EVAtech 110S/3N/1 EVA Copolymer Compound,Crosslinkable Foam Grade

Expansion-Molded Midsole and Footbed Compounds for Athletic Footwear

Finished midsole and footbed components produced from EVAtech 110S/3N/1 are typically released against chemical management requirements that vary by destination market. For European Union footwear, REACH Annex XVII entries 43, 50, 51, and 72 are the relevant screening provisions when textile, leather, or coated textile elements are bonded to the foam, with entry 50 polycyclic aromatic hydrocarbon limits applied to the foam matrix itself because of prolonged skin contact and processing oil carryover potential. In the United States, children’s footwear containing the expanded foam is assessed under CPSIA Section 101 for total lead at 100 mg/kg and Section 108 for listed phthalates at 0.1% per phthalate. Physical qualification for athletic footwear production commonly includes ASTM D638-14 tensile strength, ASTM D395-18 Method B compression set, ISO 815-1:2020 compression set after aging at 23 °C and 70 °C, and ISO 4649:2017 abrasion resistance. Brand-level restricted substance specifications often add California Proposition 65 screening for residual acetaldehyde, formaldehyde, and semicarbazide formed during azodicarbonamide decomposition; the foam producer is expected to report these residual values only after forced-air post-cure conditioning of the expanded sheet.

In downstream compounding, the base crosslinkable EVA compound is let down with 0.6–1.0 phr dicumyl peroxide as the free-radical initiator, 1.5–3.0 phr azodicarbonamide as the chemical blowing agent, 1.0–2.5 phr zinc oxide as the crosslinking activator, 0.3–0.8 phr stearic acid to moderate metal soap formation, 0.5–1.0 phr zinc stearate as a release agent, and 5–20 phr calcium carbonate when dimensional stability is weighted over rebound resilience. Density of the expanded midsoles is typically controlled within 0.08–0.25 g/cm³ by adjusting azodicarbonamide loading and cavity fill ratio rather than by filler loading alone. If dual-density midsoles are required, the outer layer may be compounded with 10–25 phr of a compatible polyolefin elastomer or EPDM to lower flexural modulus while maintaining cell-wall integrity. Published data for this specific compound configuration is limited, but production records from similar crosslinkable EVA foam grades support a pre-cure Mooney viscosity range of 80–120 ML(1+4) at 100 °C according to ASTM D1646-19a.

Production lines for compression-molded footwear typically begin with a 35 L or 55 L Banbury internal mixer at rotor speed 30–50 rpm and drop temperature 105–115 °C, followed by a two-roll mill set at 80–95 °C to generate a uniform slab. The slab is pelletized or cut into blanks, then crosslinked and expanded in a multi-daylight compression press at 160–175 °C with closing force sufficient to produce 80–120 kg/cm² cavity pressure. Cure time is held at 6–12 min depending on part thickness; demolded parts are immediately transferred to cooling jigs for 24–48 h to stabilize gas diffusion and reduce post-molding shrinkage below 2%. When production runs exceed 20 mm finished thickness, failure to maintain cooling-jig restraint during the first two hours after demolding produces unrecoverable cell collapse and density gradients from core to surface. Terminal finished product types include running shoe midsoles, sandal footbeds, slide sole units, molded orthopedic shoe components, and dual-density comfort footbeds with hardness values commonly specified between 40–60 Asker C.

Closed-cell crosslinked roll stock produced from EVAtech 110S/3N/1 for gymnastics and martial arts impact mats is supplied in roll lengths greater than 30 m and widths up to 1.5 m, with a density window of 0.06–0.12 g/cm³ selected to meet energy-absorption expectations for supervised training environments. Compression deflection and thickness recovery are evaluated according to ASTM D3575-14, Suffix B, while tear propagation resistance is measured according to ISO 34-1:2022. When mats are destined for the EU children’s activity market, documentation is aligned to REACH Annex XVII entry 50 and EN 71-9:2005+A1:2009 for organic chemical migration, particularly formaldehyde and flame-retardant carryover. Residual polycyclic aromatic hydrocarbon content is screened against the AfPS GS 2019:01 PAH limit of 0.5 mg/kg for Category 1 materials intended for prolonged skin contact. Fall-height impact attenuation is commonly assessed using ASTM F1292-20 when gym mats are specified as safety surfacing within supervised play zones; otherwise, thickness and density are correlated to drop-test records maintained by the converter.

