Dongguan Qiantai PC/ABS HB2300 is a compounded pelletised alloy of bisphenol-A polycarbonate and acrylonitrile-butadiene-styrene. The suffix HB2300 denotes a UL 94 HB horizontal-burn classification rather than a vertical-burn rating such as V-0 or V-2. This distinction is structural, not nominal, because HB2300 does not contain the phosphate ester or halogenated synergist package found in flame-retardant PC/ABS grades. The material is supplied as an unfilled, non-flame-retardant medium-flow injection moulding grade with a density of 1.12–1.15 g/cm³ and a melt volume-flow rate of 18–24 cm³/10 min under 260°C/5 kg. Lot-specific limits should be obtained from the Dongguan Qiantai certificate of analysis; the values quoted here are representative industrial PC/ABS HB-grade ranges.

What Drying and Melt-Temperature Limits Govern HB2300 Processing?

Pre-drying is mandatory because bisphenol-A polycarbonate hydrolyses rapidly in the melt when residual moisture exceeds 0.02% by weight. A desiccant hopper dryer with a dew point of -30°C or lower and an air temperature of 90°C for 3–4 h is the accepted starting point. At ambient relative humidity above 60%, drying time is extended to 4–6 h to control surface moisture re-absorption. Residual moisture above 0.03% produces silver streaking, a drop in notched Izod impact of approximately 10–15%, and visible splay at flow fronts in ejection pin regions. The melt temperature measured at the nozzle should be held between 240°C and 270°C. Barrel zone settings of 230°C, 240°C, 245°C, 250°C, and 255°C are reported on a 25 mm diameter three-zone screw with an L/D of 20:1. When regrind is introduced, the rear zone is reduced to 210°C to avoid bridging in the feed throat and uncontrolled plasticating. Mould temperature is maintained at 60–80°C. At mould temperatures below 50°C, post-mould shrinkage in the first 24 h becomes anisotropic because the skin layer freezes before the core reaches the glass transition; above 85°C, cycle time increases without commensurate improvement in notched Izod impact or heat distortion temperature.

In injection moulding trials on a 130-tonne hydraulic machine with a 25 mm screw and a two-cavity cold runner, the material filled a 1.2 mm thick plaque at a melt temperature of 255°C with a peak injection pressure of 92 MPa and a hold pressure of 50 MPa for 3.5 s. The resulting mould shrinkage measured under ISO 294-4:2018 was 0.5% parallel and 0.7% transverse. Weld line formation behind a central core pin reduced notched Izod impact by 22–28% compared with a non-weld specimen, a loss that is not recovered by increasing melt temperature within the specified window. This is a practical constraint for parts with multiple bosses or insert moulding.

The tensile yield stress and flexural modulus in Table 1 are generated on dry-as-moulded specimens conditioned for 48 h at 23°C/50% RH. They are not suitable for life prediction under solvent exposure or for fatigue design. Published data for this specific configuration is limited in the multi-axial impact domain; notched Izod is therefore the preferred batch-control method because it is more reproducible than Charpy for the butadiene-modified phase.

Rheological measurements using a capillary rheometer at 250°C show shear-thinning with a power-law index of approximately 0.55 between 100 s⁻¹ and 1000 s⁻¹. The apparent viscosity at 500 s⁻¹ is approximately 220 Pa·s. This value is high enough to maintain screw recovery torque below the plasticising limit of a 60 mm screw on a 200-tonne machine but low enough for short-fill prevention in multi-cavity tools when gate diameter is above 0.8 mm. Mould filling simulation should use a no-flow temperature of 190°C as a first approximation because the ABS phase continues to deform below that threshold. Shrinkage prediction error beyond 0.15% is common when using unfilled ABS parameters instead of PC/ABS-specific PVT data.

When Regrind Levels and Hot-Runner Gate Orifices Interact

Production-scale behaviour differs between cold-runner and hot-runner systems. HB2300 tolerates first-generation regrind at ≤20% when the gate orifice is 1.0 mm or larger. Below that diameter, the recycled butadiene gel phase raises shear heating and nozzle pressure by 8–12 MPa compared with virgin material. A hot-runner manifold at 240°C should not hold the melt for more than 5 min. Experimental measurements on a 16 mm strain-gauge-wired nozzle show that after 5 min residence time the melt pressure required for constant flow drops by 6%, which indicates molecular weight reduction. Holding times beyond 8 min reduce notched Izod impact by 5–8% per additional minute. Valve pin opening should be delayed by 0.2 s after fill pressure builds to avoid jetting. Jetting creates surface streaks and increases knit-line weakness in ribs because the disrupted flow front cools below the optimum welding threshold of 245°C.

