Dongguan Zhengxian PC/ABS 23013 is identified as a polycarbonate/acrylonitrile-butadiene-styrene alloy supplied in pellet form. Under ISO 1043-1:2011, the polymer class designation is PC+ABS. The suffix 23013 denotes a proprietary unfilled grade within the manufacturer’s alloy portfolio. End users should request a certificate of analysis for lot-specific melt volume-flow rate, density, tensile properties, and notched impact values because published data for this specific configuration is limited. The material is handled as a thermoplastic engineering alloy intended for injection molding, and its specification envelope is assessed using ISO and UL test methods. Moisture protection in storage remains a boundary condition: bags should be kept closed, and material exposed to ambient air at relative humidity above 60 % must be re-dried before processing.

What Limits the Pre-Drying Window Before Melt Processing?

Residual moisture above 0.02 wt% in the melt phase drives hydrolytic chain scission of the PC fraction and generates carbon dioxide and surface splay. Desiccant drying at 80–100 °C for 3–4 h with a dew point of no more than -30 °C reduces moisture to a process-resilient level for unfilled PC/ABS. On production-scale lines, hopper dryers without closed-loop conveying have shown batch-to-batch moisture spikes at relative humidity above 60 %; use of vacuum-transfer and dry-air purge at the feed throat is required to preserve low moisture. Overdrying at temperatures above 100 °C for extended periods may yellow the alloy and should be avoided. Lot-specific drying curves should be obtained from the supplier for regrind fractions above 20 wt%, because regrind changes bulk density and residence-time distribution in fixed-volume hopper dryers.

On production-scale injection machines with clamp force between 800 kN and 2500 kN, the melt temperature measured at the nozzle is normally held between 240 °C and 270 °C for unfilled PC/ABS. Mold temperature should be controlled between 60 °C and 80 °C; lower mold temperatures increase frozen-in orientation and reduce weld-line strength. Injection velocity is set to fill the cavity within 0.5–1.5 s for parts of 2–3 mm nominal wall thickness, while holding pressure is typically maintained at 40–60 % of peak injection pressure until gate freeze. The screw should have a compression ratio of 2.0–2.5:1 and L/D of 20:1–25:1; short L/D screws reduce melt homogeneity in PC/ABS and can produce unmelted ABS particles. No grade-specific processing window has been published for 23013, so these values are class-typical and must be optimized on tooling.

The apparent shear rate at the gate should remain below 50,000 s⁻¹ for unfilled PC/ABS; excessive shear generates shear heating and causes ABS rubber-phase degradation at the gate. Gate sizing should yield shear rates of 10,000–30,000 s⁻¹ for parts with 1.5–3.0 mm wall thickness. Hot-runner systems should use externally heated manifolds with thermal control of ±2 °C to avoid local overheating. No published gate shear limit specific to 23013 is available; mold-fill simulation using melt viscosity data obtained by capillary rheometry at three temperatures is required for critical parts.

Under multi-gate filling, weld-line strength in PC/ABS is process-sensitive. If two flow fronts meet at a meld line, the notched Charpy impact retention may fall by 30–50 % relative to a non-weld specimen tested under ISO 179-1:2023. Increasing mold temperature to 80 °C and reducing injection velocity at the meld section improves chain diffusion and raises weld-line strength. Venting at the end of fill should be at least 0.02 mm deep to allow volatile removal; insufficient venting creates burn marks and surface voids in unfilled PC/ABS.

Comparative mechanical and thermal property envelopes under ISO test methods

Because the manufacturer’s certified lot-specific datasheet for 23013 is not publicly accessible, the following envelope describes unfilled PC/ABS grades and should not be applied as a purchase specification without a certificate of analysis.

Because the 23013 suffix is positioned as an unfilled grade, substitution from mineral-filled or flame-retardant PC/ABS grades alters flow length, mold filling, impact retention, and flammability. Mineral-filled PC/ABS grades generally raise flexural modulus to 3500–5000 MPa but reduce notched Charpy impact to 8–15 kJ/m² and increase density to 1.20–1.35 g/cm³. Flame-retardant PC/ABS grades typically restrict melt temperature below 250 °C to protect phosphorus-based or brominated additives and may exhibit lower tensile yield than unfilled grades. Glass-fiber-reinforced PC/ABS grades introduce anisotropy, weld-line losses, and tool wear; they should not be considered drop-in substitutes for 23013 unless the mold cooling layout and gate location are revalidated. Unfilled PC/ABS such as 23013 generally offers higher multi-axial impact retention at low temperature than filled grades, but the absence of a certified lot-specific Charpy value for 23013 means direct numerical comparison cannot be made without physical testing.

Regrind of unfilled PC/ABS 23013 is restricted to 20 wt% in critical structural parts, due to molecular weight reduction from repeated shear and thermal history. Trials on a twin-screw extruder with L/D 40:1 and side-feeding of regrind have shown that moisture in plant regrind can exceed 0.1 wt% unless re-dried separately at 80 °C for 4–6 h. Melt flow increases with regrind use, particularly after three heat histories, so in-line MVR checks per ISO 1133-1:2022 should be performed every 2 h during extended production runs to maintain traceability.

When Metal Inserts Are Overmolded, Differential Thermal Expansion Controls Cracking Resistance

When a brass or steel insert is overmolded into an unfilled PC/ABS part, the coefficient of linear thermal expansion of the polymer is approximately 65–80 ×10⁻⁶ K⁻¹ compared with 12–18 ×10⁻⁶ K⁻¹ for steel. Cooling after ejection generates hoop stress around the insert; cracking and stress whitening occur when the wall thickness around the insert is below 2.0 mm or when the insert is not preheated. Production-scale insert molding lines preheat inserts to 100–120 °C and reduce screw-forward time to avoid packing the polymer rigidly around a cold core. For 23013, this boundary condition is class-typical, and tooling trials should include thermal cycling from -20 °C to 80 °C to evaluate crack initiation after 100 cycles; acceptance criteria should be based on visual and dye-penetrant inspection according to ISO 179-1:2023 impact testing or in-house standards.

Post-mold shrinkage of unfilled PC/ABS without filler is typically 0.5–0.7 % parallel to flow and 0.4–0.6 % perpendicular, measured after 48 h at 23 °C. Annealing at 90–100 °C for 2 h can relax molded-in stress but may increase dimensional change. Components requiring tight tolerances should be measured after conditioning according to ISO 291:2008 at 23 °C and 50 % relative humidity.

Volume resistivity of unfilled PC/ABS is often reported at 1 × 10¹⁴ Ω·cm under IEC 62631-3-1:2016, but the value is not an insulation rating. Comparative tracking index under IEC 60112:2020 for unfilled PC/ABS is commonly 175–250 V; end-product creepage requirements in IEC 62368-1:2018 use CTI to determine minimum separation distances. No 23013-specific CTI is published.

Verify End-Product Flammability and Material Documentation Separately

Material compliance for 23013 cannot be claimed from the grade designation alone; documentation must be obtained from the supplier and linked to the lot number. The following table identifies the minimum verification items for applications in information-technology equipment and appliance housings.