Luminy LX130U is a medium-flow amorphous polylactic acid injection molding grade supplied by TotalEnergies Corbion. The product is delivered as cylindrical pellets and is processed on conventional injection molding machines using general-purpose screws. Because the material is amorphous, it does not exhibit a defined crystalline melting endotherm; differential scanning calorimetry according to ISO 11357-2:2020 typically shows a glass transition temperature near 55–60°C and no significant melting peak. Representative manufacturer datasheet values include a density of 1.24 g/cm³ by ISO 1183-1:2019, a melt mass-flow rate of 13 g/10 min at 210°C under 2.16 kg by ISO 1133-1:2022, and a tensile modulus of 3500 MPa by ISO 527-2:2012. The corresponding melt volume-flow rate is approximately 10.5 cm³/10 min when corrected for a melt density near 1.24 g/cm³.

Short-term mechanical data place LX130U among stiff, low-ductility PLA materials. A tensile yield strength of 45 MPa and an elongation at break of 5% are reported under ISO 527-2:2012, flexural strength is 70 MPa under ISO 178:2019, and notched Charpy impact strength is 3.5 kJ/m² at 23°C under ISO 179-1:2023. These results are typically obtained after conditioning at 23°C and 50% relative humidity for 40 h according to ISO 291:2008. The material is therefore better suited to rigid components than to snap-fit or high-impact applications. Sharp internal corners, deep undercuts, and stress concentrations require larger radii and thicker sections than would be acceptable in unfilled polypropylene or ABS.

In unfilled form, LX130U is used for rigid injection molded parts such as cosmetic packaging, caps and closures, office equipment housings, disposable cutlery, and non-sterile medical device components. The amorphous structure reduces differential shrinkage between flow and cross-flow directions compared with nucleated or semi-crystalline PLA grades. Mold shrinkage is typically in the range of 0.3–0.5% when measured on 3.2 mm plaques after 48 h at 23°C according to ISO 294-4:2018. The grade is not intended for continuous service at temperatures above its heat deflection temperature; under a load of 0.45 MPa, the HDT B value is approximately 55°C by ISO 75-2:2013 method B. This thermal limit excludes hot-fill packaging, dishwasher-exposed articles, and automotive interior parts subject to solar load unless an annealing or nucleation strategy is validated separately.

What Morphological Constraints Govern Part Cooling and Ejection?

An amorphous PLA such as LX130U does not require a crystallization plateau during cooling. Mold temperature can be held at a comparatively low 15–40°C, which shortens cycle time and reduces energy demand on the mold temperature control unit. However, the absence of a crystalline network lowers the temperature at which the solid polymer begins to soften under load. The Vicat softening point is approximately 57°C under ISO 306:2022 method A50. Parts ejected above this temperature can show ejector-pin deformation, particularly when ejection force is concentrated on small pins. Tooling should distribute ejection force across large-diameter pins or blade ejectors and should include draft angles of at least 0.5–1° on deep draws.

Shrinkage behavior is more isotropic than in semi-crystalline PLA, but measurable post-mold shrinkage still occurs as free volume relaxes. On production-scale 120–180 t all-electric injection molding machines with 25:1 L/D general-purpose screws, molders commonly observe that holding pressure and gate freeze time influence part mass and sink more than dimensional variation. The amorphous phase does not undergo abrupt volume contraction at a crystallization temperature, so packing can be applied over a wider screw-position window without inducing gross warpage. Specific injection pressures of 80–120 MPa are typical for moderate wall sections of 1.5–3.0 mm; actual values vary with runner geometry, gate size, and flow length. Processors should not use excessive packing pressure as a substitute for adequate gate diameter, because overpacking can increase internal stress and make ejection more difficult.

Drying before processing is mandatory for LX130U because PLA undergoes hydrolysis at plastication temperatures in the presence of residual moisture. The supplier specifies a residual moisture content below 250 ppm before injection molding, with a desiccant dryer set at 80°C for 4 h and a supply-air dew point no higher than -30°C. Moisture content can be verified by Karl Fischer titration according to ISO 15512:2019. Pellets held in open containers at ambient relative humidity above 60% can regain surface moisture rapidly; hopper loading should be closed-loop, or hopper dryers should be used. At moisture levels above 500 ppm, hydrolytic chain scission produces a measurable decrease in melt viscosity, often detected as an unstable melt cushion, silver streaking on part surfaces, and reduced impact resistance.

Material handling should avoid co-mingling with polyolefins, polystyrene, polyethylene terephthalate, or other incompatible regrind streams, because small fractions of foreign polymer can alter melt viscosity and phase compatibility. Regrind of LX130U can be evaluated, but repeated heat history shifts the melt mass-flow rate upward and narrows the processing window. Published data for high-regrind LX130U is limited; regrind fractions should be validated on the production tool rather than extrapolated from virgin-pellet rheology. Purging with strong alkaline or amine-based compounds should be avoided because polyester backbones are susceptible to aminolysis and alkaline hydrolysis.

