The commercial designation Guangzhou Keyuan New Material ABS GIF is treated in this document as a glass-fiber-modified acrylonitrile-butadiene-styrene injection-molding grade; if the supplier datasheet assigns a different filler type or loading, the datasheet controls. Because third-party published data for this specific commercial grade is limited, the numerical ranges presented below are representative of glass-filled ABS compounds in the same filler-content class and must be checked against the batch certificate before tooling release. Fiber content is normally verified by ashing to ISO 3451-1, melt mass-flow rate by ISO 1133-1:2022, density by ISO 1183-1:2019, and filler retention on a 45 µm sieve after burn-off.

Drying for glass-filled ABS is controlled by moisture uptake in the styrene-acrylonitrile matrix. A desiccant dryer delivering a -40 °C dew point and 80 °C bed temperature for 3–4 h is the standard starting condition. Residual moisture should be maintained below 0.05 wt%; at higher moisture, injection molding produces surface splay, gas streaks, and reduced weld-line strength. When ambient relative humidity exceeds 60%, dried pellets should be conveyed in closed lines or kept in a hopper dryer; open-air exposure above 30 min can reabsorb enough water to degrade surface finish.

Moisture desorption in glass-filled ABS follows the polar SAN phase; glass fiber contributes little to equilibrium water uptake, but fiber-matrix interfaces act as capillary paths. A hot-air hopper dryer alone is not reliable after storage at 70% relative humidity; outlet moisture can remain above 0.08 wt% after 4 h. Drying time can be reduced to 2 h only if the desiccant dryer holds a dew point of -50 °C and incoming pellet moisture is below 0.15 wt%.

Regrind use is constrained by fiber attrition. First-generation regrind at 20 wt% addition typically changes flexural modulus by less than 5%, but notched Izod impact may fall by 15–25% because re-melting shortens glass fibers. Regrind containing burned resin or hot-runner drool should not be reused. Addition rates above 30 wt% require verification of melt flow to ISO 1133-1 and notched impact to ISO 180/1A on the production blend.

Custom coloring of glass-filled ABS should be minimized. Color masterbatch addition above 2 wt% can reduce notched Izod impact and shift fiber orientation at the surface. If color is required, an SAN or ABS-compatible carrier is preferred; the colored compound should be tested for notched Izod impact to ISO 180/1A and, for exterior exposure, UV resistance to ISO 4892-2 before production release.

What melt-temperature and residence-time limits protect ABS GIF from degradation?

For a reciprocating-screw injection press, typical barrel zone settings are 210 °C rear, 220 °C center, 230 °C front, and 230–240 °C nozzle. Melt temperature above 260 °C accelerates oxidative attack on the butadiene phase and can produce yellowing; total melt residence time should remain below 10 min. If a hot-runner manifold is used, the manifold set point should not exceed 240 °C. Published data for this specific Keyuan grade is limited, so these limits should be confirmed by purging trials on the target machine.

Shear heating is significant because glass fibers increase apparent melt viscosity. Back pressure of 4–8 bar hydraulic, screw speed of 60–120 rpm, and decompression of 3–5 mm prevent drool and excessive fiber breakage. A general-purpose screw with a compression ratio of 2.2:1–2.5:1 and check-ring clearance below 0.05 mm is preferred. On production machines with screw diameters between 35 mm and 50 mm, a tight non-return valve holds shot-weight variation near 0.3%; a worn check ring can increase variation to 1.0% or more. Cushion position should be maintained at 2–4 mm; loss below 2 mm indicates leakage or insufficient decompression.

When compounding the glass-filled class on a 40:1 L/D co-rotating twin-screw extruder, chopped strand is introduced downstream at barrel 6 of 10, after the polymer melt seal is formed. Die melt temperature is held at 230–250 °C, with screw speed limited to 250–350 rpm. Higher screw speed increases fiber fines below 100 µm and reduces notched impact without a proportional gain in stiffness.

Rheological data for this glass-filled ABS class indicate apparent melt viscosity at 240 °C and 1,000 s⁻¹ shear rate in the range of 80–150 Pa·s, compared with 40–80 Pa·s for unfilled ABS. Melt flow rate alone is insufficient because it captures only a low-shear point. Capillary rheometry to ISO 11443 is the reference method for mold-filling simulation inputs.

Mechanical property benchmarks and standardized test methods

When evaluated under laboratory conditions, tensile properties are measured to ISO 527-2, flexural properties to ISO 178, notched Izod impact to ISO 180/1A, and heat deflection temperature to ISO 75-2 at 1.8 MPa. Representative class values for a 10 wt% glass-filled ABS are tensile strength 60–70 MPa, tensile modulus 3.5–4.5 GPa, flexural modulus 4.0–5.0 GPa, HDT-A 95–110 °C, and notched Izod impact 6–12 kJ/m². These values are not product specifications; they describe the filler-content class and must be validated against the batch certificate.

The principal difference from unfilled ABS is the increase in flexural modulus at the expense of melt fluidity and surface gloss. At 10 wt% glass, flexural modulus rises by 60–100%, while notched Izod impact drops by roughly one-half to two-thirds compared with unfilled ABS. The grade should therefore be selected when stiffness and dimensional stability dominate the load case, not when high ductile impact absorption or Class-A surface appearance is required.

Fiber orientation is not isotropic in the molded skin. Fibers align with the flow direction in the skin and remain more random in the core, producing anisotropic shrinkage. For a 10 wt% glass-filled ABS class, mold shrinkage after 48 h to ISO 294-4 is commonly 0.2–0.3% parallel to flow and 0.4–0.5% transverse. The coefficient of linear thermal expansion to ISO 11359-2 is approximately 4.0–5.0 × 10⁻⁵ K⁻¹ in the flow direction and 5.5–6.5 × 10⁻⁵ K⁻¹ transverse, lower than unfilled ABS at 7.0–9.0 × 10⁻⁵ K⁻¹. This reduced CLTE improves fit retention in metal-to-plastic electronic chassis designs.

