASTM D2765-16 | 40–70% | Extraction in boiling xylene; network formation |
| Tensile strength | ASTM D638-14 | 1.5–3.5 MPa | Skin thickness and cell structure affect values |
| Elongation at break | ASTM D638-14 | 150–350% | Higher VA raises elongation |
| Tear strength | ASTM D624-00 | 5–15 kN/m | Die C; foam density dependent |
| Compression set | ASTM D395-18 Method B | 25–50% | 25% deflection, 22 h at 70°C |
Lot-to-lot control during incoming inspection should include verification of melt flow rate and vinyl acetate content against the certificate of analysis. A shift of more than ±1.5 percentage points in VA content alters hardness and ink adhesion, while a shift of more than ±1 g/10 min in MFR changes screw torque and cell size distribution in the foaming line. Blowing-agent masterbatches with a mean azodicarbonamide particle size of 3–6 µm are preferred for uniform cell nucleation; coarser particle size distributions can produce pinholes and non-uniform density profiles. The product should be stored in moisture-barrier packaging and resealed immediately after use.
For a production engineer evaluating a change from a 28% VA crosslinkable foam grade to EVAtech 140S/33C, the pilot trial should compare hardness at equal density and compression set after 70°C aging, not tensile strength alone. The 33C grade will typically mold at a slightly lower melt viscosity and may require a 2–3°C reduction in barrel temperatures to maintain the same melt pressure. Because the higher VA content lowers the crystalline melting point, the preform may also soften earlier in the mold, reducing the time available to vent trapped air before full pressure is applied. These adjustments are specific to the crosslinking and blowing-agent package in use and cannot be transferred directly from one production line to another without confirmation on the target press.