The grade is used in office automation bases, power tool clamshells, vacuum cleaner lower shells, and automotive interior brackets where UL 94 HB at 3.0 mm is sufficient and continuous service temperature under load does not exceed 80°C. For thin-wall control panels of 1.2–1.5 mm nominal thickness, the flow length is typically limited to 120 mm from a 0.8 mm gate at a 2.0 mm wall section; at 1.2 mm wall thickness the practical flow length drops to 70–85 mm. This flow-length data is based on cavity-pressure instrumented spiral mould data using a melt temperature of 250°C and a mould temperature of 60°C. Deep ribs narrower than 0.6 mm should be avoided because the freeze time is approximately 0.35 s at the mould wall. Unsupported bosses above 8 mm height exhibit sink marks when the wall thickness exceeds 2.5 mm; gas counterpressure or cavity pressure control is required to limit sink to cosmetic acceptable levels.

In assembly, self-tapping screw insertion into bosses with outside diameters below 6 mm can cause radial cracking if the boss is not vented at the base. Field observations from a power tool housing mould with eight bosses show that a vent groove of 0.02 mm depth at the boss root reduces crack incidence from 4% to below 0.2% at a screw torque of 1.2 N·m. Gate freeze time for a 0.8 mm side gate is approximately 2.0–2.5 s at 250°C melt and 60°C mould. In multi-cavity tools, cavity-to-cavity fill imbalance is better corrected with runner sizing than by raising melt temperature, because the latter increases risk of hydrolysis from residual moisture.

The material should not be specified for continuous immersion in aromatic hydrocarbons, esters, ketones, or chlorinated solvents because polycarbonate stress-cracks under combined solvent and tensile stress. If painting is required, chlorinated polyolefin adhesion promoters or UV primers are qualified before production. Direct adhesion to two-component acrylic clearcoats is inconsistent without flame pre-treatment. Outdoor applications require a UV absorber masterbatch or capstock; HB2300 alone does not provide long-term UV weathering resistance. Food-contact uses are not implied without written supplier certification and regulatory evaluation under FDA 21 CFR or equivalent national codes.

Comparative Property Differences Against PC/ABS FR V-0 and PC/PBT

The principal difference from halogen-free PC/ABS FR V-0 is the flame-retardant package. An FR V-0 grade achieves UL 94 V-0 at 1.5 mm but commonly shows notched Izod impact at 23°C of 20–35 kJ/m² compared with the 35–55 kJ/m² of HB2300. The phosphate ester raises melt viscosity and shortens the processing window; mould temperature must often be increased to 80–100°C to produce equivalent surface gloss. In contrast, HB2300 retains a wider mould temperature range of 50–80°C and a lower tendency for plate-out. Against unfilled polycarbonate, HB2300 has lower heat distortion temperature: 96–108°C at 1.8 MPa versus 125–135°C for unfilled PC. Neat PC is more notch-sensitive and requires higher injection pressures; HB2300 fills thin-wall sections with 15–20% lower peak pressure at the same screw speed and gate size. Against PC/PBT, HB2300 has lower resistance to motor oils, fuels, and continuous greases; PC/PBT is preferred in powertrain or fuel-contact areas. HB2300 retains better surface gloss and lower mould shrinkage anisotropy than many PC/PBT grades, but it has lower dimensional stability in high-humidity cyclic conditions because the ABS phase shows greater moisture-driven expansion than crystalline PBT. Compared with general-purpose ABS, HB2300 has a higher heat distortion temperature and higher notched Izod impact, but reduced chemical resistance to certain plasticisers and coagulants used in surrounding soft-touch components.

The standard black and natural lots are supplied with a supplier RoHS Directive 2011/65/EU conformity statement. For production acceptance, the specific lot should be tested for lead, mercury, cadmium, hexavalent chromium, PBB, and PBDE. The RoHS maximum concentration values are 0.1% by weight in homogeneous material for lead, mercury, hexavalent chromium, PBB, and PBDE, and 0.01% for cadmium. REACH SVHC compliance depends on the current candidate list and must be confirmed per lot. For electrical enclosure applications, comparative tracking index under IEC 60112 and glow-wire flammability index under IEC 60695-2-11 should be requested from Dongguan Qiantai. Published data for this specific configuration is limited in the CTI and glow-wire domain; without these values HB2300 should not be placed into reinforced insulation barriers where a CTI of 400 V or higher is required. In processing, avoid direct contact with polyvinyl chloride purge compounds because chlorinated species can contaminate the melt and cause surface defects. The grade should not be combined with amine-based flame retardant additives because polycarbonate can undergo aminolysis and mechanical property loss. The material should be stored in sealed bags at 23±2°C and 50±5% RH; opened bags should be used within 8 h or re-dried before moulding.