KIBISAN SAN PN-117 L100 is a general-purpose styrene-acrylonitrile copolymer supplied by Chi Mei Corporation under the KIBISAN SAN product family. The PN-117 base designation identifies a transparent injection-molding grade; the L100 suffix is producer-specific and is commonly associated with a defined melt-handling package or additive formulation. Publicly available technical literature for this exact suffix is limited, so the following processing and property data are given as representative ranges for general-purpose SAN resins of this flow class and should be replaced by the producer’s lot certificate of analysis for specification work.

The material is amorphous, transparent in natural form, and supplied as cylindrical pellets for screw-fed injection molding and extrusion lines. Because the copolymer contains a polar acrylonitrile component, it offers higher stiffness and environmental stress-cracking resistance than general-purpose polystyrene while retaining processability on standard equipment. The resin is not intended for outdoor UV exposure without stabilization, and its upper processing temperature is strictly limited.

Raw Material Feedstock and Molecular Architecture

Styrene-acrylonitrile copolymers in this product class typically contain 24 to 28 wt% acrylonitrile, although the producer controls the monomer ratio to balance flow, chemical resistance, and optical clarity. The acrylonitrile unit introduces strong dipole-dipole interactions between polymer chains. The resulting cohesive energy density raises the glass transition temperature, increases tensile strength, and reduces creep relative to polystyrene. It also reduces solubility in aliphatic hydrocarbons and cooking oils but does not confer resistance to aromatic hydrocarbons, ketones, or chlorinated solvents.

The amorphous structure eliminates spherulitic scattering, allowing high light transmittance when pigment and gel levels are controlled. Batch-to-batch molecular weight variation in well-controlled bulk polymerization is typically below ±5% in melt viscosity; this is acceptable for multi-cavity molds but may shift short-shot boundaries in parts with wall thickness below 0.8 mm. Residual styrene monomer and oligomer levels are generally low enough for low-odor applications, but the producer’s certificate should be reviewed where food-contact or medical packaging is proposed.

In continuous bulk polymerization, the styrene-acrylonitrile reaction is controlled for conversion and gel formation. Excessive conversion can raise gel content and reduce optical quality; insufficient conversion leaves residual monomers that increase odor and reduce Vicat softening temperature. The L100 suffix may involve finishing additives that reduce pellet friction during silo handling and feeding. These additives are selected to avoid plate-out on mold surfaces and to avoid interference with printing, bonding, or ultrasonic welding.

Heat deflection temperature under 1.82 MPa is commonly reported between 88°C and 95°C by ISO 75-2. Because the polymer is amorphous, service temperatures near the Vicat softening point can produce dimensional change even under low load. Mold shrinkage is usually 0.4–0.7% in the flow direction and 0.5–0.8% transverse; tool makers should verify shrinkage after 24 hours because post-molding relaxation can continue after ejection.

How Does the L100 Designation Affect Melt Processing and Cosmetic Defect Rates?

Pre-drying is the most critical processing step for the L100 modifier class. When pellet moisture exceeds 0.05 wt%, hydrolysis and rapid vaporization produce splay, silver streaking, and visible surface haze at the gate and knit lines. A desiccant hopper dryer set to 75–80°C for 2–4 hours is recommended before the first heat. In ambient relative humidity above 60%, open containers should not be used beyond 1 hour without re-drying. Drying temperatures above 85°C promote pellet discoloration and increase yellowness index.

Moisture content is best verified by a halogen moisture analyzer calibrated against a Karl Fischer titrator; weight-loss methods alone may underreport moisture because styrene-acrylonitrile pellets release volatile oligomers at high drying temperatures. A loss-on-drying value above 0.08 wt% indicates insufficient drying or contaminated dryer desiccant. Dew point of the drying air should be below −20°C; if the desiccant bed is saturated, drying time must be extended even though the dryer temperature display remains unchanged.

Barrel temperatures should be set so that the melt temperature at the nozzle is 220–240°C. A typical temperature profile for a 20:1 to 25:1 L/D general-purpose screw is rear 190–200°C, center 210–230°C, front 220–240°C, and nozzle 220–230°C. Mold temperature should be controlled between 40°C and 60°C; mold temperatures below 35°C freeze the flow front too quickly, producing visible weld lines, flow lines, and high molded-in stress in parts thinner than 1.0 mm. For polished optical molds, mold temperature is often held at the upper end to improve surface replication and reduce haze.

Residence time above 240°C must be kept below 10 minutes. At higher temperatures or longer residence, the material yellows, generates an acrid styrene-acrylonitrile decomposition odor, and deposits low-molecular-weight degradation products on mold surfaces. Purge after production interruptions with general-purpose polystyrene or a commercial purging compound; do not use PVC or acetal purging compounds because their decomposition products can contaminate the barrel and cause black specks in subsequent SAN runs.

Injection speed should be medium to fast for thin-wall parts and medium to slow for thick sections where jetting and gate blush are risks. Back pressure during screw recovery should be 5–10 bar; higher back pressure raises melt temperature and shortens residence-time limits. Screw rotation should be 60–100 rpm for a 30 mm screw; the lower end is used for larger screw diameters to limit shear heating. Vent depth on the parting line should not exceed 0.02 mm, because low-viscosity SAN tends to flash in deep vents.

On injection molding machines with clamp force in the 80–120 tonne range, thin-wall parts with projected area of 120–150 cm² and wall thickness 0.8–1.2 mm usually require injection pressure of 80–120 MPa and holding pressure of 50–80 MPa. Short shots at the end of fill often indicate gate freeze before packing, incorrect check-ring sealing, or insufficient melt temperature below 220°C. Sink marks in ribs and bosses are controlled by holding time, gate geometry, and wall thickness ratio; ribs should not exceed 40–50% of adjacent wall thickness.

