FCFC TAIRISAN SAN NF2200 is a styrene-acrylonitrile copolymer supplied by Formosa Chemicals & Fibre Corporation within the TAIRISAN product family. The grade is positioned for injection-moulding applications requiring a balance of rigidity, surface hardness, dimensional stability, and resistance to common oils and cleaning agents. Unlike rubber-modified ABS, the material contains no polybutadiene dispersed phase; this distinction raises flexural modulus and reduces notched impact strength relative to ABS while retaining optical translucency or transparency in thin sections. The material falls under the SAN copolymer classification system described in ISO 4894-1, and the supplier’s certificate of analysis should be consulted for lot-specific values of melt flow rate, residual styrene monomer, and acrylonitrile content. Published data for this specific configuration is limited in some public sources; therefore, processing and performance limits should be derived from the producer’s current technical data sheet combined with the general property envelope for injection-moulded SAN copolymers.

Because grade-specific data for NF2200 is limited, performance boundaries in this document are stated as the typical envelope for unfilled injection-moulding SAN copolymers under recognized ISO test methods. Verification against the lot certificate remains mandatory before tooling is cut. The absence of a normative grade-specific specification in public documentation does not imply that NF2200 lacks producer control limits; it indicates that the current TDS and certificate of analysis are the authoritative references.

What Distinguishes NF2200 from General-Purpose SAN and SMMA Grades?

Differentiation within the SAN range is driven by comonomer ratio, melt flow rate, and stabilizer package. The acrylonitrile fraction in general-purpose SAN typically falls between 24% and 32% by mass; this range shifts the glass transition and matrix polarity, altering oil resistance and blend compatibility. Higher acrylonitrile content usually raises tensile strength and chemical resistance but increases melt viscosity and reduces light transmittance. NF2200 is positioned for thin-wall moulding, where a higher melt flow rate under ISO 1133-1:2022—commonly reported for high-flow injection grades at 220°C with a 10 kg load—reduces injection pressure and permits shorter cycle times in multi-cavity tools. Comparative GPPS contains no nitrile comonomer and exhibits lower resistance to aliphatic hydrocarbons; ABS contains rubber particles that provide impact resistance but sacrifice transparency and lower flexural modulus. Published values for general high-flow SAN place tensile yield at 65 MPa to 75 MPa and flexural modulus at 3500 MPa to 3900 MPa under ISO 527-2 and ISO 178; identical test conditions for NF2200 should be confirmed because formulation differences within a product family can move these values by several percentage points.

Production-scale experience with unfilled SAN in injection moulding shows that moisture control is a more frequent source of surface defect than melt temperature alone. Pellets stored above 60% relative humidity should be pre-dried at 80°C to 85°C for 2 h to 4 h in a desiccant dryer with a dew point below -30°C, targeting moisture content below 0.05% by mass. Overdrying above 90°C can accelerate pellet sintering in the hopper throat and is not recommended. Hopper magnets and metal-separation equipment calibrated for ABS regrind should not be assumed sufficient for SAN because cross-contamination with GPPS or ABS changes rheology and can cause visible delamination at knit lines.

When Chemical Resistance and Optical Clarity Are Evaluated Jointly

Typical applications for TAIRISAN SAN NF2200 are found where GPPS fails in contact with cosmetic emollients, hydrocarbon-based cleaners, or food oils, and where PMMA is excluded because of higher mould shrinkage or marginal impact performance. Cosmetic packaging, appliance lenses, filter housings, and non-implant device housings are common design areas. The acceptance decision usually requires haze, light transmittance, and yellowness index testing on moulded plaques; ASTM D1003-21 for transmittance and haze or ISO 14782 for haze is applied. Rigid SAN grades generally show total luminous transmittance below that of PMMA and above that of ABS; the exact value for NF2200 should be read from the supplier’s colour-grade documentation because colour masterbatch and processing temperature shift the yellowness index. Chemical resistance screening against proprietary cosmetic formulations is advised because styrenic matrices can suffer stress cracking under sustained strain in the presence of ketones, esters, and some solvent-based fragrances. No single solvent-wipe test should be used to qualify large-area parts.

Under production-scale conditions, the material is normally processed at melt temperatures of 200°C to 250°C measured at the nozzle, with mould temperatures from 40°C to 70°C. The lower mould-temperature boundary discourages sink marks in thick bosses, while the upper boundary supports gloss and reduces visible flow lines in clear grades. Injection speed should be profiled to fill 90% to 95% of cavity volume before holding pressure is applied; hold-pressure values from 50 MPa to 80 MPa are typical for SAN in cold-runner tools with pin gates. Back pressure between 0.5 MPa and 1.5 MPa helps homogenise melt temperature without excessively raising screw recovery time. Screw recovery speed should be set so that metering is complete just before cooling opens; prolonged residence above 260°C for more than 10 min should be avoided because SAN develops yellowing and potential molecular weight reduction. A 35 mm to 40 mm general-purpose screw with L/D 20:1 is adequate, but compression ratio should be 2.0:1 to 2.5:1. Deep channels can starve the melt and generate unmelted styrenic particles; shallow barrier screws may increase shear heating and can exceed the thermal stability limit at high screw speeds.

