ELIX Polymers ABS ELIX ABS U2700 is an unfilled acrylonitrile-butadiene-styrene terpolymer supplied as pellets for injection moulding and, where melt strength is adequate, thin-gauge sheet or profile extrusion. The grade is one of the supplier’s ABS product lines, and its final formulation, colour, additive package, and mechanical properties are lot-dependent. The supplier’s certificate of analysis and technical datasheet revision are therefore the controlling documents; third-party sources may not reflect the current production formulation. Published data for this specific grade remain limited outside the manufacturer’s documentation, so the processing and application commentary below is framed around the unfilled ABS class within which U2700 is positioned, with density typically 1.04 g/cm³–1.07 g/cm³ under ISO 1183-1:2019 and melt volume-flow rate in the higher-flow region of the supplier’s ABS range under ISO 1133-1:2022.

The U2700 code is a supplier-specific grade designation, not an ISO 1043-1:2011 or ISO 2580-1 material code. Before this material is transferred into an existing mould or extrusion line, the incoming lot should be compared with the incumbent material using the same test methods: melt viscosity at the relevant shear rate, notched impact, Vicat softening temperature, and flexural modulus. Nominal commercial descriptions are not sufficient because two ABS grades with similar melt flow can differ substantially in rubber-phase architecture, gloss retention, and stress-cracking resistance.

Where the supplier datasheet is complete, the property set should include melt volume-flow rate under ISO 1133-1:2022 at 220 °C and 10 kg, density under ISO 1183-1:2019, tensile modulus and yield stress under ISO 527-2:2012, flexural modulus under ISO 178:2019, Charpy notched impact under ISO 179-1:2010, and Vicat softening temperature under ISO 306:2022 method B50. If any required value is absent, it should be measured by an accredited laboratory on the same colour and conditioning history before production release.

What is the practical difference between U2700 and high-heat or PC/ABS grades in the same tool?

The main boundary is melt temperature and residence time. Unfilled high-flow ABS of this class is normally processed at first-stage melt temperatures of 230 °C to 260 °C, whereas heat-resistant ABS may require 250 °C to 280 °C, and PC/ABS blends commonly require 260 °C to 300 °C. A tool qualified for U2700 may suffer from existing ABS residues degrading if the barrel is raised to PC/ABS temperatures, especially in hot-runner dead zones. Conversely, U2700 should not be placed into a tool with very thin walls and restrictive gates designed for a very low-viscosity PC/ABS without first confirming flow length under realistic injection pressure because unfilled ABS may have lower spiral-flow length at equivalent melt temperature.

Mechanical differences are equally important. PC/ABS grades generally provide higher low-temperature notched impact and higher deflection temperature under load than unfilled ABS. U2700 should be evaluated under ISO 179-1:2010 for Charpy notched impact and ISO 75-2:2013 for heat deflection temperature in the relevant specimen thickness. Published comparative data for this specific grade are limited; a side-by-side moulding trial using identical tool geometry remains the only reliable qualification method for replacement of a high-heat or PC/ABS material.

Drying, screw geometry, and melt residence boundaries for production-scale start-up

Before processing, pellets should be dried in a desiccant dryer with supply air dew point no higher than -40 °C. A drying temperature of 80 °C for 2 h to 4 h is typical for unfilled ABS to reach residual moisture below 0.05 % by weight. Where ambient relative humidity exceeds 60 %, hopper residence should be shortened or drying time extended. Failure to reach the moisture target commonly produces splay, silver streaks, weld-line surface defects, and gloss variation on polished cavity surfaces because absorbed moisture volatilises at the melt front.

Reciprocating-screw machines with screw diameter 30 mm to 80 mm, L/D ratio 20:1 to 24:1, and compression ratio 2.5:1 to 3.0:1 are normally suitable for unfilled ABS. A melt cushion of 3 mm to 6 mm, back pressure from 0.5 MPa to 1.5 MPa, and screw recovery speed between 40 rpm and 100 rpm are practical starting points. These settings are not lot-specific; they must be adjusted against the measured U2700 melt volume-flow rate and part geometry.

Total residence time at melt temperature should be kept below 5 min. Barrel settings above 260 °C can discolour unfilled ABS, increase yellowness index, and generate a sharp degradation odour. If production is interrupted, barrel temperatures should be reduced to approximately 180 °C or the barrel purged with a compatible styrenic purge compound.

Mould temperature is a primary variable for gloss, weld-line strength, and dimensional stability. For unfilled ABS, mould temperatures between 40 °C and 80 °C are used; lower settings shorten cycle time but may reduce gloss and weld-line performance. High-gloss visible parts often require the upper end of this range with separately circuited cores to maintain uniform surface temperature. Weld-line improvement is usually achieved by increasing local mould temperature and relocating gates, not by raising barrel temperature alone.

