| HS Code | 563390 |
| Density | 0.947 g/cm³ |
| Melt Index 190 C 2 16 Kg | 0.35 g/10 min |
| High Load Melt Index 190 C 21 6 Kg | 10 g/10 min |
| Tensile Strength At Yield | 26 MPa |
| Tensile Strength At Break | 30 MPa |
| Elongation At Break | >600% |
| Flexural Modulus | 1,200 MPa |
| Vicat Softening Point | 124 °C |
| Melting Point | 131 °C |
| Crystallization Temperature | 117 °C |
| Brittleness Temperature | -70 °C |
| Environmental Stress Crack Resistance 100 Igepal | >1000 h |
| Hardness Shore D | 65 |
| Thermal Conductivity | 0.45 W/m·K |
| Specific Heat Capacity | 1.9 kJ/kg·K |
| Coefficient Of Linear Thermal Expansion | 1.2E-4 cm/cm/°C |
| Water Absorption | <0.01% |
| Mold Shrinkage | 1.5-3.0% |
As an accredited Bayport Polymers (Baystar) HDPE CD-471 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Bayport Polymers (Baystar) HDPE CD-471 is packaged in 25 kg polyethylene-lined bags, palletized and stretch-wrapped for secure shipment. |
| Container Loading (20′ FCL) | Container Loading (20′ FCL): Bayport Polymers (Baystar) HDPE CD-471, palletized 25 kg bags, dry container, floor-loaded, secured, approx. 22 MT net. |
| Shipping | Shipping description: Bayport Polymers (Baystar) HDPE CD-471 is a nonhazardous, pelletized high-density polyethylene. It is packaged in 25 kg bags, bulk bags, or bulk trucks/railcars. Not DOT/IMDG/IATA regulated; no UN number or placards required. Store dry, away from heat/UV, and handle per SDS. |
| Storage | Store Bayport Polymers (Baystar) HDPE CD-471 indoors in a cool, dry, well-ventilated area, away from direct sunlight, heat, ignition sources, and strong oxidizers. Keep original containers or bags sealed on pallets to prevent moisture, dust, and contamination. Avoid prolonged UV exposure and excessive stacking. Protect from water, solvents, and incompatible materials. Use first-in, first-out rotation and consult the SDS. |
| Shelf Life | Stable under normal conditions; no defined shelf life. Store cool, dry, away from sunlight and incompatible materials to preserve properties. |
In tight-head drum blow molding, Bayport Polymers HDPE CD-471 is processed on an accumulator-head machine with a shot capacity of 8–25 kg and a barrier screw having an L/D ratio between 24:1 and 30:1. The barrel profile is set at feed 165 °C, compression 175 °C, metering 185 °C, and die zones 195–210 °C, yielding a melt temperature of 195–210 °C. Parison programming is used to control wall thickness distribution, normally 2.5–4.5 mm in the sidewall and 3.0–5.0 mm at the pinch-off. Blow air pressure is held at 0.6–0.8 MPa, mold cooling water is set at 10–25 °C, and cycle time ranges from 90 s to 180 s depending on wall thickness and shot size. The resin is processed neat for chemical-contact service. Regrind from trimmed flash is added at 10–20 wt%, and color concentrate is used at 1–3 wt% for standard colors; carbon black masterbatch is added at 2–4 wt% when UV stabilization of the container is required. Addition of polypropylene-contaminated regrind above 2 wt% introduces PP domains that reduce pinch-off weld strength and produce intermittent drop-test failures. Finished products include 20–60 L tight-head jerricans, 120–220 L open-head drums, and intermediate bulk container inner bottles. Compliance is verified under 49 CFR §178.603, §178.604, §178.605, and §178.606; the drop test is performed at -18 °C, and the hydraulic pressure test is performed after 30 min conditioning at 40 °C. The limiting property is environmental stress crack resistance; for this density class, ESCR is normally above 600 h under ASTM D1693-15 Condition B in 10% Igepal CO-630 at 50 °C. Each lot must be checked because ESCR shifts with comonomer distribution and cooling rate in thick-walled pinch-off zones.
