{
  "spore": "profile",
  "id": "hdpe",
  "spore_version": "0.2",
  "family": "polyolefins",
  "name": "High-density polyethylene",
  "abbreviation": "HDPE",
  "role": "light, tough, chemically resistant thermoplastic for molded, machined and extruded parts",
  "category": "polymers",
  "type": "polyolefins",
  "summary": "High-density polyethylene (HDPE) is the linear, high-density form of polyethylene, a light and tough thermoplastic. A general-purpose virgin injection grade (SCG H5818J) has a density of 0.959 g/cm3 and a tensile strength at yield of 290 kg/cm2. A machining sheet grade (Weerg PE1000) gives a yield strength of 18 MPa and a melting range of 130 to 135 °C. In a UV lamp test, pure HDPE monofilament lost 66.0% of its elongation at break after 600 hours. Polyethylene in the LDEF space experiment eroded under atomic oxygen at 3.97 x 10-24 cm3 per atom, but that sample is only named polyethylene.\n",
  "best_for": "Light, tough, moisture-resistant plastic parts that are kept out of sunlight and out of heat",
  "weakest_at": "UV and heat: pure HDPE lost 66.0% of its elongation after 600 h of UV lamp ageing, and its heat-deflection temperature is 42 to 70 °C under light load",
  "identity": {
    "formula": "(C2H4)n, polymer of ethylene with a -CH2-CH2- repeat unit",
    "cas": "9002-88-4",
    "designations": [],
    "source": "scg-sds",
    "where": "Section 3, polyethylene homopolymer, CAS 9002-88-4. Section 1.1 says this SDS applies to all HDPE grades made by Thai Polyethylene."
  },
  "tags": {
    "environments": [],
    "stresses": [
      "uv",
      "atomic-oxygen",
      "extreme-heat"
    ],
    "applications": [
      "structures",
      "mechanisms"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, general-purpose HDPE injection grade H5818J",
      "value": 0.959,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "grade": "H5818J (HDPE, general purpose, injection molding)",
        "temperature": "not stated"
      },
      "method": "ASTM D 1505, as printed in a manufacturer grade page",
      "status": "ground",
      "source": "scg-h5818j",
      "where": "Physical table, row Density",
      "source_detail": {
        "title": "SCG Chemicals grade page, H5818J general purpose HDPE for injection molding",
        "url": "https://www.scgchemicals.com/en/products-grade/h5818j",
        "kind": "datasheet",
        "license": "Manufacturer product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melt_flow_rate",
      "label": "Melt flow rate, HDPE injection grade H5818J",
      "value": 18,
      "bound": "exact",
      "unit": "g/10 min",
      "scope": "material",
      "conditions": {
        "grade": "H5818J",
        "temperature": "190 °C",
        "load": "2.16 kg"
      },
      "method": "ASTM D 1238, as printed in a manufacturer grade page",
      "status": "ground",
      "note": "Melt flow rate has no entry in the canonical property list, so the name melt_flow_rate is used.",
      "source": "scg-h5818j",
      "where": "Physical table, row Melt Flow Rate at 190 °C and 2.16 kg",
      "source_detail": {
        "title": "SCG Chemicals grade page, H5818J general purpose HDPE for injection molding",
        "url": "https://www.scgchemicals.com/en/products-grade/h5818j",
        "kind": "datasheet",
        "license": "Manufacturer product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Tensile strength at yield, HDPE injection grade H5818J",
      "value": 290,
      "bound": "exact",
      "unit": "kg/cm2",
      "scope": "material",
      "conditions": {
        "grade": "H5818J (HDPE, injection molding)",
        "test_speed": "crosshead 50 mm/min"
      },
      "method": "ASTM D 638, as printed in a manufacturer grade page",
      "status": "ground",
      "note": "Printed in kg/cm2 and not converted. 290 kg/cm2 is about 28.4 MPa (1 kgf/cm2 = 0.0980665 MPa, a unit conversion, not a source value).",
      "source": "scg-h5818j",
      "where": "Mechanical table, row Tensile Strength at Yield",
      "source_detail": {
        "title": "SCG Chemicals grade page, H5818J general purpose HDPE for injection molding",
        "url": "https://www.scgchemicals.com/en/products-grade/h5818j",
        "kind": "datasheet",
        "license": "Manufacturer product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "flexural_modulus",
      "label": "Flexural modulus, HDPE injection grade H5818J",
      "value": 13000,
      "bound": "exact",
      "unit": "kg/cm2",
      "scope": "material",
      "conditions": {
        "grade": "H5818J (HDPE, injection molding)",
        "temperature": "not stated"
      },
      "method": "ASTM D 790, as printed in a manufacturer grade page",
      "status": "ground",
      "source": "scg-h5818j",
      "where": "Mechanical table, row Flexural Modulus",
      "source_detail": {
        "title": "SCG Chemicals grade page, H5818J general purpose HDPE for injection molding",
        "url": "https://www.scgchemicals.com/en/products-grade/h5818j",
        "kind": "datasheet",
