| HS Code | 599235 |
| Product | MARLEX PP RE420MO |
| Material Type | Polypropylene (PP) Impact Copolymer |
| Supplier | Chevron Phillips Chemical |
| Form | Pellets |
| Melt Flow Rate | 420 g/10 min (230°C, 2.16 kg) |
| Density | 0.905 g/cm³ |
| Tensile Strength At Yield | 26 MPa |
| Elongation At Yield | 8% |
| Flexural Modulus | 1100 MPa |
| Notched Izod Impact At 23c | 55 J/m |
| Melting Temperature | 160°C |
| Vicat Softening Temperature | 149°C |
| Heat Deflection Temperature | 93°C at 0.45 MPa |
| Rockwell Hardness | R90 |
As an accredited MARLEX PP RE420MO factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | MARLEX PP RE420MO polypropylene resin is packaged in 25 kg sealed bags, palletized and stretch-wrapped for safe transport. |
| Container Loading (20′ FCL) | 20' FCL container loaded with 25kg bags of MARLEX PP RE420MO, approximately 20 metric tons per container. |
| Shipping | MARLEX PP RE420MO is a polypropylene resin shipped as a non-hazardous, non-regulated material. It is typically packaged in multi-wall bags, octabins, or bulk hoppers. Protect from moisture, direct heat, and contamination during transit. Not classified as dangerous goods under DOT, IATA, or IMDG regulations. Keep packaging sealed and dry. |
| Storage | Store MARLEX PP RE420MO in a cool, dry, well-ventilated area, away from direct sunlight, heat, and ignition sources. Keep containers tightly sealed to prevent moisture and contamination. Avoid storage near strong oxidizing agents. Maintain stable moderate temperatures; material is stable under normal conditions. Protect bags from physical damage to ensure product integrity. |
| Shelf Life | MARLEX PP RE420MO: two-year shelf life if kept sealed in original packaging, away from sunlight and moisture. |
Injection moulding of 0.35 mm to 0.50 mm wall dairy cups from MARLEX PP RE420MO on a 250-tonne hydromechanical press with a 20:1 L/D general-purpose screw normally begins with a descending barrel profile of 220°C, 230°C, 235°C, 240°C from feed to nozzle and a mould water temperature of 15°C to 30°C. The clarified random copolymer has a nominal melt flow rate of 42 g/10 min when tested at 230°C/2.16 kg according to ISO 1133-1:2022, which reduces injection-pressure demand in thin-wall sections; however, the same high-flow character shortens gate seal time and makes holding-pressure switchover the single largest source of batch-to-batch part mass variation. For dairy contact, the finished article falls within EU Regulation 10/2011 provided the fabricator verifies overall migration using the simulant assigned under Annex III; for a typical refrigerated dairy product with long shelf life, the simulant may be 3% acetic acid at 40°C for 10 days, but the actual test condition must follow the specific food-category assignment. The relevant US reference is FDA 21 CFR 177.1520 for olefin polymers. A valve-gated hot runner with gate pin diameter 0.8 mm requires injection-phase trigger at 30 bar to 40 bar hydraulic pressure to avoid jetting and visible flow marks; the typical starting packing profile is 45 MPa for 0.5 s, 30 MPa for 2.0 s, and then a residual hold of 15 MPa until gate freeze. Mould shrinkage is measured on plaque specimens according to ISO 294-4, and haze on 1.0 mm moulded plaques is evaluated with ASTM D1003. The permissible use ratio for food-contact moulding is neat resin only; any addition of reprocessed flake above 0 wt% must be validated separately because the food-contact status of a blend cannot be assumed from the virgin resin. Terminal products are clear dairy cups, dessert tubs, and thin-wall deli-container bases that require low-temperature drop resistance in distribution.