The formulation for sports mat roll stock is shifted toward lower crosslink density and higher tear resistance: 0.5–0.8 phr dicumyl peroxide, 1.0–2.0 phr azodicarbonamide, 0.5–1.5 phr zinc oxide, 10–20 phr ethylene-octene polyolefin elastomer, and 1.0–3.0 phr titanium dioxide for light-color surfaces. An endothermic blowing agent masterbatch based on sodium bicarbonate and citric acid derivatives is added at 0.5–1.5 phr to limit free-formaldehyde byproduct release during expansion. Foam density is maintained at 0.06–0.12 g/cm³ by controlling blowing agent ratio and press cushion pressure. For roll stock that will be laminated with flexible PVC cover film, the foam surface is corona-treated to 38–44 dyn/cm before adhesive application; failure to reach this surface energy results in edge peeling after repeated rolling.

Compounding is performed in an intermeshing twin-screw extruder with L/D 32:1–44:1 and vacuum venting at −0.08 MPa to strip moisture and low-molecular-weight volatiles. The pelletized compound is calendered into a pre-sheet at 80–100 °C and transferred to a multi-daylight hot press where expansion and crosslinking occur simultaneously at 165–180 °C. Post-cure forced-air venting at 70–80 °C for 24 h reduces residual blowing agent byproducts that would otherwise migrate into top-layer films or nonwoven backings. Terminal finished product types include roll-up gymnastics mats, martial arts landing pads, yoga mats with microfibre tops, interlocking fitness floor tiles, veterinary kennel mats, die-cut knee pads, and balance-training mat surfaces.

Why Does Low-VOC Peroxide Selection Control VDA 278 Compliant Door-Panel Padding?

EVA foam for interior door panel padding and headliner impact pads is qualified through automotive interior emission and flammability protocols rather than general consumer foam specifications. FMVSS 302 flammability testing typically applies a maximum burn rate of 100 mm/min, while ISO 3795:1989 provides the parallel international method for interior material burn classification. Emission performance is evaluated under VDA 278:2011 for volatile organic compounds and fogging condensate; representative OEM limits for trimmed interior foam are total volatile organic compounds below 100 µg/g and fogging condensate below 500 µg/g, though final values are project-specific. Cabin atmosphere simulation is addressed under ISO 12219-1:2021, with formaldehyde limits commonly set at 10 µg/m³ or lower in luxury vehicle programs. European end-of-life vehicle compliance is aligned to ELV Directive 2000/53/EC Annex II for cadmium, lead, mercury, and hexavalent chromium, while REACH Annex XVII continues to apply to the compound itself.

The dominant formulation difference in automotive interior padding is replacement of dicumyl peroxide with 1,4-bis(tert-butylperoxyisopropyl)benzene at 0.8–1.4 phr. This peroxide shifts decomposition byproducts away from acetophenone and cumyl alcohol, reducing the odor and fogging burden in sealed cabin interiors. Azodicarbonamide loading is lowered to 1.2–2.5 phr for a density of 0.06–0.10 g/cm³, with 0.8–1.5 phr zinc oxide and 0.5–1.0 phr zinc stearate. A blowing agent residue scavenger is applied at 0.5–1.0 phr where semicarbazide or cyanic acid residues must be suppressed below customer detection limits. Published data for this specific scavenger configuration is limited, but the mechanism targets decomposition residues formed during thermal blowing agent breakdown, not crosslinker termination products. The resulting foam remains closed-cell, but the cell walls are thinner than those of footwear grade because the automotive process uses continuous expansion rather than mold-restricted compression foaming.

Production of door-panel padding begins with twin-screw compounding at barrel temperatures of 90–110 °C, with side-fed filler injection and vacuum venting to keep pellet moisture below 500 ppm. Pellets are extruded through a sheet die at 80–100 °C and fed directly into a three-zone hot-air expansion tunnel. The preheat zone operates at 120–140 °C, the crosslinking and expansion zone at 190–210 °C, and the annealing zone at 60–80 °C. Total residence time is 8–15 min, with cure state monitored by solvent extraction to maintain 90–95% gel content. The foamed sheet is then thermoformed to door-panel contours and die-cut to final shape. If the foam is post-laminated with a decorative skin, the thermoformed surface must be flamed or corona-treated to 38–44 dyn/cm before adhesive coating to prevent delamination at door panel edges.