        "license": "Manufacturer product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "izod_impact_strength",
      "label": "Izod impact strength, HDPE injection grade H5818J",
      "value": 27,
      "bound": "exact",
      "unit": "J/m",
      "scope": "material",
      "conditions": {
        "grade": "H5818J",
        "temperature": "23 °C",
        "notch": "as the standard specifies"
      },
      "method": "ASTM D 256, as printed in a manufacturer grade page",
      "status": "ground",
      "note": "The name izod_impact_strength is not in the canonical property list.",
      "source": "scg-h5818j",
      "where": "Mechanical table, row Izod Impact Strength at 23 °C",
      "source_detail": {
        "title": "SCG Chemicals grade page, H5818J general purpose HDPE for injection molding",
        "url": "https://www.scgchemicals.com/en/products-grade/h5818j",
        "kind": "datasheet",
        "license": "Manufacturer product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, HDPE machining sheet (Protolabs)",
      "value": 0.955,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "grade": "HDPE sheet for CNC machining, grade name not printed",
        "temperature": "not stated"
      },
      "method": "ASTM D792, as printed in a manufacturer datasheet",
      "status": "ground",
      "source": "protolabs-hdpe",
      "where": "Properties table, row Density",
      "source_detail": {
        "title": "Protolabs HDPE CNC material data sheet",
        "url": "https://www.protolabs.com/media/rkzn2wud/2026-026-cnc-material-data-sheet_hdpe.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "moisture_absorption",
      "label": "Water absorption, HDPE machining sheet (Protolabs)",
      "value": 0.1,
      "bound": "upper",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "test": "ASTM D570",
        "exposure": "not stated on the datasheet"
      },
      "method": "ASTM D570, as printed in a manufacturer datasheet (the sheet prints an upper limit)",
      "status": "ground",
      "source": "protolabs-hdpe",
      "where": "Properties table, row Water Absorption",
      "source_detail": {
        "title": "Protolabs HDPE CNC material data sheet",
        "url": "https://www.protolabs.com/media/rkzn2wud/2026-026-cnc-material-data-sheet_hdpe.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Maximum service temperature in air, HDPE machining sheet (Protolabs)",
      "value": 180,
      "bound": "exact",
      "unit": "°F",
      "scope": "material",
      "conditions": {
        "environment": "air",
        "grade": "HDPE sheet for CNC machining"
      },
      "method": "As printed in a manufacturer datasheet; no test standard is named on the sheet",
      "status": "ground",
      "source": "protolabs-hdpe",
      "where": "Properties table, row Maximum Service Temperature, Air",
      "source_detail": {
        "title": "Protolabs HDPE CNC material data sheet",
        "url": "https://www.protolabs.com/media/rkzn2wud/2026-026-cnc-material-data-sheet_hdpe.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "heat_deflection_temperature",
      "label": "Heat deflection temperature at 264 psi, HDPE machining sheet (Protolabs)",
      "value": 165,
      "value_high": 176,
      "bound": "range",
      "unit": "°F",
      "scope": "material",
      "conditions": {
        "load": "264 psi",
        "test": "ASTM D648"
      },
      "method": "ASTM D648, as printed in a manufacturer datasheet (range)",
      "status": "ground",
      "source": "protolabs-hdpe",
      "where": "Properties table, row Heat Deflection Temperature at 264 psi",
      "source_detail": {
        "title": "Protolabs HDPE CNC material data sheet",
        "url": "https://www.protolabs.com/media/rkzn2wud/2026-026-cnc-material-data-sheet_hdpe.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Tensile strength at yield, HDPE machining sheet (Protolabs)",
      "value": 4000,
      "bound": "lower",
      "unit": "psi",
      "scope": "material",
      "conditions": {
        "test": "ASTM D638",
        "grade": "HDPE sheet for CNC machining, grade name not printed"
      },
      "method": "ASTM D638, as printed in a manufacturer datasheet (lower limit)",
      "status": "ground",
      "source": "protolabs-hdpe",
      "where": "Properties table, row Tensile Strength at Yield",
      "source_detail": {
        "title": "Protolabs HDPE CNC material data sheet",
        "url": "https://www.protolabs.com/media/rkzn2wud/2026-026-cnc-material-data-sheet_hdpe.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break, HDPE machining sheet (Protolabs)",
      "value": 400,
      "bound": "lower",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "test": "ASTM D638",
        "grade": "HDPE sheet for CNC machining, grade name not printed"
      },
      "method": "ASTM D638, as printed in a manufacturer datasheet (lower limit)",
      "status": "ground",
      "source": "protolabs-hdpe",
      "where": "Properties table, row Elongation @ Break",
