Chimei KIBISAN SAN PN-127 L150 FG is a rigid, transparent styrene-acrylonitrile copolymer supplied for injection molding and extrusion operations that require high melt flow, low residual monomer profile, and food-contact suitability. The product belongs to the KIBISAN SAN family, in which styrene contributes optical clarity, stiffness, and processability, while acrylonitrile raises glass transition temperature, mechanical strength, and resistance to aliphatic hydrocarbons, alcohols, salts, and household cleaning agents compared with general-purpose polystyrene. The L150 designation is associated with a nominal melt mass-flow rate of 15 g/10 min under ISO 1133-1:2022 or ASTM D1238 as stated on the supplier certificate of analysis. Representative mechanical data for unfilled high-flow SAN in this product class include tensile yield strength of 65–72 MPa under ASTM D638-14, flexural modulus of 3400–3700 MPa under ASTM D790-17, notched Izod impact of 1.8–2.4 kJ/m² under ASTM D256-23, and heat deflection temperature of 84–90 °C at 1.82 MPa under ASTM D648-18. The material is amorphous, with no crystalline melting point; a nominal glass transition temperature near 105 °C governs dimensional stability and creep resistance at elevated end-use temperatures. Density is approximately 1.08 g/cm³ under ISO 1183-1:2019, and the butadiene-free structure maintains light transmission near 90% at 2 mm thickness with haze below 1.5% under ASTM D1003-21 for clean, contaminant-free surfaces.

Published data for the exact FG suffix are limited in public sources; therefore the mechanical values above are representative of the PN-127 family and high-flow SAN formulations with equivalent melt-flow class. Converter validation should include review of the certificate of analysis and, for critical optical or food-contact parts, first-article testing under the same test methods and specimen thicknesses used in the purchasing specification. The grade is inherently stiffer and more chemically resistant than general-purpose polystyrene, but it is not an impact-modified material; in applications involving repeated drop loading or clamping stress, the lower notched Izod range must be checked against energy-absorption requirements.

How does the PN-127 L150 FG grade differ from standard SAN, high-heat SAN, and butadiene-modified styrenics?

Compared with a general-purpose SAN grade such as KIBISAN PN-117C, the PN-127 L150 FG shifts the melt-flow balance toward shorter injection cycle times and thinner wall sections. The change from a nominal 4–5 g/10 min to 15 g/10 min enables filling of wall sections below 1.5 mm without excessive injection pressure, but it is achieved through controlled molar mass adjustment or chain-transfer modification; the usual trade-off is a slight reduction in notched impact and a small decrease in heat deflection temperature. In multi-cavity closures and thin-walled kitchenware, the high-flow variant can reduce peak injection pressure by approximately 15–30% relative to standard-flow SAN at identical wall thickness and gate geometry, based on spiral-flow behavior.

Compared with high-heat SAN such as the PN-127H class, the L150 grade trades 4–8 °C of Vicat softening temperature for roughly a twofold melt-flow rate increase. It is therefore selected when cycle time and cavity-to-cavity fill weight variation are more important than sustained use above 90 °C. Compared with butadiene-modified styrenics such as ABS, the unfilled SAN lacks the polybutadiene phase that supplies notched Izod values of 15–30 kJ/m² in medium-impact ABS; the result is lower energy absorption but higher transparency, lower total extractable content, and better indoor color stability. Compared with GPPS, the acrylonitrile content increases resistance to fatty food simulants, household detergents, and alcohols, particularly under cyclic dishwashing where stress cracking of GPPS can occur.

At 220 °C, the material is a pseudoplastic melt; apparent viscosity decreases from approximately 1000 Pa·s at 100 s⁻¹ to 60–120 Pa·s at 1000 s⁻¹, although direct capillary rheometry on the exact FG configuration is not publicly available. The shear-thinning behavior permits high injection speeds through small gates, but the critical shear rate for melt fracture in unfilled SAN is approximately 10,000 s⁻¹. Gate shear rates above this threshold risk jetting, surface haze, and reduced weld-line strength. Therefore, gate diameters below 0.5 mm are generally avoided in transparent SAN molds unless validated by short-shot studies.

Pre-drying in a desiccant dryer with air dewpoint of −30 °C or lower at 80 °C for 2–4 h is required for humid storage or silo-to-press transfer. Moisture levels above 0.05 wt% produce surface splay and haze in hot sprue and gate areas. On production-scale injection molding machines with clamping force of 0.5–0.7 tonnes per cm² of projected area and screw L/D ratios of 20:1 to 24:1, melt temperature should be profiled from 190 °C in the rear zone to 230 °C at the nozzle; mold temperature is typically maintained at 40–70 °C to balance surface replication and cycle time. Back pressure of 0.5–1.5 MPa improves melt homogeneity without excessive shear heating. Residence time above 5 min at 230 °C should be avoided because acrylonitrile-containing copolymers can undergo thermal yellowing and oligomer formation. For thin-wall parts, injection speed should be set high enough to maintain flow-front velocity above 100 mm/s in gates of 0.8–1.2 mm diameter, preventing premature freeze-off and visible gate blush. Cooling time is strongly wall-thickness dependent; for a 2 mm SAN wall in a 60 °C mold, cooling time is typically 8–12 s, while a 1 mm wall may require 3–5 s. The high-flow grade allows lower packing pressure and reduced clamp tonnage, but pack time must still be sufficient to avoid sink marks at rib bases.

