Ateva 4030ACX EVA Copolymer Resin,40% VA,55 MI,Low Gel,Insulation Shield Grade

When MV XLPE Cable Designs Demand a Strippable Insulation Shield with Controlled Peel Behaviour

In medium-voltage power cable construction rated 6 kV to 35 kV under IEC 60502-2:2014, the outer semiconductive insulation shield is co-extruded over XLPE dielectric and must simultaneously prevent air void formation at the shield-dielectric interface during load cycling and allow clean, residue-free peel at termination. Ateva 4030ACX is selected as the base polymer for this layer because the 40% vinyl acetate comonomer content increases polarity sufficiently to wet conductive carbon black at loadings of 35–55 phr, while the melt mass-flow rate of 55 g/10 min determined at 190°C/2.16 kg by ISO 1133-1:2022 supports thin-gauge extrusion without excessive head pressure. The designation “low gel” refers to a reduced count of unmelted gel particles per unit area, not to a low crosslinked gel fraction after vulcanization; this is critical at insulation shield thicknesses of 0.8 mm to 1.2 mm, where a single protrusion can concentrate the electrical field and lower partial-discharge inception voltage. This grade is not used as the XLPE dielectric itself; moisture uptake and dielectric loss associated with 40% vinyl acetate exceed the limits for primary insulation in IEC 60502-2:2014.

Compliance for this application is evaluated against IEC 60502-2:2014, HD 620 S2:2020, and ICEA S-93-639/NEMA WC 74:2016. Non-metallic screen volume resistivity is determined by ASTM D257-14 and is typically held at or below 500 Ω·m at 90°C after cure; tensile elongation is tested per ASTM D638-14, and melt flowability is retested per ASTM D1238-20. Peel force is not defined as a single IEC requirement; utility specifications commonly derive peel force from 25 mm wide strips pulled at 180°, and published data for this specific configuration is limited, so strippability windows must be established on the target cable construction and conductor size. Moisture content above 0.05% warrants pre-drying at 60–70°C for 2–4 h before compounding.

A typical strippable shield formulation uses Ateva 4030ACX at 100 phr, corresponding to approximately 58–66 wt% of the finished compound. The remaining components and their dosage ranges are listed below.

Production-scale compounding is performed in a 160 L Banbury internal mixer or a co-rotating twin-screw extruder with 40:1 L/D, using side feed for carbon black. A two-pass mixing sequence is common: the first pass at 110–130°C disperses carbon black and antioxidant; the second pass at 100–115°C incorporates dicumyl peroxide and minimizes scorch. For this application, amine-based additives are avoided because they can interfere with dicumyl peroxide decomposition. Melt is filtered through 140–150 mesh screens before pelletizing to remove carbon black agglomerates and residual gel particles. The cable layer is applied on a triple-layer crosshead in a catenary continuous vulcanizing line; the shield extruder is typically a 60–75 mm single-screw machine with 24:1 L/D, barrier screw, and a melt pump. Melt temperature at the die is held between 115°C and 125°C; premixing lines and screw elements are cooled to avoid premature vulcanization. Cure proceeds at 180–250°C under 10–20 bar nitrogen or steam pressure. After cooling, stress-relief annealing is applied before rewinding to prevent layer shrinkage. Terminal finished product types include 6/10 kV, 12/20 kV, and 18/30 kV XLPE-insulated power cables used in wind farm feeders, underground residential distribution, and industrial medium-voltage feeders.

Low-smoke building and transit cables that must pass IEC 60332-1-2:2015 vertical flame testing place a different set of demands on Ateva 4030ACX than semiconductive shield layers: here the 40% vinyl acetate content is exploited for filler wetting and char formation rather than carbon black conductivity. The resin permits filler loadings of 120–180 phr alumina trihydrate and 0–50 phr magnesium dihydrate without the surface melt fracture seen in low-VA ethylene copolymers. The 55 g/10 min melt flow rate under ISO 1133-1:2022 maintains extrusion output on 60–90 mm sheathing extruders despite high filler volume fractions. Low gel count reduces pinhole formation in thin-wall sheaths down to 0.6 mm nominal thickness.

