{
  "spore": "profile",
  "id": "toray-m55j",
  "spore_version": "0.2",
  "family": "glass-and-composites",
  "name": "Torayca M55J high-modulus carbon fibre and #2500 epoxy composite",
  "abbreviation": "M55J",
  "role": "structural composite reinforcement",
  "category": "composites",
  "type": "carbon-fiber-reinforced",
  "summary": "Torayca M55J is a high-modulus carbon fibre from Toray. The Toray US datasheet (revision 04/22/2025) gives a fibre tensile modulus of 540 GPa and a fibre tensile strength of 4020 MPa. In a composite normalised to 60 % fibre volume and cured with #2500 epoxy, the same datasheet gives 338 GPa and 2020 MPa, while the Toray EU datasheet gives 340 GPa and 2010 MPa for its own 2500 resin system.\n",
  "best_for": "Stiff, dimensionally stable structures such as antenna reflectors and structural panels: 540 GPa fibre tensile modulus per the Toray US datasheet",
  "weakest_at": "Strength across the fibres: 37 MPa transverse tensile strength in the composite, and 0.8 % strain at failure for the fibre (Toray US datasheet)",
  "identity": {
    "formula": "Carbon fibre, >99% carbon (Toray US datasheet, Chemical Composition row), supplied as untwisted 6,000 filament tows; the composite tests use #2500 epoxy",
    "designations": [
      {
        "system": "Trade name",
        "code": "M55J",
        "note": "Torayca M55J high-modulus carbon fibre (product designation)",
        "source": "toray-m55j-us",
        "where": "Title and Product Designation table"
      }
    ],
    "source": "toray-m55j-us",
    "where": "Chemical Composition row of the Functional properties table; Product Designation table"
  },
  "tags": {
    "environments": [],
    "stresses": [
      "vacuum-and-outgassing"
    ],
    "applications": [
      "structures",
      "optics-and-cameras"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density of the M55J fibre",
      "value": 1.91,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "carbon fibre tow, 6,000 filaments",
        "temperature": "not stated"
      },
      "method": "Typical value printed in the Toray US datasheet (test method TY-030B-02); the Toray EU datasheet prints the same 1.91 g/cm3 (TY-QA-003)",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Fiber properties table, Density row, metric column",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Tensile modulus of the M55J fibre",
      "value": 540,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "carbon fibre tow, 6K",
        "unit_in_source": "78.2 Msi",
        "test": "TY-030B-01"
      },
      "method": "Value printed in the Toray US datasheet in GPa and Msi; the Toray EU datasheet prints 540 GPa (TY-QA-002)",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Fiber properties table, Tensile Modulus row, metric column",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength of the M55J fibre",
      "value": 4020,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "form": "carbon fibre tow",
        "unit_in_source": "583 Ksi",
        "test": "TY-030B-01"
      },
      "method": "Value printed in the Toray US datasheet; the Toray EU datasheet prints 4020 MPa (410 kgf/mm2, TY-QA-002)",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Fiber properties table, Tensile Strength row, metric column",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Strain at failure of the M55J fibre",
      "value": 0.8,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "form": "carbon fibre tow",
        "test": "TY-030B-01"
      },
      "method": "Value printed in the Toray US datasheet; the Toray EU datasheet prints 0.8 % elongation (TY-QA-002)",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Fiber properties table, Strain at Failure row",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Specific heat of the M55J fibre",
      "value": 0.732,
      "bound": "exact",
      "unit": "J/g·°C",
      "scope": "material",
      "conditions": {
        "form": "carbon fibre",
        "temperature": "not stated on the datasheet",
        "unit_in_source": "0.732 J/g·°C"
      },
      "method": "Value printed in the Toray US datasheet (Functional properties table). The Toray EU datasheet prints a different unit (0.17 Cal/g.°C, nominal), which is not converted here.",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Functional properties table, Specific Heat row",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of thermal expansion of the M55J fibre",
      "value": -1.1,
      "bound": "exact",
      "unit": "1x10-6/°C",
      "scope": "material",
      "conditions": {
        "form": "carbon fibre",
        "temperature": "not stated on the datasheet",
        "unit_in_source": "-1.1 x 10-6/°C"
      },
      "method": "Value printed in the Toray US datasheet (Functional properties table); the Toray EU datasheet prints the same -1.1 (10-6/°C).",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Functional properties table, CTE row",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength of M55J composite, US datasheet",
      "value": 2020,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "#2500 epoxy cured at 130 °C",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D3039",
        "unit_in_source": "293 Ksi"
      },
      "method": "Typical value printed in the Toray US datasheet. It differs from the EU datasheet value of 2010 MPa for a different cure (see the EU rows); both are kept, neither is averaged.",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Composite properties table, Tensile Strength row",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Tensile modulus of M55J composite, US datasheet",
      "value": 338,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "#2500 epoxy cured at 130 °C",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D3039",
        "unit_in_source": "49 Msi"