Dimensional control is aided by isotropic mold shrinkage of 0.4–0.7%. The amorphous structure produces low post-mold crystallization shrinkage, but batch-to-batch melt-flow variability of approximately ±15% relative to nominal and regrind-induced shifts should be included in statistical process control limits. Linear coefficient of thermal expansion is approximately 6–8 × 10⁻⁵ K⁻¹, lower than many polyolefins but higher than glass, so metal-to-plastic overmolding or screw inserts can build hoop stress.

When food-contact status is a requirement, migration testing and residual acrylonitrile control become decisive

The FG suffix indicates that the resin is intended for food-contact applications under relevant compliance frameworks. The polymer backbone falls within the scope of FDA 21 CFR 177.1040 for acrylonitrile/styrene copolymers and EU Regulation (EU) No 10/2011 Annex I for plastic materials and articles intended to come into contact with food. Final-article compliance is formulation-dependent and process-dependent; colorants, lubricants, mold-release agents, and regrind sources must also comply. Residual acrylonitrile monomer is the principal toxicological concern because acrylonitrile has a low specific migration limit under EU No 10/2011. The supplier certificate of analysis should be reviewed for residual acrylonitrile and styrene monomer concentrations, and migration tests under simulants such as 3% w/v acetic acid, 10% v/v ethanol, and vegetable oil should be performed on finished parts when the contact ratio, temperature, and duration require automated compliance assessment.

Compliance declarations should specify the intended food types and use temperatures. KIBISAN SAN PN-127 L150 FG is not suitable for retort or steam sterilization above 100 °C because the amorphous SAN matrix will soften, creep, and develop haze in sustained hot-water contact. For dishwasher-safe parts, the molder should validate dimensional stability and gloss retention after repeated exposure to water at 65–75 °C with alkaline detergent. Resistance to aqueous acids and bases is acceptable within pH 2–12 at room temperature, but strong oxidizing acids and aromatic hydrocarbons attack the styrene segments. Acetone, methyl ethyl ketone, and ethylene dichloride are aggressive solvents for SAN and must be excluded from contact specifications.

Material handling and regrind control are critical because FG status is documented at the resin level; cross-contamination with non-FG styrenics or lubricating oils invalidates food-contact documentation. Dedicated silos, hoppers, grinders, and vacuum receivers are required. Regrind usage should be limited to 30 wt% unless the molder validates optical haze and residual monomer levels, because repeated heat histories increase acrylonitrile oligomer formation. Avoid use of metal stearate mold releases above 0.1 wt% because they can raise haze and affect organoleptic properties. If external ultrasonic welding or solvent bonding is planned, testing should be performed on molded parts because SAN is sensitive to ketone and ester solvents used in some adhesives; this is an operational boundary, not a bulk material defect. Store in sealed containers away from direct sunlight and high humidity. At warehouse relative humidity above 60%, drying time should be extended to 4–6 h or the dryer dewpoint lowered to −40 °C.

Surface cosmetics, optical haze, and gate design in high-flow SAN molds

Because the grade is transparent and high-flow, gate location and melt-front convergence determine visible weld lines. Numerical flow simulation should be used to place weld lines away from high-cosmetic surfaces. Hot-runner systems with externally heated manifolds and valve gates of 2–5 mm diameter reduce gate blush, but thermal homogeneity must be maintained below 250 °C. Cold-runner direct gates may produce splay if the gate diameter is below 1.0 mm and the melt temperature is below 210 °C. Polished mold surfaces of SPI A-1 or SPI A-2 finish improve light transmission, but the high flow rate can replicate micro-scratches; mold venting of 0.02–0.03 mm depth prevents burn marks and haze around the end of fill. When knit lines cannot be avoided, increasing melt temperature within the allowable window and adding generous venting at the knit-line location often improve visual appearance, but knit-line tensile strength remains lower than unknit material and should be evaluated by tensile testing across the weld zone.

Typical applications for KIBISAN SAN PN-127 L150 FG include transparent food processor bowls, blender jars, kitchen scales, cosmetic jars, dispenser components, and stationary parts. In food processor bowl molding, the material’s melt flow permits filling of thick-to-thin transitions without visible knit lines, while its chemical resistance maintains surface integrity after repeated exposure to detergent solutions at 60–70 °C. For cosmetic packaging, the grade provides a hard, scratch-resistant surface that resists ethanol-containing formulations better than GPPS, though strongly polar solvents and ketones used in some nail polish removers can attack SAN and should be excluded from contact specifications. Prolonged outdoor UV exposure should be separately qualified because SAN can yellow under solar irradiance; published data for this specific configuration under long-term weathering is limited.