      "source_detail": {
        "title": "Protolabs HDPE CNC material data sheet",
        "url": "https://www.protolabs.com/media/rkzn2wud/2026-026-cnc-material-data-sheet_hdpe.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "flexural_modulus",
      "label": "Flexural modulus, HDPE machining sheet (Protolabs)",
      "value": 174000,
      "value_high": 185000,
      "bound": "range",
      "unit": "psi",
      "scope": "material",
      "conditions": {
        "test": "ASTM D790",
        "grade": "HDPE sheet for CNC machining, grade name not printed"
      },
      "method": "ASTM D790, as printed in a manufacturer datasheet (range)",
      "status": "ground",
      "source": "protolabs-hdpe",
      "where": "Properties table, row Flexural Modulus",
      "source_detail": {
        "title": "Protolabs HDPE CNC material data sheet",
        "url": "https://www.protolabs.com/media/rkzn2wud/2026-026-cnc-material-data-sheet_hdpe.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength, HDPE PE1000 sheet (Weerg)",
      "value": 18,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "test": "ISO 527",
        "grade": "PE1000 HDPE, grade name beyond HDPE not printed"
      },
      "method": "ISO 527, as printed in a manufacturer datasheet",
      "status": "ground",
      "source": "weerg-pe",
      "where": "Material properties, row Yield strength ISO 527",
      "source_detail": {
        "title": "Weerg PE1000 HDPE technical datasheet v2.1 (CNC machining)",
        "url": "https://weerg.com/hubfs/Datasheets/Datasheets%202024/ENG/EN_Polietilene.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Elastic modulus, HDPE PE1000 sheet (Weerg)",
      "value": 750,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "test": "ISO 527",
        "grade": "PE1000 HDPE"
      },
      "method": "ISO 527, as printed in a manufacturer datasheet",
      "status": "ground",
      "source": "weerg-pe",
      "where": "Material properties, row Elastic modulus ISO 527",
      "source_detail": {
        "title": "Weerg PE1000 HDPE technical datasheet v2.1 (CNC machining)",
        "url": "https://weerg.com/hubfs/Datasheets/Datasheets%202024/ENG/EN_Polietilene.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break, HDPE PE1000 sheet (Weerg)",
      "value": 50,
      "bound": "lower",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "test": "ISO 527",
        "grade": "PE1000 HDPE"
      },
      "method": "ISO 527, as printed in a manufacturer datasheet (lower limit)",
      "status": "ground",
      "source": "weerg-pe",
      "where": "Material properties, row Elongation at break ISO 527",
      "source_detail": {
        "title": "Weerg PE1000 HDPE technical datasheet v2.1 (CNC machining)",
        "url": "https://weerg.com/hubfs/Datasheets/Datasheets%202024/ENG/EN_Polietilene.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "heat_deflection_temperature",
      "label": "Heat deflection temperature at 0.45 MPa, HDPE PE1000 sheet (Weerg)",
      "value": 70,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "load": "0.45 MPa",
        "test": "ISO 75",
        "grade": "PE1000 HDPE"
      },
      "method": "ISO 75, as printed in a manufacturer datasheet",
      "status": "ground",
      "source": "weerg-pe",
      "where": "Material properties, row HDT 0.45 MPa ISO 75",
      "source_detail": {
        "title": "Weerg PE1000 HDPE technical datasheet v2.1 (CNC machining)",
        "url": "https://weerg.com/hubfs/Datasheets/Datasheets%202024/ENG/EN_Polietilene.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "heat_deflection_temperature",
      "label": "Heat deflection temperature at 1.8 MPa, HDPE PE1000 sheet (Weerg)",
      "value": 42,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "load": "1.8 MPa",
        "test": "ISO 75",
        "grade": "PE1000 HDPE"
      },
      "method": "ISO 75, as printed in a manufacturer datasheet",
      "status": "ground",
      "source": "weerg-pe",
      "where": "Material properties, row HDT 1.8 MPa ISO 75",
      "source_detail": {
        "title": "Weerg PE1000 HDPE technical datasheet v2.1 (CNC machining)",
        "url": "https://weerg.com/hubfs/Datasheets/Datasheets%202024/ENG/EN_Polietilene.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "vicat_softening_temperature",
      "label": "Vicat softening temperature, HDPE PE1000 sheet (Weerg)",
      "value": 80,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "test": "ISO 306",
        "grade": "PE1000 HDPE"
      },
      "method": "ISO 306, as printed in a manufacturer datasheet",
      "status": "ground",
      "source": "weerg-pe",
      "where": "Material properties, row Vicat softening temperature ISO 306",
      "source_detail": {
        "title": "Weerg PE1000 HDPE technical datasheet v2.1 (CNC machining)",
        "url": "https://weerg.com/hubfs/Datasheets/Datasheets%202024/ENG/EN_Polietilene.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting temperature, HDPE PE1000 sheet (Weerg)",
      "value": 130,
      "value_high": 135,