When the grade is substituted for unfilled ABS in a load-bearing automotive bracket

In automotive interior brackets, HVAC actuator arms, and seat side brackets, substitution from unfilled ABS to the ABS GIF class often permits wall-section reduction from 3.0 mm to 2.2 mm while maintaining flexural stiffness, because bending stiffness scales with the cube of wall thickness. A 2.2 mm glass-filled section with flexural modulus 4.5 GPa provides equivalent stiffness to a 3.0 mm unfilled section with flexural modulus 2.4 GPa. The wall reduction lowers shot weight and cooling time but raises injection pressure; a 120 t clamp-force press may require 100–130 MPa specific injection pressure for glass-filled ABS long flow paths, compared with 70–90 MPa for unfilled ABS.

Weld-line strength must be evaluated before rib and boss placement is fixed. In glass-filled ABS, tensile strength at a knit line may retain only 40–60% of the un-welded value; unfilled ABS may retain 70–85%. The lower retention occurs because fibers align parallel to the weld plane and do not bridge the interface. Gates should be positioned to move knit lines into low-stress regions; dead-ended ribs behind bosses should be avoided because they create high-stress weld lines. If a weld line cannot be moved, the rib should be flow-through or the local wall thickness increased to reduce stress concentration.

For a tight-tolerance electronic chassis frame inspected to ±0.1 mm, tooling contraction allowances must account for flow direction and glass orientation. A central gate creates radial flow; radial shrinkage may differ from tangential shrinkage by 0.1 percentage point. Dimensional capability studies should measure at least three cavity positions across 30 consecutive shots after thermal equilibrium. Process capability is improved by raising packing pressure to 80 MPa and holding until gate freeze, rather than by increasing melt temperature. Warpage is managed by balancing the flow front, holding mold surface temperature at 60–80 °C, and avoiding cavity-core temperature differences above 20 °C. Lower mold temperatures below 40 °C freeze the skin too rapidly, increase frozen-in orientation, and worsen flatness deviation.

Surface splay and gate blush are linked to fountain-flow skin rupture

Surface splay in the ABS GIF class arises from volatile evolution during filling. The volatile source may be residual moisture, low-molecular-weight degradation products from melt overheating, or air entrapment ahead of the fiber-rich flow front. The first corrective step is verification of dryer dew point and residual moisture; the second is reduction of nozzle temperature from 240 °C to 230 °C; the third is lowering screw-recovery speed. If air entrapment is suspected, a vent at the end of fill should be added. Gate blush appears as a white hazy streak around the gate when the fountain flow stretches the skin too rapidly. Increasing gate diameter by 20–30% and reducing injection velocity from 100 mm/s to 60 mm/s often removes it. These are class-level corrective conditions; the specific Keyuan grade may require tool-specific validation.

Glass-filled compounds are abrasive to melt-processing equipment and mold surfaces. Screw, barrel, check ring, and gate inserts should be protected with bimetallic barrel linings, through-hardened screw flights, and mold inserts having surface hardness above 50 HRC. Gate wear in glass-filled ABS can reach 0.01–0.03 mm per 100,000 shots, so shot weight and gate diameter should be monitored every 50,000 cycles. A polyamide-based purge compound should be avoided after processing because SAN degradation residues can react with the purge and leave carbon deposits on the screw; low-viscosity ABS or HDPE is preferred.

Differences from PC/ABS and mineral-filled ABS in enclosure applications

Compared with PC/ABS blends used for electronic enclosures, the glass-filled ABS class has lower notched impact and lower chemical resistance to skin-care agents and solvents. PC/ABS may show notched Izod values above 40 kJ/m²; the glass-filled ABS class is generally below 12 kJ/m². However, the ABS GIF class offers higher flexural modulus per unit material cost and a lower melt temperature, which reduces cooling time. It should not be specified where repeated impact at -20 °C is required; the SAN matrix embrittles near its glass transition and glass fibers create local stress concentrations.

Mineral-filled ABS grades typically provide lower warpage but lower tensile strength than glass-filled grades. A 20 wt% talc-filled ABS may show flexural modulus near 3.5 GPa, whereas a 10 wt% glass-filled ABS can approach 5.0 GPa. The glass-filled material therefore permits thinner sections for equivalent stiffness. The trade-off is surface quality: glass fibers raise the coefficient of friction against mold steel and produce a dull surface with visible fiber read-through at the gate. Mineral-filled grades are preferred when painted or grained surfaces are required. In a washing-machine impeller or electric-motor support bracket where continuous service temperature remains below 80 °C, the ABS GIF class may replace mineral-filled PP or unfilled ABS, but creep modulus under 1,000 h loading to ISO 899-2 may decrease to 50–70% of the short-term flexural modulus. Long-term load-bearing designs require creep testing on the candidate batch before approval.

Regulatory status must be confirmed for the specific batch and color. Glass-filled ABS compounds of this class are often evaluated under RoHS 2011/65/EU, REACH 1907/2006, and, where applicable, POPs Regulation (EU) 2019/1021. Flame-retardant performance should not be inferred from an unfilled ABS listing; glass fiber can change drip and burn behavior, and many glass-filled ABS grades are HB rather than V-0 unless flame-retardant additives are incorporated. If a UL 94 classification is required, the yellow-card data for the exact grade and tested wall thickness must be requested.