Terminal finished product types include door-panel cushioning pads, headliner impact pads, rear parcel shelf padding, trunk side trim padding, floor mat underlay, and HVAC gasket strips. The material is not specified for functional low-frequency soundproofing without a mass-loaded barrier layer, because closed-cell EVA foam alone provides limited transmission loss below 200 Hz in multi-layer vehicle floor assemblies.

For non-structural marine decking and water-sports comfort padding, closed-cell foam produced from EVAtech 110S/3N/1 is specified only when ultraviolet stability, low water absorption, and resistance to plasticizer migration from vinyl cushion covers are established through long-duration wet aging. The primary biological resistance screen is ISO 846:2019 under high-humidity fungal and bacterial exposure, while accelerated xenon-arc aging is performed according to ASTM D2565-16 for 500 h to evaluate surface embrittlement and color shift. Closed-cell sponge density and compression-deflection behavior are classified according to ASTM D1056-14. Recreational marine decking shipments within the European Union are screened for REACH Annex XVII restricted substances and for heavy metals under RoHS Directive 2011/65/EU when the foam is bonded into electrical or electronic watercraft assemblies. The material is not certified under ISO 12402 as primary buoyancy foam; where buoyancy certification is required, a dedicated marine-grade foam with documented inherent buoyancy and age-resistant cell closure must be selected instead.

Formulation for outdoor marine exposure uses a stabilizer package consisting of 0.3–0.8 phr hindered amine light stabilizer, 0.2–0.5 phr benzotriazole UV absorber, 0.2–0.5 phr hindered phenolic antioxidant, and 1.0–3.0 phr UV-stable carbon black or iron oxide masterbatch. Dicumyl peroxide is held to 0.5–0.7 phr and azodicarbonamide to 1.0–1.8 phr to generate a fine closed-cell structure with water absorption below 3% by volume after 24 h immersion in conditioned testing based on ASTM D1056-14. In embossed anti-slip sheet, 2–6 phr of polymerized microsphere blowing agent may partially replace azodicarbonamide to reduce surface cratering without lowering crosslink density below effective cell closure. The foam is intentionally formulated at lower expansion ratio than packaging foam because marine decking must survive repeated compressive loading from footwear and deck hardware without permanent thickness loss.

Compounding for marine-grade sheet begins in a tangent Banbury mixer with drop temperature 100–115 °C, followed by open-mill sheeting and hot-press foaming at 160–175 °C under hydraulic pressure of 15–25 MPa. Cooling is performed under flat-bed pressure or vacuum to prevent warpage in sheet widths above 1.0 m. Bonding to decorative top layers uses a two-component polyurethane adhesive applied at 30–60 µm wet film thickness after flame or corona activation to 36–48 dyn/cm. CNC routing and water-jet cutting are used for deck contour shapes; cutter feed speed is controlled to keep edge temperature below 110 °C, above which the EVA cell walls fuse into a glazed edge crust that reduces adhesive bond strength and creates visible edge defects. Terminal finished product types include boat deck mats, helm station knee pads, kayak seat pads, swim-platform covers, personal watercraft traction mats, and recreational camping mat surfaces.

When EVAtech 110S/3N/1 Replaces Crosslinked Polyethylene in Protective Case Inserts

Protective packaging inserts fabricated from crosslinked EVA foam are specified when repeated-impact recovery, low abrasion against painted aluminium or glass, and close-thickness cutting tolerance justify the material cost relative to crosslinked polyethylene. Dynamic cushioning performance is screened using ASTM D1596-14 for shock-absorbing packaging materials, while compression set and tensile behavior are measured under ASTM D3575-14. Distribution-level package testing is not assigned to the foam in isolation; instead, the complete packed assembly is validated under ISTA 2A or ASTM D4169-22 depending on the logistic profile. In European industrial and consumer packaging applications, the insert foam must comply with REACH Annex XVII substance restrictions. Although RoHS Directive 2011/65/EU applies to electronic equipment rather than packaging, customer-specific material declarations for electronic product handling often mirror IEC 62474 reporting thresholds for lead, cadmium, mercury, and selected phthalates.