      "bound": "range",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "test": "ISO 11357",
        "grade": "PE1000 HDPE"
      },
      "method": "ISO 11357, as printed in a manufacturer datasheet (range)",
      "status": "ground",
      "source": "weerg-pe",
      "where": "Material properties, row Melting temperature ISO 11357",
      "source_detail": {
        "title": "Weerg PE1000 HDPE technical datasheet v2.1 (CNC machining)",
        "url": "https://weerg.com/hubfs/Datasheets/Datasheets%202024/ENG/EN_Polietilene.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "atomic_oxygen_erosion_yield",
      "label": "Atomic-oxygen erosion yield, polyethylene on LDEF (grade not stated)",
      "value": 3.97,
      "bound": "exact",
      "unit": "x10^-24 cm3/atom",
      "scope": "material",
      "conditions": {
        "material_name_in_source": "Polyethylene (grade, density and form not stated)",
        "exposure": "LDEF Experiment A0114, row 9, leading edge (flight)",
        "fluence": "9.0e21 atoms/cm2 assumed, stated as preliminary",
        "uncertainty": "plus or minus 0.23"
      },
      "method": "Erosion yield reported by the author from erosion depth (357 plus or minus 21 micrometres); the LDEF fluence is preliminary and the author warns to check the final value",
      "status": "flight",
      "note": "A flight result, but the source names the polymer only as polyethylene. Treat it as the nearest data for HDPE, not an HDPE-specific value. The name atomic_oxygen_erosion_yield is not in the canonical property list.",
      "source": "ntrs-ao",
      "where": "Table, Erosion depths and rates for polymers on LDEF, row Polyethylene (also the comparison table, prior STS value 3.32 to 3.74)",
      "source_detail": {
        "title": "Erosion rates for polymers measured on LDEF (Experiment A0114, UAH), J. Gregory, LDEF Workshop, Langley, November 1991",
        "url": "https://ntrs.nasa.gov/api/citations/19930002806/downloads/19930002806.pdf",
        "kind": "report",
        "license": "Public domain (NASA)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Ultraviolet light (UVA-340 lamp, continuous, 50 °C, 55% relative humidity)",
      "headline": "Pure HDPE monofilament lost 66.0% of its elongation at break and 54.5% of its breaking strength after 600 hours of UV lamp ageing.",
      "effect": "The same test gave a 52.0% loss of yield strength. The authors describe the failure as rapid brittle failure. Carbonyl index and unsaturation rose with exposure, and the start of thermal decomposition, by TGA, fell 28 °C for pure HDPE. Adding 20% UHMWPE to the HDPE cut the elongation loss to 54.0%.",
      "rating": "severe",
      "conditions": {
        "lamp": "UVA-340 fluorescent, irradiance 0.76 W/m2 at 340 nm",
        "temperature": "50 °C",
        "humidity": "55% relative humidity",
        "exposure": "continuous illumination, 0 to 600 h",
        "material": "drawn HDPE monofilament with a compound antioxidant added, not an uncoated sheet"
      },
      "source": "pmc-uv",
      "where": "Section 2.3 (UV ageing conditions); Results, mechanical properties (paragraph on 600 h of aging); Abstract (thermal decomposition T5%)"
    },
    {
      "environment": "Humid air and water (moisture uptake)",
      "headline": "HDPE sheet takes up very little water: under 0.10% by the ASTM D570 test.",
      "effect": "The Protolabs datasheet describes HDPE as having low moisture absorption and gives an upper limit of 0.10% for water absorption by ASTM D570. The datasheet does not give the immersion time or the humidity, so this is a limit, not a humidity-ageing result.",
      "rating": "low",
      "conditions": {
        "test": "ASTM D570",
        "exposure": "not stated on the datasheet"
      },
      "source": "protolabs-hdpe",
      "where": "Properties table, row Water Absorption; Description"
    },
    {
      "environment": "Heat (sustained, under load)",
      "headline": "HDPE softens well below its melting range under load: a heat-deflection temperature of 42 to 70 °C is printed at light loads.",
      "effect": "The Weerg PE1000 sheet gives a heat-deflection temperature of 70 °C at 0.45 MPa and 42 °C at 1.8 MPa, and a Vicat softening temperature of 80 °C. The Protolabs sheet gives a maximum service temperature in air of 180 °F (82 °C) and a heat-deflection temperature of 165 to 176 °F at 264 psi. No long-term thermal ageing time or retained-property figure was read for HDPE.",
      "rating": "moderate",
      "conditions": {
        "loads": "0.45 MPa and 1.8 MPa (ISO 75); 264 psi (ASTM D648)",
        "standards": "ISO 75, ISO 306, ASTM D648",
        "service_temperature": "maximum in air, no time given"
      },
      "source": "weerg-pe",
      "where": "Material properties, rows HDT 0.45 MPa, HDT 1.8 MPa, Vicat softening temperature; Protolabs Properties table (Maximum Service Temperature, Air)"
    },
    {
      "environment": "Oxidising and reducing chemicals, strong acids and bases",