Compliance for this application is checked against IEC 60754-1:2011 and IEC 60754-2:2019 for halogen acid evolution, IEC 61034-2:2005 for smoke density, IEC 60332-1-2:2015 for vertical flame propagation, and EN 50363-7:2005 for halogen-free flame-retardant sheathing compounds. Regulatory status for EU shipments is documented under REACH (EC) No 1907/2006 and RoHS Directive 2011/65/EU. Hot set elongation after peroxide or silane crosslinking is evaluated per IEC 60811-507:2012; tensile and elongation before aging are determined by IEC 60811-501:2012. The formulation addition ratio starts with Ateva 4030ACX at 100 phr, with ATH at 120–180 phr, optional MDH at 0–50 phr, a vinyl silane or maleic anhydride compatibilizer at 1–2 phr, a hindered phenolic antioxidant at 0.5–1.5 phr, and a processing aid at 2–4 phr. On a total weight basis, the resin content is approximately 26–33 wt%.

Compounding is run on a co-rotating twin-screw extruder with 48:1 L/D and multiple side feeders to prevent filler bed compression. Melt temperature is controlled between 100°C and 140°C; the upper limit is set below the dehydration onset of ATH at approximately 180°C. Vacuum devolatilization is used to keep moisture below 0.05%, and the melt is filtered through 100–120 mesh screens. Cable sheathing is extruded on a 60–90 mm single-screw extruder with 25:1 L/D and a temperature profile of 120–150°C; a melt pump and profile gauge reduce wall-thickness variation. Batch-to-batch variation in filler particle size distribution can shift melt viscosity by 10–15%, so torque rheometer data are used to adjust shear rate and temperature profile before start-up. Terminal finished product types include building riser cables, mass transit rolling-stock cables, data center power distribution cables, and shipboard low-smoke cables.

What Electron Beam Dose Produces a 50% Gel Fraction in 40% VA EVA Heat-Shrink Tubing?

Radiation-crosslinked heat-shrinkable sleeving for cable joints and terminations uses Ateva 4030ACX as a high-VA base because the polar comonomer broadens the radiation dose window and improves dimensional recovery after expansion. In production, gel fraction is a more reliable control variable than beam current. A formulation containing Ateva 4030ACX at 100 phr, conductive carbon black at 30–50 phr, a flame-retardant package at 60–100 phr, an antioxidant at 1.5–2.5 phr, a radiation sensitizer at 1–3 phr, and a processing aid at 2–4 phr produces a resin content of 38–50 wt% and a radiation response that reaches 50–65% gel fraction after 15–25 Mrad electron beam exposure. Gel fraction is measured by ASTM D2765-16.

Product specifications reference ASTM D2671-21 for heat-shrinkable tubing, IEC 60684-3:2019 for flexible insulating sleeving, and UL 224:2021 for extruded insulated tubing. Low-temperature flexibility is verified through ASTM D2671-21 test methods; hot set after crosslinking is evaluated per IEC 60811-507:2012. Production begins with twin-screw compounding at 110–140°C to disperse carbon black without degrading the vinyl acetate comonomer. The compound is extruded into tubing on a 30–60 mm single-screw extruder with a vacuum calibration sleeve; melt temperature is held at 120–140°C. The extruded tube is irradiated in an electron beam unit to an absorbed dose of 15–25 Mrad, targeting 50–65% gel fraction. After irradiation, the tubing is heated to 150–180°C in hot air or liquid medium, expanded onto a mandrel or by internal air pressure, and quenched to lock in the expanded shape. Because 40% vinyl acetate reduces crystalline melting point, storage of expanded tubing above 50°C may initiate premature recovery. Terminal finished product types include heat-shrinkable cable joint outer sleeves, termination kits, busbar insulation sleeves, and breakouts for medium-voltage accessories.

