INEOS Styrolution ABS TERLURAN HH-202 is an amorphous acrylonitrile-butadiene-styrene injection moulding grade positioned in the high-heat segment of the Terluran portfolio. It is supplied as pelletized granules with a three-phase morphology consisting of a styrene-acrylonitrile matrix, dispersed polybutadiene rubber particles, and a grafted SAN shell. The product is specified where intermittent service temperatures exceed the practical ceiling of general-purpose ABS but do not justify the higher density, higher melt viscosity, and higher compound cost of PC/ABS alloys. Representative manufacturer-published values place density at 1.06 g/cm³ per ISO 1183-1, melt volume-flow rate at 7 cm³/10 min under 220°C/10 kg per ISO 1133-1, and Vicat softening temperature B/50 at approximately 119°C per ISO 306. These values are typical reference points rather than specification limits; lot-specific certificates of analysis remain controlling for final part qualification.

Which Thermal and Rheological Boundaries Define the Component Design Space?

The material is formulated to shift the short-term heat resistance upward while retaining a melt viscosity compatible with multi-cavity injection moulding. In comparison with general-purpose ABS grades, which typically exhibit Vicat B/50 values between 95°C and 98°C, TERLURAN HH-202 extends the softening boundary to approximately 119°C under the same ISO 306/B50 heating rate of 50 K/h with a 50 N indenter load. The trade-off is a reduction in flow length and a narrowing of the processing window at lower barrel temperatures. Melt volume-flow rate of 7 cm³/10 min at 220°C under 10 kg load places the grade below high-flow ABS variants that may reach 20 cm³/10 min or above; thin-wall parts with flow-length-to-wall-thickness ratios above 150:1 require gate placement and pressure-drop verification rather than assumption of standard ABS flow behaviour.

Heat deflection temperature under 1.8 MPa load is reported near 104°C per ISO 75-2/A. The gap between Vicat softening and HDT is significant because ABS is amorphous and softens gradually rather than exhibiting the sharp melting transition of semicrystalline polymers. Component design must consider creep and load-bearing behaviour above 90°C, particularly for snap-fit geometry and threaded bosses. At 23°C, the notched Charpy impact strength is approximately 12 kJ/m² per ISO 179-1eA; at -30°C, the value falls to near 5 kJ/m². The low-temperature impact retention is inferior to PC/ABS alloys with notched Charpy values commonly above 30 kJ/m², which limits specification of HH-202 in crash-relevant interior trim or exterior exposed parts in cold climates.

When compared with lower-heat ABS grades, the increase in Vicat comes from a modified SAN matrix and controlled rubber content. The impact-stiffness trade-off is evident in the tensile modulus near 2300 MPa per ISO 527-2, which is slightly higher than many general-purpose ABS grades. Flexural modulus is reported in the range of 2400 MPa per ISO 178. The material does not contain mineral or glass reinforcement; therefore, anisotropic shrinkage and elevated density associated with filled thermoplastics are absent. Mould shrinkage of 0.4%–0.7% per ISO 294-4 is within typical ABS range, but high-heat grades can show greater sensitivity to packing pressure and gate freeze-off due to faster solidification at the wall.

Predrying, Residence Time, and Gate Freeze-Off Boundaries

Moisture control is a hard process boundary. ABS pellets absorb atmospheric moisture, and the rubber phase can hold water at the interface. Pre-drying at 80°C for 2 h to 4 h in a desiccant dryer with a dew point no higher than -20°C is required. Residual moisture above 0.05% produces splay, silver streaking, and dimensional variation in moulded parts. Hopper loads exceeding 4 h residence in humid plant air above 60% RH can reintroduce moisture even when the dryer is functioning; closed conveyance from dryer throat to feed throat is required in high-humidity regions.

Melt temperature at the nozzle is maintained between 230°C and 260°C. Below 230°C, unmelted SAN domains and insufficient rubber phase dispersion can cause surface delamination and gate blush. Above 260°C, the butadiene phase begins to degrade, producing yellowing and a measurable loss in impact strength. The upper boundary is more restrictive than for general-purpose ABS because the high-heat formulation has a higher softening point and therefore may tempt processors to raise temperature to reduce viscosity. The thermal degradation pathway is autocatalytic once free acrylic acid or butadiene breakdown products accumulate in the barrel; prolonged residence time at high temperature accelerates the effect.

Screw design should use a general-purpose three-zone screw with an L/D ratio of 20:1 to 24:1 and compression ratio near 2.0:1. Back pressure is maintained between 0.5 MPa and 1.5 MPa, sufficient for homogenization without excessive shear heating. Screw speed should be adjusted to achieve a melt residence time below 5 min at 240°C; long withdrawal times on large machines can produce brown streaks and an odour threshold shift. Hot runner manifold and nozzle temperatures should not exceed 260°C by more than 5°C, even during start-up. Thermocouple drift in hot runner zones above 10°C from setpoint has been associated with gate-cavity blocking and local char formation on multicavity automotive instrument panel trim tools.

Mould temperature is selected between 40°C and 80°C. High-heat ABS exhibits a narrow gloss retention window; mould temperatures below 40°C produce low gloss, visible weld line weakness, and increased moulded-in stress. Temperatures above 80°C extend cycle time without proportional improvement in mechanical properties and can produce plate-out on textured cavity surfaces. Water-fed mould temperature control units with a setpoint stability of ±2°C are standard. For grained interior surfaces, cavity-side temperatures at the upper end of the range are used to reproduce grain depth and reduce stress whitening around ribs. For dimensional stability, holding pressure profiles must be adjusted for gate freeze-off timing; high-heat ABS typically freezes gates faster than general-purpose ABS at the same wall thickness because the solidification front advances earlier.