CD-471 is applied as the HDPE cap and regrind layers in a six-layer coextrusion blow molding structure for gasoline and diesel fuel tanks. The layer stack is set as outer virgin HDPE at 20–30 wt%, adhesive tie layer at 2–3 wt%, EVOH barrier at 1.5–3.5 wt%, regrind at 35–50 wt%, adhesive tie layer at 2–3 wt%, and inner virgin HDPE at 15–25 wt%. HDPE extruders operate at melt temperatures of 200–220 °C; the EVOH extruder is held at 205–225 °C to prevent barrier degradation. Parison programming must maintain the EVOH layer continuous through the pinch-off and insert sections. Blow pressure is maintained at 0.7–0.9 MPa, mold temperature below 20 °C, and final wall thickness between 3 mm and 6 mm. The fuel tank volume is typically 40–100 L. Permeation compliance is evaluated by SHED methods under EPA 40 CFR Part 86, Subpart S, and CARB LEV III evaporative emission limits. A six-layer structure with EVOH reduces hydrocarbon permeation by 90–98% relative to monolayer HDPE. The operational boundary is methanol-blended fuel above M15, where EVOH plasticization and HDPE swelling produce elevated permeation and interlayer shear stress. Published data for CD-471 in high-altitude canister load cycles is limited; vehicle-level diurnal breathing loss testing is required before release.
Regrind return from trimmed flash and rejected tanks is used at up to 50 wt% but must be ground, dried to below 0.05 wt% moisture, and melt-filtered through a 100–150 µm screen pack. Above 50 wt% regrind, gel counts increase; gels larger than 400 µm can fracture the EVOH layer during parison inflation. Heavy metal content is controlled under EU ELV Directive 2000/53/EC, Annex II, and process control follows REACH Regulation (EC) No 1907/2006, Article 33 for substances of very high concern. The pinch-off weld must be inspected by sectioning because barrier delamination can occur when the adhesive layer drops below 2 wt% at the weld.
With thick-walled sections of 6–10 mm, outdoor marine floatation and dock fender blow molding uses CD-471 in accumulator-head machines with 10–15 kg shot capacity. The compound is prepared with 1.5–2.5 wt% hindered amine light stabilizer masterbatch and 2.0–3.0 wt% carbon black masterbatch; for high-visibility yellow parts, 2–3 wt% UV-stabilized yellow pigment replaces carbon black. Melt temperature is held at 195–215 °C, die head temperature at 200–215 °C, mold temperature at 10–20 °C, and blow pressure at 0.5–0.7 MPa. Cooling time is extended to 300–900 s because the thick wall retains heat and premature demolding causes post-mold shrinkage and internal voids. The mold must include vacuum venting to prevent gas entrapment at the weld line. Finished parts include marina buoys, dock fenders, wave attenuation floats, and water tank floats. Weathering is checked under ISO 4892-2 with UV-A 340 lamps at 0.55 W/m² for 1000 h, with delta E below 3 for black parts. Impact retention is tested under ASTM D256 Izod at 23 °C after weathering, with acceptance at no less than 80% of initial value. Free amine-based additives are avoided because they accelerate HDPE oxidative degradation during multi-year outdoor exposure. Calcium carbonate filler above 5 wt% is not used because creep modulus under constant wind and wave load falls below design limits.
For non-food extrusion blow molded containers containing post-consumer recycled HDPE, CD-471 is used as a virgin letdown resin at a ratio of 85:15 to 65:35 virgin-to-PCR. The PCR stream is sorted to at least 95 wt% HDPE, with polypropylene limited to 2 wt% and residual PET below 50 mg/kg. The PCR is dried at 80 °C for 2 h in a desiccant dryer to reduce surface moisture below 0.05 wt%; higher moisture produces parison pitting and weld-line porosity. CD-471 and PCR are gravimetrically dosed into a single-screw extruder with grooved feed, an L/D between 25:1 and 30:1, and a Maddock mixing section. Melt temperature is maintained at 190–210 °C, and a 100–150 µm screen pack is installed before the die head to remove agglomerates. Above 35 wt% PCR, melt flow can shift by 0.03–0.06 g/10 min and ESCR under ASTM D1693-15 Condition B may fall below 200 h. Finished parts include detergent bottles, windshield washer fluid bottles, and non-UN pails. Compliance is governed by REACH Regulation (EC) No 1907/2006, Article 33 for substance communication, RoHS Directive 2011/65/EU, Annex II for cadmium below 100 ppm and lead below 1000 ppm, and FDA 21 CFR 177.1520 only when a food-contact suitability letter covers the PCR supply chain.
