WENEW Braskem America DVR 002A EVA Copolymer,50% Recycled Content,Foam & Footwear Grade

Compression-molded midsole production using WENEW Braskem America DVR 002A EVA Copolymer, 50% Recycled Content, Foam & Footwear Grade typically begins with verification that the incoming pelletized lot complies with EU REACH EC 1907/2006 Annex XVII entry 52 for phthalate concentration in recycled feedstock, with a documented limit of 0.1% by mass per plasticized material, and with the footwear brand restricted substance list for total volatile organic compounds, residual blowing agent degradation products, and polycyclic aromatic hydrocarbons. In a standard midsole compound, the resin is introduced at 70–85 phr of the total polymer fraction, together with 15–30 phr of virgin EVA, 2.5–3.5 phr azodicarbonamide blowing agent, 0.6–1.2 phr dicumyl peroxide crosslinking agent, 1.0–1.5 phr zinc oxide, and 0.5–1.0 phr zinc stearate; the recycled-containing lot should be pre-dried at 70°C for 2 h when ambient relative humidity exceeds 60%, because residual moisture in the recycled fraction produces surface blisters at cure stage. Mixing at production scale generally uses an internal mixer with fill factor 0.75–0.85, ram pressure 0.50–0.65 MPa, and drop temperature 105–115°C, followed by a two-roll mill set with a nip gap of 0.5–2.0 mm and front-roll temperature 70–85°C to form a sheet that is pelletized or directly slabbed for the compression press. The foaming and crosslinking operation is carried out in a multi-daylight compression molding press with heated platen uniformity of ±2°C, mold temperature 160–178°C, and molding pressure 12–15 MPa for cycles between 8 and 15 min depending on stock thickness; after demolding, the bun is cooled through a water channel and stored for 24–48 h to allow dimensional stabilization before splitting. The resulting terminal products include die-cut or hot-pressed athletic midsoles, removable insoles for running and court footwear, and cushioning inserts for casual and work shoes; physical acceptance tests typically follow ISO 845:2006 for apparent density, ASTM D638-14 for tensile strength, ASTM D624-00(2020) for tear resistance, and ISO 1856:2018 for compression set.

Does the recycled fraction alter melt stability during high-shear injection unit-sole production?

During high-shear injection molding of unit soles and cupsole shells, the main process risk arises not from the EVA copolymer itself but from residual crosslinked or high-molecular-weight domains in the recycled fraction, which can elevate melt pressure ahead of the non-return valve and create short shots if the screw recovery time is compressed. For this application, the compound typically uses 80–100 phr DVR 002A as the base polymer, with 0–20 phr polyolefin elastomer or virgin EVA for flow adjustment, 0.4–1.0 phr dicumyl peroxide as a mild cure modifier, 1.5–2.5 phr azodicarbonamide blowing agent if a microcellular structure is required, and 0.3–0.8 phr antioxidant package; the melt temperature should be held below the decomposition onset of the blowing agent in the screw compression zone, usually with barrel settings from 150°C to 175°C and nozzle temperature from 165°C to 180°C. Production-scale equipment includes injection molding machines with clamp force from 250 to 500 t for multi-cavity tools, screw L/D ratio 20:1–24:1, compression ratio 2.4:1–2.8:1, and injection pressures in the range of 80–120 MPa; mold temperatures are maintained at 35–55°C for rapid skin formation, and cycle times of 60–120 s are typical depending on wall thickness. Industry compliance for this footwear component is usually driven by brand RSL compliance under REACH EC 1907/2006 Annex XVII entry 52 for phthalate restrictions in articles, together with ISO 1133-1:2022 melt mass-flow rate verification of incoming resin and ASTM D638-14 tensile testing of molded plaques; formaldehyde and odour screening under footwear RSL applies to recycled content. Published data for this specific configuration is limited, so compounders often run capillary rheometry at 190°C across shear rates 100–10,000 s⁻¹ to map lot-to-lot viscosity before transferring the formulation to production. The downstream terminal outputs are injection-molded unit soles for running shoes, lifestyle sneakers, and semi-rigid cupsole frames, where the foam density is usually higher than compression-molded midsole foam, in the range of 0.35–0.55 g/cm³.

Expanded foam sheet for die-cut insoles and thermoformed orthotic shells

Sheet-foaming lines using DVR 002A typically compound the resin at 60–80 phr of total polymer, with 20–40 phr of reclaimed EVA regrind or virgin EVA depending on sheet thickness and required hardness, 2.0–3.0 phr azodicarbonamide, 0.5–1.0 phr dicumyl peroxide, and 0.5–1.5 phr calcium carbonate or precipitated silica as cell nucleator; the use of 50% recycled content in the base resin reduces the need for additional post-industrial regrind and assists mass-balance accounting under ISO 14021:2016. The downstream production process proceeds through a continuous sheet-foaming line: the compound is first mixed in an internal mixer, then transferred to a two-roll mill and calender to produce a pre-sheet of 1.5–4.0 mm thickness, after which the sheet is passed through a hot-air or infrared foaming oven at 170–190°C with residence time 3–8 min to activate the blowing agent and crosslink the matrix; post-foam thickness typically reaches 3–8 mm depending on formulation gas yield and line speed. For thermoformed orthotic shells, the expanded sheet is reheated to 110–135°C and vacuum-formed onto foot-positive molds with pressure differential 0.6–0.9 bar, then trimmed with CNC routers or die-cutting presses. Compliance for this segment includes ISO 10993-10:2010 skin irritation testing for prolonged skin-contact orthoses, ISO 1856:2018 compression set, and EN 71-3:2019+A1:2021 only if the finished foam is intended for children’s insoles; for general footwear insoles, brand RSL limits for residual blowing agent decomposition products are applied. Terminal products include flat die-cut insoles for athletic and casual footwear, thermoformed arch-support shells for orthotic sandals, and cushioned inserts for medical-grade recovery clogs.

