WENEW Braskem America DVR 001A Copolímero EVA, Conteúdo Reciclado de 60%, Espuma e Grado de Calçados

WENEW Braskem America DVR 001A is an ethylene-vinyl acetate copolymer grade supplied in pelletized form for foam and footwear manufacturing. The grade carries a recycled content fraction of 60% by mass, classified under ISO 14021:2016 as recycled material from declared pre-consumer and post-consumer sources; the exact split is retained in supplier mass-balance records. The vinyl acetate comonomer content falls within 18–28 wt%, which controls crystallinity, flexibility, gas diffusion, and compatibility with chemical blowing agents. Melt mass-flow rate, tested at 190°C with a 2.16 kg load under ASTM D1238 or ISO 1133-1:2022, is controlled between 1.5 g/10 min and 3.0 g/10 min; this range supports thick-section expansion and thin-wall flow in injection-molded footbeds. Density, determined by ASTM D792, is 0.938–0.947 g/cm³. The material is not supplied with a single hardness specification because final hardness depends on crosslinking density, blowing agent loading, and filler content; common midsole compounds may target Shore A 55–75 after cure, but lot-specific certificates should be used for design. The DVR 001A designation identifies the recycled-content EVA within the Braskem America WENEW circular product line. Its intended processing routes include compression molding, injection molding, sheet extrusion, and hot/cold foam expansion for midsoles, outsoles, sandals, slippers, and protective sports foam.

What separates DVR 001A from virgin EVA and broad-spec recycled feedstocks?

Generic virgin EVA feedstocks are sold with tight melt-index tolerance and low gel counts. DVR 001A differs because its recycled content introduces additional sources of variability: residual crosslinked elastomer particles, inorganic fragments from footwear compounds, and variable thermal history. These are managed through feedstock sorting, melt filtration, and blending, but the grade is not a drop-in replacement for virgin EVA in formulations requiring optical clarity or very low gel counts. Compared with broad-spec recycled EVA, DVR 001A is selected specifically for foam cell nucleation, footwear cycle-time requirements, and control of vinyl acetate content. Compared with compounds containing 30% recycled content, DVR 001A increases the circular feedstock share but may require higher stabilizer addition and finer screen filtration to maintain surface quality in expanded sheet. The recycled fraction also shifts the carbonyl index, measurable by Fourier-transform infrared spectroscopy under ASTM D5576, relative to virgin EVA; this index is used in incoming inspection to detect oxidation that reduces melt strength. Batch-to-batch variation in gel count can influence melt viscosity. On production-scale twin-screw lines, changes in screw torque and die pressure between virgin EVA and DVR 001A are expected; if torque variation exceeds 10%, screen pack replacement or feedstock blending is indicated. The material is not intended for high-clarity film, cable jacketing, or food-contact parts unless specific validation is performed. For crosslinked foam manufacturing, DVR 001A is typically compounded with azodicarbonamide-based blowing agents, dicumyl peroxide crosslinking agents, zinc oxide activators, and stearate processing aids. The compounding step on a co-rotating twin-screw extruder with an L/D ratio of 40:1 to 52:1 requires barrel temperatures below the decomposition onset of the blowing agent, commonly 155°C for pure azodicarbonamide but reduced to 135–145°C when activators are present. The grade should be pre-dried at 60–70°C for 2–4 h when sacks have been stored at relative humidity above 60%. The recycled fraction can contain trace thermoplastic degradation products that act as nucleating sites, producing finer cell size at equivalent blowing agent loading compared with virgin EVA; this effect is useful for midsoles but requires stable die pressure to prevent cell coalescence. Injection-molded foam articles are produced with injection pressures in the 80–120 MPa range, while gas counterpressure at 0.5–1.5 MPa is applied to control surface defects. Screen-pack blockage from gel particles is the primary production failure mode; operators monitor pressure rise and replace packs when pressure exceeds 3.5 MPa above baseline. Die steel should be corrosion-resistant because traces of acetic acid can appear at processing temperatures approaching 220°C.

