| HS Code | 552758 |
| Material Type | High Density Polyethylene (HDPE) |
| Color | Black |
| Form | Pellets |
| Density | 0.959 g/cm³ |
| Melt Flow Rate | 0.3 g/10 min (190°C/5 kg) |
| Tensile Modulus | 1100 MPa |
| Tensile Stress At Yield | 25 MPa |
| Elongation At Break | >600% |
| Charpy Notched Impact Strength At 23 C | 10 kJ/m² |
| Vicat Softening Temperature | 125°C |
| Melting Temperature | 130°C |
| Thermal Conductivity | 0.4 W/mK |
| Carbon Black Content | 2.5% |
| Uv Stabilization | Yes |
As an accredited Borealis HDPE MB7541 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Borealis HDPE MB7541 is packaged in 25 kg polyethylene bags, palletized, or supplied in 1,000 kg octabins for bulk handling. |
| Container Loading (20′ FCL) | Borealis HDPE MB7541 loaded in a 20′ FCL dry container: palletized 25 kg bags, shrink-wrapped and secured for ocean transport. |
| Shipping | Borealis HDPE MB7541 is a non-hazardous polyethylene resin supplied as pellets. It is typically shipped in 25 kg bags, octabins, or bulk trucks and railcars. Keep packaging closed and dry, away from heat, direct sunlight, and ignition sources. Not regulated as dangerous goods; avoid contamination during transport. |
| Storage | Store Borealis HDPE MB7541 in a cool, dry, well-ventilated area, away from sunlight, heat, ignition sources, and strong oxidizers. Keep original packaging closed and palletized off the floor to prevent moisture, dust, and contamination. Avoid excessive stacking and high temperatures. Use first-in, first-out stock rotation. Follow the supplier’s SDS and local regulations. Do not smoke or use open flames. |
| Shelf Life | Store dry, cool, well-ventilated, away from direct sunlight; shelf life is 24 months from production date in original packaging. |
Extrusion blow moulding of 500 mL to 5 L household chemical bottles from Borealis HDPE MB7541, a bimodal Borstar high-density polyethylene with nominal density 0.954 g/cm³ and melt flow rate 0.45 g/10 min under ISO 1133-1:2022, uses melt temperatures between 185 °C and 205 °C at the die head. Parison programming with 15–25 die-gap steps is necessary because the high-molecular-weight fraction extends hang time but increases die swell; on a 70 mm grooved-barrel extruder with a 24:1 L/D ratio, die swell can reach 25–40 % once throughput exceeds 110 kg/h. Sidewall thickness is trimmed to 0.6–1.2 mm, while pinch-off zones are held above 0.8 mm to limit stress whitening. Blow air pressure is set between 0.6 MPa and 1.0 MPa, mould temperature is maintained at 10–25 °C, and post-mould shrinkage is held below 1.5 % by controlling demoulding temperature. Household and cosmetic packaging compliance is verified through EU Regulation No 10/2011 Annex I overall migration limits below 10 mg/dm², FDA 21 CFR 177.1520(c) paragraph 3.1b for olefin polymers, and REACH Regulation (EC) No 1907/2006. Colour masterbatch is dosed at 1.0–3.0 wt%; a fluoroelastomer processing aid is introduced only if surface melt fracture appears, at 0.02–0.05 wt%. The resulting articles are mono-layer bottles for bleach, multi-surface cleaner, and dish-washing liquid.
A 5 L UN-type jerrycan for emulsifiable concentrate crop-protection formulations demands uniform sidewall distribution because the drop test under UN Model Regulations Chapter 6.1, section 6.1.5.2.4, and hydraulic pressure retention under design type UN 3H1 detect thin spots at the shoulder radius and pinch-off. Borealis HDPE MB7541 is processed at melt temperatures of 190–210 °C with a die gap of 2.0–3.0 mm; parison programming places 1.8–2.5 mm in the shoulder and 1.5–2.0 mm at the sidewall centre. Carbon black masterbatch is dosed at 2.0–2.5 wt% for outdoor UV stability, and UV stabilizer masterbatch is added at 0.5–1.0 wt% when the filled container is stored in direct sunlight. Carbon black masterbatch stored at relative humidity above 60 % must be pre-dried at 80 °C for 2 h to prevent surface pitting. Chemical compatibility is assessed by storage at 40 °C for 28 days followed by environmental stress-crack resistance evaluation under ASTM D1693-15, Condition B. Finished containers from 1 L to 20 L are certified as UN 3H1 packaging; monolayer structures are not assigned for pure aromatic hydrocarbons or halogenated solvents, where permeation control requires fluorination or coextruded barrier layers.
