Acrylonitrile-butadiene-styrene (ABS) grade TERLURAN® E-116, supplied by INEOS Styrolution, is an extrusion/thermoforming ABS designed for sheet lines and downstream deep-draw forming. The material consists of a continuous styrene-acrylonitrile (SAN) matrix with dispersed polybutadiene rubber particles; this two-phase morphology controls both low-temperature impact and hot-sheet stiffness. E-series nomenclature separates the product from injection-moulding Terluran GP and HI series: the E designation is assigned to grades formulated for elevated melt strength, controlled sag, and wider thermoforming windows. Typical applications include refrigerator door liners, automotive interior trim substrates, luggage shells, and sanitary components. Property declarations for this grade should be read against the method codes in the supplier technical datasheet; nominal physical values are consolidated in the following table.

Interpreting E-116 property declarations across ISO method codes

The values below are nominal single-point or range data for natural resin. Conditioning before mechanical testing follows ISO 291 at 23°C and 50% relative humidity unless the method requires otherwise. Lot-to-lot variation may move Charpy notched impact at −30°C by several kJ/m²; therefore process-capability studies should use production-scale sheet specimens, not only granule data.

Within the extrusion die, the shear-thinning index of E-116 can be approximated by a power-law exponent between 0.25 and 0.40 over the shear-rate range 50 s⁻¹ to 1000 s⁻¹ at 230°C, but this must be confirmed by capillary rheometry on the actual lot. Melt strength measured by extensional rheometry is not a datasheet value; however, sheet sag tests on a pilot line with 1.5 mm sheet and 300 mm free span differentiate E-116 from general-purpose injection ABS. The lower melt volume-flow rate corresponds to a longer relaxation time, measurable as higher apparent extensional viscosity at Hencky strains above 1.0; this supports plug-assisted forming without excessive curtain thinning.

What limits the drying and extrusion window?

Pre-drying in a dehumidified-air dryer is mandatory when material has been exposed to ambient humidity, not because ABS is strongly hygroscopic but because surface moisture and retained SAN-bound water generate silver streaks and internal voiding. The supplier-processing guideline for Terluran E-116 specifies drying at 80°C for 2–4 h, with a dew point no higher than −30°C and an air flow sufficient to exchange the hopper volume 4–6 times per hour. Target residual moisture before extrusion is below 0.1 wt%, measured by a Karl Fischer or moisture balance. Overdrying or drying above 95°C can cause granule blocking in the hopper and feed-throat bridging.

Extrusion trials with L/D 33:1 single-screw machines fitted with a barrier screw and Maddock mixer typically operate with a flat-to-reverse barrel profile from 180°C in the feed zone to 220°C at the metering zone, with adapter and die zones held at 225–235°C. A melt temperature measured by immersion probe should remain between 220°C and 240°C. At melt temperatures above 260°C, polybutadiene unsaturation can undergo thermal oxidation and cross-linking, producing gel specks, yellowing, and lower Charpy impact. Throughput on a 75 mm single-screw extruder running 1–2 mm sheet is governed by screw speed, melt pump pressure, and die-lip shear rate; shear rates at the die lips commonly fall between 100 s⁻¹ and 500 s⁻¹. A gear pump upstream of the die is recommended to remove screw-borne pressure pulsation, because thickness variation in thermoformed parts is amplified by the square of draw ratio.

On a 90 mm single-screw extruder with L/D 33:1, typical head pressure for a 1.2 mm sheet die at 300 kg/h throughput lies between 80 bar and 140 bar depending on die gap and restrictor bar settings. Pressure variation across the die width should remain within ±5 bar; larger variation shifts local flow and creates transverse gauge bands. Screen pack specifications commonly start at 40/60/80 mesh and may use a final 100 mesh layer when surface quality demands are high. Frequent screen changes may be required if regrind contains dust from trimming operations.

The processing window narrows when regrind content increases: dried regrind with reduced bulk density feeds less uniformly, and aged polybutadiene phase raises melt viscosity variance. A common production remedy is to maintain regrind below 30 wt% in monolayer sheet unless line trials validate higher ratios with constant melt-pressure standard deviation below 2 bar.

When asymmetric draw ratios create corner thinning, hot-sheet stiffness governs wall distribution

Thermoforming E-116 sheet requires surface temperatures of 140°C to 180°C, with lower temperatures favouring grain retention and higher temperatures favouring deep-draw duplication. The grade’s principal difference from standard injection ABS is not higher impact but a broader rubber-phase relaxation and higher melt strength that resists sheet sag. In plug-assist forming, the plug material is typically syntactic foam, cast nylon, or POM; plug temperature is held at 80–110°C to prevent chilling the sheet before final air pressure of 3–5 bar. Wall-thickness distribution on a 600 mm deep rectangular liner with surface draw ratio 3:1 is sensitive to sheet gauge variation, plug entry speed, and mold temperature. Mold temperatures below 70°C can induce stress whitening at sharp radii; temperatures above 90°C lengthen cycle time and can promote gloss loss on textured surfaces.

