Toray Industries TOYOLAC ABS 100-322U is a general-purpose injection-moulding grade of acrylonitrile-butadiene-styrene copolymer supplied in pellet form. The 100-series architecture is formulated around a low-to-medium rubber content, which shifts the property balance toward melt flow, surface gloss, hardness, and dimensional stability while limiting low-temperature impact toughness relative to high-rubber ABS grades. The U suffix denotes a UV-stabilised variant; the exact stabiliser chemistry is proprietary, and published accelerated-weathering data specific to this grade are limited. Consequently, exterior-service qualification should be performed on the finished moulded article rather than inferred from resin selection alone. The grade is used in moulded electronic housings, small appliance covers, automotive interior trim, and general industrial components. Unless otherwise stated, the datasheet values reproduced here are typical and are not to be interpreted as specification limits.

What separates 100-322U from the unmodified 100-322 base resin and higher-impact TOYOLAC series?

In the Toray TOYOLAC nomenclature, the numerical prefix 100 identifies the general-purpose ABS series. The 322 position typically tracks the flow and viscosity target, while the U suffix is associated with ultraviolet stabilisation for improved colour and gloss retention under indirect sunlight and fluorescent indoor exposure. Mechanical properties of 100-322U are generally close to those of 100-322; the differentiating variable is the stabiliser package rather than a shift in rubber content. When the material is compared with the 300-series high-impact ABS grades, 100-322U exhibits a higher melt volume-flow rate and a lower notched impact strength. Published datasheet values indicate a nominal MVR of 32 cm³/10 min at 220 °C and 10 kg for 100-322U, while high-impact 300-series grades may fall in the 12–15 cm³/10 min range. The corresponding notched Charpy impact strength of 100-322U is typically 16 kJ/m² at 23 °C, whereas high-impact grades can exceed 28 kJ/m². This trade-off is deliberate: 100-322U fills thin-wall, complex-flow-length cavities with lower injection pressure than high-impact ABS, but it is not the preferred choice for snap-fit housings exposed to multi-axial impact below 0 °C.

The following typical values are reported for natural-colour pellets under standard conditioning. The test specimen geometry and conditioning protocol influence results; values from a different laboratory should be expected to vary.

Rheological characterisation of this grade should not rely on MVR alone. MVR is a low-shear single-point index at 220 °C and 10 kg; injection moulding involves apparent shear rates at gates between 10³ s⁻¹ and 10⁵ s⁻¹. At these shear rates, the non-Newtonian viscosity of ABS 100-322U decreases substantially. For mould-filling simulation, capillary rheometry data over a shear-rate range of 10¹–10⁴ s⁻¹ and temperatures 220–250 °C should be used. A Cross-WLF viscosity model fitted to these data is typically adequate. Thermal conductivity and specific heat values for ABS are approximately 0.17 W/(m·K) and 1.4 kJ/(kg·K), respectively; these should be measured on the production lot when exact shrinkage or warpage prediction is required. The linear mould shrinkage is anisotropic, with parallel-to-flow shrinkage of 0.4–0.6 % and transverse shrinkage of 0.5–0.7 %. The unfilled formulation produces relatively low warpage in flat covers, but wall-thickness transitions above 25 % of the nominal wall can generate sink marks and asymmetric shrinkage.

Processing Window, Drying Thresholds, and Machine Configuration

Moisture control is the first process boundary. ABS 100-322U pellets develop surface moisture at rates dependent on ambient relative humidity; above 60 % RH, pre-drying in a desiccant dryer is mandatory because vented moisture above 0.08 wt% creates splay, bubbles, and loss of surface gloss. A closed-loop desiccant dryer with a dew point of -40 °C or lower, set at 80 °C for 2–4 h, reduces residual moisture to below 0.05 wt%. Drying time should be extended to 4–6 h for regrind blends above 30 % recycled content. The melt processing window is 220–250 °C. Prolonged residence above 260 °C initiates polybutadiene thermo-oxidative degradation, visible as yellowing and black specks; the maximum recommended hot-runner manifold temperature is 240 °C, and total residence time should remain under 10 min. Mould temperature between 40 °C and 80 °C controls gloss and internal stress. For high-gloss housings, a mould temperature of 60–80 °C and sufficient holding pressure are required; for lower cycle time, 40–50 °C is used but increases pressure loss and weld-line visibility. Injection speed is selected to avoid shear heating. Because ABS is pseudoplastic, apparent viscosity at gate shear rates of 10³–10⁵ s⁻¹ falls substantially below low-shear rotational viscometer values. Screw geometry with an L/D ratio of 20:1 to 24:1 and compression ratio 2.0:1–2.5:1 is adequate for uniform plastication. Back pressure of 0.5–1.0 MPa is common; excessive back pressure raises stock temperature and shortens the thermal window. On a machine with a clamping force of 80–200 tonnes, specific injection pressure at the screw tip of 70–120 MPa is typical for thin-wall parts; the exact value depends on flow length ratio and gate geometry.