Motor-oil bottles blown from HDPE MB7541 on four-station rotary wheel machines run at screw speeds of 80–120 min⁻¹ and melt temperatures of 195–215 °C. Neck finishes are calibrated to 38 mm or 43 mm closure diameters, and sidewall thickness is maintained between 0.9 mm and 1.5 mm. Hydrocarbon permeation is reduced by in-line surface fluorination; barrier performance is measured on finished containers according to ASTM D2684/D2684M, and fluorination uptake is monitored gravimetrically because published permeation data for this specific MB7541 motor-oil configuration is limited. Without barrier treatment, monolayer HDPE is suitable only for low-viscosity mineral-oil products stored below 40 °C; synthetic lubricant base stocks and high-aromatic industrial oils require coextruded polyamide barrier structures with the polyamide layer maintained at 3–7 % of total wall thickness and tie-layer thickness of 0.05–0.10 mm. Blow air pressure is kept between 0.6 MPa and 1.0 MPa, and mould temperature is held at 8–20 °C to stabilize neck dimensions. Containers for classified industrial oils are marked UN 3H1; non-classified motor oils are packaged in non-UN bottles with tamper-evident closures. The final articles are 1 L, 4 L, and 5 L motor-oil and hydraulic-oil bottles.
When post-consumer recycled HDPE is introduced at 20–30 wt% into a three-layer parison with virgin MB7541 skin layers, the melt flow of the recycled core shifts upward by 10–25 % and parison sag becomes visible on continuous shuttle lines when die gaps exceed 2.0 mm. Skin layers are each maintained at 15–25 wt% of final wall thickness, and the post-consumer recycled core is restricted to 40–60 wt%. The recycled core extruder is operated with a backpressure of 50–80 bar and a melt temperature of 180–200 °C to limit gel-particle generation; the virgin skin layers are run at 185–205 °C. Amine-based light stabilizers are excluded from the colour masterbatch because residual bleach or acidic personal-care constituents can generate surface defects during storage at 40 °C. Compliance for the finished personal-care bottles is managed under EU Regulation (EC) No 1223/2009 for the cosmetic article and REACH Regulation (EC) No 1907/2006 for intentional additives. The end products are 200 mL–1 L shampoo, body-wash, and liquid-soap bottles with wall thickness of 0.5–1.0 mm.
Under hood vibration and thermal cycling from −30 °C to 80 °C, a windshield washer reservoir blow moulded from MB7541 must maintain pinch-off weld-line integrity and creep resistance at mounting bosses. The part is produced on 3D suction blow moulding machines with wall thickness controlled between 2.0 mm and 3.5 mm; the die gap is set at 2.5–4.0 mm, and melt temperature is held at 185–205 °C. Low-temperature impact is evaluated with ISO 179-1:2023 Charpy notched specimens conditioned at −30 °C, while ultraviolet resistance is assessed under SAE J2527 xenon-arc exposure. Environmental stress-crack resistance in methanol-water washer fluid is assessed under ISO 22088-3. Carbon black is dosed at 2.0–2.5 wt% to limit UV embrittlement during vehicle storage; no plasticizer or migratory processing aid is permitted because drained washer fluid must remain free of extractable residues. The finished reservoirs range from 2 L to 5 L, with high-density polyethylene screw caps and ethylene-propylene-diene gasket seals.
