Copolímero de acetato de vinilo de etileno Ateva 1820

Injection-grade EVA foam production for athletic footwear midsoles consumes Ateva 1820 as a primary base polymer because the 18 wt% vinyl acetate segment lowers crystallinity sufficiently to permit uniform gas nucleation while retaining enough melt strength for cell growth during chemical blowing. The resin is normally pre-blended in an internal mixer at a dump temperature of 105–115 °C with dicumyl peroxide at 0.5–1.0 phr as crosslinking agent, azodicarbonamide at 1.5–3.5 phr as chemical blowing agent, zinc oxide at 1.0–2.0 phr as decomposition activator, stearic acid at 0.5–1.0 phr as lubricant, and calcium carbonate at 5–15 phr as a cell nucleating filler. Production-scale reciprocating-screw injection molding machines use barrel zones maintained at 90–105 °C in the feed section, 105–115 °C in the compression section, and 115–125 °C in the metering section, while the nozzle is held no higher than 125 °C to prevent premature gas release; the mold cavity is heated to 165–180 °C so that the blowing agent decomposes only after the melt has filled the cavity. The foaming window is intentionally narrow: if the mold temperature falls below 160 °C, azodicarbonamide conversion remains incomplete and molded density rises above 0.25 g/cm³, whereas mold temperatures above 180 °C produce cell coalescence, surface gas marks, and inconsistent shrinkage. Compliance for the resin itself is normally documented by the producer against REACH Regulation EC No 1907/2006, while finished foam components may be evaluated under ASTM D3575-20 for closed-cell polyolefin foam properties including density, compression set, and tensile behavior. Terminal products include injection-molded running shoe midsoles, sandal soles, flip-flop outsoles, and orthotic shoe inserts.In compression-molded EVA foam sheet manufacture for gymnasium mats, anti-fatigue floor tiles, and wall padding, Ateva 1820 is charged as the largest single resin component in two-roll mill mixing. A representative industrial formulation combines 100 parts by weight of Ateva 1820 with 2.0–4.0 phr azodicarbonamide, 0.8–1.5 phr dicumyl peroxide, 1.0 phr zinc stearate or equivalent dispersing agent, and 10–20 phr mineral filler. The two-roll mill is maintained at 90–100 °C so that the peroxide is blended below its decomposition threshold; the milled sheet is then cut and placed into a hydraulic compression press with platens heated to 165–175 °C and pressure of 10–15 MPa. Residence time ranges from 8 to 15 minutes per 10 mm of sheet thickness, allowing simultaneous crosslinking and gas expansion. Batch-to-batch variance in production-scale sheet lines is controlled by holding the front roll within ±2 °C and the rear roll within ±3 °C; wider deviation produces visible density variation, especially in sheets above 20 mm thickness. Article-level compliance for consumer children’s play mats may require EN 71-3 migration limits for certain elements, while industrial matting is commonly tested under ASTM D3575-20. Finished product types include 5–50 mm EVA exercise mats, anti-fatigue standing mats, children’s play mats, and industrial knee pads.

What Heat-Seal Initiation Range Arises from an 18 wt% Vinyl Acetate Comonomer Distribution in Coextruded Sealant Webs?

Within coextruded flexible packaging lines, the heat-seal initiation temperature of an EVA sealant layer is governed by melting of the ethylene crystallites and the free volume contributed by the 18 wt% vinyl acetate side groups. Ateva 1820 is typically blended with LLDPE or LDPE in the sealant web at an addition ratio of 60–100 wt% EVA in the sealant resin fraction; the remainder may be an ethylene-butene LLDPE with density 0.918 g/cm³ added to raise hot-tack strength. In three-layer structures, the sealant layer is coextruded at 15–30 µm thickness between the product contact side and a tie layer, with extrusion temperatures limited to 200–220 °C at the die and a reverse temperature profile to avoid resin degradation. The downstream conversion process is blown film or cast film coextrusion followed by form-fill-seal packaging on horizontal or vertical machines. On packaging lines, the sealant layer displays a seal initiation range of 85–105 °C under ASTM F2029-16 conditions of 0.28 MPa seal pressure and 0.5 s dwell, depending on film gauge and blending ratio; lower addition ratios of Ateva 1820 move the seal initiation upward, while 100% EVA seals at the lower end. Compliance for direct food contact requires the fully formulated film to meet FDA 21 CFR 177.1350 for ethylene-vinyl acetate copolymers and, in the EU, Regulation EU No 10/2011 with an overall migration limit of 10 mg/dm²; specific migration of vinyl acetate monomer must be verified under intended time-temperature conditions because residual monomer is a function of polymerisation and degassing efficiency. Terminal products include frozen food pouches, liquid detergent stick-packs, shredded cheese packaging, and medical device overwrap where additional ISO 11607-1:2019 seal integrity validation is completed by the converter.