      "headline": "Most HDPE grades resist strong acids, strong bases and gentle oxidants and reducing agents.",
      "effect": "Wikipedia says most LDPE, MDPE and HDPE grades have excellent chemical resistance: they are not attacked by strong acids or strong bases, and they resist gentle oxidants and reducing agents. The article gives no concentration, temperature or time. Crystalline samples do not dissolve at room temperature.",
      "rating": "low",
      "conditions": {
        "basis": "qualitative statement, no concentration, temperature or time printed"
      },
      "source": "wiki-polyethylene",
      "where": "Chemical resistance section"
    },
    {
      "environment": "Atomic oxygen in low-Earth-orbit-like flight exposure (LDEF tray, leading edge)",
      "headline": "Polyethylene eroded by about 357 micrometres at the leading edge of the LDEF tray.",
      "effect": "The LDEF polyethylene sample lost 357 plus or minus 21 micrometres of depth, which gives an erosion yield of 3.97 x 10-24 cm3 per atom. The same paper lists other polymers in the same range: polystyrene 4.17, PMMA 6.3 and Kapton 2.89 (x 10-24 cm3 per atom), and PTFE 0.37. Polyethylene here is not named as HDPE, and the fluence used is preliminary.",
      "rating": "severe",
      "conditions": {
        "fluence": "9.0e21 atoms/cm2 assumed for row 9, preliminary",
        "exposure": "flight, LDEF Experiment A0114",
        "polymer": "polyethylene, grade not stated"
      },
      "source": "ntrs-ao",
      "where": "Table, Erosion depths and rates for polymers on LDEF; footnote on the LDEF fluence"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "The SCG HDPE safety data sheet classes the product as not hazardous under GHS and under EU CLP, with no signal word and no hazard statements.",
        "ghs": [],
        "source": "scg-sds",
        "where": "Section 2.1 (classification) and 2.2 (labelling)"
      },
      {
        "text": "Pellets on the floor are a slipping hazard, and hot polymer can cause thermal burns to the skin and eyes.",
        "ghs": [],
        "source": "scg-sds",
        "where": "Section 2.2 and 2.3 (other hazards); Section 4 (first aid, burns)"
      },
      {
        "text": "Dust is the hazard at processing: pneumatic conveying and mechanical handling can generate large static charges, and dust can be ignited.",
        "ghs": [],
        "source": "scg-sds",
        "where": "Section 7.1 (precautions for safe handling)"
      }
    ],
    "failure_risks": [
      {
        "mode": "Softening under load at moderate temperature",
        "trigger": "Part held under load at or near its heat-deflection temperature (42 °C at 1.8 MPa, 70 °C at 0.45 MPa)",
        "consequence": "The part deforms or creeps under load well before its melting range of 130 to 135 °C.",
        "severity": "moderate",
        "source": "weerg-pe",
        "where": "Material properties, rows HDT 1.8 MPa and HDT 0.45 MPa; Melting temperature"
      },
      {
        "mode": "Brittle failure after UV ageing",
        "trigger": "Continuous UV exposure at 50 °C and 55% relative humidity, 600 h, drawn monofilament",
        "consequence": "Elongation at break falls 66.0% and breaking strength 54.5%. The authors describe the failure as rapid brittle failure, and the carbonyl index rises, which means surface oxidation.",
        "severity": "high",
        "source": "pmc-uv",
        "where": "Results, mechanical properties (600 h); Abstract"
      }
    ],
    "side_effects": [
      {
        "text": "In a fire the product gives off carbon dioxide, carbon monoxide, other organic vapours and soot.",
        "affects": "Fire crews and the enclosure around the part",
        "source": "scg-sds",
        "where": "Section 5.2 (special hazards arising from the substance)"
      },
      {
        "text": "Molten material must not be hit with a direct water jet in a fire, and contaminated firefighting water must not enter the sewer.",
        "affects": "Fire crews and the drainage system",
        "source": "scg-sds",
        "where": "Section 5.3 (fire fighting procedure)"
      }
    ],
    "handling": [
      {
        "text": "Store in a dry, cool, dust-free, well-ventilated area below 50 °C, away from heat and direct sunlight.",
        "source": "scg-sds",
        "where": "Section 7.2 (conditions for safe storage)"
      },
      {
        "text": "Avoid forming dust and electrically bond and ground equipment that handles pellets or powder to reduce the risk of dust explosions.",
        "source": "scg-sds",
        "where": "Section 7.1 and 7.2 (handling and storage)"
      }
    ],
    "mitigations": [
      {
        "text": "Blending 20% UHMWPE into HDPE cut the 600 h UV loss of elongation at break from 66.0% to 54.0%, and the loss of breaking strength from 54.5% to 43.7%. The authors attribute this to the UHMWPE phase, which limits surface cracking.",
        "source": "pmc-uv",
        "where": "Abstract; Results, mechanical properties"
      }
    ]
  },
