Dongguan Hengtaisheng PC/ABS 2950 is a compounded polycarbonate/acrylonitrile-butadiene-styrene alloy supplied as injection-molding pellets. The grade designation 2950 positions the material within the medium-flow, general-purpose PC/ABS segment; it is specified where low-temperature impact strength, heat resistance, and surface finish are required without the density increase associated with glass reinforcement. Under ISO 1043-1:2011, the material is classified as a PC/ABS blend with no intentionally added filler. The product is typically used in electronic device enclosures, automotive interior trim brackets, small appliance housings, and painted structural components. Published data for this specific formulation is limited in independent peer-reviewed sources; therefore, the values cited below are the indicative envelope for unfilled medium-flow PC/ABS grades of equivalent nominal melt flow rate and must be confirmed against the lot-specific certificate of analysis.

The 2950 designation does not imply a flame-retardant classification. Where a UL 94 rating is required, the application specification must identify the exact thickness and color, and the yellow card for Dongguan Hengtaisheng PC/ABS 2950 should be consulted before part design. General-purpose PC/ABS alloys of this class are often classified HB at 1.5 mm, but flame-retardant and high-heat variants are separate products.

Material Specification and Indicative Property Envelope

The table does not list a UL 94 classification because the 2950 designation does not, by itself, guarantee flame-retardant behavior. Impact values are sensitive to specimen notch radius and molding skin orientation; a 0.25 mm notch radius per ISO 180:2023 produces lower values than the unnotched specimen, and injection-molded skins can raise practical part toughness above the value measured on machined specimens. Across production lots, notched Izod impact may shift by ±8 kJ/m² even when melt mass-flow rate remains within the specified envelope.

On a production-scale injection molding machine with 30 mm screw diameter, 20:1 L/D ratio, and 1200 kN clamp force, the material must be dried to residual moisture below 0.02 %. Desiccant drying at 80–100 °C for 3–4 h with a −40 °C dew-point air supply is required when ambient relative humidity exceeds 60 %. Moisture above 0.03 % hydrolyzes the polycarbonate phase during plastication, producing splay streaks, weld-line weakness, and a notched Izod impact reduction to 30 kJ/m² or lower after molding. Barrel setpoints are 240–260 °C rear, 250–270 °C center, and 255–275 °C front, with nozzle temperature at 260–270 °C. Measured melt temperature should remain near 260 °C; residence times above 8 min at melt temperatures above 280 °C accelerate chain scission and yellowing. A change in yellowness index greater than 2.5 units per ASTM E313-20 indicates incipient degradation during molding or compounding.

Mold temperature is controlled at 60–80 °C with a maximum measured cavity-surface variation of ±5 °C. At wall thickness below 1.0 mm, a mold temperature near 80 °C is used to delay skin solidification and improve weld-line strength. Screw back pressure of 0.5–1.5 MPa and screw surface speed of 50–100 min⁻¹ are typical for melt homogeneity. Injection speed is set between 50 mm/s and 150 mm/s depending on gate size; injection speeds above 200 mm/s at thin-wall gates can induce shear heating, local melt temperature excursions, and gate blush. Holding pressure in the range 50–70 MPa for 4–8 s compensates for volumetric shrinkage; insufficient hold pressure produces sink marks and increases flow-axis shrinkage anisotropy.

At the compounding stage, medium-flow PC/ABS products of this type are typically produced on a twin-screw extruder with 36:1 to 44:1 L/D ratio, using barrel temperatures between 230 °C and 260 °C. The specific stabilizer and lubricant package for Dongguan Hengtaisheng PC/ABS 2950 is proprietary. Dispersion of the ABS phase is evaluated by scanning electron microscopy at 5000× magnification; an ABS domain size of 0.5–2.0 µm is associated with the impact retention range given above. Published data for this specific grade’s compounding morphology is limited.

Regrind addition is limited to 20 wt% for unpainted cosmetic parts. At 30 wt% regrind, notched Izod impact may fall below 35 kJ/m² and heat deflection temperature may drop by 3–5 °C compared with virgin granulate. Regrind from painted or metallized parts is not recommended without melt filtration and lot validation because paint residues and metal flakes can create localized hydrolysis or conductive pathways.

How Does 2950 Compare with High-Heat and Flame-Retardant PC/ABS Grades?

The 2950 grade is not a high-heat grade. Heat-stabilized PC/ABS products contain silicone-based or polycarbonate-rich formulations that raise the heat deflection temperature under 1.8 MPa above 115 °C, whereas the 2950 envelope remains near 98–112 °C per ISO 75-2:2013. Flame-retardant PC/ABS grades contain halogenated or organophosphate additive systems and are specified when a UL 94 V-0 rating is required at 1.5 mm or 0.8 mm; the 2950 designation cannot be substituted for these products without yellow-card verification. Glass-reinforced PC/ABS grades with 20 wt% or 30 wt% glass fibre raise flexural modulus to 4000–5200 MPa per ISO 178:2019 but reduce notched Izod impact to 10–18 kJ/m² per ISO 180:2023 and introduce anisotropic shrinkage. The table below summarizes the differentiation for engineering selection.

