Chimei KIBISAN SAN PN-108L100 enters cosmetic packaging production as a high-flow styrene-acrylonitrile copolymer processed into moulded cream jars, compact powder covers, lipstick outer shells, and transparent closure bodies. Pre-drying at 80°C for 2–4 h is applied when ambient relative humidity exceeds 60%. Barrel temperature settings are typically split between 210°C in the rear zone and 225°C at the nozzle. Mould surface temperature is held at 40–55°C. The grade is processed in hot-runner multi-cavity tools with valve-gate sequencing to minimise visible gate blush on the outer surface. Regrind addition is limited to ≤20 wt% because higher levels raise haze and reduce lot-to-lot colour consistency under ISO 13468-1 transmittance testing. External mould release agents are excluded to maintain the high surface gloss required for transparent outer shells. Finished articles are measured by ISO 2813:2014 for specular gloss at 60° and by ISO 13468-1:2019 for total luminous transmittance. Closure fit between jar body and cap is verified through dimensional checks after 24 h conditioning at 23°C and 50% relative humidity.

Failure modes observed on production-scale hydraulic toggle machines include sink marks opposite gate bosses and stress whitening at the snap-fit undercut. When clamp force is set below 2.5 tonnes per square inch of projected area, flash appears on parting lines. Barrel residence time is limited to ≤5 min because longer thermal exposure increases residual styrene and acrylonitrile monomers. Air shots are purged after any interruption exceeding 2 min. The dimensional tolerance for jar neck thread diameter is held within ±0.05 mm using in-line optical gauging. These controls allow the same PN-108L100 lot to serve both high-gloss outer surfaces and snap-fit closure structures without secondary coating. The main operational boundary is gate-string formation at excessive injection velocity. Process technicians reduce peak injection speed when short shots occur in thin hinge areas or when jetting appears on the cavity wall.

How Does PN-108L100 Perform in Continuous-Thread Closures Exposed to Ester-Based Formulations?

PN-108L100 is selected for continuous-thread closures and pump bases used with oil-based facial serums, body lotion pumps, and solvent-free leave-on formulations. The acrylonitrile segment reduces swelling in the presence of monoethylhexyl adipate and isopropyl myristate compared with general-purpose polystyrene. Diffusion-limited sorption tests are performed under ASTM D543-20 practice for evaluating resistance of plastics to chemical reagents. Moulded closures are exposed for 72 h at 40°C in the selected ester. The lot-release protocol requires a weight change below 0.5% and no visible crazing after exposure. The closure shell is produced with a regrind ratio of ≤15 wt%. A silicone-free permanent antistat is not used because it migrates to the top surface and reduces print adhesion. A high-flow nozzle design with separate shut-off needle is used to prevent drooling during screw retraction. Holding pressure is applied at 55–70 MPa hydraulic pressure to maintain thread concentricity. Final products include dropper bottle collars, serum pump bases, and cosmetic jar outer caps.

Packaging-level mechanical safety is specified by the purchaser’s incoming inspection protocol, while heavy metal content is controlled under EU Directive 94/62/EC Article 11. The thread-start region is examined with polarised light after torque cycling at 1.5 N·m to detect residual stress. Closure torque above 3 N·m at the thread root can accelerate environmental stress cracking in ester-containing formulations. The process window therefore prioritises moderate gate pressure and extended holding time over excessive compaction. Screw recovery speed is limited to 50–70 rpm to avoid frictional overheating. Air entrapment at the thread boss is controlled by vacuum evacuation of the cavity before injection. When the mould is run on electric toggle machines, inertia-based peak injection pressure is reduced by 10–15% compared with hydraulic machines.

For transparent electronics covers, PN-108L100 is dried to a moisture target of ≤0.05% before injection because residual moisture causes silver streaks and weakens knit lines. Melt temperature is kept between 220°C and 235°C, and mould surface temperature is maintained at 35–50°C for thin-wall optical windows. The material is processed in 32-cavity to 80-cavity hot-runner tools with direct edge gates on non-appearance surfaces. A masterbatch ratio of 1.0–2.0 wt% is used only when the customer colour target cannot be achieved with natural resin. The natural resin typically carries an UL 94 HB classification at 3.2 mm under IEC 60695-11-10, but grade-specific yellow card data must be confirmed before mass production. Final products include transparent printer document covers, air purifier front covers, and small appliance light guides.

RoHS compliance is addressed through raw material declarations under Directive 2011/65/EU Annex II for lead, cadmium, mercury, hexavalent chromium, PBB, and PBDE concentrations. REACH candidate list screening is conducted by the moulder on the moulded part rather than on pellet only. The main process risk is warp in large flat covers caused by asymmetric cooling. Sequential valve gates are opened in a cascading pattern from the centre to the outer edge. Packing pressure is held until the gate is frozen. Gate freeze time is verified with short-shot progression studies. Sink marks above the gate boss are controlled by maintaining a melt cushion of 3–5 mm on the screw. When warp exceeds 0.4 mm across a 200 mm span, the cooling channels are rebalanced or steel inserts are added to the core side.

