Celanese UHMW-PE 4150 ECO-B is a high-molar-mass polyolefin grade positioned within the GUR 4000 series of ultra-high-molecular-weight polyethylene resins. The base grade is characterized by a viscosity-average molecular weight near 9.0 × 10⁶ g/mol determined by solution viscosity according to ISO 1628-3, with density reported at 0.930 g/cm³ under ISO 1183-1. Unlike conventional linear HDPE grades, the material exhibits no practical melt flow under the standard 190 °C and 21.6 kg condition of ISO 1133-1; the melt-state deformation resistance is therefore specified through solution viscosity and molar mass rather than melt flow rate. The ECO-B suffix denotes a mass-balance chain-of-custody variant that incorporates bio-circular feedstock into the ethylene polymer chain, as indicated by the supplier’s material declaration; independent quantitative bio-content values are not supplied in generic grade literature and must be obtained from a batch-specific certificate of analysis. The product is supplied as a free-flowing powder for ram extrusion, compression molding, and sintering operations. Published data for this specific configuration is limited when compared with the fossil-naphtha GUR 4150 control, so first-lot qualification should include full mechanical testing under ISO 527-2 and ISO 11542-2. Because the grade is supplied as powder, storage conditions are a release parameter; moisture regain in humid air remains below 0.01%, but electrostatic charging can reduce bulk-flow consistency. Silo design should account for the powder’s low bulk density, typically 0.40–0.50 g/cm³; the exact value varies with particle size distribution and should not be taken from pellet data. The supplier’s certificate of analysis should therefore include viscosity-average molecular weight, bulk density, and particle size distribution.

How does 4150 ECO-B differ from GUR 4120 and GUR 4170 in molar architecture and end-use selection?

The principal differences between the grades are molar mass and the resulting resistance to cold flow and abrasive wear. In the published GUR series hierarchy, GUR 4120 is typically described with a viscosity-average molecular weight near 4.5 × 10⁶ g/mol, GUR 4150 near 9.0 × 10⁶ g/mol, and GUR 4170 near 10.5 × 10⁶ g/mol; these values are supplied as typical, not specification limits. Increasing molar mass reduces melt-state diffusion and raises the compression force and dwell time required for void-free sintering. The 4150 position is therefore selected when abrasive wear in sliding contact and low-temperature impact resistance are required, but where the extended cycle time and higher backpressure of a 4170-type material would overload a ram extruder or slow a multi-cavity compression press. Compared with a lower-molecular-weight 4120 material, the 4150 ECO-B grade offers a more entangled network, which is associated with lower measured abrasion loss under sand-slurry testing and higher notched impact energy under ISO 11542-2. The ECO-B designation itself does not alter the mechanical property class; it is a feedstock credential that places the grade in a bio-circular supply chain. Processors should not assume that existing dryer, vent, or reclaim systems tuned for fossil GUR 4150 will behave identically with the mass-balance grade until the first production lot is evaluated, because published data for this specific configuration is limited.

Ram-extrusion and compression-molding equipment used for 4150 ECO-B operate within narrow thermal boundaries because the ultra-high molar mass prevents convective mixing and limits heat transport. Industrial practice for UHMW-PE ram extrusion sets the barrel and die zones between 190 °C and 210 °C, with die-land pressure generated by a reciprocating plunger rather than a screw; die-land length-to-diameter ratios between 10:1 and 30:1 are common for round profiles and solid wear strips. Compression molding is conducted at platen temperatures of 200–220 °C and pressures staged from 5 MPa to 10 MPa. Because the powder particles consolidate by diffusion rather than viscous flow, hold times must be extended relative to lower-molecular-weight HDPE, and premature pressure removal produces microvoids that lower Izod impact predictability. Pre-drying is typically unnecessary because water absorption is below 0.01% by ISO 62; surface condensation from cold storage should be removed with dry air below 60 °C before feeding. Sustained processing above 230 °C or localized frictional overheating promotes thermo-oxidative chain scission, shifting the molar-mass distribution and degrading abrasion resistance. The material is not a practical injection-molding grade because the melt will not fill conventional runners at standard injection pressures; attempts to raise melt temperature above 230 °C produce oxidation-related gelling and black specks. Batch-to-batch variation in oxidation induction time should be monitored under ISO 11357-6 when extended sintering dwells are used.

