Copolímero de acetato de vinilo de etileno EVAtech EVA 140T/9D

Carbon black masterbatch lines processing 38–48 wt% furnace black in LDPE/LLDPE film and injection moulding applications impose a carrier-resin requirement that is not met by standard low-density polyethylene at the same let-down ratio: a melt mass-flow rate of 9 g/10 min at 190°C/2.16 kg under ISO 1133-1:2022 balances screw intake in the feed zone with sufficient melt strength to prevent die-hole drool at pelletizing temperatures. The 14 wt% vinyl acetate comonomer in 140T/9D lowers the crystalline melting plateau relative to LDPE and broadens the wetting front around carbon black aggregates during the mixing stage, which reduces filter-screen pressure rise and permits carbon black loadings of 38–48 wt% without exceeding 220°C melt temperature. A typical masterbatch formulation contains 38–45 wt% carbon black, 35–50 wt% 140T/9D carrier, 5–10 wt% PE wax or Fischer-Tropsch wax, and 0.1–0.5 wt% antioxidant/stabiliser package; the concentrate is let down in LDPE/LLDPE at 2–5 parts per 100, equivalent to 0.5–2.0 wt% vinyl acetate in the final film compound. Production is carried out on a co-rotating twin-screw extruder with L/D 40:1 or greater, segmented kneading blocks configured with two or three intensive mixing zones, barrel temperature profile 160–210°C, screw speed 400–800 rpm, and melt pump discharge pressure held below 250 bar to minimise shear heating. The strand is pelletised through a water-ring cutter, and the resulting pellets are typically tray-dried at 60–70°C for 2–4 h when packaged in moisture-proof bags. This configuration is compliant with REACH Regulation (EC) No 1907/2006 as an article constituent, and where indirect food-contact packaging use is foreseen, the compounded film must comply with EU 10/2011 and, for US-bound packaging, FDA 21 CFR 177.1350 for ethylene-vinyl acetate copolymers. Terminal finished products include black concentrate pellets supplied to blown-film lines for agricultural mulch or refuse sacks and to injection moulders of crates, pails, and closures where carbon black dispersion below 30 μm agglomerate size is specified.

Why Is 140T/9D Selected as the Low-VA Component in Crosslinked EVA Foam Blends?

In crosslinked EVA foam production for footwear midsoles and sports mats, the primary polymer is conventionally a copolymer with 18–28 wt% vinyl acetate because it provides the required expansion and elastic recovery; however, single-polymer formulations exhibit high tack, lower Shore C hardness, and elevated compound cost. The 14 wt% VA grade 140T/9D is introduced as a low-VA dilution component at 15–30 phr of total polymer to raise compound hardness by 3–7 Shore C at constant density, reduce surface tack after demoulding, and shift the compression set curve without eliminating the expansion window. The critical process conflict is the matching of azodicarbonamide decomposition to dicumyl peroxide crosslinking. In a typical foam recipe, polymer blend is 70–85 phr of 18–26 wt% VA EVA and 15–30 phr 140T/9D; azodicarbonamide is added at 2.5–4.5 phr, dicumyl peroxide at 0.5–1.2 phr, zinc oxide at 1.0–2.0 phr, stearic acid at 0.5–1.0 phr, and calcium carbonate filler at 5–20 phr where density modification is required. The zinc oxide-accelerated azodicarbonamide decomposition exotherm begins near 155–170°C, while the half-life of dicumyl peroxide is approximately 1 min at 171°C; if the peroxide crosslink network forms before gas release, cell growth is constrained and part thickness may fall below the tool gap. Mixing is performed in a Banbury internal mixer with jacketed temperature 75–110°C, followed by a two-roll mill set at 80–95°C, where the compound is sheeted to 1.0–3.0 mm thickness for sheet foam or pelletised for injection-compression moulding. Curing and blowing are conducted in a hydraulic press at 160–175°C for 8–15 min at 150–180 kg/cm², followed by direct cooling under pressure to stabilise cell geometry; foam density typically ranges from 0.08 g/cm³ to 0.25 g/cm³ depending on blowing-agent loading and press pressure. Compliance testing for foam slabs uses ASTM D3575 for flexible cellular materials, ASTM D395 for compression set, ISO 845 for apparent density, and ASTM D624 for tear strength; REACH compliance is required for the azodicarbonamide decomposition product semicarbazide where applicable in EU food-contact or toy fillers, and toy-grade foams are additionally evaluated under EN 71-3 for element migration. Terminal finished products are compression-moulded or injection-expanded midsoles, footbeds, flip-flop sole sheets, and crosslinked EVA sports-mat slabs.

