Dongguan Zhongen PC/ABS 365 is an unfilled polycarbonate/acrylonitrile-butadiene-styrene alloy supplied as cylindrical pellets for injection molding. The grade is designated for rigid technical components in which notched impact strength, heat deflection temperature, and dimensional stability carry greater weight than optical clarity or extreme chemical resistance. In the melt, polycarbonate forms a continuous phase around dispersed ABS domains, which increases the softening point measured by ISO 306 relative to an equivalent ABS grade while retaining injection moldability. The product is positioned as a general-purpose engineering thermoplastic. No independent UL 94 Yellow Card for the 365 designation is publicly accessible at the time of writing, so fire-resistance requirements must be verified by lot-specific test data or a recognized third-party file.

Typical supply form is a pelletized compound with a moisture content below 0.06% by weight when freshly sealed. Because the alloy is hygroscopic, exposure to ambient air at relative humidity above 60% can raise surface moisture within 30 min to levels that cause hydrolysis during melt processing. A sealed desiccant drying system is therefore used instead of a hot-air tray dryer.

What Melt-Processing Boundaries Constrain Dongguan Zhongen PC/ABS 365 in Production?

Predrying is the first processing constraint. The resin should be dried in a desiccant dryer with an inlet air dew point at or below -40°C, an outlet temperature of 80–100°C, and a residence time of 4–6 h. The target residual moisture is below 0.02% by Karl Fischer titration or equivalent. At temperatures above 100°C, pellet surface tacking can obstruct dryer discharge and create feed instability. If the molding room operates above 60% relative humidity, machine hoppers should be insulated and purged with dry air because partially dried pellets re-absorb surface moisture within minutes.

Melt temperature at the nozzle should be held between 240°C and 270°C, with an optimal band of 250–265°C. Above 275°C, the PC segments begin thermal degradation, producing yellowing, black specks, and a drop in notched impact strength. Below 235°C, melt viscosity rises enough to cause hesitation lines, flow freeze at thin sections, and delamination at high-shear gates. The thermal stability window is wider than some filled blends, but residence time still matters: at 265°C, total melt residence should not exceed 6 min. Idle machines should be purged or cooled to 150°C standby.

Mold temperature is controlled between 60°C and 90°C, and should be held within ±5°C across the cavity to avoid differential gloss, warpage, and residual stress. Higher mold temperatures within the range improve knit-line strength and produce lower molded-in stress, but increase cycle time. Filling pressure typically falls between 70 MPa and 140 MPa, with holding pressure set to 40–80% of peak filling pressure. Back pressure should be 0.3–0.7 MPa, and screw rotation should be kept between 40 rpm and 120 rpm, with lower speeds preferred for large shot sizes to reduce shear heating.

Screw geometry influences the processing window. A general-purpose screw with L/D 20:1–24:1 and compression ratio 2.0:1–2.5:1 is acceptable; a high-compression polyethylene-type screw can create unmelted PC particles and surface pitting. Maintain a cushion of 3–6 mm and decompression of 2–5 mm to prevent drool without pulling air into the melt.

Compared with neat ABS, the alloy raises heat deflection temperature under 1.8 MPa by approximately 15–30°C when tested according to ISO 75-2:2013 method A. Tensile yield stress is commonly 3–8 MPa higher than a medium-impact ABS, and low-temperature notched impact is less notch-sensitive. The trade-off is higher melt viscosity and a stricter drying routine. Compared with unmodified polycarbonate, the grade sacrifices light transmission and upper-end continuous-use temperature, but exhibits lower melt viscosity and easier flow into thin-wall sections. Injection pressure during filling can be 15–25% lower than a medium-flow polycarbonate under the same tool design. This positioning makes the 365 designation useful where ABS would distort near heat sources and unfilled polycarbonate would demand excessive clamp force or melt temperature.

Within the broader PC/ABS family, 365 is not a flame-retardant grade. It should not be substituted for a UL 94 V-0 PC/ABS in unattended electrical applications unless a specific lot has been listed. It also lacks the high modulus of glass-filled PC/ABS; its flexural modulus is approximately half that of a 20% glass-filled alloy, but its knit-line toughness and surface appearance are superior in unpainted parts.

Mechanical, Thermal, and Rheological Reference Data

Because the supplier’s publicly available datasheet for the 365 designation does not list a complete ISO 10350 property set, the following values are class-typical for an unfilled PC/ABS alloy with density near 1.14 g/cm³. Acceptance tests should use lot-specific certificates of analysis rather than these reference windows.