Mechanical property benchmarks and associated test methods for the 4150 family

The typical values below are derived from GUR 4150 documentation and should be treated as comparative engineering benchmarks, not guaranteed design limits. The ECO-B mass-balance variant is produced to the same base grade specification, but first-lot verification is required.

Single-point values do not capture creep at elevated service temperatures. For bearing applications, design calculations should use compressive creep modulus curves obtained under ISO 899-2 and wear rates measured under ISO 15527 or ASTM G65, because the ratio of wear life to initial tensile yield can change sharply when applied surface pressure exceeds 5 MPa at ambient temperature. For components operating below -40 °C, low-temperature Charpy data should be requested, since published data for this specific configuration is limited. Tribological qualification for 4150 ECO-B requires distinguishing between two-body and three-body abrasive wear. In dry sliding against a polished steel counterface, the material exhibits a dynamic coefficient of friction that is strongly velocity-dependent; standard pin-on-disk data under ASTM G99 may not correlate with plant experience when the counterface temperature exceeds 40 °C. Three-body wear involving sand, coal fines, or crystalline particulates is better evaluated with the sand-slurry test under ISO 15527 or the rubber-wheel dry-sand test under ASTM G65. Published data for this specific configuration is limited, so wear-rate comparisons to fossil GUR 4150 should be generated on the same lot and the same test equipment. In conveyor wear-strip service, the practical failure mode is not always mass loss; it is often the formation of a burr or lip at the strip edge. This burr initiation is governed by the shear yield stress and the local temperature rise from frictional heating, not solely by molar mass. Therefore the ratio of Shore D hardness to elongation at break is sometimes a better early screening parameter than a single abrasion index. Reports from production lines with reciprocating ram extruders indicate that batch-to-batch variation in powder particle size distribution below 100 µm can shift extrusion backpressure by 5–10% and alter surface finish; incoming powder should be checked by sieve analysis or equivalent laser diffraction according to ISO 13320 before switching lots.

Wear strips, chain guides, filter press plates, pump wear plates, and dry-bulk handling screw flights represent the principal application space for 4150 ECO-B. In these applications the high molar mass and low coefficient of friction against polished steel reduce surface erosion when fine-particle slurries or granulated solids are conveyed at low surface velocities. Food-contact uses such as cutting boards, guide rails, and FDA-compliant wear components are permitted only when the specific grade is listed under 21 CFR §177.1520; the fabricator must verify the supplied certificate because the ECO-B mass-balance feedstock must not affect final food-contact test results. The geometric design should account for the material’s high coefficient of linear thermal expansion relative to steel, typically near 1.5 × 10⁻⁴ K⁻¹, by providing slotted or oversized fasteners. Continuous service under load above 80 °C should be avoided because creep accelerates and the material loses bearing clearance; steam sterilization above 121 °C is outside the recommended range. The polymer resists many dilute acids, alkalis, and salt solutions, but strong oxidizing acids such as concentrated nitric acid cause oxidative attack at elevated temperature. Hot-gas welding should not be used; joining should be done by butt fusion, spin welding, or mechanical fastening. UV exposure without carbon black or hindered-amine stabilization leads to surface embrittlement within a few thousand hours of outdoor exposure; unstabilized natural-grade material is intended for indoor or non-UV service. The final part specification should be controlled under ASTM D4020 or ISO 11542-2 for UHMW-PE materials. In filter press plates, resistance to hydraulically loaded deformation is governed by flexural modulus and creep, not tensile yield; plates should be machined from compression-molded sheet rather than extruded profile to minimize weld-line porosity. In pump wear plates, edge-gating of the original molding blank can create anisotropic wear behavior; the fabricator should orient the machined wear face such that the primary sliding direction is parallel to the blank surface, not through the thickness.

If compliance documentation is required for food-contact, transport, or industrial export, which designations apply?

Compliance statements for 4150 ECO-B must be product-specific and supported by the supplier’s material declaration. The following matrix identifies the standard designations most often referenced in requests for quotations and incoming-material release.

The ECO-B mass-balance claim introduces an additional documentary obligation: users who publish renewable-content statements must obtain the supplier’s third-party mass-balance certificate and a batch-specific attestation. Absent that documentation, only the base UHMW-PE mechanical specification should be communicated. Regulatory compliance is not automatic; fabricators must validate migration limits specific to their part geometry, food simulant, and temperature conditions under Regulation (EU) No 10/2011 or 21 CFR §177.1520 as applicable.