Head pressure should not exceed 35 MPa to avoid screen deformation and melt-temperature override. The extrusion line must be purged with a metallocene polyethylene purge compound between material changeovers because black speck contamination from degraded PCR accumulates on the screw root. The operational boundary is gel dispersion; when gels exceed 500 particles per 100 g above 400 µm, blow mold surface replication degrades and leakage at the weld line increases. The ratio of CD-471 may be increased to 80:20 or lower PCR when wall thickness is below 1.2 mm, because thin-wall parison stability requires higher virgin melt strength.
| Application segment | Test standard/code | Condition | Typical acceptance criterion |
|---|---|---|---|
| UN tight-head jerrican | 49 CFR §178.603–§178.606 | -18 °C drop; 40 °C hydraulic | No rupture or leakage |
| Automotive fuel tank | EPA 40 CFR Part 86; CARB LEV III | SHED diurnal cycle | Vehicle evaporative limit |
| Outdoor floatation | ISO 4892-2; ASTM D256 | UV-A 1000 h; Izod 23 °C | ≥80% impact retention |
| Recyclate blend non-food container | RoHS Directive 2011/65/EU, Annex II | Cd ≤100 ppm; Pb ≤1000 ppm | Compliant total content |
| Thermoformed load floor | ISO 178; ISO 527-2 | 23 °C flexural/tensile | Flexural modulus 900–1200 MPa typical |
| Agrochemical bottle | ASTM D1693-15 Condition B; 49 CFR §178.603 | ESCR 50 °C; -18 °C drop | ESCR ≥200 h |
On sheet extrusion lines converting CD-471 into thermoformed load floors, a 120 mm single-screw extruder with an L/D ratio of 30:1 and a barrier screw is operated at melt temperatures of 200–220 °C. The resin is run neat or with 2–4 wt% mineral-filled masterbatch to raise flexural modulus. The melt exits through a flat die with a lip gap of 1.2–3.5 mm onto a polished three-roll stack maintained at 60–80 °C. The sheet is then thermoformed at surface temperatures of 165–185 °C using plug-assisted vacuum forming. Typical final sheet thickness is 2.0–4.0 mm. Final parts include automotive load floors, industrial dunnage trays, and reusable pallet covers. Flexural modulus for the 0.945–0.950 g/cm³ HDPE class is typically 900–1200 MPa under ISO 178, and tensile yield strength is 23–27 MPa under ISO 527-2. These values are not a substitute for lot certification; published data for this specific sheet configuration is limited. Differential shrinkage must be accommodated in the mold with 1.5–2.5% machine-direction allowance and 1.0–2.0% transverse-direction allowance. Filled masterbatch above 6 wt% is avoided because the higher melt strength causes die lines and uneven plug stretch during heavy-gauge forming.
In agricultural chemical packaging, CD-471 is blow molded into 1–10 L containers where environmental stress crack resistance under solvent and surfactant exposure governs service life. Monolayer designs use 100% CD-471 with 1–2 wt% color concentrate; coextruded designs use an outer layer of CD-471 and an inner polyamide-based barrier layer at 5–10 wt% of total wall thickness. Melt temperature is set lower than standard HDPE blow molding, at 185–205 °C, to preserve polyamide barrier stability. The finished containers are subjected to 48 h contact with the actual formulated product at 40 °C, followed by drop testing at -18 °C under 49 CFR §178.603. ESCR is evaluated under ASTM D1693-15 Condition B in 10% Igepal CO-630 at 50 °C, with a typical threshold of 200 h for concentrated formulations. The primary service failure is environmental stress cracking at the bottom pinch-off weld; to reduce this, mold parting line mismatch is held below 0.2 mm and parison wall thickness in the weld region is maintained at a minimum of 2.0 mm. Internal amide-based slip additives and external lubricants are excluded from the HDPE layer because migration to the surface reduces label print adhesion and can accelerate stress cracking in contact with nonionic surfactants.
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Bayport Polymers LLC supplies the high-density polyethylene grade designated Baystar HDPE CD-471 as a bimodal high-density polyethylene copolymer intended for corrugated pipe and conduit profile extrusion. The resin is manufactured at the Bayport, Texas, polyethylene facility and is supplied in pellet form. Primary downstream applications include annular corrugated drainage pipe qualified under AASHTO M294 and ASTM F2306, agricultural drain tubing evaluated under ASTM F667, and electrical conduit where the fabricated conduit body meets NEMA TC 7. CD-471 is not positioned as a pressure-pipe resin for potable water service; no hydrostatic design basis is assigned in manufacturer literature for sustained internal-pressure service.
The grade is differentiated from general-purpose unimodal HDPE by its bimodal molecular weight distribution. A high-molecular-weight chain fraction raises the concentration of tie molecules between crystalline lamellae, which improves environmental stress crack resistance and slow crack growth resistance. A lower-molecular-weight fraction reduces high-shear viscosity, permitting corrugation filling at production rates without excessive screw torque or die head pressure. Compared with unimodal HDPE pipe grades of similar density, CD-471 therefore shows higher resistance to slow crack propagation in stressed pipe walls while retaining enough shear thinning for thick-wall profile extrusion.