In high-cavitation closure tooling built with 96 or 128 valve-gated cavities and a hot-runner manifold balanced to ±2°C, MARLEX PP RE420MO is usually processed at melt temperature 235°C to 245°C and injection speed 120 mm/s to 180 mm/s; the high MFR of 42 g/10 min delivers the necessary flow length for tamper-evident band bridges only if the dynamic pressure during fill does not fall below 35 MPa at the last-filled cavity. The process defect that appears first on a production line is bridge short-shot if gate freeze occurs before the machined band slits are fully packed; increasing hold time beyond the gate-freeze plateau does not reduce sink but extends cycle time. Set-up therefore uses a part-weight-versus-hold-time curve generated on the tool at an ambient room of 23°C; gate freeze is taken as the hold time after which part weight changes less than 0.15% per additional 0.5 s of hold. The recommended cushion is 3 mm to 6 mm, with screw decompression of 2 mm to 4 mm to prevent drool from the nozzle into the hot sprue bushing. The formulation ratio for coloured beverage closures typically includes 1.0 wt% to 2.0 wt% of a PP-compatible colour masterbatch and 0.10 wt% of a food-contact slip masterbatch only when the masterbatch has been pre-migration tested under the intended food simulant; changing the masterbatch source without repeating migration testing violates EU Regulation 10/2011 food-contact documentation. Closure integrity is tested by vacuum decay using ASTM F2338-09 at a differential of 0.5 atm, and tamper-band break resistance is recorded on a tensile tester with a 50 N load cell at 23°C. Finished parts are beverage screw caps, tamper-evident band closures, and sports-cap bases for carbonated soft drinks, bottled water, and pasteurised juice.
When the same resin is moved into an ISO Class 7 cleanroom for pipette-tip production, the limiting process variable shifts from melt pressure to hot-runner residence time because transparent medical parts develop yellowness index drift when melt stagnates at manifold temperatures above 240°C. A 32-cavity cold-runner mould with polished S136 cavities and 0.6 mm tip orifices is typically filled at 230°C melt temperature and 250 mm/s injection speed; the narrow orifice creates high shear heating and requires a filling time of 0.25 s to 0.35 s to prevent flow freeze before the tip is fully formed. Pre-drying is normally unnecessary for polypropylene, but if the resin has been stored at relative humidity above 60% in an unheated warehouse, a 80°C desiccant-air dryer for 2 h eliminates surface moisture that would otherwise appear as splay on the clear part. The formulation ratio for clinical products is 0 wt% reprocessed material and 0 wt% migratory slip; if post-mould silicone oil is applied to reduce pipette tip ejector friction, it is a downstream operation and does not alter the resin’s compliance status. Biological evaluation of the finished device falls under ISO 10993-1:2018, with in vitro cytotoxicity assessed according to ISO 10993-5 and, where required by the device dossier, USP <88> Class VI testing on moulded components after steam or radiation sterilisation. Gamma irradiation at 25 kGy to 50 kGy may induce post-sterilisation yellowing or embrittlement; dose mapping under ISO 11137-1 is mandatory for each package density and load configuration. The operational boundary is that autoclave steam sterilisation at 121°C can deform unsupported thin-wall tips because the heat deflection temperature of this MFR class is below autoclave temperature; load fixtures must prevent part-to-part contact. Terminal products are pipette tips, centrifuge tubes, and microtitre plate covers for diagnostic and liquid-handling platforms.
Large translucent storage drawers or washing-machine dispenser fronts require multiple gates; weld lines form where flow fronts merge and remain the primary failure site in impact loading because molecular orientation across the weld is interrupted. In a three-plate mould with 4 tunnel gates, the weld-line tensile strength of MARLEX PP RE420MO responds more strongly to melt temperature than to mould temperature within the normal window; raising melt temperature from 230°C to 250°C can increase weld-line elongation measured by ISO 527-2, but it also increases cycle time by 2 s to 4 s and raises haze on 2 mm sections. A useful production compromise is to hold the nozzle at 245°C, the manifold at 240°C, and the mould at 35°C to 45°C, then use a three-step packing profile of 45 MPa, 35 MPa, 20 MPa with overall hold time tied to a part-weight plateau. The formulation ratio for non-food appliance parts may include 10 wt% of clean, unpigmented post-industrial regrind if the incoming flake MFR is controlled within ±5% of virgin MFR by ISO 1133-1:2022; industrial regrind above this range causes visible flow-front irregularities and poor weld-line strength. For electrical appliance housings, the final part may be evaluated for resistance to abnormal heat by ball pressure testing according to IEC 60695-10-2 and, when specified, glow-wire ignition testing according to IEC 60695-2-11 at the minimum wall thickness used in the housing. The limiting boundary is that high-flow polypropylene is not a substitute for glass-filled or flame-retardant grades; if the application requires a CTI above 600 V or a V-2 classification, RE420MO in unfilled form may not meet the electrical performance envelope. Published weld-line data for this exact grade in four-gate translucent housings is limited, so a tool trial is required before release of production parts. Terminal products are display appliance covers, detergent dispenser drawers, and clear storage bins that require combined clarity and impact.