Thermal and Rheological Boundaries That Define the LX130U Processing Window

Processing temperatures must balance melt fluidity against thermal degradation. A starting barrel profile for a general-purpose screw ranges from a rear zone of 160–180°C, a center zone of 180–200°C, and a front zone and nozzle of 200–210°C. Melt temperature measured at the nozzle should not exceed 210°C during continuous operation. Residence time above 220°C should be kept below 5 min because PLA undergoes thermal chain scission and lactide formation, which can lower viscosity and generate plate-out on tool surfaces. In hot-runner systems, manifold and drop-tip temperatures should be maintained within 190–210°C to prevent cold slugs without creating stagnant degradation zones.

Mold temperature has a direct effect on part gloss, replication of micro-textures, and ejection behavior. For unfilled LX130U, a mold temperature of 15–25°C is sufficient for short-cycle work when cooling water is supplied at 10–15°C. Higher mold temperatures up to 40°C improve surface gloss and filling of fine features but extend cycle time. Extended holding above the glass transition is not required because crystallization does not proceed at a commercially useful rate in this grade. Ejector pins should be polished, and the tool should be kept dry to reduce friction; PLA tends to stick to warm metal surfaces when packing pressure is excessive.

Injection speed profiling affects part aesthetics because jetting and gate blush are more likely in low-viscosity amorphous melts. Medium injection speeds of 30–100 mm/s are typically used for wall thicknesses of 1.5–3.0 mm. For thin-wall parts below 1.0 mm, high-speed fill is required, but published data for LX130U in sub-millimeter walls is limited. Screw back pressure is normally set between 0.5 and 1.5 MPa to ensure consistent melt density without excessive shear heating; decompression after plasticating should be minimized to prevent air entrapment in the shot. Screw recovery settings should be adjusted so that the total cycle does not exceed the thermal stability limit of the material.

Compliance for LX130U must be confirmed at the finished-article level rather than at pellet level. The following matrix summarizes the regulatory and test-method framework commonly used to evaluate the grade.

LX130U differs from semi-crystalline PLA injection grades primarily in thermal resistance and dimensional behavior. A nucleated or annealed semi-crystalline PLA can reach HDT B values above 100°C after annealing, whereas amorphous LX130U remains below 55°C. The trade-off is lower and more isotropic mold shrinkage and reduced warpage in large, flat, or round components. In applications such as shallow trays, caps, and cosmetic housings, the amorphous grade may provide better flatness and circularity, but at the expense of elevated-temperature performance.

Compared with high-flow amorphous PLA grades, LX130U has a lower melt mass-flow rate. This implies longer plasticating time and slightly higher fill pressure in very thin walls. The advantage appears in melt cushion stability and reduced flash formation in multi-cavity tools with tight parting-line tolerances. Processors seeking wall sections below 0.8 mm or cycle times below 6 s should evaluate high-flow alternatives; published data for LX130U under these conditions is limited. Where part thickness is 1.5–3.0 mm and dimensional stability is more important than extreme fill speed, LX130U is a more conservative processing choice.

Compared with petroleum-based amorphous materials such as general-purpose ABS or polystyrene, LX130U has lower continuous-use temperature and higher moisture sensitivity. Its density of 1.24 g/cm³ is lower than filled PBT but higher than unfilled polypropylene. The material is biodegradable only under industrial composting conditions, not in ambient soil or marine environments. Compostability claims should be supported by certification such as EN 13432:2000 or ASTM D6400-23 on the finished article. These standards require specific disintegration and biodegradation thresholds and heavy-metal limits, and they do not automatically apply to multi-material assemblies, printed components, or adhesively bonded parts.

Typical industrial applications for LX130U include rigid consumer packaging, caps and closures, cosmetic components, office equipment housings, and non-sterile medical device components. For load-bearing or long-term exterior use, published data for this specific grade is limited; creep and weathering data should be generated according to ISO 899-2:2020 or ISO 4892-2:2013 before final material selection. Steam sterilization is not recommended because autoclave temperatures exceed the Vicat softening point; ethylene oxide or gamma irradiation may be considered but must be validated for molecular weight retention.

In injection molding production, LX130U should be purged with polypropylene or low-viscosity polyethylene before shutdown to reduce thermal degradation in the barrel. The material is incompatible with strong alkalis, amines, and prolonged contact with hot water above 50°C, all of which accelerate hydrolysis of the polyester backbone. Dimensional inspection of molded parts should occur after 24–48 h conditioning at 23°C and 50% relative humidity because short-term post-mold shrinkage can shift critical dimensions by 0.1–0.3% between ejection and final stabilization.