Manufacturer-published typical property data for CD-471 are reproduced below. The values are nominal lot averages, not specification limits, and current certificates of analysis govern commercial shipment.
| Property | Test method | Nominal value |
|---|---|---|
| Density | ASTM D1505 | 0.947 g/cm³ |
| Melt flow rate | ASTM D1238, 190 °C/2.16 kg | 0.7 g/10 min |
| Tensile strength at yield | ASTM D638, Type IV specimen, 50 mm/min | 24 MPa |
| Elongation at break | ASTM D638 | >800% |
| Flexural modulus | ASTM D790 | 1000 MPa |
| Environmental stress crack resistance, Condition B, F50 | ASTM D1693, 10% Igepal CO-630 | >1000 h |
| Brittleness temperature | ASTM D746 | < -75 °C |
| Vicat softening point | ASTM D1525, 10 N, 50 °C/h | 124 °C |
The F50 ESCR value in the table is generated on compression-molded plaques with a standard notch; it does not directly predict pipe performance under field load. For corrugated pipe, AASHTO M294 and ASTM F2306 require finished-pipe tests, including pipe stiffness, impact, and joint integrity. CD-471 is selected because it contributes high ESCR to the pipe wall, but the installed product performance depends on pipe profile geometry, processing conditions, and installation practice. The tensile and flexural data are generated on laboratory specimens under 23 °C and 50% relative humidity; field performance at 0 °C or below should be verified by impact testing on finished pipe samples.
Parallel-plate oscillatory rheometry of CD-471 at 190 °C shows a broader relaxation spectrum than unimodal HDPE of equivalent melt flow rate. The storage modulus at low frequencies is higher, which corresponds to higher melt strength and parison stability. The crossover frequency between storage and loss modulus shifts to lower shear rates, indicating longer terminal relaxation time. This rheological signature is characteristic of bimodal resins and explains the observed lower sag in corrugated pipe forming. However, the grade is not formulated for foam extrusion or blown film, where extensional hardening behavior is required; in those processes, the bubble stability and foam cell nucleation of CD-471 are not optimized.
At a nominal density of 0.947 g/cm³ and a melt flow rate of 0.7 g/10 min, CD-471 occupies a medium-high stiffness position among bimodal HDPE pipe resins. The density is deliberately lower than that of high-modulus HDPE grades in the 0.955–0.960 g/cm³ range, which increases ring stiffness but can sacrifice slow crack growth resistance. The melt flow rate is higher than that of bimodal blow-molding and large-part extrusion grades near 0.3 g/10 min, giving CD-471 the ability to fill thin corrugation elements without excessive head pressure. This combination places the grade in the corrugated-pipe segment rather than in solid-wall pressure pipe or high-stiffness twin-wall storm pipe designs.
The comonomer content and the high-molecular-weight fraction are balanced to preserve pipe wall fracture toughness. In bending and denting events on installed drainage pipe, the pipe wall experiences both compressive and tensile strain; the tensile side is the site where slow crack growth can initiate. CD-471’s high-molecular-weight fraction induces a broader tie-molecule distribution, which delays craze breakdown under repeated loading. A unimodal HDPE of the same density and melt flow rate generally exhibits a narrower molecular weight distribution and a lower F50 ESCR value under ASTM D1693, particularly at the same processing history. For this reason, CD-471 is specified in corrugated pipe applications where the pipe is exposed to highway load cycling and trench backfill stress.
On corrugated pipe lines, CD-471 is typically run on single-screw extruders with grooved feed sections and 30:1 to 36:1 L/D ratios. Screw compression ratios between 2.5:1 and 3.5:1 are common. Barrel temperature settings are ramped from 180–200 °C in the feed zone, 200–220 °C in the compression zone, and 210–230 °C in the metering zone. Adapter and die zones are maintained at 210–230 °C. Melt temperature should be kept below 245 °C; prolonged operation above this threshold accelerates oxidative degradation. The corrugator vacuum setting and cooling water temperature are machine-specific, but mold block water is usually controlled between 10 °C and 20 °C to remove heat rapidly without forming condensation-related surface defects.
The melt stiffness of CD-471 permits a wider die-to-nip gap than less-elastic unimodal materials, but processors should validate the maximum allowable gap by measuring pipe wall thickness variation on the liner side. Wall thickness uniformity in the corrugation valley is the critical operator-measured parameter. On 75 mm to 120 mm single-screw lines, output typically becomes limited by corrugator cooling and not by plastication when processing CD-471; the grade’s lower high-shear viscosity prevents excessive screw torque at elevated throughput. When die head pressure is compared with a unimodal HDPE of identical melt flow rate, CD-471 generally produces lower pressure because the high-molecular-weight fraction increases shear thinning. This can decrease the energy input required for equivalent output and lower melt temperature at the die exit.