Table 1 provides a comparative envelope for unfilled injection-moulding styrenics. The SAN column does not represent a guaranteed NF2200 specification but illustrates the relative property position of high-flow SAN grades against GPPS and ABS.

These differences explain why SAN is chosen over GPPS where oil and cleaning-agent resistance is required, and over ABS where transparency or higher rigidity is the controlling requirement. The relatively low notched impact of SAN means that NF2200 should not be substituted for ABS in snap-fit closures, living hinges, or components subject to impact at temperatures below 0°C; the material has a ductile-brittle transition that is unfavourable in notched sections. Drop-impact acceptance should be evaluated on production tooling using ISO 6603-2 rather than material supplier data alone.

Rheological Boundary Conditions and Gate-Freeze Limits

Gate design for NF2200 must account for the solidification behaviour of a rigid amorphous polymer. Pin gates from 0.8 mm to 1.2 mm are common for small clear parts, but valve or direct sprue gates are used for thicker housings. Gate freeze time is typically estimated from part thickness squared divided by thermal diffusivity; for SAN, the practical gate-freeze time in a 1 mm wall is on the order of 0.3 s to 0.8 s at 40°C mould temperature, although exact values require mould-filling simulation with grade-specific pvT and viscosity data. If the gate is too small, the holding-pressure time must be shortened to avoid gate-cracking and gate stringing. If the gate is too large, the cavity decompresses through the gate and sink marks develop in thick bosses. Runner balancing is required in multi-cavity tools because SAN has a lower melt elasticity than ABS; shear-induced imbalanced filling in geometrically balanced runner systems can be severe at high injection-speed settings. Simulation with cross-WLF viscosity parameters fitted from capillary rheometry according to ISO 11443:2021 is recommended before cutting steel.

For lot-to-lot quality control, incoming material should be tested for melt flow rate stability under ISO 1133-1:2022 and for colour shift on a standard moulded chip. Melt flow rate variation outside the supplier’s stated control limits can require transfer-point adjustment in thin-wall tools. Dimensional stability of SAN is generally better than GPPS in humid environments, but moulded parts can still show post-mould shrinkage of 0.4% to 0.6% in the flow direction and 0.3% to 0.5% in the transverse direction after 24 h at 23°C. These values should be verified on the actual tool because anisotropy develops even in unfilled parts due to molecular orientation. Annealing at 70°C for 2 h is sometimes used to stabilise dimensions before assembly; annealing temperature should remain below the Vicat softening temperature to avoid distortion. Water absorption after 24 h immersion under ISO 62 is typically below 0.3% for SAN.

Temperature-Residence Time Trade-Offs Govern Colour Stability

At melt temperatures below 200°C, incomplete plastication becomes the primary defect mechanism. Unmelted pellets can pass through a 2.5:1 compression-ratio screw if back pressure is lower than 0.3 MPa and the screw speed is high. At the upper end, processing above 250°C triggers thermal degradation of the SAN chain and residual diluent volatilisation; visible signs include yellowing, silver streaking, and carbon specks after prolonged hold times. The critical upper limit is not a single value but a function of residence time and screw recovery cycle. For a 100 t hydraulic injection moulding machine with a shot weight occupying 50% of barrel capacity, a melt temperature of 240°C with a total cycle time of 30 s may be tolerable, while the same temperature with a cycle time of 60 s can shift yellowness index beyond customer acceptance. Barrel capacity utilisation should therefore be maintained between 20% and 60% when moulding heat-sensitive SAN grades.

For supply chain acceptance, the material documentation package should include the ISO 4894-1 designation block, a lot-specific melt flow rate report under ISO 1133-1:2022, and a statement of REACH Article 33 SVHC content under Regulation (EC) No 1907/2006. RoHS Directive 2011/65/EU compliance for cadmium, lead, mercury, hexavalent chromium, PBB, and PBDE should be confirmed by supplier X-ray fluorescence screening or digestion testing. If the final article is marketed as food-contact or medical, additional market-specific migration and biocompatibility testing is required; the polymer type alone does not establish compliance. Material substitutions from other SAN grades should not be made without a full review of the moulding window, because colour masterbatch carriers and lubricant packages may differ even when the base SAN meets the same ISO designation.