Carrier Resin Performance in High-Load Polyolefin Masterbatch on Co-rotating Twin-Screw Lines

Co-rotating twin-screw compounding lines with length-to-diameter ratios from 44:1 to 52:1 and screw diameters from 35 mm to 75 mm use Ateva 1820 as a carrier resin for pigment, additive, and filler concentrates that are subsequently diluted into polyethylene and EVA-based extrusion or injection moulding processes. The addition ratio in the masterbatch formulation is governed by the targeted loading: for 30–50 wt% pigment concentrates, Ateva 1820 comprises 50–70 wt% of the batch, with the balance consisting of dispersing waxes and the active pigment or additive; for 70–80 wt% calcium carbonate or talc concentrates, the carrier fraction falls to 20–30 wt%. The lower crystallinity of the 18 wt% vinyl acetate comonomer contributes to wetting of the pigment surface and permits lower melt temperatures in the side-fed section, typically 130–160 °C, which is critical for heat-sensitive organic pigments. Production-scale lines feed the majority of the mineral or pigment via a side-stuffer located at 16D–20D from the main feed throat to preserve screw fill and to avoid surging; vacuum devolatilisation at -0.08 MPa to -0.09 MPa removes low-molecular-weight volatiles trapped by the EVA melt. The concentrate is pelletised through a water-ring or underwater pelletiser with die-face temperatures kept below 180 °C to prevent resin yellowing and acetic acid release. Regulatory compliance for colourants and additives in food-contact packaging is not determined by the carrier alone but by the complete masterbatch under EU No 10/2011 and FDA 21 CFR 174.5 for indirect additives; a certificate of composition and migration testing on the final packaging article are required. Terminal downstream articles include coloured polyethylene film, injection-moulded caps and closures, EVA foam, and polyolefin pipe.

The principal standard references across these conversion sectors are consolidated below.

Conversion sector	Standard or regulation	Test method or clause	Measured parameter
Flexible packaging sealant	FDA 21 CFR 177.1350	EVA copolymer food-contact limitations	Food-contact suitability
Flexible packaging sealant	EU No 10/2011	Annex II migration testing	Overall migration ≤ 10 mg/dm²
Injection-moulded footwear foam	ASTM D3575-20	Closed-cell polyolefin foam test methods	Density, compression set, tensile
Resin incoming control	ISO 1133-1:2022	Condition 190 °C/2.16 kg	Melt mass-flow rate 2.0 g/10 min
Hot-melt adhesives	ASTM D3236-15	Brookfield Thermosel	Viscosity at 180 °C
Halogen-free cable jacket	IEC 60754-2	Combustion gas pH and conductivity	pH ≥ 4.3, conductivity ≤ 10 μS/mm

When a low-vinyl acetate EVA base is selected for packaging hot-melt adhesives, the melt viscosity at 180 °C and the cohesive strength at low temperature become the primary formulation variables. Ateva 1820 is incorporated at 15–25 wt% in standard packaging hot-melt formulations, combined with 30–50 wt% hydrogenated hydrocarbon or rosin ester tackifier, 10–20 wt% Fischer-Tropsch or paraffin wax, and 0.5–1.0 wt% hindered phenolic or phosphite antioxidant. The production process is batch or continuous mixing in a jacketed vessel under nitrogen blanketing at 150–170 °C; the molten adhesive is then applied through roller coaters, slot nozzles, or spraying systems to corrugated board, folding cartons, and paperboard. Equipment selection matters because the EVA phase can undergo deacetylation and viscosity drift if hot spots exceed 200 °C; large-capacity melters with recirculating manifolds should be calibrated to hold melt temperature within ±5 °C. Adhesion performance is tested under ASTM D4498-07 for heat-fail temperature of hot melt adhesives and ASTM D3236-15 for viscosity at 180 °C using a Brookfield thermosel; ring-and-ball softening point is measured under ASTM E28-18. Compliance for adhesive use in food packaging requires FDA 21 CFR 175.105 for indirect food additives and EU Framework Regulation EC No 1935/2004, but published data for this exact grade in every specific adhesive configuration is limited because tackifier compatibility screening determines final peel, shear, and cold-flex performance. Terminal products include case and carton sealing, tray erection, bag closing, and labelling adhesives.

Low-Smoke Jacketing Compounds Derive Char Integrity from 18 wt% Vinyl Acetate Segments

Flame-retardant cable jacketing compounds based on EVA/LLDPE blends utilise the vinyl acetate fraction as a char-forming carbon source and as a compatibility bridge for high loadings of magnesium hydroxide or aluminium trihydrate. Ateva 1820 is typically incorporated at 30–50 wt% of the polymer fraction, with the remainder being LLDPE or maleic anhydride-grafted polyethylene; the total polymer fraction usually represents 35–45 wt% of the compound, while halogen-free mineral flame retardants account for 50–60 wt%, supplemented by 1–2 wt% processing aids, 0.2–0.5 wt% antioxidants, and 0.5–2.0 wt% zinc borate or organoclay synergists. Mixing is conducted in an internal mixer at a final melt temperature of 150–170 °C or in a co-rotating twin-screw extruder with length-to-diameter ratio of 44:1–52:1 and downstream side-feeding of the mineral filler to avoid excessive shear heating. The resulting compound is pelletised and then extruded as a jacket onto insulated conductors in a single-screw extruder with a temperature profile of 140–190 °C, a low-compression screw with a compression ratio of 2.0:1–2.5:1, and a pressure screen pack to trap agglomerates. Halogen-free performance is tested according to IEC 60754-1 for halogen acid gas content and IEC 60754-2 for combustion gas pH and conductivity, typically requiring pH ≥ 4.3 and conductivity ≤ 10 μS/mm, with smoke density evaluated under IEC 61034-2; flame spread is assessed by IEC 60332-1 or IEC 60332-3 depending on cable construction. Crosslinking of the jacket may be carried out by electron beam irradiation at 60–150 kGy to improve hot-set performance, but uncrosslinked EVA/LLDPE jackets based on Ateva 1820 are generally limited to service temperatures not exceeding 70 °C under continuous load. Terminal products include low-voltage control cable sheathing, building wire insulation, and halogen-free data cable jackets where local building codes require low-smoke, zero-halogen materials.