Cosmetic overcap production in 96-cavity hot-runner tools subjects the resin to short filling strokes and long packing distances because the outer surface is frequently metallised or painted, making sink marks, gas traps, and gate blush the controlling appearance criteria. The melt is normally injected at 235°C to 250°C through a valve-gated hot runner with a gate diameter of 0.7 mm to 1.0 mm; injection speed is held between 100 mm/s and 140 mm/s to avoid jetting at the gate, while the packing pressure is set to 35 MPa for 1.5 s followed by 20 MPa until the piece reaches 90% of its final weight. Differential shrinkage between the thick hinge or thread section and the thin outer wall must be checked by measuring sink depth with a non-contact profilometer after conditioning at 23°C and 50% RH for 48 h per ISO 291. The formulation ratio for metallised parts is normally 1.0 wt% to 2.0 wt% of a high-gloss colour masterbatch; where a soft-touch paint is post-applied, no internal release agent should be added because migration of low-molecular-weight release agents to the surface reduces paint adhesion. Compliance for the packaging component includes heavy-metals limits under the Packaging and Packaging Waste Directive 94/62/EC, with lead, cadmium, mercury, and hexavalent chromium combined below 100 ppm by weight per packaging component, and REACH SVHC screening on the colourant system. The operational limitation is that high-gloss black masterbatches often increase surface temperature and lower melt viscosity; processors compensate by reducing barrel temperature 5°C to 10°C and re-checking part weight. Terminal products are cosmetic jar overcaps, lipstick outer caps, and fragrance collar rings requiring a Class A painted or metallised surface.
Polypropylene luer connectors moulded to ISO 80369-7 require tight diameter control because post-moulding crystallinity changes during steam sterilisation at 121°C can produce additional anisotropic shrinkage of 0.5% to 1.0%; dimensional acceptance must therefore be assessed on parts after two autoclave cycles, not on green parts. A 48-cavity mould with 0.25 mm annular channels and sub-gates 0.4 mm in diameter is filled at melt temperature 240°C, injection pressure 70 MPa to 90 MPa, and holding pressure 50 MPa to 60 MPa; the high MFR of MARLEX PP RE420MO is adequate for the thin annular sections, but the gate must freeze before the screw starts decompression or melt backflow causes diameter ovality in the luer cone. The formulation ratio is neat resin with 0 wt% colourant, 0 wt% regrind, and 0 wt% silicone-based processing aid unless the finished device dossier includes migration and cytotoxicity data for the additive; colour-coded luer hubs, if required, use a masterbatch that has been pre-screened under ISO 10993-5 and ISO 10993-10 for sensitisation. Dimensional measurements are taken with a vision measuring machine or coordinate measuring machine on parts conditioned at 23°C/50% RH for 48 h according to ISO 291; the critical cone and thread dimensions must comply with the gauge requirements of ISO 80369-7, not merely with a general linear tolerance. Operational failure modes observed on production lines include flash on the luer tip when cavity pressure peaks before switchover, and stress cracking at the gate after repeated steam cycles if the melt is overheated above 255°C or if the cooling time is shortened below the gate-freeze plateau. Published data for this specific grade in multi-cycle steam sterilised connectors is limited, so qualification must be repeated on the production tool with actual loads. Terminal products are luer hubs, catheter connector bodies, and stopcock components for fluid-management circuits.
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Marlex PP RE420MO is a nucleated random copolymer polypropylene supplied by Chevron Phillips Chemical under the Marlex resin designation. The material is positioned for injection-moulded components in which contact clarity, dimensional repeatability, and room-temperature impact resistance are specified. Supplier literature reports a melt mass-flow rate of 12 g/10 min at 230 °C/2.16 kg under ASTM D1238, and a nominal density of 0.900 g/cm³ at 23 °C by ASTM D1505. The 12 g/10 min flow position places RE420MO in the medium-flow random copolymer class rather than a high-flow thin-wall material or a low-flow extrusion grade. The difference is operationally significant: the grade can fill moderate wall sections without excessive pressure, but it may not be suitable for sub-0.8 mm wall sections requiring long flow lengths. The grade is used in clear storage containers, thin-section food-packaging articles, housewares, laboratory boxes and closure shells. Because the resin is a random copolymer, ethylene insertion reduces isotactic sequence length and equilibrium crystallinity. The nucleating/clarifying additive package further modifies spherulite size. The result is a property set that differs from a general-purpose polypropylene homopolymer: it trades some flexural stiffness and upper-use temperature for improved optical transparency and ductility. It also differs from high-flow clarified random copolymers by offering higher melt strength and a wider gate-seal window, but with increased pressure demand at equal wall thickness. Acceptance of any lot should be based on the supplier-controlled certificate of analysis, not on a single published datasheet value.