Screw geometry should include a barrier zone or mixing section if carbon black masterbatch is let down at high concentrations; otherwise, agglomerates can appear as black specks in natural or yellow conduit. Use of a grooved feed section ensures positive conveying but increases barrel wear; barrel temperatures in the feed throat should not exceed 70 °C to prevent pellet bridging. The feed hopper throat should be maintained dry, and condensation from cold outdoor pellet storage should be removed before processing.
Substitution of a unimodal HDPE of 0.945–0.950 g/cm³ density and 0.6–0.8 g/10 min melt index with CD-471 requires re-evaluation of die temperature and forming conditions. The bimodal molecular weight distribution produces stronger low-shear melt strength and more pronounced shear thinning than a unimodal equivalent. Operators can often reduce melt temperature by 5–8 °C while maintaining equivalent corrugation fill. Lower melt temperature improves parison stiffness and reduces sag between the die face and the corrugator nip. However, if the melt temperature is reduced too far, the lower-molecular-weight fraction does not shear-thin sufficiently to replicate cavity fill at thin-wall sections, and pipe wall thickness variation increases. The acceptable melt temperature window on a specific line must be determined by a designed experiment, not by comparison with a previous unimodal grade.
Die head pressure often decreases by 10–15% at the same screw speed when CD-471 replaces a unimodal HDPE of similar melt index. This lower pressure may be used to increase throughput if downstream cooling capacity is available. The die gap may require adjustment because CD-471’s higher melt elasticity can increase die swell. Excessive die swell can produce nonuniform corrugation depth and poor liner contact with the mold blocks. Operators should therefore measure die swell at production melt temperature and adjust die land length or draw ratio accordingly. Published data for CD-471 in every corrugator configuration are limited; die setup remains a plant-specific optimization.
The principal failure mode observed when replacing unimodal HDPE without adjusting die gap is liner-side thinning in the corrugation valley, which reduces impact resistance under install conditions. This defect is detected by sectioning a pipe sample and measuring wall thickness at the valley, shoulder, and crown as required by AASHTO M294. A change in screw temperature profile alone will not correct a die-swell imbalance; the die must be recentered and the mandrel position changed.
CD-471 must be protected from prolonged exposure to melt temperatures above 245 °C. During corrugator stoppages, stagnant melt in adapters or spiral-mandrel dies can degrade within 15–20 minutes; the line should be purged with CD-471 or a purge compound before restarting production. Oxidative chain scission increases melt flow rate and reduces ESCR. The resin should not be stored in direct sunlight or in vented silos at high ambient temperature for extended periods unless the storage system is designed for polyolefin pellets. Surface moisture from condensation is generally not an issue, but if pellets are transported from cold outdoor storage to a warm processing area, the surface condensation should be dried at 80 °C for 2 hours before extrusion to prevent surface defects in the finished pipe wall.
Regrind use must be validated against field performance requirements. Clean in-plant corrugated scrap is commonly added at up to 20 wt%. At higher regrind levels, the cumulative heat history reduces F50 ESCR under ASTM D1693, and published data for CD-471 containing more than 30 wt% regrind are limited. Carbon black masterbatch is required for outdoor drainage pipe. The final pipe wall should contain 2.0–2.5 wt% carbon black to meet UV stabilization provisions of AASHTO M294 and ASTM F2306. CD-471 in natural pellet form does not provide long-term UV resistance without this compounding step. For electrical conduit applications, the fabricated conduit body must be tested under NEMA TC 7; impact and low-temperature brittleness testing are governed by the relevant conduit specification. Processors should confirm current REACH and RoHS compliance from the supplier certification for each lot exported to regulated jurisdictions.
Within the family of bimodal HDPE grades, CD-471 differs from higher-density, lower-melt-flow-rate grades designed for pressure pipe or large-diameter solid-wall pipe. Those grades normally exhibit densities of 0.950–0.955 g/cm³ and melt flow rates near 0.2–0.5 g/10 min, along with hydrostatic design basis values derived from ISO 9080 or ASTM D2837. CD-471 sacrifices some long-term hydrostatic strength in favor of higher flow and faster corrugated-pipe output. The resin also differs from bimodal HDPE blow-molding grades used for intermediate bulk containers, which require high melt strength but lower density for drop-impact toughness and are not optimized for thin-wall corrugated profile accuracy.