In sandal factories, compliance for flip-flop outsoles is driven by ISO 20871:2018 outsole abrasion, DIN 53516 mass-loss limits, and REACH EC 1907/2006 Annex XVII entry 52 for phthalates. A starting formulation places DVR 002A at 80–100 phr with 0–20 phr virgin EVA, 10–20 phr silica or calcium carbonate, 1.8–3.0 phr azodicarbonamide, and 0.8–1.5 phr dicumyl peroxide; multi-station rotary injection molding at clamp force 60–200 t, barrel temperature 150–175°C, and cycle time 35–90 s yields single-color and multi-color flip-flop soles, EVA sandal footbeds, and molded comfort sandals.

When EVA foam moves into child-oriented play mats and recreational floor tiles

Compliance with EN 71-3:2019+A1:2021 migration limits for elements, ASTM F963-23 soluble heavy metals, CPSIA Section 101 lead content and Section 108 phthalates, and REACH EC 1907/2006 Annex XVII entry 51 for child-use phthalates becomes non-negotiable once the foam is directed into child-oriented applications because the recycled fraction may contain legacy substances that are restricted in articles intended for children. In this sector, formulation addition ratios usually use 50–80 phr DVR 002A, with 20–50 phr virgin EVA or metallocene polyolefin elastomer to reduce process odour and improve colour consistency, 2.0–3.5 phr azodicarbonamide, 0.5–1.0 phr dicumyl peroxide, and 1.0–2.0 phr zinc oxide plus zinc stearate; colour masterbatch is added at 1–4 phr but must be selected for heavy-metal-free pigment chemistry. The downstream process is typically continuous hot-press foaming in large daylight presses: the pre-mixed and pre-sheeted compound is loaded into frame molds, foamed at 155–170°C under 8–12 MPa, and then decompressed in a controlled sequence to create a closed-cell mat of 8–20 mm thickness; the expanded plank is then cooled on a flat-bed conveyor, sanded, edge-trimmed, and embossed or printed before die-cutting into interlocking floor tiles. Published data for this specific configuration is limited to general recyclate quality requirements rather than grade-specific toxicological thresholds; therefore each incoming lot requires chromatographic screening for phthalates and polycyclic aromatic hydrocarbons. Terminal products include interlocking play mats, puzzle-edge floor tiles, recreational gym mats, and soft underlay for children’s play areas.

Hot-press molded foam planks for orthopedic and recovery footwear follow a lower-cure thermal envelope

The lower-cure thermal envelope becomes necessary because the recycled fraction can broaden the exotherm and reduce the width of the gel point window; the compound is therefore formulated with a slightly reduced peroxide level and longer soak time rather than elevated temperature. The formulation addition ratio places DVR 002A at 70–90 phr of total polymer, with 10–30 phr virgin EVA for consistency, 2.0–3.0 phr azodicarbonamide, 0.5–0.9 phr dicumyl peroxide, 1.0–1.5 phr zinc oxide, and 0.5–1.0 phr zinc stearate; curing is run at 155–165°C instead of 170–178°C, with mold residence extended to 12–20 min for plank thickness above 30 mm. The downstream production process uses a multi-daylight hot press with forced cooling of the platens before decompression, because uncontrolled venting leads to internal splits and warpage in recovery footwear planks; the molded plank is split into sheets on a band-knife splitting machine, then buffed and skived to taper the forefoot and heel zones. Industry compliance for this segment includes ISO 10993-5:2009 cytotoxicity and ISO 10993-10:2010 skin irritation for prolonged skin contact, REACH EC 1907/2006 Annex XVII entry 52 for phthalates in articles, and ISO 845:2006 for density consistency across the plank. Terminal products are molded footbeds for diabetic recovery footwear, post-operative shoe inserts, and custom-milled orthotic midlayers.

For lightweight protective padding in team sports and outdoor recreation, the compounder must balance energy return, bulk density, and impact attenuation without crossing brand-specific volatile organic content limits. DVR 002A is usually added at 60–80 phr of the polymer fraction, with 20–40 phr of ethylene-octene elastomer to lower the glass transition and improve impact resilience, 2.0–3.5 phr azodicarbonamide, 0.6–1.0 phr dicumyl peroxide, and 1.5–3.0 phr high-structure carbon black or silica for tear strength; the compound is foam-injection molded or compression molded into sheets and dies with density 0.12–0.25 g/cm³. The downstream process often uses a continuous foam extruder with L/D 44:1–52:1, downstream calibration, and a hot-air crosslinking tunnel at 180–200°C; manufacture of contoured protective inserts uses compression molding of pre-foamed planks at 150–165°C with 8–10 MPa pressure. Compliance includes EN 1621-1:2012 for limb impact protectors where applicable, ISO 179-1:2023 Charpy impact for material characterization, and REACH EC 1907/2006 Annex XVII entry 52 for restricted phthalates; for outdoor recreational foam, accelerated weathering under ISO 4892-2:2013 may be specified by the buyer to evaluate UV yellowing and embrittlement. The terminal finished product types include knee and elbow protective pads, helmet comfort liners, backpack padding, hip pads for motorcycling garments, and anti-vibration mats for sports flooring.