Gate size should be selected to avoid jetting while providing adequate shear heating. Pin gates of 0.8 mm to 1.2 mm are used for many unfilled ABS parts, but small gates can freeze prematurely; exact gate dimensions require flow analysis using the grade’s actual viscosity curve. Hot-runner manifolds should be set at 240 °C to 260 °C with insulated drops. Dead spots or unheated nozzle tips can retain material and produce dark streaks. On multi-cavity tools, cavity-to-cavity fill imbalance below 5 % is recommended to prevent pressure peaks and overpacking.

When U2700 is evaluated for exterior or UV-exposed components

The U-suffix should not be interpreted as an automatic guarantee of UV stabilisation unless the supplier’s datasheet explicitly states the stabiliser package. If the application includes exterior or semi-exterior exposure, weathering resistance must be verified by lot-specific accelerated weathering data under ISO 4892-2:2013 or ASTM G155-13, not by grade name. UV-stabilised ABS can still show gloss loss, yellowing, and surface microcracking before bulk tensile strength degrades; pigmented or coated surfaces are often required for long-term appearance retention.

Accelerated weathering using xenon-arc equipment with daylight filters at 0.35 W/m² at 340 nm, black-standard temperature near 65 °C, and water spray is often used for screening. However, a colour or gloss result after 1000 h does not alone establish service life. Qualification requires correlation with real-time outdoor exposure in the intended climate, particularly where UV intensity and humidity differ from laboratory cycles.

The ISO 2580-1 designation block for ABS is the correct framework for comparing U2700 with other ABS grades. It encodes melt volume-flow rate, Vicat softening temperature, notched impact, flexural modulus, and other prescribed values in a fixed order. Because U2700 is a commercial grade code, its ISO designation can only be assembled from the manufacturer’s released data. Comparing two ABS grades on melt flow alone is insufficient; capillary rheometry at shear rates between 100 s⁻¹ and 1000 s⁻¹ provides the viscosity curve relevant to mould filling, while extensional melt strength governs extrusion sag and thermoforming behaviour.

Tensile and flexural data must be read with the exact standard. ISO 527-2:2012 uses specimen type 1A and separates modulus and yield measurements by test speed; ASTM D638-14 Type I specimens are pulled under different conventions. Therefore tensile modulus generated under ISO 527-2 is not automatically interchangeable with ASTM D638 values. Conditioning at 23 °C and 50 % relative humidity according to ISO 291 is commonly required for comparable moisture-sensitive results, but certificate-of-analysis values may be dry-as-moulded.

Notched Charpy impact under ISO 179-1:2010 uses edgewise type 1 specimens with notch type A; notched Izod under ASTM D256-23 uses a different pendulum geometry and specimen. Values in J/m and kJ/m² are not directly convertible. If U2700 is compared with a North American grade, both materials should be tested on the same colour, thickness, and method before a substitution decision.

Compliance under REACH and RoHS 2011/65/EU is lot-level. Unfilled ABS is not inherently a halogenated flame-retardant compound, but stabilisers and processing aids vary. Food-contact statements under FDA 21 CFR 177.1020 or EU Regulation (EU) No 10/2011 must be obtained from the manufacturer for the specific U2700 formulation, colour, and application condition; migration and end-use restrictions are component-specific. If a UL 94 flame rating is required for an electrical or electronic housing, the exact grade, colour, and minimum thickness should be verified against the supplier’s UL Yellow Card because thin-wall behaviour below 1.5 mm can differ from a rating at 3.0 mm.

Chemical resistance is a stress-cracking issue rather than only solubility. Unfilled ABS is attacked by ketones, esters, aromatic hydrocarbons, and certain chlorinated solvents; contact with MEK, acetone, or toluene can produce environmental stress cracking, especially in moulded parts with frozen-in stress. Chemical compatibility should be tested under ISO 22088-3:2006 or ASTM D543-21 using the actual fluid mixture and maximum service temperature. Room-temperature immersion without visual change does not predict long-term exposure at elevated temperature or under load.

For extrusion and thermoforming, U2700 should be processed on a single-screw extruder with L/D 24:1 to 30:1, a barrier screw with mixing elements, and screen packs of 60/120/60 mesh or equivalent. Melt temperatures at the die of 220 °C to 240 °C are typical starting points for unfilled ABS; the exact setting depends on melt strength and die pressure. Thermoforming of sheet produced from this class is usually conducted at surface temperatures of 130 °C to 180 °C. Published forming data for U2700 are limited, so forming trials with the actual sheet gauge are required before tool commissioning.