In-house regrind from HDPE MB7541 food-grade bottles undergoes shear-induced chain scission during repeated extrusion; when regrind content exceeds 30 wt%, the melt flow rate under ISO 1133-1:2022 can rise by more than 15 % and parison draw-down accelerates on high-speed rotary blow moulding lines running at 12 000–18 000 bottles/h. The extruder barrel temperature profile is set from 190 °C at the feed zone to 220 °C at the die, and die gaps are reduced to 1.2–2.0 mm to compensate for decreased melt strength. Food-contact compliance requires FDA 21 CFR 177.1520 and EU Regulation No 10/2011 Annex I, with specific migration limits for antioxidants and neutralizers drawn from the grade’s formulation. The virgin-to-regrind ratio is maintained at 70:30 maximum for monolayer direct food contact; if the application requires higher recycled content, a virgin skin layer of at least 0.2 mm is placed on the food-contact side. The end articles are 200 mL–2 L milk, juice, and fermented dairy bottles with cap thread finishes from 38 mm to 48 mm.
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Borealis HDPE MB7541 is a bimodal high-density polyethylene developed for extrusion blow moulding of rigid containers, closures, and technical parts. The resin is produced by a tandem slurry-loop polymerisation process that yields a bimodal molecular weight distribution; the high-molecular-weight fraction governs melt strength and environmental stress crack resistance, while the low-molecular-weight fraction lowers die pressure and improves surface finish. The nominal density is 0.954 g/cm³ when measured to ISO 1183-1:2019, and the melt flow rate at 190 °C under 2.16 kg is 0.6 g/10 min according to ISO 1133-1:2022. Tensile modulus is typically 1050 MPa per ISO 527-2:2012, and tensile yield stress is approximately 28 MPa. These properties place MB7541 in the intermediate-density HDPE range, where stiffness, bottle top-load performance, and environmental stress crack resistance are balanced for packaging of household chemicals, industrial liquids, and agrochemicals. The material is supplied as natural pellets with a general-purpose phenolic/phosphite stabiliser system for processing at melt temperatures up to 220 °C.
In a conventional unimodal HDPE blow moulding grade, the average molecular weight must be increased to raise environmental stress crack resistance, but this simultaneously elevates die head pressure and promotes surface roughness during parison extrusion. MB7541 separates these functions. The high-molecular-weight tail increases zero-shear viscosity and extensional strain hardening, which stabilises the parison against sag between die exit and mould closing. The low-molecular-weight fraction acts as a processing aid, maintaining die land shear stress below the level at which melt fracture or shark-skin defects appear. Published rheological data for this specific configuration is limited, but the practical result on production equipment is a wider parison programming window and more uniform wall thickness in large flat-sided containers than would be obtained from a unimodal grade of equal melt flow rate. The environmental stress crack resistance is assessed by ASTM D1693-15, Procedure B, using 10% Igepal CO-630 at 50 °C. Typical F50 values for compression-moulded plaques exceed 1000 h; this test is relevant for bottles holding surfactant-based formulations because hoop stress and surface-active agents accelerate brittle failure in low-ESCR resins.
| Property | Typical value | Unit | Test method |
|---|---|---|---|
| Density | 0.954 | g/cm³ | ISO 1183-1:2019 |
| Melt flow rate at 190 °C, 2.16 kg | 0.6 | g/10 min | ISO 1133-1:2022 |
| Tensile modulus at 1 mm/min | 1050 | MPa | ISO 527-2:2012 |
| Tensile yield stress | 28 | MPa | ISO 527-2:2012 |
| Elongation at yield | 9 | % | ISO 527-2:2012 |
| Charpy notched impact strength at 23 °C | 14 | kJ/m² | ISO 179-1:2010 |
| Charpy notched impact strength at -30 °C | 9 | kJ/m² | ISO 179-1:2010 |
| Environmental stress crack resistance, F50 | >1000 | h | ASTM D1693-15, Procedure B |
| Vicat softening temperature, A50 at 10 N | 126 | °C | ISO 306:2022 |
These values are typical properties from standard specimens and are not intended as release limits or part-property guarantees. For finished containers, top-load strength is influenced by tooling, parison programming, and pinch-off design and must be validated on the converted article using ISO 8113 or the applicable customer specification.