Gate design influences melt flow and molecular orientation. Direct edge gates must be sized at 60–80% of part wall thickness; subgates and tunnel gates should be no smaller than 0.8 mm diameter for reliable freeze-off and reduced shear heating. In hot-runner systems, thermal balancing of drops is critical. Drop temperature differences above 5°C create cavity-to-cavity filling imbalance, visible as weight variation and differential shrinkage. Valve-gate hot runners may require lower hold pressure because gate sealing is mechanical; open hot runners require precise gate cooling to prevent stringing and gate vestige.

Regrind from sprues and runners can be mixed with virgin material at 20–30 wt% for non-optical applications. For transparent parts, regrind use must be validated by haze measurement because each heat history increases gel formation and yellowing. Drying mixed regrind is more difficult because the particle size distribution is irregular; a double pass through the desiccant dryer or extended drying at 75°C for 4 hours is required.

Injection-molded specimens for quality control should be conditioned at 23°C and 50% relative humidity for 24 hours before testing according to ISO 291. Melt volume-flow rate should be checked after first heat because moisture and thermal history shift the result; a deviation greater than 10% from the producer’s nominal value may indicate incorrect drying or barrel residence. Yellowness index measured according to ASTM E313 on 3 mm plaques is useful for detecting thermal degradation before visible brown streaks appear.

When Acrylonitrile Content Determines Chemical Resistance and Barrier Performance

The primary technical distinction between KIBISAN SAN PN-117 L100 and other polystyrene-based transparent resins is the acrylonitrile content. The nitrile group reduces sorption of nonpolar liquids and raises stress-cracking resistance against aliphatic hydrocarbons, cooking oils, fatty acids, and dilute aqueous acids. Typical applications include cosmetics packaging, household appliance windows, dry-cell battery jackets, transparent stationery components, office-equipment covers, and interior indicator lenses.

Relative to KIBISAN SAN PN-117C, the L100 suffix often represents a lot-level or packaging modification rather than a fundamentally different molecular weight or acrylonitrile content; published data for this exact configuration is limited. Compared with higher-acrylonitrile KIBISAN SAN grades such as the PN-127 class, PN-117 L100 belongs to the standard chemical-resistance tier. Higher-acrylonitrile grades improve resistance to ethanol-water systems, mineral oil, and detergent stress cracking but may increase melt viscosity and reduce notched impact strength. Relative to transparent ABS, the SAN product has higher optical clarity and surface hardness but lower room-temperature and low-temperature impact resistance; ABS is preferred when impact loading or hinge performance is required.

Chemical compatibility testing should follow ISO 175 at the expected service temperature. Stress cracking in SAN appears at weld lines, gate areas, and sharp external radii when residual stress exceeds the critical stress for the fluid. Annealing at 70°C for 2 hours reduces molded-in stress in machined or heavy-section parts but causes some dimensional relaxation. Design features such as radiused corners above 1.0 mm, uniform wall sections, and properly sized gates reduce stress-cracking failures more effectively than material changes alone.

In cosmetic packaging, contact with ester-based fragrances, alcohol-water mixtures, and fatty acids should be tested under first-use and shelf-storage temperatures. Failure often starts as microcrazing at the neck finish or thread root when the part is filled and capped. In dry-cell battery applications, resistance to potassium hydroxide and dimensional stability under internal pressure are relevant; material selection should include stress-cracking tests with the actual electrolyte concentration. For office-equipment covers and appliance windows, the resin is selected for scratch resistance and surface hardness, but it cannot replace polycarbonate where transparency after impact or high heat above 100°C is required.

Optical parts require control of melt temperature, regrind content, and colorant carriers. Only SAN- or polystyrene-compatible masterbatches should be used; olefinic or incompatible carriers cause visible delamination and haze. Pigment loading should be minimized in transparent tinted parts because high pigment levels increase melt viscosity and reduce light transmittance. Laser marking is generally feasible on natural and light-colored SAN grades, but contrast is lower than on ABS and may require additive adjustment.

Compared with polymethyl methacrylate, SAN offers better chemical resistance to household cleaners and lipids but lower surface hardness and weatherability. Compared with polycarbonate, SAN offers lower melt temperature and easier flow but much lower impact resistance and heat resistance. These differences define the specification window for PN-117 L100: transparent rigid parts that do not experience high impact, continuous UV, hot water, or aggressive solvent exposure but require higher stress-cracking resistance than general-purpose polystyrene and lower cost than acrylic or polycarbonate.

Regulatory documentation for this grade should be secured from the producer. RoHS compliance is typically assessed against European Union Directive 2011/65/EU; REACH SVHC status and food-contact clearances, where required, must be confirmed from the lot-specific certificate of compliance. For food contact, relevant regional standards include European Commission Regulation (EU) No 10/2011 and U.S. FDA requirements for styrene-acrylonitrile copolymers; the specific grade, colorant, and additive package must be listed in the producer’s clearance documentation.

The main operational boundaries are moisture sensitivity, thermal degradation above 240°C, limited UV resistance, and incompatibility with aromatic solvents, ketones, chlorinated hydrocarbons, and concentrated mineral acids. Outdoor use without UV stabilization leads to yellowing and surface microcracking; a UV-stabilized SAN or an acrylic cap layer is required for exterior weatherable parts. For service with hot water above 60°C or aggressive detergent solutions, a higher-acrylonitrile SAN grade or a chemically resistant engineering polymer should be evaluated.