CHIMEI (Chi Mei) ABS D-1600

CHIMEI (Chi Mei) ABS D-1600 is a general-purpose injection-moulding-grade acrylonitrile-butadiene-styrene resin supplied by Chi Mei Corporation. The material consists of a styrene-acrylonitrile continuous phase with a dispersed polybutadiene rubber phase; the SAN phase contributes stiffness, heat resistance, and melt processability, while the polybutadiene phase provides room-temperature and low-temperature notched impact resistance. Published distributor data list polymer density at 1.04 g/cm³ under ASTM D792, a melt flow rate of 18 g/10 min at 220°C/10 kg under ASTM D1238, and a mould shrinkage range of 0.4–0.6% under ASTM D955. The resin is not formulated for transparent moulding or inherently UV-stable outdoor exposure beyond standard ABS behaviour.

Mechanical properties reported on 3.2 mm injection-moulded specimens include a tensile yield stress of 43 MPa under ASTM D638, flexural modulus of 2.3 GPa under ASTM D790, and notched Izod impact strength of 294 J/m at 23°C under ASTM D256, equivalent to approximately 30 kJ/m² under ISO 180/A. Heat deflection temperature at 1.82 MPa is approximately 87°C under ASTM D648; Vicat softening temperature is approximately 100°C under ASTM D1525. These values are typical published data from distributor literature rather than guaranteed specification limits; incoming-quality laboratories should generate lot-specific data under ISO 1133-1 and ISO 180/A when qualifying the grade for load-bearing enclosures.

Why Does Pre-Drying and Moisture Control Dominate D-1600 Process Stability?

Moisture in ABS is not as hydrolytically aggressive as in polyamide or polycarbonate, but excess moisture in D-1600 causes surface splay, silver streaking, and a measurable reduction in notched impact retention. Desiccant drying at 80°C for 2–4 h to a residual moisture content below 0.05% is the standard pre-processing condition; a hopper dryer alone is not sufficient when ambient relative humidity exceeds 60%. The drying dew point of the desiccant bed should remain below -30°C. On production-scale moulding cells with central drying systems, batch-to-batch variations in pellet bed height and return-air temperature can generate moisture differentials that appear as intermittent splay at the gate area even when the nominal set-point is unchanged. Dry-air generators with dew-point monitoring and insulated hopper legs are therefore preferred over floor-standing hot-air hoppers for this grade.

Melt temperature measured at the nozzle should be maintained between 200°C and 240°C; excursions above 250°C accelerate thermal degradation of the butadiene phase, producing surface discolouration and a sharp decline in impact strength. The recommended mould temperature is 40–70°C. Melt residence time at the upper end of the range should not exceed 5 min; hot-runner systems with dead spots or unmelted boundaries can increase local residence time and generate brown streaks. Back pressure of 0.5–1.5 MPa is adequate for homogenising colour masterbatch, while screw speed should be limited to 50–100 rpm to avoid frictional overheating in general-purpose screws with 20:1 to 25:1 L/D ratios.

The upper processing temperature at 240°C is not a hard ceiling, but the degradation rate of the polybutadiene phase rises sharply above 250°C; dissolved oxygen and residual transition-metal catalyst residues accelerate auto-oxidation. In practice, the temperature differential between barrel zones and the nozzle should be controlled within ±5°C to avoid local overheating at the check-ring or nozzle adaptor. The difference between heater-band set-point and actual melt temperature can reach 10–15°C at high screw speeds due to viscous dissipation, so nozzle-temperature verification with a pyrometer or insertion thermocouple is required during initial process validation.

D-1600 is commonly evaluated for consumer appliance housings, small appliance bases, vacuum cleaner shrouds, and general industrial covers where the combination of high notched Izod impact and moderate heat resistance is sufficient. On a 120-ton toggle-clamp machine with a 40 mm screw and a single-edge-gated tool, injection pressures of 70–120 MPa are typically observed for wall sections of 2.0–2.5 mm; the material generates lower cavity pressure than high-viscosity grades such as PA-747, but it does not fill long thin-wall flow paths as readily as a high-flow ABS with a melt flow rate above 25 g/10 min. Moulders evaluating D-1600 as a replacement for PA-747 in large structural housings must verify not only the melt flow difference but also the lower melt strength during gas-assisted or water-assisted injection moulding; published data for this specific gas-assisted configuration are limited.