On single-station and double-station extrusion blow moulding lines with screw diameters between 45 mm and 90 mm, MB7541 is processed at a barrel temperature profile of 170 °C to 210 °C. The die head temperature is maintained between 190 °C and 210 °C. The band is deliberately narrow because a drop below 185 °C increases die swell and can produce flow lines at the pinch-off, while sustained operation above 220 °C accelerates thermo-oxidative degradation. A desiccant dryer is not mandatory when pellets are stored in sealed containers at ambient relative humidity below 60%; however, after cold storage, pre-drying at 70 °C for 2 h is recommended to avoid pinholes and splay in the parison. Screw designs with 24:1 to 30:1 L/D and compression ratios of 2.5:1 to 3.0:1 are adequate, provided the barrier section is not operated with excessive shear. In accumulator-head machines, melt temperature in the accumulator should not exceed 215 °C at high residence times because oxidative chain scission can increase the melt flow rate and reduce parison melt strength.
Where accumulator heads are specified with first-in-first-out flow paths, direct addition of incompatible purging compounds should be avoided. Polyolefin-based purges are preferred. Avoid direct melt-phase addition of amine-based antistatic agents above 0.5% because interactions with the phenolic stabiliser package can reduce oxidative stability during processing and lower the thermal-oxidative threshold of the final article.
When wall-thickness programming is used to compensate for parison sag, the die gap is varied during extrusion to create a preform with thicker bottom sections and thinner shoulder sections. For MB7541, the operating window is controlled by die swell and parison sag rate. Tooling geometry dominates die swell; die land ratios between 10:1 and 20:1 are common, with longer die lands reducing die swell at the cost of increased head pressure. At shear rates above approximately 1000 s⁻¹, the parison surface may develop melt fracture, particularly with polished die exits. The melt temperature should therefore be kept high enough to reduce shear stress, but low enough to maintain parison integrity. On a shuttle blow moulding line with a 60 mm 24:1 extruder and a 2.5 L detergent bottle mould, the pinch-off weld line is normally the most critical site for ESCR failure; MB7541 resists cracking at the weld line when the pinch-off land is compressed with a land angle between 15° and 30°. If the pinch-off becomes too thin or too cold, the weld line becomes a stress concentrator and the advantage in ESCR is lost.
In comparison to a conventional unimodal HDPE of identical density and melt flow rate, MB7541 typically shows higher ESCR at equivalent bottle wall thickness. The bimodal distribution also permits downgauging in non-load-bearing regions by 10–15% while retaining top-load performance, although this is tool-dependent and must be verified by ISO 8113 top-load testing on finished containers. Unlike injection moulding HDPE grades with melt flow rates of 4–10 g/10 min, MB7541 would develop excessive pressure in multi-cavity injection tools and is not recommended for thin-wall injection moulding, rotational moulding, film extrusion, or fibre spinning. The grade is also not formulated for prolonged outdoor ultraviolet exposure; in uncoloured form it generally provides less than 6 months of outdoor stabilization. For outdoor hydrocarbon or agrochemical containers, UV-stabilised masterbatches or pre-compounded variants are required.
The base resin may be suitable for food contact applications when processed under clean conversion conditions, but the final article must be tested because additives, masterbatch carriers, and processing history affect migration. The following matrix identifies the principal regulatory boundary conditions associated with the base polymer as supplied.
| Regulatory reference | Scope | Condition or limit applicable to MB7541 |
|---|---|---|
| FDA 21 CFR 177.1520 | Olefin polymers | High-density polyethylene with density not below 0.94 g/cm³; end-use migration testing required for fatty and aqueous food simulants |
| EU Regulation (EU) No 10/2011 | Plastics in food contact | Overall migration limit of 10 mg/dm² or 60 mg/kg according to EN 1186-1; specific migration limits for additives must be confirmed by the converter |
| REACH (EC) No 1907/2006 | Registration and SVHC obligations | Substances of very high concern below 0.1% per Article 33 and Article 59 screening; full declaration depends on lot and supply chain |
| RoHS Directive 2011/65/EU | Restricted substances in electrical and electronic equipment | Annex II screening applies when the resin is incorporated into EEE components; no intentionally added lead, cadmium, mercury, hexavalent chromium, PBB, or PBDE |
The grade is not intended for medical implant applications, high-temperature automotive fuel tank service, or pressure pipe use unless converter validation demonstrates compliance with the applicable product-specific directive and long-term performance standard. Direct food contact suitability of a finished container depends on the complete formulation, melt temperature history, and post-processing steps, and must be assessed through overall migration and specific migration testing rather than inferred solely from the base resin designation.
