Arlanxeo

On continuous automotive glass run channel and weatherstrip extrusion lines operating at 18–25 m/min through 90 mm cold-feed pin-barrel extruders with L/D 16:1, screw temperature set points of 65–80 °C, and die head pressure of 120–180 bar, Arlanxeo EPDM grades with ethylene contents of 55–70 wt% and ethylidene norbornene contents of 4.5–9.0 wt% are compounded with high-structure N550 carbon black at 110–130 phr, paraffinic plasticizer at 80–100 phr, calcium carbonate at 50–70 phr, and a sulphur donor cure system composed of 0.8–1.2 phr mercaptobenzothiazole, 1.2–1.8 phr tetramethylthiuram disulfide, 0.4–0.6 phr dipentamethylenethiuram tetrasulfide, 5.0 phr zinc oxide, and 1.0 phr stearic acid. Mixing is completed in a 270 L intermeshing tangential internal mixer at ram pressure 0.6 MPa and drop temperature 135–145 °C, giving Mooney viscosity ML(1+4) at 100 °C of 55–70 MU per ISO 289-1:2018. Die swell is normally held below 35% at apparent die shear rate 1,200 s⁻¹; surface melt fracture appears above 2,500 s⁻¹ in compounds with narrow molecular weight distribution, and is corrected by increasing die temperature to 90–100 °C or raising paraffinic oil content from 80 phr to 100 phr. Hot air vulcanisation uses tunnel oven temperatures of 230–250 °C and residence time of 3–5 min, producing crosslink density biased toward monosulphidic bonds and compression set below 35% after 22 h at 70 °C per ISO 815-1:2019. Mandatory release checks include tensile strength ≥ 10 MPa and elongation at break ≥ 350% per ISO 37:2017, heat ageing 70 h at 100 °C per ISO 188:2011 retaining ≥ 70% of original elongation, and tear strength per ISO 34-1:2022. The following gradient is observed when N550 carbon black loading is varied at fixed oil and cure levels.

What Limits Chloroprene Rubber in Low-Temperature Crystallization-Resistant Cable Jackets?

Low-temperature flexibility in polychloroprene cable jackets is controlled less by glass transition temperature than by crystallisation kinetics. In Arlanxeo chloroprene rubber produced by continuous emulsion polymerisation with mercaptan chain transfer, the slower crystallisation rate arises from irregular trans-1,4 microstructure distribution; at −10 °C, such polymers can remain ductile for 8–16 h, whereas xanthogen-modified grades with higher stereoregularity harden within 2–5 h. This difference is measured by low-temperature compression set after 22 h at −10 °C per ISO 815-1:2019 and by cold bend testing on finished sheathed cable per IEC 60811-504:2012. A production jacket compound is mixed in an internal mixer to a drop temperature of 105–115 °C and calendered to 0.8–1.2 mm thickness before continuous vulcanisation in pressurised steam at 180–190 °C and 1.4–1.6 MPa; residence time of 60–90 s is set to achieve accelerated cure without surface bloom. The acid acceptor system contains 5.0 phr zinc oxide and 4.0 phr magnesium oxide to neutralise hydrogen chloride released by dehydrochlorination during long service at elevated temperature. Accelerator selection follows EU CLP Regulation (EC) No 1272/2008; ethylene thiourea is replaced with thiadiazole-based accelerators at 1.0–1.5 phr to maintain a favourable toxicological profile without losing scorch safety. For cables that must limit acid gas generation, 15–30 phr calcium carbonate or hydrotalcite is added as acid scavenger, but the resulting modulus increase requires recalibration of low-temperature performance. Mechanical acceptance relies on DIN 53504:2017 tensile strength ≥ 9 MPa and elongation at break ≥ 400%, while hot air ageing 7 days at 100 °C per ISO 188:2011 requires retention of ≥ 70% elongation. Smoke density is measured per IEC 61034-2:2005 and acid gas evolution per EN 50267-2-2:1999. Polychloroprene jackets are not recommended for continuous exposure above 100 °C because dehydrochlorination accelerates, and antioxidant addition of octylated diphenylamine at 1–2 phr extends process stability but does not remove the upper temperature boundary.