Formulation for protective inserts uses a tighter crosslinker range than footwear and a lower blowing agent ratio to maintain uniform flatness and lower closed-cell expansion stress. Typical addition levels are 0.6–0.9 phr dicumyl peroxide, 1.0–2.0 phr azodicarbonamide, 0.8–1.5 phr zinc oxide, and 0.3–0.5 phr stearic acid. Densities between 0.04–0.10 g/cm³ are selected for cushioning devices up to 25 kg, while densities up to 0.15 g/cm³ are used for tool trays and instrument cases requiring tighter dimensional recovery. For non-ESD-sensitive packaging, no antistatic filler is compounded into the foam because internal antistatic agents increase water-extractable conductivity and can generate microclimate corrosion on metal contact points. When static-sensitive assemblies are handled, the foam is laminated with a dissipative polyurethane film rather than modifying the foam formulation itself.

Processing begins with compression molding of thick foam planks, which are then split into sheets with skiving tolerance of 1–3 mm. Water-jet cutting, die-cutting, or CNC routing creates insert geometries. For optical and medical device inserts, cut parts are washed in deionized water at 40–50 °C and dried at 50 °C in low-humidity chambers to remove debris without inducing dimensional step changes. Newly foamed sheets must be conditioned for 24–48 h after press cure to complete shrinkage before lamination or final cutting; otherwise, die-cut parts smaller than 150 mm show progressive edge lifting after adhesive-backed fabric wraps are applied. Terminal finished product types include CNC-cut camera and lens case inserts, instrument transport trays, printed circuit board rack fillers, mobile device presentation trays, and industrial tool chest drawer liners.

In building expansion joint filler production, EVAtech 110S/3N/1 is foamed into closed-cell planks that are selected for compression recovery above 75% after 50% compression under repeated cycling. Acceptance for highway and bridge joint applications is anchored to ASTM D1752-18, Type 1 or Type 2 preformed expansion joint filler classifications, while building envelope fire classification is assessed under EN 13501-1:2018 to determine the applicable Euroclass grade. Raw material restrictions follow REACH Annex XVII and, where project specifications require, RoHS Directive 2011/65/EU heavy-metal limits. Acoustical underlayment is evaluated as part of a floor assembly through ISO 10140-2:2021 impact sound insertion loss; the foam alone is not treated as a standalone acoustic product, and its contribution to low-frequency attenuation below 200 Hz is limited unless it is combined with a mass-loaded barrier.

For expansion joint and anti-vibration pad production, crosslinking is increased to elevate compression resistance. The formulation uses 0.8–1.2 phr dicumyl peroxide, 1.0–2.0 phr azodicarbonamide, 1.0–2.0 phr zinc oxide, 0.5–1.0 phr stearic acid, and 20–40 phr calcium carbonate or talc to raise density to 0.15–0.30 g/cm³. Higher filler loading improves dimensional tolerance under long-term load but reduces rebound resilience and increases compression set sensitivity to temperature cycling. For exterior grade material, 0.5–1.0 phr carbon black and 0.3–0.5 phr UV absorber are added to resist embrittlement and solar surface cracking.

Manufacturing begins with twin-screw compounding at 100–115 °C, followed by single-screw extrusion into thick preforms and continuous hot-melt calendering to remove trapped air pockets. Crosslinking and expansion are carried out in a salt-bath or hot-air tunnel at 190–210 °C with line speed adjusted to deliver 10–20 min total dwell. After cooling, the planks are cut into 2–10 mm thick sheets and converted into strip widths by sawing, skiving, or water-jet cutting. In expansion joint filler installation, the product is set with 25–50% pre-compression in the joint. Compression set is verified according to ASTM D1056-14 after 24 h at 70 °C; values above 40% indicate insufficient crosslink density and require reformulation of the peroxide level or variation in curing dwell. Terminal products include bridge and highway expansion joint fillers, building facade joint filler strips, basement slab isolation boards, HVAC curb vibration isolation pads, and laminated acoustic underlayment planks for multi-family residential flooring assemblies.