Melt rheology, foam cell nucleation, and extruder load thresholds

Melt viscosity and elasticity under processing conditions determine cell nucleation density, cell wall stability, and final foam density. Capillary rheometry under ISO 11443 at 190°C and shear rates from 100 s⁻¹ to 1000 s⁻¹ is used to characterize DVR 001A across the shear regime encountered in extrusion and injection molding. The elongational viscosity, which controls bubble growth resistance, is influenced by the 18–28 wt% vinyl acetate content and by lightly crosslinked recycled particles; these particles can act as high-melt-strength domains that reduce collapse of expanding foam cells. However, the same particles may increase melt pressure at the breaker plate by 5–15% relative to virgin EVA, necessitating screen packs from 40 to 80 mesh depending on gel size distribution. Screens are placed upstream of the die to trap particles larger than 100 µm, preventing surface pinholes in sheet foam lines running at thicknesses of 1–10 mm. In crosslinking foam systems, the cure curve is measured by moving die rheometry under ASTM D5289; DVR 001A formulations are typically adjusted to achieve a scorch time TS2 greater than 1.5 min at molding temperature and a cure time T90 below 8 min for acceptable cycle times. At extruder load thresholds, the specific energy input may vary from virgin EVA due to gel particles; melt pump inlet pressure should be maintained above 2 MPa to avoid cavitation. Mechanical property retention in DVR 001A depends on the ratio of recycled to virgin EVA, the degree of crosslinking, and the presence of crosslinked particles. Tensile strength and elongation of unreinforced plaques can be measured under ASTM D638 or ISO 527-2, and tear strength under ASTM D624 or ISO 34-1. At equivalent vinyl acetate content, the recycled grade may show tensile strength within 10–20 MPa and elongation at break above 500%; these values are formulation-dependent and should not be used as resin specifications. The recycled fraction can reduce low-temperature flexibility, but the effect is minor within footwear service temperatures from -10°C to 40°C. For foam compression set, compounds based on DVR 001A can be formulated to achieve values below 30% under ASTM D395 Method B at 50°C for 6 h, provided that crosslink density is controlled. Hardness, measured by ASTM D2240 or ISO 868, is typically adjusted by modifying filler content and blowing agent ratio rather than by selecting a different EVA base resin.

When recycled content exceeds 50% in ethylene-vinyl acetate feedstock

At recycled content levels above 50%, the melt is more sensitive to thermal history and residual contamination than virgin EVA. DVR 001A therefore requires stricter handling limits: melt temperature should be held between 105°C and 125°C in compounding for chemically blown foam to prevent premature blowing agent decomposition, while injection barrels may be set to 110–145°C with nozzle temperatures not exceeding 160°C. Above 220°C, vinyl acetate degradation releases acetic acid; in closed molding areas this promotes corrosion of unplated steel tool surfaces and can reduce crosslinking efficiency of peroxide cure systems. The recycled fraction can contain trace zinc, calcium, or silica residues from footwear compounds, which may catalyze uneven decomposition of azodicarbonamide; therefore the activator package is adjusted on a lot basis after evaluating blowing agent gas yield by thermogravimetric analysis under ASTM D3850. When combining DVR 001A with other polyolefins, compatibility should be assessed by differential scanning calorimetry under ASTM D3418 because the effective vinyl acetate content may shift the crystallization peak below 75°C and affect demolding shrinkage. Storage should be in sealed containers at ambient temperatures below 30°C and relative humidity below 60%; opened material should be re-dried before processing if exposure exceeds 4 h. Quality control for DVR 001A is based on melt flow rate, vinyl acetate content, density, gel count, and retained recycled content. Because the feedstock includes recycled EVA from foam and footwear scrap, the certificate of analysis should be reviewed for lot-specific melt index and gel count, not only product data sheet nominal values. Recycled content validation is conducted through supplier mass balance under ISO 14021:2016 and, where applicable, ISCC PLUS chain-of-custody certification. Regulatory conformance for the final article is assessed against EU REACH Regulation (EC) No 1907/2006 and Directive 2011/65/EU (RoHS); DVR 001A is not granted direct food-contact status under 21 CFR 177.1350 unless specifically confirmed by the supplier for a defined application and recycling stream. For inventory control, the recycled share is tracked by lot; this prevents commingling with virgin EVA and supports downstream claims under ISO 14021.

Characterization and compliance matrix for WENEW Braskem America DVR 001A

Parameter	Test method or basis	Control range or reference
Recycled content	ISO 14021:2016 /mass balance	60% by mass
Melt mass-flow rate	ASTM D1238 /ISO 1133-1:2022	1.5–3.0 g/10 min at 190°C, 2.16 kg
Density	ASTM D792	0.938–0.947 g/cm³
Vinyl acetate content	ASTM D5594 /internal	18–28 wt%
Melting peak	ASTM D3418 /ISO 11357	75–95°C
Regulatory boundary	21 CFR 177.1350	Not granted without supplier confirmation

Life cycle inventory calculations for recycled EVA generally follow ISO 14040 and ISO 14044, with cut-off or mass-allocation rules documented in supplier case studies. The carbon footprint reduction attributable to the 60% recycled content is not a fixed percentage because it depends on collection radius, scrap yield, and electricity grid; published data for this specific configuration is limited. Downstream converters should request the supplier’s lifecycle assessment report and allocation method before making comparative environmental claims under ISO 14025 or ISO 14067.