Toray Industries supplies the ABS 100NC grade within the TOYOLAC acrylonitrile-butadiene-styrene product family as an unfilled, natural-colored injection-molding resin. The alphanumeric designation “100” identifies an unfilled general-purpose flow class in the manufacturer’s melt-flow hierarchy, while the suffix “NC” denotes natural color, supplied without carbon black or pigment masterbatch. The material is opaque, amorphous, and has a density of 1.05 g/cm³ under ISO 1183-1:2019. Manufacturer-published data list a melt mass-flow rate of 21 g/10 min at 220 °C and 10 kg load under ISO 1133-1:2022. On injection-molded specimens, tensile yield stress is approximately 43 MPa, elongation at break is approximately 20% under ISO 527-2:2012, flexural strength is approximately 67 MPa, and flexural modulus is approximately 2,300 MPa under ISO 178:2019. Notched Charpy impact strength is approximately 20 kJ/m² at 23 °C under ISO 179-1:2010. Heat deflection temperature is approximately 81 °C at 1.82 MPa under ISO 75-2:2013, and Vicat softening temperature is approximately 94 °C under ISO 306:2022. Rockwell hardness is approximately 110 R under ISO 2039-2:2018. Mold shrinkage for unfilled natural ABS typically falls between 0.5% and 0.7%, depending on wall thickness, gate geometry, and packing pressure. The grade carries a UL 94 HB classification at 1.5 mm specimen thickness. In application terms, 100NC is specified for injection-molded electronic housings, appliance fascias, small appliance structural shells, and interior trim parts where a melt mass-flow rate above 15 g/10 min and a notched Charpy impact above 15 kJ/m² are acceptable.

Lot-to-lot variation in melt flow rate should be verified against the Toray certificate of analysis, because natural resin color state can shift melt viscosity across production campaigns. Parts requiring tight gloss or weld-line strength targets should not substitute color-compounded ABS without checking melt flow rate, mold shrinkage, and notched impact retention on the production tool.

What Distinguishes ABS 100NC from High-Impact and Heat-Resistant TOYOLAC Grades?

Compared with impact-modified TOYOLAC 700-series grades, 100NC has a lower notched Charpy impact strength under ISO 179-1:2010 and a higher melt mass-flow rate under ISO 1133-1:2022. The grade is therefore selected when filling thin-wall multi-cavity tools below 1.5 mm nominal wall is more limiting than impact resistance. Compared with heat-resistant TOYOLAC 900-series grades, 100NC has a lower heat deflection temperature at 1.82 MPa and a lower Vicat softening temperature, but it processes at lower melt temperature and does not require high-temperature hot-runner systems. Compared with glass-fiber reinforced ABS grades, 100NC is unfilled; it avoids screw-barrel abrasion, displays a smooth high-gloss cavity surface, but has lower flexural modulus and greater anisotropic mold shrinkage. Compared with polycarbonate/ABS blends, 100NC has lower sub-zero impact and lower heat resistance, but achieves comparable flow at 220–240 °C melt temperature without demanding polycarbonate-level drying temperatures. Natural-color supply differentiates 100NC from pre-colored ABS: downstream addition of color concentrate can alter notched impact and mold shrinkage. Pellet-to-pellet color concentrate segregation in hopper-fed systems may shift mechanical properties when concentrate loadings exceed 3 wt%, so gravimetric blending or pre-compounded color is recommended. Published data for this specific configuration is limited; therefore, property retention after masterbatch dilution must be confirmed on the production tool.

On injection molding lines equipped with general-purpose reciprocating screws of 20:1 L/D and non-return valves, 100NC is normally processed at melt temperatures from 210 °C to 240 °C. Pellets must be dried in a desiccant dryer at 80 °C to 90 °C for 2 h to 4 h to achieve residual moisture below 0.05%. Moisture above 0.05% volatilizes during plastication and produces surface splay, silver streaking, and reduced weld-line strength on polished cavities. Mold temperature should be maintained between 40 °C and 60 °C; below 40 °C, weld lines become brittle and surface gloss decreases, while above 60 °C, cycle time increases without proportional improvement in part toughness. For mirror-polished cosmetic surfaces, mold temperature setpoints should be held within ±5 °C to avoid visible gloss banding. Injection pressure typically ranges from 60 MPa to 100 MPa, with hold pressure maintained at 50–70% of the peak injection pressure to suppress sink marks. Screw back pressure should be held between 0.5 MPa and 1.0 MPa, and screw surface speed is typically 50–100 rpm. On 350-ton clamp injection molding machines with 20:1 L/D general-purpose screws, back pressure below 0.3 MPa has been associated with unmelted particle streaking and non-uniform melt temperature, while back pressure above 1.2 MPa increases residence time and may cause yellowing. Total melt residence time should remain below 6 min at 240 °C to limit degradation of the butadiene phase. Hot runner manifold and nozzle temperatures above 250 °C are outside the recommended operating envelope and may cause brown streaking, gloss loss, and decomposition of the styrene-acrylonitrile matrix. Regrind from sprues and runners should be limited to 20 wt%; higher levels may reduce notched impact and increase yellowing. The drying system should supply air with a dew point below -20 °C; desiccant beds operating above -10 °C dew point may not remove sufficient moisture in the specified drying time. At a projected area of 500 cm², a peak cavity pressure of 40 MPa requires a clamp force of at least 2,000 kN; machines below this value may flash because cavity pressure exceeds clamp capacity.