Comparative Flow and Impact Profile Against PA-757 and PA-747

D-1600 overlaps substantially with Chi Mei PA-757 in published mechanical and thermal values. The practical difference is often not a step-change in datasheet properties but rather grade registration, colour supply, lot size, and local certification status. Relative to PA-747, the distinctions are broader and more functionally relevant. D-1600 has approximately 3.3× the melt flow rate of PA-747 and about 25% lower notched Izod impact at 23°C. This positions D-1600 for moderate-flow injection moulding, while PA-747 is selected for high-impact sheet extrusion and deep-draw thermoforming where higher melt viscosity is required for sag resistance.

High-heat ABS grades with HDT above 100°C will outperform D-1600 in automotive interior parts exposed to upper-dash thermal loads. Published data for D-1600 in continuous 100°C service are limited, and a high-heat ABS should be selected when heat deflection is the controlling specification. Electroplating grades are chemically etched and must have controlled butadiene domains; D-1600 is not marketed as an electroplating resin. Parts requiring electroplated ABS should use Chi Mei’s dedicated electroplating grade, such as PA-726M, rather than D-1600.

When D-1600 Replaces PA-747 in Injection-Moulded Housings

Replacing PA-747 with D-1600 in an existing injection-moulded housing requires a systematic re-validation of melt temperature, injection speed, and packing pressure. Because D-1600 has a higher melt flow rate than PA-747, it may reduce injection pressure by 15–25% in the same tool, but it may also change gate freeze time and sink-mark formation. Packing pressure should be re-optimised using cavity pressure sensors rather than transfer-position settings alone. The holding pressure window is typically 50–80% of peak injection pressure for wall sections of 2.0–3.0 mm; excessive packing can create moulded-in stress that reduces environmental stress cracking resistance.

Projected area clamping requirements are comparable to other ABS grades: cavity pressure of 30–50 MPa is typical for a 2.0 mm wall section with a conventional cold runner. A preliminary machine-selection factor of 0.5–0.8 tonnes/cm² is used, but flow-length-to-wall-thickness ratio and gate placement determine the actual required clamp force. On a 120-ton hydraulic clamp with 2.5 mm nominal wall thickness, moulders should expect screw recovery to be faster than with PA-747, which may require adjustment of screw-back position to maintain consistent shot weight.

The molecular weight distribution, as inferred from melt flow rate under ASTM D1238, indicates lower melt viscosity than PA-747 and similar viscosity to PA-757. The structural position produces the grade’s characteristic balance: adequate impact for appliance housings, but limited melt strength for thick-section extrusion blow moulding. When reporting under ISO conditions, the melt volume rate is approximately 17 cm³/10 min at 220°C/10 kg under ISO 1133-1; the difference from the mass-based value reflects the 1.04 g/cm³ density. Incoming inspection should specify whether the supplier reports mass flow or volume flow because an uncontrolled unit switch between ASTM and ISO testers can produce apparent lot-to-lot drift of 10% or more.

Chemical compatibility follows general ABS behaviour: aromatic hydrocarbons, ketones, esters, and chlorinated solvents attack the SAN phase; prolonged exposure to these agents can produce environmental stress cracking under tensile load. The grade is not recommended for continuous hot water exposure above 60°C or for outdoor load-bearing applications without UV-stabilised capstock or paint. Published data for D-1600-specific chemical resistance are limited; therefore, customer-specific immersion testing under ASTM D543 should be performed when the part contacts cleaning agents, lubricants, or plasticised PVC gaskets.

Regulatory and Certification Status for D-1600

The flammability classification for D-1600 is HB at 3.0 mm under UL 94. Any electrical enclosure requiring V-0 at 1.5 mm will require a flame-retardant ABS grade, not D-1600. Regulatory compliance is batch- and supplier-document-dependent; the resin supplier’s current certificate should always be requested.

The terpolymer composition is based on acrylonitrile, butadiene, and styrene, with the monomers identifiable by CAS 107-13-1, 106-99-0, and 100-42-5. Residual monomer content is controlled to supplier specifications, but the exact residual styrene concentration is not disclosed in distributor literature. For applications involving skin contact or food-contact migration, supplementary testing is mandatory because general-purpose ABS is not automatically cleared for direct food contact in every jurisdiction.