Rheologically, the alloy is shear-thinning between 10 s⁻¹ and 1000 s⁻¹. Apparent melt viscosity at 260°C and 1000 s⁻¹ for this class lies generally between 120 Pa·s and 220 Pa·s; published data for the specific Zhongen 365 configuration is limited. Melt flow rate alone does not predict thin-wall filling because the material deviates from Newtonian behavior, especially in gates and runners with high shear rates.

Applications for Dongguan Zhongen PC/ABS 365 are concentrated in interior automotive trim carriers, electronic enclosure frames, appliance consoles, and industrial housings where long-term ambient service temperatures remain below 90°C and contact with mild cleaning agents is intermittent. In automotive interior use, nominal wall thickness between 2.0 mm and 3.0 mm helps control sink marks and warpage. Rib height should be limited to 0.6× nominal wall, and gate location should keep weld lines away from snap-fit roots. The material is suited to low-gloss molded surfaces; however, unpainted interior parts exposed to high UV levels require an approved UV stabilization package because the unfilled reference grade is not presumed to contain long-term UV stabilizers.

For electronic enclosures, bosses and snap fits should be designed so that repeated deflection strain stays below the tensile yield strain of 4–5%. Molded-in stress intensifies around metal inserts; post-molding annealing at 80–90°C for 1–2 h can reduce stress-cracking risk but should not be used as a substitute for correct gate design. The product is not assigned a public flame class in this reference documentation. If unattended circuits or high-energy ignition sources are present, a flame-retardant PC/ABS grade or a recognized UL 94 test is required.

Appliance bezels benefit from lower mold shrinkage than many ABS grades, which reduces part-to-part variation in dimensions. Dimensional stability is also aided by the alloy’s lower coefficient of linear thermal expansion relative to unfilled polycarbonate; however, direct steam exposure above 65°C is outside the intended service envelope because hydrolysis of the polycarbonate segment can reduce notched impact strength before visible surface change appears.

When Aromatic Solvents, Alkaline Cleaners, and Hot-Water Contact Limit Service Life

Environmental stress cracking is the primary field failure mode for unfilled PC/ABS alloys. The molded part may retain high short-term notched impact strength, but contact with aromatic hydrocarbons, esters, ketones, chlorinated solvents, or strong alkaline solutions can initiate crazing at residual molded-in stress. Compatibility evaluations should follow ISO 22088-2:2006 or ASTM D543-21 using molded plaques under fixed strain of 0.5–1.0%, not unstressed immersion alone. Cleaning agents containing strong oxidizers or quaternary ammonium disinfectants should not be applied without molded-stress testing.

Hygrothermal aging in water above 60°C progressively hydrolyzes carbonate linkages in the polycarbonate phase. At 85°C in water, a class-typical unfilled PC/ABS part can lose more than 30% of notched Izod impact strength within 500 h; published data for the 365 designation under identical conditions is limited. The material is therefore unsuitable for continuous hot-water plumbing fittings, steam sterilizer components, or constant immersion service. Acids, bases, and oil-based lubricants are not automatically compatible; each new fluid should be tested at the intended service temperature and strain level.

Melt Filtration and Screw Configuration Control Delamination at the Gate

Delamination in PC/ABS 365 moldings often appears as flaking at the gate or along flow fronts. Production troubleshooting should separate moisture-driven splay from shear-induced delamination. Moisture-driven defects appear as random silver streaks across the surface and are reduced by lowering residual moisture below 0.02% and raising back pressure slightly. Shear-induced delamination appears as local separation near the gate or in thin walls; it is corrected by increasing gate diameter to 0.8–1.5 mm for small parts, reducing injection velocity, or moving the melt temperature toward the upper end of the 250–265°C band.

On a general-purpose 90-tonne injection molding machine with 22:1 L/D, a medium-compression screw with 2.0:1 compression ratio and smear tip produces fewer unmelted PC agglomerates than a high-compression polyethylene screw. Parting-line vent depth should be 0.02–0.04 mm, with land length of 3–5 mm, to release gas without flash. Contamination control relies on clean regrind handling; regrind addition above 25 wt% can reduce Izod notched impact by 10–20%, and any regrind fraction above 20 wt% should be validated per lot. Predrying regrind separately from virgin pellets prevents moisture stratification in the hopper, especially when blending at machine side.

For export-oriented supply chains, lot release documentation typically includes a safety data sheet, RoHS screening by IEC 62321-5:2013 for lead and IEC 62321-7-1:2015 for cadmium, and a supplier declaration for REACH candidate list substances. Since the 365 designation may be compounded from multiple raw-material lots, batch-to-batch melt flow rate variation should be monitored at 260°C/5 kg; a deviation greater than ±15% from the approved lot may require injection speed adjustment or gate modification. If a component is intended for food contact, FDA 21 CFR 177.1580 is not presumed to cover the PC/ABS alloy; migration testing under the intended food simulant is required.