At 220 °C, the melt mass-flow rate of 21 g/10 min corresponds to low-pressure flow in thick sections; however, in thin sections below 1.0 mm, shear heating can raise melt temperature by 10–15 °C at screw surface speeds above 100 rpm. Capillary rheometry at 1,000 s⁻¹ and 240 °C is recommended for mold-filling simulation; published viscosity curves for natural grade are lot-dependent and should be regenerated when regrind fraction exceeds 20 wt%. Mold-filling simulations based on generic ABS data may underestimate pressure drop by 10–20% in hot-runner systems with small gate diameters below 0.8 mm.

Because the composition is amorphous and unfilled, post-mold shrinkage is anisotropic. Plaques molded at 240 °C melt temperature and 60 °C mold temperature under ISO 294-4:2018 exhibit shrinkage typically 0.5% parallel to flow and 0.6% transverse to flow; this difference creates bowing in flat parts when wall thickness varies by more than 20%. When dimensional tolerance is below ±0.1 mm, gate position, packing time, and cooling channel uniformity are more critical than material substitution. The coefficient of linear thermal expansion is approximately 70×10⁻⁶ K⁻¹ to 90×10⁻⁶ K⁻¹ between -30 °C and 60 °C; metal inserts should be preheated to 80 °C to 100 °C to prevent early freeze-off and microcracking during overmolding. Weld-line strength in thin-wall parts is sensitive to melt temperature and mold temperature; at wall thickness below 1.2 mm, raising mold temperature from 40 °C to 60 °C improves weld-line burst pressure in pressurized enclosures by approximately 10–15% when measured by air-leak testing at 0.1 MPa internal pressure. This improvement is specific to the cavity layout and should not be extrapolated without tool validation. In unreinforced ABS, long flow paths above 150:1 flow-length-to-wall-thickness require fast injection speeds and careful gate sizing; linear gate velocity above 300 mm/s without a fan or tab gate may cause jetting and surface defects.

Chemical Resistance and Regulatory Verification

Chemical resistance is evaluated under ISO 175:2010 using immersion at 23 °C for 7 days; the grade is resistant to dilute aqueous acids, alkalis, and aliphatic hydrocarbons but is incompatible with ketones, esters, aromatic hydrocarbons, and chlorinated solvents. Stress-crack resistance under chemical load is geometry-dependent and must be tested on molded parts, not raw pellets. Continuous outdoor UV exposure without UV stabilization causes surface chalking and loss of impact; exterior applications require painted, metallized, or UV-stabilized outboard layers. The material is not recommended for continuous load-bearing use above 80 °C because heat deflection temperature at 1.82 MPa is near 81 °C and creep modulus declines with temperature. The compliance matrix below lists regulatory positions for natural unpigmented supply; custom masterbatch and end-article testing must be evaluated separately.

In thin-wall electronic battery housings with wall thickness below 1.2 mm, 100NC is selected when a spiral flow length above 300 mm at 2 mm wall thickness is required under 80 MPa injection pressure. Multi-cavity tools with gate-to-flow-end ratios above 150:1 require melt temperature near 240 °C and fast injection speeds; however, gate blush and jetting may occur if linear gate velocity exceeds 300 mm/s without a fan or tab gate. In production trials on 250-ton to 500-ton toggle-clamp machines, mold temperature setpoints below 40 °C reduced gloss and produced brittle weld lines, while temperatures above 60 °C extended cooling time by 15–20% without proportional improvement in impact. The absence of glass fiber reinforcement permits direct electroplating and painting adhesion when molded surfaces are prepared according to the coating supplier’s surface-energy specification, typically requiring a dyne level above 38 dyn/cm on the as-molded tie layer. Published data for this specific configuration is limited; validation on the production tool with lot-specific pellet analysis remains required before release.