SABIC ABS EX75 is an unfilled acrylonitrile-butadiene-styrene terpolymer supplied as a pelletised extrusion grade for flat-sheet extrusion, co-extruded cap layers, and cut-sheet thermoforming. The grade is distinguished by a melt-volume-flow rate below that of thin-wall injection-molding ABS, while retaining a notched Charpy impact value above typical general-purpose extrusion ABS. In practice, the product is selected when sag resistance in a heated oven or during roll-stack conveyance is the primary determinant of acceptable wall-thickness distribution, rather than spiral-flow length or short-shot performance in a multi-cavity mold. The phase structure consists of a continuous styrene-acrylonitrile matrix with dispersed polybutadiene rubber particles; this morphology produces the characteristic balance of rigidity and energy absorption.

How does EX75 occupy the processing window between extrusion-grade and injection-molding ABS?

The distinction between EX75 and an injection-molding grade is not compositional alone; it is expressed in shear-viscosity behavior under standardized flow testing. EX75 is typically reported at 9 cm³/10 min under ISO 1133-1:2022 at 220 °C/10 kg. Injection-molding ABS grades intended for high fluidity may be specified in the 25–35 cm³/10 min range under the same load, allowing filling of wall stocks below 1.2 mm at moderate injection pressures. That flow advantage reverses in sheet extrusion, where a higher melt viscosity stabilizes the web against draw-down and reduces gauge variation across the die width. The difference in molecular weight distribution also affects screw torque: low-flow grades generate higher head pressure at a given screw speed, and therefore require either a larger extruder drive or a lower screw speed to remain within the available melt-pressure envelope.

The representative values in the table are lot-average values from supplier technical literature; production release limits may be narrower or wider and are stated on the certificate of analysis. The comparison with high-flow injection grades is most relevant for processors who attempt to substitute a general-purpose injection ABS into sheet extrusion: the sheet will sag, lose thickness at the web edges, and may fail to track through the roll stack. Conversely, using EX75 for thin-wall injection molding is unlikely to satisfy the fill-speed and flow-length requirements of a mold designed for 15 cm³/10 min or higher melt volume-flow rate.

Prior to extrusion, moisture uptake must be controlled. The polybutadiene phase in ABS is not as hydrolysis-sensitive as polyamide, but residual moisture above approximately 0.05 % by mass can produce silver streaking and a measurable reduction in notched impact strength. Desiccant dryers with a dew point of −30 °C or lower are recommended, with pellet residence at 80 °C for 4 h. If the material is exposed to ambient air above 60 % relative humidity for more than 2 h, re-drying is required. The dryer hopper should not be operated above 95 °C, because prolonged exposure at that temperature can oxidize the polybutadiene phase and shift the product color. On a 30:1 to 36:1 L/D single-screw extruder, typical barrel temperatures are 200–230 °C with the die held at 230 °C, producing a measured melt temperature of 230–250 °C. Head pressure in the range of 150–180 bar is common for a clean screen pack; a rise above 220 bar at constant screw speed indicates screen blockage or insufficient rear-zone melting. Published data for this specific configuration is limited; processors should establish their own baseline using the SABIC processing guide and the actual extruder size.

Thermoforming sag resistance imposes a narrow sheet-temperature band

EX75’s high melt strength is useful only if the sheet temperature profile remains within the forming window. Surface temperatures of 150–170 °C and core temperatures of 140–160 °C are typical for thick-gauge blanks of 3–6 mm. At surface temperatures below 135 °C, elongation is insufficient and microcracks can initiate during plug contact; above 185 °C, the rubber phase can degrade and the sheet shows surface blisters or gloss nonuniformity. In a shuttle oven, the heat time is therefore adjusted to avoid large temperature differences between the sheet edges and center. A temperature differential above 20 °C across the forming area can lead to non-uniform wall thickness, especially in deep-draw parts with draw ratios above 1.5:1. Plug-assist tools made from syntactic foam or glass-filled nylon are used to prestretch the sheet; plug speed is typically kept below 0.7 m/s to reduce plug-contact thinning. Mold temperature is normally maintained at 60–80 °C to balance surface gloss and part release without inducing excessive post-mold shrinkage. Residual stress in the formed part can be annealed by conditioning at 80 ± 5 °C for 1 h, although this practice may increase overall cycle time and is justified only where dimensional stability under subsequent thermal load is critical.

The SAN phase of EX75 is attacked by aromatic hydrocarbons, ketones, esters, and chlorinated solvents. Stress-cracking may occur at external fiber stresses below the yield point when such solvents are present; evaluation of cracked-edge behavior should follow ISO 22088-2:2006 or an equivalent constant-strain method. For interior automotive or appliance components that require paint, a surface treatment to a wetting tension of 40–60 mN/m after flame or plasma treatment is used before priming. Water-based and two-pack polyurethane coatings generally exhibit adequate adhesion when the sheet has been correctly cleaned and static-dissipated. Silicone-based mold release is not recommended because it contaminates the surface and prevents uniform film formation. Published data for paint adhesion on EX75-specific substrates is limited; the converter should run a full adhesion cross-hatch test according to ISO 2409:2020 on production samples. For continuous outdoor exposure, ultraviolet stabilization is required because the polybutadiene phase is susceptible to photodegradation and chalking unless adequately protected.

Regulatory compliance matrix and food-contact verification requirements

RoHS 2011/65/EU restricts lead, mercury, cadmium, hexavalent chromium, PBB, and PBDE. EX75 is typically supplied with documentation stating that these substances are not intentionally added, but a certificate of conformity is required for each production lot. Under EC 1907/2006 REACH, the supplier must provide information on substances of very high concern above 0.1 % w/w. For food-contact use, migration testing under EU 10/2011 and compliance with 21 CFR 181.32 depend on the final article thickness, food simulant, temperature, and time; the resin supplier’s statement should not be used as a substitute for end-use migration testing. The grade’s position under ISO 2580-2:2019 as an ABS moulding and extrusion material requires the designation block to be stated on technical data sheets. For potable-water or medical applications, no global approval should be assumed without explicit certification from SABIC.

When low-temperature impact response determines grade selection for freezer liners

Selecting EX75 for a freezer liner involves a different property ladder than selecting a room-temperature appliance housing. At −30 °C, the measured notched Charpy impact value is in the 12 kJ/m² range, which is adequate for moderate impacts but does not guarantee ductile failure if a sharp notch coincides with a high strain-rate event. Standard general-purpose ABS grades often show a brittle-to-ductile transition above −20 °C, while EX75 retains some ductility below that threshold because of its higher rubber content and optimized rubber particle size. The exact transition temperature is influenced by sheet orientation: thermoforming can align rubber particles and shift the transition by several degrees Celsius. If the application requires failure in a ductile mode at −40 °C, a polycarbonate-modified ABS or high-rubber ABS with a low-temperature impact additive is necessary. The product selection should therefore be supported by notched impact data at the lowest service temperature and by instrumented puncture testing, not by room-temperature Izod values alone.

Pellet handling should avoid contamination with polycarbonate, acrylic, or PVC dust. These contaminants can form domains that alter surface appearance and reduce the consistency of the co-extruded cap layer. Magnetic removal and sieve packs before the hopper are standard on extrusion lines handling regrind. Regrind content should not exceed 20 % of the feed stream unless the application is non-appearance-critical; higher levels increase the risk of gel specks and reduce impact strength. The processing window, particularly in the heated oven and on the roll stack, must be validated on the production line because published data for this specific configuration is limited; only end-use approval against the applicable standard defines the operational boundary.