When the Specification Requires Vicat B/50 Above 118°C Without PC/ABS Cost Structure

Applications for TERLURAN HH-202 concentrate in heated interior enclosures, ventilation ducts, electrical housings, and domestic appliance components exposed to steep thermal gradients. Instrument cluster surrounds, centre console trim, switch bezels, and automotive interior vent assemblies are produced by injection moulding at clamp forces commonly between 800 kN and 3000 kN depending on projected area and number of cavities. The material is selected when the part must survive 110°C continuous or 120°C intermittent soak without visible deformation. Dimensional testing under heat ageing is often performed based on ISO 175 chemical resistance or ISO 1110 accelerated conditioning, with part-level acceptance commonly fixed at less than 0.5 mm deflection after 500 h at the upper service temperature.

Household appliances use HH-202 in toaster housings, iron skirts, heater fan grilles, and control panels. The UL 94 rating is HB at 1.6 mm, not V-0; therefore, parts requiring flame retardancy must either use a different grade or be evaluated for application-specific exemptions. Electrical tracking index and surface resistivity are not enhanced by conductive additives; the material is electrically insulating but not inherently antistatic. For printed circuit board enclosures, ventilation openings and rib spacing must account for a lower melt flow than flame-retardant ABS grades. Published data for specific electrical current-carrying shrouds in IEC 60695 test configurations is limited; the grade is not a drop-in replacement for flame-retardant ABS in proximity to live parts without additional barrier design.

In comparison with PC/ABS alloys, TERLURAN HH-202 has lower density, typically 1.06 g/cm³ versus 1.12–1.16 g/cm³, and lower minimum processing temperature. However, its notched low-temperature impact is substantially lower, and its chemical resistance to aggressive cleaning agents is typical of ABS rather than polycarbonate-containing blends. Avoid combination with ketone-based cleaning solvents and aromatic hydrocarbons; ABS undergoes stress-cracking under tensile load in the presence of these fluids. For medical or food-contact applications, only the specific regulatory confirmation on the manufacturer datasheet for the production lot applies; the base material is not automatically designated for repeated food contact across all regions.

Thermal Degradation Signatures and Incompatibilities

Thermal degradation in TERLURAN HH-202 is first visible as yellowing, accompanied by a fall in notched Charpy impact and an increase in melt-flow rate due to chain scission. The rubber phase is the most thermally sensitive component; exposure above 260°C for more than 5 min can generate free rubber radicals that reduce impact strength by more than 20% relative to the dry-as-moulded baseline. Operators can detect the onset through a characteristic change in purge colour from natural to tan, followed by brown streaking. Regrind incorporation is permitted up to 20% by weight when the regrind is generated from properly dried, uncontaminated sprues and runners; higher regrind ratios increase batch-to-batch variability in melt viscosity and surface gloss. The grade should not be blended with amine-based antistatic packages or certain copper-containing stabilizers, as these can accelerate rubber-phase oxidation at processing temperatures. PC/ABS blends should not be mixed with this material unless the blend ratio and thermal stabilizer package have been pre-validated, because the two systems have different viscosity-temperature profiles and phase compatibilization requirements.

Moisture re-uptake in silo storage above 60% RH restores surface moisture within 8 h to 12 h even after correct drying. This operational boundary is frequently overlooked in plants where dried material is conveyed through non-dried hoppers. The solution is not increased barrel temperature but a closed drying and conveying loop with dry air purge. In an actual production line using an 1800 kN injection moulding machine and a 16-cavity hot runner tool for automotive ventilation louvres, gate freeze-off variation above ±1.5 s produced unacceptable part-to-part shrinkage scatter; the defect disappeared only after holding pressure was paired with cavity-specific cooling control and a stable melt cushion of 3 mm to 5 mm. Such results are consistent with high-heat ABS behaviour but are not a substitute for tool-specific process validation.

When painted or metallized, TERLURAN HH-202 requires surface preparation typical of ABS: power wash, deionized rinse, and a primer matched to the substrate. Solvent-based primers containing high proportions of ketones or chlorinated solvents should be qualified for stress-cracking tendency before use. Adhesion testing per ISO 2409 cross-cut or DIN 53151 is applied on textured surfaces after paint cure. The high heat grade does not eliminate the need for adhesion promoters on grained interior surfaces; plasma or corona pretreatment may be used when surface tension falls below 38 mN/m as measured by test inks complying with ISO 8296. Published data for this specific configuration is limited; therefore, surface treatment settings must be established by line trials.

For dimensional stability, parts moulded in HH-202 show post-mould shrinkage due to stress relaxation and moisture uptake. Annealing at 85°C for 2 h can reduce subsequent dimensional movement in parts exposed to elevated service temperatures, but this is not a universal requirement. Geometric features with abrupt wall-thickness transitions must be radiused; notch and sharp corner geometry reduces the effective impact resistance by concentrating stress in the SAN phase. Rib thickness should not exceed 50% of the nominal wall thickness to avoid sink marks and internal voids. Gate size for high-heat ABS is often made 10%–15% larger than for general-purpose ABS to compensate for the earlier freeze-off and to transmit holding pressure during solidification.