Production-scale observation indicates that MVR batch-to-batch variation of ±3 cm³/10 min is sufficient to alter fill behaviour in multi-cavity tools. When the MVR shifts upward, flash may appear at vent depths of 0.02–0.03 mm; when it shifts downward, short shots occur at the end-of-fill cavity. A gate freeze study and short-shot sequence should be run after each lot change. Weld-line impact retention is a known limitation: the notched impact at a knit line can drop to 6–8 kJ/m² because the high-flow architecture has less rubber available to bridge the knit line. For snap-fit arms located on a weld line, design revisions such as an increased radius of 0.5 mm or a relocated gate are more effective than raising melt temperature alone. Tool vents of 0.02–0.03 mm depth at the parting line are required to prevent gas burn after fast injection. Polished cavity surfaces of SPI A2 or higher improve release and gloss consistency.

When 100-322U is specified for UV-exposed automotive interior and industrial covers

U-stabilised ABS remains an indoor or indirect-exposure material. Published accelerated-weathering data for this specific configuration is limited, so exterior unpainted exposure should not be approved without component-level testing. A qualification programme can use ISO 4892-2:2013 cycle 1 xenon-arc weathering for 1,000 h at a black-standard temperature of 65 °C and water spray, followed by colour change measured per ISO 7724 and gloss retention per ISO 2813. Typical high-gloss ABS surfaces retain less than 50 % of initial 60° gloss after prolonged outdoor exposure, and photo-oxidation raises the yellowness index. For painted or chrome-plated exterior parts, the material acts as a substrate; adhesion must be verified after mould release removal, because silicone-based mould release residues reduce surface energy below the 44 mN/m threshold required for consistent paint wetting. Unlike ASA or PC/ASA weatherable grades, ABS 100-322U does not provide comparable long-term outdoor colour stability, and its selection is justified only when UV exposure is moderate, interior, or shielded. The U suffix does not imply that the grade is suitable for direct tropical sunlight for multi-year service. Compared with the non-U 100-322 base resin, the stabiliser package improves colour stability under fluorescent and filtered sunlight, but the underlying mechanical profile is unchanged.

The comparative position of 100-322U within the TOYOLAC ABS portfolio is summarised below. The values are typical and should be confirmed against the current supplier certificate of analysis.

Chemical resistance follows general ABS behaviour. Per ISO 175:2010 and ISO 2812-1:2017, the grade is not resistant to ketones, low-molecular-weight esters, aromatic hydrocarbons, and chlorinated solvents; these agents cause swelling and environmental stress crazing. Short-term contact with aliphatic alcohols, dilute acids, and dilute alkali is typically acceptable at room temperature. Stress-crazing resistance should be evaluated on finished parts under service strain, not on unstressed plaques. The resin is not intended for direct food-contact, medical, or implant applications unless a specific regulatory certificate for the exact lot and processing history is issued. Compliance with RoHS Directive 2011/65/EU and REACH Regulation (EC) No 1907/2006 is normally declared by the supplier, but the converter must verify that additives, masterbatch, and processing aids do not introduce restricted substances. For traceability, retain certificate of analysis and production lot numbers against each shipment.

Operational boundaries should be treated as follows: melt temperature above 250 °C and residence time above 10 min cause degradation; moisture above 0.08 wt% causes surface defects; regrind content above 30 % without re-drying shifts MFR and impact; and direct contact with strong solvents can induce stress cracking. Published data for this specific configuration is limited in exterior weatherability, so component-level qualification remains mandatory before service approval.