  "uses": [
    {
      "application": "structures",
      "device": "Injection-molded general parts, household products, bottle caps and closures, and toys",
      "example": "SCG lists the H5818J injection grade for general injection parts, household products, bottle caps and closures, and toys, with good flow for high-productivity moulding.",
      "source": "scg-h5818j",
      "where": "Product description and application list on the grade page (H5818J)"
    },
    {
      "application": "mechanisms",
      "device": "Machined parts such as chain guides, tanks, pipe systems and chemical containers",
      "example": "Protolabs lists HDPE for chain guides, water storage, tanks, pipe systems, chemical containers and food cutting boards, and gives a density of 0.955 g/cm3.",
      "source": "protolabs-hdpe",
      "where": "Description and applications paragraph; Properties table, row Density"
    }
  ],
  "supply": [
    {
      "subject": "Polyethylene (feedstock is ethylene; no HDPE production split was read)",
      "abundance": "Not a mineral. Demand, not production: China accounts for 34% of global polyethylene demand in 2024 (Argus, all PE grades).",
      "producers": [],
      "critical_lists": [],
      "recycling": "SCG lists certified post-consumer recycled HDPE grades (PCRH01BN, PCRH02BW, PCRH03BB) for blow moulding. The grades are not for food contact, pharmaceutical or medical use.",
      "substitutes": [],
      "source": "scg-h5818j",
      "where": "Grade listing on the SCG product page (PCR grades); the Argus demand share is in the abundance field and is cited as argus-pe-2024"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "SCG Chemicals grade page, H5818J general purpose HDPE for injection molding",
      "type": "datasheet",
      "url": "https://www.scgchemicals.com/en/products-grade/h5818j",
      "year": 2026
    },
    {
      "title": "SCG Chemicals HDPE safety data sheet (applies to all HDPE grades made by Thai Polyethylene)",
      "type": "sds",
      "url": "https://www.scgchemicals.com/uploads/sdsscgc-hdpeem-sds-9001-5.pdf",
      "year": 2026
    },
    {
      "title": "Weerg PE1000 HDPE technical datasheet v2.1 (CNC machining)",
      "type": "datasheet",
      "url": "https://weerg.com/hubfs/Datasheets/Datasheets%202024/ENG/EN_Polietilene.pdf",
      "year": 2024
    },
    {
      "title": "Protolabs HDPE CNC material data sheet",
      "type": "datasheet",
      "url": "https://www.protolabs.com/media/rkzn2wud/2026-026-cnc-material-data-sheet_hdpe.pdf",
      "year": 2026
    },
    {
      "title": "Erosion rates for polymers measured on LDEF (Experiment A0114, UAH), LDEF Workshop 1991",
      "type": "report",
      "url": "https://ntrs.nasa.gov/api/citations/19930002806/downloads/19930002806.pdf",
      "year": 1991
    },
    {
      "title": "Fishery HDPE/UHMWPE blend monofilament UV ageing study (open access, PMC)",
      "type": "paper",
      "url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12899940/",
      "year": 2026
    },
    {
      "title": "NIST Atomic Weights and Isotopic Compositions for All Elements (carbon, hydrogen)",
      "type": "database",
      "url": "https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=C&all=all&ascii=ascii",
      "year": 2026
    }
  ],
  "gaps": [
    "No designations found: HDPE has no UNS or EN number in any source checked, and the ASTM D4976 or D3350 PE classification did not appear on a fetched page.",
    "No producer split for HDPE by country or company was read. Argus gives a demand share for all polyethylene, which is not a production share. Ethylene feedstock (naphtha or ethane) was not confirmed from a fetched page.",
    "No HDPE-specific atomic-oxygen result: the LDEF value is for polyethylene, grade not stated. No HDPE mass-loss or outgassing (TML or CVCM) value was read.",
    "No radiation-dose, electron or proton test result for HDPE was read in a fetched page.",
    "Environmental stress cracking (ESCR, ASTM D1693) of HDPE: the Pertachem table gives hours at 25% Igepal, but the columns are flattened, so no figure is entered.",
    "No thermal-oxidation or long-term heat-ageing time to a retained-property figure was read for HDPE. The UV figures come from a monofilament with an antioxidant added, not from a sheet or moulding.",
    "Weerg PE1000 density (0,94 g/cm3) and water absorption (0,01 %, ISO 62) print a decimal comma. They were read but are not entered as properties, because the verify script does not match a comma decimal; they are recorded here. The Weerg data are for a machining sheet, grade not named.",
    "Melt flow rate and Izod impact have no canonical name in the property list; melt_flow_rate and izod_impact_strength are used and noted in the properties.",
    "Recythen recycled HDPE data sheet could not be opened, so recycled-grade values are not entered.",
    "Flash point and auto-ignition temperature do not appear in the SCG safety data sheet text that could be extracted (section 9 gave no such figures)."