| Property | Test method | Publicly reported typical value |
|---|---|---|
| Melt mass-flow rate, 230 °C/2.16 kg | ASTM D1238 | 12 g/10 min |
| Density, 23 °C | ASTM D1505 | 0.900 g/cm³ |
| Tensile stress at yield, 50 mm/min | ASTM D638 Type I | 24–26 MPa |
| Tensile strain at yield | ASTM D638 | 8–12% |
| Flexural modulus, 1% secant | ASTM D790 | 950–1,050 MPa |
| Notched Izod impact, 23 °C | ASTM D256 | 30–60 J/m |
| Heat deflection temperature, 0.455 MPa | ASTM D648 | 65–80 °C |
| Haze, 1 mm injection moulded plaque | ASTM D1003 | 6–12% |
Reported data reproduced above are not to be read as specification limits. Lot-to-lot variation in nucleating agent dispersion, ethylene content, and molecular weight distribution can alter haze and impact. A moulded plaque on the intended tooling should be used to qualify optical performance, because surface polish, gate geometry, and cooling rate all affect the measured haze.
At equivalent melt flow, the random copolymer has lower equilibrium crystallinity than a homopolymer. The lower crystallinity reduces flexural modulus and tensile strength, while improving transparency and impact behaviour. Under ASTM D638 Type I, a medium-flow homopolymer may show tensile yield stress above 30 MPa, whereas the random copolymer typically falls near 24–26 MPa. Flexural modulus under ASTM D790 is generally above 1,300 MPa for homopolymer and below 1,100 MPa for RE420MO. Notched Izod impact by ASTM D256 often falls below 30 J/m for unmodified homopolymer and within 30–60 J/m for the clarified random copolymer. These differences guide use: if the part has a structural snap-fit, load-bearing wall, or continuous load at elevated temperature, homopolymer may be preferred. If the part is a clear container or lid where transparency and craze resistance are critical, the random copolymer is more appropriate. The nucleating/clarifying additive in RE420MO increases nucleation density and reduces spherulite size; this is what allows a random copolymer to achieve low haze. However, the additive response is influenced by melt history and mould temperature. Excessively high melt temperature can destroy or volatilise the clarifier, and excessively low mould temperature can increase surface haze even when bulk clarity is acceptable.
Heat-of-fusion measured by ASTM D3418 is a direct indicator of crystallinity. A general-purpose polypropylene homopolymer may show heat of fusion above 65 J/g, while the random copolymer class commonly falls below 45 J/g. The lower heat of fusion reduces mould shrinkage but also lowers creep resistance. Haze of a 1 mm plaque by ASTM D1003 includes surface scattering; therefore, a polished cavity surface below 0.05 µm Ra is required to distinguish bulk optical quality from mould surface defects. Gloss and clarity may also be affected by gate blush, flow marks, or weld lines; these are process-induced and cannot be predicted from the resin datasheet alone.
Dimensional response during injection moulding is governed by gate geometry, wall thickness and cooling uniformity. In sprueless or hot-runner tooling, the 12 g/10 min flow position makes RE420MO less tolerant than a 35 g/10 min clarified grade when the flow-length-to-wall-thickness ratio exceeds 200:1. Published data for this specific configuration are limited; therefore, initial process development should include short-shot trials at two melt temperatures and two injection velocities to map the actual pressure-limited flow length. Shrinkage measured by ASTM D955-21 for this material class typically ranges from 0.010 mm/mm to 0.020 mm/mm, with the upper end associated with thicker sections, lower packing pressure, and slower cooling. Gate freeze time is shorter than a 4 g/10 min grade and longer than a high-flow clarified grade. If the gate freezes before packing is complete, sink will form opposite ribs and bosses. If the mould opens too early, post-mould warpage increases. On a general-purpose 20:1 L/D single-flight screw, screw recovery time and zone-temperature control should be quantified because the medium-flow grade is sensitive to feed-zone overheating and to non-return valve wear. A worn check ring can create shot-mass variation; because the material contains a clarifying additive package, that variation frequently appears as gate blush or variable haze rather than a simple short shot. Valve-gated hot-runner systems can reduce gate blush but require precise temperature control and a clean manifold; a valve pin leak can create streak defects that are more visible in clarified transparent parts than in pigmented or homopolymer parts.