Food Contact Blender Jar Formation Requires Weld-Line Toughness and Migration Compliance

PN-108L100 is processed into transparent blender jars, coffee grinder containers, and spice grinder cups where food-contact compliance and impact resistance are evaluated jointly. The grade is run at melt temperatures of 215–225°C to reduce monomer regeneration while still filling thick-wall sections from 2.5 mm to 4.0 mm. Injection speed is set at 120–160 mm/s until 85% fill, followed by switchover to holding pressure at 60–80 MPa hydraulic pressure. Mould temperature is controlled at 45–60°C using pressurised water units. The food-contact basis is evaluated under FDA 21 CFR 177.1040 for acrylonitrile/styrene copolymers. The finished article is tested under EU Regulation (EC) No 10/2011 as amended for overall migration and specific migration of acrylonitrile. Migration testing follows EN 1186-1 methods using food simulants selected for the intended food category.

Weld-line strength is the limiting mechanical criterion in blender jar moulds because the melt flow front recombines around the handle insert and at the thread ring. Test specimens are cut from the jar wall with the weld line at mid-gauge length and tested under ISO 527-2:2012. A tensile strength retention below 60% of unwelded reference strength triggers process adjustment. Notched impact toughness is measured under ISO 179-1 or ASTM D256-10 on specimens cut from the threaded rim. The melt temperature is raised by 5°C when weld-line retention is below the threshold. Screw back pressure is maintained at 3–5 bar to homogenise the melt without excessive shear heating. Regrind usage in food-contact jars is limited to in-house production scrap and is tested in migration studies before use above 10 wt%.

When PN-108L100 Replaces Polycarbonate in Transparent Diagnostic Housings

Release agent-free processing is mandatory for transparent diagnostic housings because surface residues interfere with adhesive bonding of membranes, labels, and gaskets. The injection cell uses a dedicated screw and barrel reserved for transparent medical grades to avoid contamination from coloured ABS or PC residues. The resin is dried to ≤0.05% moisture before moulding. Melt temperature is reduced to 215–225°C to limit monomer regeneration, and screw recovery speed is set to 50–70 rpm. Regrind is not used. No post-consumer recyclate is permitted. Colour masterbatch, if required, must be supplied with ISO 10993-1 supporting documentation. Final products include housings for benchtop diagnostic readers, transparent windows in handheld analysers, and lateral flow reader enclosures. The material is intended for enclosure applications and not for prolonged patient tissue contact.

Biocompatibility evaluation follows ISO 10993-1 for limited contact with intact skin or no direct contact, with cytotoxicity testing under ISO 10993-5. Ethylene oxide sterilisation is preferred because SAN does not require autoclave-level heat resistance. Gamma irradiation of this specific PN-108L100 configuration has limited published stabilisation data. Discolouration and odour after 25 kGy to 50 kGy gamma exposure are not predictable without grade-specific trial. The mould cavity is vented to 0.02–0.04 mm depth to prevent burn marks. Clamp force is calculated from the projected area of the multi-cavity cleanroom tool. Dimensional stability after ethylene oxide is checked on critical locating bosses with a tolerance of ±0.08 mm. If the part fails dimensional checks, the mould temperature is adjusted before considering design changes.

Inside cabin trim suppliers, PN-108L100 is applied to clear control lenses located below the beltline to avoid direct solar load. The material is processed without external release agents because subsequent tampo printing or laser marking of symbols requires a clean surface. Regrind level is restricted to ≤15 wt% from uncontaminated transparent parts. Melt temperature is set at 220–230°C. Mould temperature is held at 40–50°C. The process uses short injection time and rapid packing transition to maintain symbol legibility on the lens back side. End products include HVAC control knobs, instrument cluster clear covers, shift indicator windows, and translucent switch buttons. Flammability is tested under ISO 3795 for interior materials. Volatile organic compound emission is screened by VDA 277 or purchaser-specific limit values.

Chemical resistance to sunscreen and hand cream is evaluated internally because SAN can stress-crack when exposed to aggressive carriers under continuous flexural stress. Test plaques are exposed for 24 h at 80°C under 0.5% flexural strain using a three-point bending fixture. If no grazing appears, the material is released for the customer. The upper service temperature is constrained by the deflection temperature under load of the grade. For unannealed SAN mouldings, shape stability is verified at 70–80°C for short exposure. Parts located near instrument cluster lamps require lamp-coating temperature testing under the vehicle manufacturer’s thermal profile. If the measured surface temperature exceeds the grade-specific deflection temperature under load, the design is moved to a lower thermal zone or replaced with a higher-heat transparent resin.