When Arlanxeo Hydrogenated Nitrile Is Specified for Progressive Cavity Pump Stator Elastomers in Sour Service

Arlanxeo hydrogenated nitrile butadiene rubber with residual double bonds below 5.5% and acrylonitrile contents from 34 wt% to 44 wt% is selected for progressive cavity pump stators in produced fluids containing 1–20% hydrogen sulphide and 2–30% carbon dioxide at bottomhole temperatures up to 150 °C. High hydrogenation is essential; free double bonds above 5.5% undergo progressive sulphide attack, causing hardness increase and surface cracking under sour gas conditions. The base compound uses 5–7 phr dialkyl peroxide on calcium carbonate carrier, 1.5–2.5 phr triallyl isocyanurate coagent, 45–55 phr N330 carbon black, 5–10 phr trioctyl trimellitate, 1.5 phr zinc oxide, and 0.5 phr 4,4'-di-tert-octyldiphenylamine. Mixing is divided into two passes: masterbatch insertion in an intermeshing internal mixer at final temperature 125–130 °C, followed by peroxide addition on a two-roll mill at 50–60 °C to prevent scorch. Stator blanks are compression moulded at 175–180 °C under 10–15 MPa for 20–30 min; injection moulding of large stators requires a low-shear screw with check ring and barrel temperatures of 80–95 °C to minimise premature cure. Qualification is performed in simulated sour gas at 100 °C, 10 MPa, 95 h with gas composition 5% H₂S, 20% CO₂, and 75% CH₄ based on modified ISO 23936-2:2011 and NORSOK M-710. Acceptance limits require hardness change ≤ 10 Shore A, volume change ≤ 15%, and tensile strength change ≤ 50%. The following comparative data across acrylonitrile content were obtained on press-cured compounds with 50 phr N330 and peroxide cure.

Published data for specific downhole configurations are limited; operator validation under NORSOK M-710 remains mandatory before field installation. Low-temperature performance is screened by TR10 brittleness per ISO 812:2017, and solvent resistance by ASTM D471-16a after 72 h at 23 °C in ASTM reference fuel C. Higher acrylonitrile content decreases fuel swell but raises the TR10 temperature and hardens the compound; plasticizer addition above 10 phr is partially extracted by crude oil and gas, causing volume loss and possible seal failure. HNBR is also incompatible with amine-based corrosion inhibitors, methanol slugs, and phosphate ester fire-resistant fluids unless full immersion testing demonstrates otherwise.

For halogen-free flame-retardant jackets in rolling-stock and offshore topside cable constructions, Arlanxeo ethylene-vinyl acetate copolymers with vinyl acetate contents of 50–80 wt% are compounded with 120–180 phr precipitated aluminium hydroxide, 10–25 phr zinc borate, 2–3 phr vinyl silane coupling agent, and 2.5–4.0 phr dicumyl peroxide. Mixing is carried out in a Buss co-kneader with L/D 15:1 and pin temperature 60–70 °C; the high vinyl acetate content lowers crystalline melting and permits filler dispersion at 90–105 °C without scorch. Cable extrusion is performed on a 60 mm barrier screw extruder with L/D 24:1, melt temperature 95–110 °C, and line speed 25–50 m/min; vulcanisation follows in a dry-air line at 200–220 °C with air velocity 1.0 m/s. Crosslink density is monitored by hot set testing per IEC 60811-507:2012 at 200 °C under 0.2 MPa; elongation under load is limited to ≤ 175% and permanent set to ≤ 15%. Flame retardance is evaluated by limiting oxygen index per ISO 4589-2:2017 with a typical result of ≥ 34%, acid gas evolution per IEC 60754-1:2011 with pH ≥ 4.3 and conductivity ≤ 10 µS/mm, and smoke density per IEC 61034-2:2005 with light transmittance ≥ 60% after 60 min. The high filler loading reduces tensile strength to 8–11 MPa per ISO 37:2017 and increases density to 1.45–1.55 g/cm³. Formulations must avoid amine-based antioxidants and amine-functional silanes because these additives scavenge peroxide radicals and can reduce crosslink density by 25–40%. Pre-drying at 70 °C for 2–4 h is mandatory when storage relative humidity exceeds 60% to prevent steam porosity in thick jackets.