Where a cable compounder supplies multiple triple-layer lines, Ateva 4030ACX is also employed as the carrier resin in conductive carbon black masterbatch because the 55 g/10 min melt flow rate and 40% vinyl acetate permit carbon black loadings of 35–45 wt% with fewer carrier dilution problems than LDPE. The masterbatch route is preferred when site dust control and dispersion repeatability are more critical than direct compounding. Masterbatch quality is checked by melt flow rate per ISO 1133-1:2022, volume resistivity of compression-molded plaques per ASTM D257-14, and density per ASTM D792-20. If the masterbatch is intended for EU cable grades, documentation covers REACH (EC) No 1907/2006 and RoHS Directive 2011/65/EU.

Carrier resin content is set at 45–60 wt%; carbon black at 35–45 wt%; process aids at 2–5 wt%; antioxidant at 0.5–1.5 wt%. Typical let-down ratio into a finished semiconductive shield compound is 1:4 to 1:6 by weight, depending on the target final carbon black level of 35–45 phr. Published data for the exact let-down ratio in a specific compounder setting is limited; the stated range reflects typical equipment capability. Masterbatch is produced on a co-rotating twin-screw extruder with 40:1 L/D, side-fed carbon black, and a screw profile using high-shear kneading blocks followed by low-shear distributive elements. Melt temperature is maintained at 130–160°C; underwater pelletizing is followed by classifier and moisture control to below 0.05%. The pellets are metered into the cable compounder at the let-down ratio stated above; no additional pre-drying is required if sealed packaging is used and storage relative humidity remains below 60%. Terminal outputs are conductive black masterbatches used in insulation shield and conductor shield compounds for medium-voltage power cable, and in semi-conductive jackets for underground cable accessories.

Bonded Conductor Shield Extrusion over Stranded Copper at Line Speeds above 20 m/min

On triple-layer extrusion lines, the inner semiconductive conductor shield is applied over stranded copper or aluminum conductors at nominal thicknesses of 0.5–0.8 mm before the XLPE insulation layer. Ateva 4030ACX provides the melt flow required to penetrate the outer strands and fill interstices without forming voids at the conductor-shield interface. The 55 g/10 min melt flow rate under ISO 1133-1:2022 allows extrusion at low melt pressure, but the same flow can reduce melt viscosity to the point where die drool increases; the extruder must therefore be configured with a melt pump and a screen pack of 100–150 mesh to stabilize output.

Conductor shield compounds are validated under IEC 60502-2:2014 and HD 620 S2:2020; volume resistivity is measured by ASTM D257-14 and is typically required to remain below 500 Ω·m at 90°C. Pre-cure scorch time is assessed by a moving-die rheometer at 125°C to confirm safe residence time before the die. The formulation addition ratio uses Ateva 4030ACX at 100 phr, conductive carbon black at 40–60 phr, antioxidant at 0.8–1.5 phr, processing aid at 1–3 phr, and dicumyl peroxide at 0.8–1.8 phr. Resin content is approximately 52–60 wt% of the final compound.

The conductor is preheated to 90–110°C before entering the triple-layer crosshead; shield melt temperature is controlled at 115–125°C, while the XLPE insulation extruder runs higher. The crosshead is designed to maintain draw ratio between 1.2:1 and 1.6:1 to prevent layer necking. The line is purged with nitrogen at start-up; any resin stagnation above 130°C can initiate premature peroxide crosslinking and generate gel particles in the screen pack. After crosslinking and cooling, the cable is tested for partial discharge, layer thickness, and conductor adhesion. Terminal finished product types include 1 kV to 35 kV XLPE-insulated power cables for overhead line conversion, industrial plant feeders, and wind turbine tower and nacelle cabling.