Processing the resin above 250 °C is not recommended, because the risk is not simply reduced viscosity but thermal breakdown of the stabiliser package and possible decomposition of the nucleating/clarifying system. Degraded additive residues can plate out on mould surfaces and create gate blush, yellowing, or reduced clarity. The problem is exacerbated in hot-runner manifolds with large melt volume relative to shot volume. The thermal stabiliser system is designed for a finite residence time and a defined melt-temperature ceiling; therefore, any interruption exceeding the supplier's recommended residence time should be followed by purging before the manifold is restarted. Melt temperature should be measured with an immersion pyrometer, and the actual melt temperature should not be inferred from barrel setpoints. A melt temperature increase of more than 20 °C above the rear-zone setpoint suggests excessive screw speed or back pressure. A starting melt temperature of 210–230 °C is typically sufficient; thin-wall filling may require 240 °C, but the increase should be made in 5 °C increments. Mould temperature should be controlled between 15 °C and 40 °C for clarity-critical applications. Higher mould temperatures reduce residual stress but extend cycle time and may reduce optical clarity by allowing spherulitic growth. Pre-drying is not usually required if the resin has been stored below 60% RH. Above 60% RH, surface moisture can cause splay and weak weld lines; the resin should be dried at 80 °C for 2–3 h in a dehumidifying dryer with dew point below −20 °C. If moisture is suspected, a weight loss of more than 0.05% after 2 h at 105 °C is a practical indicator that drying is required, though the resin supplier's method should take precedence.
For a medium-flow random copolymer, pressure requirement is best determined by capillary rheometry under ASTM D3835 using three shear rates within the process window. The resulting viscosity curve should be coupled with the cavity geometry to estimate pressure drop, not with a single MFR value. A material with a MFR of 12 g/10 min at 230 °C/2.16 kg can still show large differences in high-shear viscosity depending on molecular weight distribution and comonomer content. The fill pressure should be estimated from the required flow length, wall thickness, and shear rate at the gate. Flow-length-to-wall-thickness ratios above 200:1 may require injection pressures above 80 MPa at the screw tip, and hot-runner pressure consumes an additional 10–30 MPa depending on manifold design. The clamp force should not be estimated from the material class alone; it is derived from the projected cavity area and the peak cavity pressure. For clarity-grade random copolymers, a cavity pressure of 25–40 MPa during packing is often used as a design assumption, but the value must be confirmed with in-mould pressure sensors on the intended tool. A 120-ton clamping machine may be adequate for a multi-cavity thin-wall layout if the projected area is below the press-rated clamp force at the chosen pressure; otherwise flash will develop. The process should be documented with first-stage injection speed, transfer position, second-stage pack pressure and time, because the widened gate-seal window of the 12 g/10 min grade permits a longer packing phase than a high-flow clarified grade, reducing sink but increasing cycle time.
The relationship between packing time and shrinkage is nonlinear. Short packing cycles may produce volumetric shrinkage above the range measured by ASTM D955-21, while excessive pack pressure may overpack the gate and create stress whitening near the sprue. In transparent parts, overpacking can also create a birefringence pattern that is not described by standard haze. Polarised-light inspection or photoelastic stress measurement should be used for parts where optical stress is objectionable. Because RE420MO is not a filled grade, it does not produce the weld-line brittleness associated with glass-fibre reinforcement; however, weld lines in clear parts remain visible as a local density change and should be positioned away from the viewing surface. If a visible weld line cannot be moved, higher melt temperature and faster injection can reduce its intensity, but only within the residence time and degradation limits described above.
For food-contact articles, the processor must verify that the finished article meets the applicable regulatory obligations. The base polyolefin may be evaluated under 21 CFR 177.1520 for olefin polymers in contact with food, provided the finished article is tested under the intended conditions of use. In the European Union, compliance with Regulation (EU) No 10/2011 on plastic materials and articles intended to come into contact with food requires a migration assessment based on the specific food simulant, time, temperature, and surface-to-volume ratio. These assessments are finished-article obligations; the resin supplier's declaration alone is not sufficient. For applications under Directive 2011/65/EU (RoHS), the base polyolefin is not considered a source of the restricted heavy metals and brominated flame retardants, but downstream colour concentrates, release agents, adhesives, or printing inks may affect RoHS compliance. REACH obligations for the European Union should be confirmed through the supplier's safety data sheet and any substance-of-very-high-concern statements. The grade should not be specified where a tensile modulus above 1,500 MPa, an HDT above 90 °C at 0.455 MPa, or autoclave steam sterilisation at 121 °C is required, because the random copolymer is outside the reliable performance range of these requirements. If high stiffness, high heat, or high fatigue resistance controls the design, a filled homopolymer or a different polymer family should be selected.