  ],
  "story": {
    "why": "High-density polyethylene is the light, tough and chemically resistant form of polyethylene. Its linear chains pack densely, which gives a density of 0.959 g/cm3 for the virgin injection grade. Its weaknesses are heat and sunlight: it softens under load well below its melting range, and UV exposure breaks the surface down. Where those are not the design limits, it is a light, moulded or machined material.",
    "uses": [
      {
        "where": "Injection-moulded parts",
        "line": "The SCG H5818J grade is a general-purpose injection HDPE for household products, bottle caps and closures, and toys. It has a density of 0.959 g/cm3 and a tensile strength at yield of 290 kg/cm2."
      },
      {
        "where": "Machined parts",
        "line": "Protolabs lists HDPE sheet for chain guides, tanks, pipe systems and chemical containers. Its sheet has a density of 0.955 g/cm3, a yield strength above 4,000 psi and an elongation at break above 400%."
      }
    ],
    "can_do": [
      {
        "label": "Density",
        "line": "The virgin injection grade H5818J has a density of 0.959 g/cm3 (ASTM D 1505). A machining sheet is printed at 0.955 g/cm3 (ASTM D792).",
        "benchmark": "density",
        "scope": "material",
        "value": "0.959 g/cm3"
      },
      {
        "label": "Yield strength",
        "line": "H5818J gives a tensile strength at yield of 290 kg/cm2 (about 28 MPa, a unit conversion). The PE1000 sheet gives 18 MPa (ISO 527).",
        "benchmark": "yield_strength",
        "scope": "material",
        "value": "290 kg/cm2"
      },
      {
        "label": "Heat",
        "line": "Heat-deflection temperature is 70 °C at 0.45 MPa and 42 °C at 1.8 MPa (ISO 75) for the PE1000 sheet. The Vicat softening temperature is 80 °C.",
        "benchmark": "heat_deflection_temperature",
        "scope": "material",
        "value": "70 °C at 0.45 MPa"
      }
    ],
    "compare": "Within this profile, the virgin injection grade (0.959 g/cm3) and the machining sheet (0.955 g/cm3) give similar densities, and the machining sheet's yield strength (18 MPa) is lower than the injection grade's (about 28 MPa, converted from 290 kg/cm2). The sheets give a heat-deflection temperature of 42 to 70 °C under light load. Without stabilisers or a blend, UV exposure degrades HDPE quickly, so the comparison with other polymers in the collection depends on the UV limit the part must meet.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Yield strength",
        "benchmark": "yield_strength",
        "scope": "material"
      },
      {
        "label": "Maximum service temperature",
        "benchmark": "max_service_temp",
        "scope": "material"
      }
    ],
    "handling": [
      "The SCG safety data sheet gives no hazard classification. Use dust control, and bond and ground equipment that moves pellets.",
      "Keep the material dry and below 50 °C, away from heat and direct sunlight.",
      "Hot polymer causes burns; keep the molten material away from skin and eyes."
    ],
    "good_for": [
      "Light parts. The virgin injection grade is 0.959 g/cm3 and the machining sheet 0.955 g/cm3.",
      "Moisture resistance. The machining sheet absorbs under 0.10% water by ASTM D570.",
      "Chemical resistance. Most HDPE grades are not attacked by strong acids or bases."
    ],
    "watch_out": [
      "UV: 66.0% loss of elongation after 600 h of lamp ageing for pure monofilament. Stabilise or shield the part.",
      "Heat: 42 °C at 1.8 MPa and 70 °C at 0.45 MPa for the PE1000 sheet, so a loaded part softens far below its melting range.",
      "Space: LDEF eroded polyethylene by 357 micrometres. HDPE was not measured on its own, and no outgassing value was read."
    ],
    "verdict": "HDPE is the practical, light and chemically resistant choice for rigid parts at room temperature. It is a poor choice for loaded parts in sunlight or heat. The sourced values are two virgin or machining HDPE grades, one set of UV ageing data for monofilament, and one LDEF flight result for polyethylene, which is not named as HDPE.",
    "recipe": {
      "line": "HDPE is polyethylene made from ethylene (C2H4). Its repeat unit is -CH2-CH2-, and the chains have little branching, so they pack densely. Industrial routes use Ziegler-Natta catalysts, the Phillips slurry process with silica-based catalysts, or metallocene catalysts (Wikipedia, High-density polyethylene).",
      "parts": [
        {
          "name": "Carbon",
          "symbol": "C",
          "role": "Forms the backbone of each repeat unit."
        },
        {
          "name": "Hydrogen",
          "symbol": "H",
          "role": "Fills the remaining bonds on the carbon backbone. The formula is (C2H4)n."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The SCG safety data sheet classes HDPE as not hazardous under GHS and EU CLP. The hazards are physical, from hot polymer and dust at processing.",
        "points": [
          {
            "label": "The pellets",
            "line": "The data sheet gives no signal word and no hazard statements. Pellets on the floor are a slipping hazard."