Infrared sheet-heating systems with ceramic or quartz emitters tune wavelength to ABS absorption; at sheet thickness above 2 mm, surface-to-core temperature differentials can exceed 10°C and produce forming defects. Plug entry speed above 300 mm/s can induce local orientation and stress whitening. After forming, parts cool in the mold until surface temperature falls below the Vicat softening point; ejection above 95°C may cause corner distortion. Shrinkage after demoulding follows the datasheet moulding shrinkage values; post-forming fixtures are used for 24 h at ambient temperature to stabilize dimensions. Published data for E-116 wall-thickness distributions across all tool geometries is limited; tool trials are required to establish local draw-ratio limits.

Extrusion-grade E-116 versus injection-moulding GP-22 and HI-10

The Terluran E, GP, and HI families are not differentiated solely by melt-flow rate. Terluran GP-22 is a general-purpose injection-moulding ABS with a higher melt volume-flow rate, making it suitable for thin-wall injection filling. Terluran HI-10 is a high-impact injection-moulding grade with a higher rubber content for impact-dominated parts. Terluran E-116 is formulated for sheet extrusion and thermoforming; the lower melt volume-flow rate and higher melt strength reduce sag and edge-webbing during forming. Direct comparison of notched impact values must account for specimen type: Charpy ISO 179-1/1eA values for E-116 at 23°C should not be compared to Izod ISO 180/A values without conversion and the same notch radius.

Laboratory injection-moulded Type 1A tensile bars according to ISO 527-2 are not fully representative of extruded-sheet mechanical properties because sheet orientation and cooling rates differ. When comparing grades, test specimens should be machined from sheet parallel and perpendicular to extrusion direction; Charpy values perpendicular to extrusion may be lower by 5–15% in oriented sheet, depending on draw. Published data for this specific configuration is limited. In production, E-116 has shown lower injection-speed sensitivity than GP grades in thick-walled tooling, but it is not an injection-moulding recommendation; the supplier may direct thin-wall injection applications to GP or HI grades. The E-series also tends to have a different rubber particle size distribution and SAN molecular weight distribution, but published comparative morphological data for these specific grades is limited.

Coextrusion of E-116 as a cap layer over a filled or recycled substrate requires melt viscosity matching at 100 s⁻¹ and 230°C. If the substrate is polycarbonate or PC/ABS, interdiffusion and layer adhesion are generally good, but the layer ratio must keep E-116 wall thickness above 0.3 mm to maintain impact. High-gloss deep-draw parts may require textured tooling to reduce visible sheet flow lines.

Regulatory status, migration limits, and end-use compliance

Compliance statements for Terluran E-116 depend on the final formulation, colorants, processing aids, and food-contact conditions. The base ABS resin may be assessed against 21 CFR 177.1020 for acrylonitrile/butadiene/styrene copolymers, but end-use articles require migration testing under the intended temperature and simulant profile. The supplier should be consulted for a grade-specific declaration under EU Regulation (EU) No 10/2011; specific migration limits for acrylonitrile and butadiene must be verified on the finished article. The product is typically evaluated against REACH Article 33 for substances of very high concern, and against RoHS 2011/65/EU Annex II for cadmium, lead, mercury, hexavalent chromium, PBB, and PBDE.

Operational boundaries include avoidance of melt temperatures above 260°C, residence times above 15 min, and direct contact with ketone, ester, or chlorinated solvents during forming or assembly. Stress cracking can occur when E-116 parts contact plasticising oils, aromatic hydrocarbons, or some synthetic lubricants under strain; annealing stress-relieved parts and selecting water-based or silicone release agents reduce the risk. Flame-retardant addition must be validated for phase compatibility, because some amine-based synergists can interact with residual acrylonitrile groups and alter colour stability. For coextruded structures, the E-116 cap layer must be matched to a substrate with similar melt viscosity to prevent interfacial flow instability; viscosity mismatches above 2:1 at 230°C and 100 s⁻¹ can produce wavy interfaces. Production-scale sheet lines with closed-loop thickness gauges typically hold gauge variation below ±0.05 mm for 1 mm sheet, but this is equipment-specific and should not be assumed without line verification.