Butyl Rubber Pharmaceutical Closure Compounds and Steam Sterilisation Limits

Pharmaceutical closure compounds based on Arlanxeo bromobutyl and chlorobutyl polymers with halogen contents of 1.1–2.0 wt% and Mooney viscosity ML(1+8) at 125 °C of 32–52 MU are used for injection vial stoppers, lyophilisation closures, and blood collection closures because of low gas permeability and high damping. Clean pharmaceutical closure formulations use 3–5 phr zinc oxide, 1–2 phr stearic acid, and 0.5–1.5 phr magnesium oxide; sulfur-containing accelerators are excluded where low extractable and low nitrosamine profiles are required under ICH M7. Filler selection is limited to calcined kaolin at 40–80 phr and precipitated silica at 5–15 phr; carbon black is not used in high-purity closure compounds because it contributes to particulate contamination and UV fluorescence failures in aqueous extracts tested per USP ⟨381⟩ and EP 3.2.9. Compression moulding is performed at 165–175 °C and 10–15 MPa for 8–12 min; injection moulding requires a low-compression screw with L/D 12:1 and shut-off nozzle to prevent hold-up and scorch. Cure is monitored by moving die rheometer at 180 °C, 1° arc, 15 min; target t90 is 5–8 min and MH−ML is ≥ 0.5 dN·m. Vulcanisate tensile strength per ISO 37:2017 is ≥ 8 MPa, elongation at break ≥ 600%, and hardness 40–55 Shore A per ISO 7619-1:2018. Autoclave sterilisation at 121 °C for 30 min or 134 °C for 3 min requires buffered formulations to keep aqueous extract pH between 5.5 and 7.5 per ISO 8871-1:2003. Inadequate magnesium oxide or zinc oxide activity allows hydrogen halide accumulation in the autoclave, lowering extract pH below 4.0 and causing USP ⟨381⟩ failure. Bromobutyl compounds are not recommended where endotoxin depyrogenation above 200 °C is used because halogen loss accelerates and acidic decomposition products can degrade the elastomer network.

Polybutadiene Particle Size Distribution Governs HIPS Notched Izod Response Across Phase Inversion

In high-impact polystyrene polymerisation, Arlanxeo low-cis polybutadiene with cis-1,4 content of 35–40%, Mooney viscosity ML(1+4) at 100 °C of 35–55 MU, and 5 wt% solution viscosity in styrene of 170–190 mPa·s is dissolved in styrene at 18–22 wt% rubber content for continuous stirred tank pre-polymerisation at 95–110 °C. Phase inversion occurs when conversion reaches 15–25%, at which point the initially continuous polybutadiene-rich phase becomes dispersed as grafted rubber particles; this transition is monitored by torque change and dispersive analysis. Free-radical grafting with 0.01–0.05 phr tert-butyl perbenzoate and 0.02–0.08 phr benzoyl peroxide generates polybutadiene-grafted polystyrene, and the resulting particle size distribution is controlled to 0.5–3.0 µm because notched Izod impact rises with particle size within this window but falls when coarse particles above 10 µm appear as unpigmented surface defects. Devolatilisation is carried out in a two-stage vacuum unit at 220–240 °C and 3–9 kPa absolute pressure to reduce residual styrene below 500 mg/kg; excessive shear in the devolatiliser decreases rubber crosslinking and lowers impact strength. Mechanical acceptance uses ASTM D638-14 tensile yield strength ≥ 25 MPa, ASTM D256-23a notched Izod at 23 °C of 80–120 J/m for medium-impact HIPS and 150–200 J/m for high-impact grades, ASTM D1238-23a melt flow rate at 200 °C/5 kg of 3–10 g/10 min, and ASTM D1003-21 light transmittance of 20–40% depending on mineral oil content. Rubber bales stored above 25 °C exhibit cold flow, which destabilises dissolving tank feed; pre-milling or slicing at 10–15 °C is required to maintain uniform dissolution. Residual styrene above 500 mg/kg violates food-contact requirements under EU Regulation (EC) No 10/2011 unless the specific HIPS grade is demonstrated to meet overall migration limits for the intended food type.