Cast-film sealant webs for lamination to oriented polypropylene or PET require a resin with reduced seal initiation temperature relative to LDPE but with higher strength after the sealing jaw opens than higher-VA EVA grades. In this configuration 140T/9D is run as a sealant-layer constituent rather than as a bulk structural layer: it is added at 70–100 wt% of the sealant layer, with the balance being C4-LLDPE, while the sealant layer itself accounts for 10–25% of total film thickness. The resulting seal can be processed through a three-layer cast coextrusion line with single-screw extruders of L/D 30:1, melt temperature 200–240°C, die gap 0.6–1.0 mm, air gap 100–200 mm, and chill roll temperature 12–18°C at line speeds up to 400 m/min. For food-grade lamination structures, the sealant web must comply with FDA 21 CFR 177.1350, EU 10/2011, and REACH Regulation (EC) No 1907/2006; published data for the exact seal-initiation temperature of this grade in a commercial three-layer structure is limited, and line trials are required to establish the jaw-temperature profile. Terminal finished products include lamination films for coffee pouches, snack packaging, medical overwrap, and label films where medium hot-tack strength and controlled seal-through-contamination performance are specified.

Halogen-Free Cable Jacketing Compound Modifier and Filler Wetting Limits

Halogen-free flame-retardant cable jackets are formulated on a polyolefin matrix containing high loadings of aluminium trihydroxide and magnesium dihydroxide. In this system, 140T/9D is introduced not as the sole base resin but as a polar modifier at 15–30 phr in a compound containing 70–85 phr LDPE, 5–10 phr maleic anhydride-grafted polyethylene coupling agent, 120–160 phr aluminium trihydroxide, and 30–60 phr magnesium dihydroxide. The vinyl acetate functionality increases filler wetting and permits total filler loading up to 60–65 wt% without melt fracture at jacket-line shear rates. Processing is constrained on the upper end by aluminium trihydroxide dehydration beginning near 200°C and by acetic acid evolution from the vinyl acetate group under basic filler catalysis, so compounding is carried out on a co-rotating twin-screw extruder with L/D 40:1, side-feed for fillers, two-stage vacuum venting, and melt temperature held below 190°C. Jacket extrusion uses a single-screw extruder with temperature profile 120–170°C, compression screw with L/D 24:1, and pressure screen pack 80–120 mesh; pre-drying is required at 60–70°C for 2–4 h if relative humidity exceeds 60%. Tensile and elongation after ageing are tested under IEC 60811-501, with jacketing compounds typically specified for minimum elongation at break of 125% after 7 days at 100°C. Terminal finished products are single-core and multi-core low-voltage power cable jackets, control cable sheaths, and railway signalling cable sheaths where halogen-free performance is mandatory.

When 140T/9D Replaces Standard LDPE in Impact-Modified Injection Moulding Compounds

Replacing a portion of standard LDPE with 140T/9D in injection moulded flexible articles reduces environmental stress-cracking in detergent-contact closures and improves cold-temperature drop resistance in containers. The resin is added at 10–30 wt% of the total LDPE compound, with the balance LDPE and, where required, 2–5 wt% processing aid or colour masterbatch. Injection moulding is carried out on a reciprocating-screw machine with barrel temperature 180–230°C, back pressure 5–15 bar, and mould temperature 15–40°C; pre-drying at 60°C for 2 h is required only when ambient relative humidity exceeds 60% or when recycled LDPE with retained moisture is included. Low vinyl acetate content limits acetic acid generation during residence times below 5 min, but vented cylinders are recommended if the compound contains heavily contaminated regrind. Tensile properties are evaluated under ISO 527-2, notched Izod impact under ISO 180, and Vicat softening temperature under ISO 306; food-contact articles require FDA 21 CFR 177.1350 or EU 10/2011 compliance. Terminal finished products include flexible lids, caps, squeeze bottles, housewares, and cable jointing sleeves where stress-crack resistance under surfactant exposure is a primary specification.

Closed-loop reprocessing of post-industrial LDPE film scrap frequently produces a melt with reduced elongation at break and unstable bubble geometry on blown-film lines because of chain scission from prior heat history and residual print inks. Addition of 5–15 wt% 140T/9D to the regrind stream raises the low-strain modulus and improves bubble stability at blow-up ratios from 2.0:1 to 2.8:1 without requiring a separate compatibiliser. The recycled compound is processed on a single-screw recycling extruder with degassing, barrel temperature 160–210°C, continuous screen changer with 120–150 mesh filtration, and downstream pelletising or direct sheet feed. Because the feedstock contains post-industrial LDPE that may retain printing inks and processing aids, the resulting film is not assigned to direct food-contact applications unless a functional barrier is separately validated under EU 10/2011 or FDA 21 CFR 177.1350; compliance thresholds under REACH Regulation (EC) No 1907/2006 for recycled articles are fulfilled through supplier declaration of the incoming scrap stream. Terminal finished products include refuse sacks, construction film, temporary protective film, and non-food carrier bags where a defined minimum elongation at break under ISO 527-3 must be achieved at 15–25 wt% recycled content.