Compared with unfilled polycarbonate, the 2950 grade has lower melt viscosity and improved flow into long ribs and thin-wall bosses, but it sacrifices optical clarity and chemical resistance. Compared with ABS, the 2950 grade has higher heat resistance and low-temperature impact, but it requires closer drying control and has a higher melt temperature. The quantitative differences are moderate in the unfilled PC/ABS family but become substantial when glass reinforcement or flame-retardant additives are present.

When Mold Temperature Drops Below the Recommended Setpoint

When mold temperature falls below 50 °C on a polished P20 steel tool with 0.8–1.2 mm wall thickness, the solidification rate of the PC/ABS skin exceeds the filling rate. This condition freezes the outer layer before the core polymer melt has packed out, increasing residual stress and reducing gloss on textured surfaces. On a cavity with a hot-runner valve gate, low mold temperature may increase gate blush because the frozen skin at the gate is sheared by continuing melt flow; the blush zone width can exceed 2 mm and become visible on cosmetic surfaces. Residual stress can be evaluated qualitatively by immersion in n-propyl acetate for 3 min per the practice in ASTM D543-21; cracks propagate at high-stress areas such as gate bases, ejector-pin bosses, and sharp corners when molded-in stress is excessive.

Weld lines formed behind core pins or multi-gate layouts are sensitive to mold temperature. At a mold temperature of 40 °C, a notched Izod specimen cut at the weld line may retain only 55 % of the base resin impact value; raising mold temperature to 70 °C can raise weld-line retention to approximately 75 % in medium-flow PC/ABS alloys. The exact retention for Dongguan Hengtaisheng PC/ABS 2950 under a specific tool configuration is not available in independent literature and should be confirmed by mold trials using the production gate geometry and ISO 180:2023 specimens machined across the weld plane. Cooling time is extended by 10–20 s when mold temperature is raised from 40 °C to 70 °C on a 2 mm wall part; this increases cycle time but improves dimensional stability after demolding.

Parts ejected with a surface temperature below 80 °C and a mold temperature below 50 °C show higher initial shrinkage anisotropy: flow-direction shrinkage of 0.5–0.7 % and cross-flow shrinkage of 0.6–0.9 % after 48 h at 23 °C and 50 % RH per ISO 294-4:2018. A mold temperature at the upper end of the recommended window reduces the difference between flow and cross-flow shrinkage and lowers the risk of bowing in flat bezel parts. On a 900 kN machine, raising mold temperature from 40 °C to 70 °C increases cycle time by 8–15 %; the production trade-off is evaluated through the reject rate for sink marks, blush, and post-mold warpage.

For painted or metallized parts, residual stress associated with cold molding becomes apparent during topcoat cure at 80–90 °C for 30–60 min. Under thermal stress, cold-molded parts release frozen-in orientation as warpage or surface grain distortion; paint adhesion testing per ISO 2409:2020 may show delamination at edges where stress concentration is highest. Maintaining mold temperature above 60 °C and annealing at 100 °C for 30 min before painting reduces such failures, although annealing adds a secondary operation and is not indicated for every part design.

Chemical Incompatibility Is Concentrated in Solvents, Alkalis, and Amine-Based Additives

Unfilled PC/ABS 2950 is not resistant to aromatic hydrocarbons, ketones, chlorinated solvents, or strong alkaline solutions. Static exposure to methyl ethyl ketone or toluene at 1 % strain for 24 h reduces tensile elongation to 5 % or less and produces visible microcracking per ASTM D543-21. The use of amine-cured epoxy adhesives or amine-based mold release agents at gate and bond locations can catalyze polycarbonate chain scission under humid conditions; this requires verification by a stress-cracking test using a 0.3 % strain jig and 48 h exposure to the candidate agent. Isopropanol may be used as a short-dwell cleaning agent if the part is unstressed and the solvent is removed within 30 s; prolonged contact with molded-in stress produces crazing. For applications in contact with automotive interior cleaners, wipe-resistance testing under GMW14445 or an equivalent customer specification is recommended because commercial cleaner formulations vary in hydrocarbon and glycol ether content.

Regulatory screening under RoHS Directive 2011/65/EU and REACH SVHC must be conducted on the exact formulation and lot because PC/ABS products differ in flame-retardant and stabilizer packages. If the grade is sold as halogen-free, the absence of chlorine and bromine above applicable thresholds must be verified per IEC 61249-2-21 or customer-specific limits. If the grade is used in food-contact or medical applications, migration testing under EU Regulation (EC) No 1935/2004 or FDA 21 CFR is not assumed from the polymer class alone; the final compounded product, colorants, and processing aids must be assessed individually.