          },
          {
            "label": "Molten polymer",
            "line": "Hot polymer can cause thermal burns to skin and eyes."
          },
          {
            "label": "Dust",
            "line": "Pneumatic conveying can build large static charges, and dust can be ignited. Keep dust down and bond and ground the equipment."
          }
        ],
        "level": 0,
        "verdict": "Not classified hazardous"
      },
      {
        "title": "If it fails",
        "lead": "The failure routes are heat under load and sunlight.",
        "points": [
          {
            "label": "Softening under load",
            "line": "A PE1000 sheet has a heat-deflection temperature of 70 °C at 0.45 MPa and 42 °C at 1.8 MPa. The melting range is 130 to 135 °C."
          },
          {
            "label": "UV ageing",
            "line": "In a UV lamp test at 50 °C, pure HDPE monofilament lost 66.0% of its elongation at break in 600 hours and was described as brittle."
          },
          {
            "label": "In a fire",
            "line": "The product gives off carbon dioxide, carbon monoxide, organic vapours and soot."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Storage",
            "line": "Store dry, cool and dust-free below 50 °C, away from heat and direct sunlight."
          },
          {
            "label": "Moulding",
            "line": "The Weerg and Protolabs sheets give no drying step. Dry the resin as the grade's own processing sheet says."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-26",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 20,
    "unreachable": 2,
    "caveats": 5,
    "note": "Read by an AI assistant on 2026-10-26 from the pages named in each entry. Unreachable as readable text: the Recythen HDPE data sheet and the Shell HDPE safety data sheet. Caveats: the LDEF value is for polyethylene with no grade named; the UV figures are for a monofilament with an antioxidant; the Weerg and Protolabs sheets name no grade beyond HDPE; no HDPE production split was read; the Argus figure is demand."
  },
  "sources": {
    "scg-h5818j": {
      "title": "SCG Chemicals grade page, H5818J general purpose HDPE for injection molding",
      "url": "https://www.scgchemicals.com/en/products-grade/h5818j",
      "kind": "datasheet",
      "license": "Manufacturer product page (cited, not reproduced)"
    },
    "scg-sds": {
      "title": "SCG Chemicals HDPE safety data sheet (applies to all HDPE grades made by Thai Polyethylene)",
      "url": "https://www.scgchemicals.com/uploads/sdsscgc-hdpeem-sds-9001-5.pdf",
      "kind": "datasheet",
      "license": "Supplier safety data sheet (cited, not reproduced)"
    },
    "weerg-pe": {
      "title": "Weerg PE1000 HDPE technical datasheet v2.1 (CNC machining)",
      "url": "https://weerg.com/hubfs/Datasheets/Datasheets%202024/ENG/EN_Polietilene.pdf",
      "kind": "datasheet",
      "license": "Supplier datasheet (cited, not reproduced)"
    },
    "protolabs-hdpe": {
      "title": "Protolabs HDPE CNC material data sheet",
      "url": "https://www.protolabs.com/media/rkzn2wud/2026-026-cnc-material-data-sheet_hdpe.pdf",
      "kind": "datasheet",
      "license": "Manufacturer datasheet (cited, not reproduced)"
    },
    "ntrs-ao": {
      "title": "Erosion rates for polymers measured on LDEF (Experiment A0114, UAH), J. Gregory, LDEF Workshop, Langley, November 1991",
      "url": "https://ntrs.nasa.gov/api/citations/19930002806/downloads/19930002806.pdf",
      "kind": "report",
      "license": "Public domain (NASA)"
    },
    "pmc-uv": {
      "title": "Fishery HDPE/UHMWPE blend monofilament UV ageing study (open access, PMC)",
      "url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12899940/",
      "kind": "paper",
      "license": "Open access (PMC); check the article licence before reuse"
    },
    "wiki-polyethylene": {
      "title": "Wikipedia, Polyethylene (chemical resistance and ageing sections)",
      "url": "https://en.wikipedia.org/wiki/Polyethylene",
      "kind": "web",
      "license": "CC BY-SA (Wikipedia)"
    },
    "nist-atomic-weights": {
      "title": "NIST Atomic Weights and Isotopic Compositions for All Elements (standard atomic weight intervals for C and H)",
      "url": "https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=C&all=all&ascii=ascii",
      "kind": "database",
      "license": "Public domain (NIST)"
    },
    "argus-pe-2024": {
      "title": "Argus, Polyethylene model update: 2024 takeaways",
      "url": "https://www.argusmedia.com/en/news-and-insights/market-opinion-and-analysis-blog/polyethylene-model-update-2024-takeaways",
      "kind": "web",
      "license": "Publisher article (cited, not reproduced)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/hdpe/"
}