      },
      "method": "Typical value printed in the Toray US datasheet; the EU datasheet prints 340 GPa for its own 2500 system",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Composite properties table, Tensile Modulus row",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Tensile strain of M55J composite, US datasheet",
      "value": 0.61,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "#2500 epoxy cured at 130 °C",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D3039"
      },
      "method": "Typical value printed in the Toray US datasheet",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Composite properties table, Tensile Strain row",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Flexural strength of M55J composite, US datasheet",
      "value": 1180,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "#2500 epoxy cured at 130 °C",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D790",
        "unit_in_source": "171 Ksi"
      },
      "method": "Typical value printed in the Toray US datasheet",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Composite properties table, Flexural Strength row",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "flexural_modulus",
      "label": "Flexural modulus of M55J composite, US datasheet",
      "value": 274,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "#2500 epoxy cured at 130 °C",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D790",
        "unit_in_source": "40 Msi"
      },
      "method": "Typical value printed in the Toray US datasheet",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Composite properties table, Flexural Modulus row",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "compressive_strength",
      "label": "Compressive strength of M55J composite, US datasheet",
      "value": 890,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "#2500 epoxy cured at 130 °C",
        "fibre_volume": "60 % (normalised)",
        "test": "SACMA SRM 1R-94",
        "unit_in_source": "129 Ksi"
      },
      "method": "Typical value printed in the Toray US datasheet",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Composite properties table, Compressive Strength row",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "interlaminar_shear_strength",
      "label": "Interlaminar shear strength of M55J composite, US datasheet",
      "value": 73.2,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "#2500 epoxy cured at 130 °C",
        "fibre_volume": "60 % (normalised)",
        "test": "SACMA SRM 8R-94",
        "unit_in_source": "11 Ksi"
      },
      "method": "Typical value printed in the Toray US datasheet (ILSS row)",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Composite properties table, ILSS row",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "in_plane_shear_strength",
      "label": "In-plane shear strength of M55J composite, US datasheet",
      "value": 68,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "#2500 epoxy cured at 130 °C",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D3518",
        "unit_in_source": "10 Ksi"
      },
      "method": "Typical value printed in the Toray US datasheet",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Composite properties table, In Plain Shear Strength row",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "transverse_tensile_strength",
      "label": "Tensile strength across the fibres of M55J composite, US datasheet",
      "value": 37,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "90 degree (transverse) specimens",
        "matrix": "#2500 epoxy cured at 130 °C",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D3039",
        "unit_in_source": "5 Ksi"
      },
      "method": "Typical value printed in the Toray US datasheet (90 degree tensile strength row)",
      "status": "ground",
      "source": "toray-m55j-us",
      "where": "Composite properties table, 90º Tensile Strength row",
      "source_detail": {
        "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
        "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength of M55J composite, EU datasheet",
      "value": 2010,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "Toray 2500 resin system, cured at 120°C",
        "temperature": "room temperature (RT)",
        "fibre_volume": "60 % (normalised)",
        "unit_in_source": "2010 MPa (205 kgf/mm2)"
      },
      "method": "Nominal value printed in the Toray EU datasheet. It differs from the US datasheet value of 2020 MPa, which used #2500 epoxy at 130 °C; both are kept side by side.",
      "status": "ground",
      "source": "toray-m55j-eu",
      "where": "Composite properties table, Tensile Strength row",
      "source_detail": {
        "title": "Torayca M55J Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers Europe, commercial documentation AQ. 866-13, July 2024",
        "url": "https://toray-cfe.com/wp-content/uploads/2025/02/Torayca-M55J-Technical-Data-Sheet.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Tensile modulus of M55J composite, EU datasheet",
      "value": 340,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "Toray 2500 resin system, cured at 120°C",
        "temperature": "room temperature (RT)",
        "fibre_volume": "60 % (normalised)",
        "unit_in_source": "340 GPa (34.5 kgf/mm2 x 10^3)"
      },
      "method": "Nominal value printed in the Toray EU datasheet; the US datasheet prints 338 GPa for the #2500 epoxy system",
      "status": "ground",
      "source": "toray-m55j-eu",
      "where": "Composite properties table, Tensile Modulus row",
      "source_detail": {
        "title": "Torayca M55J Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers Europe, commercial documentation AQ. 866-13, July 2024",
        "url": "https://toray-cfe.com/wp-content/uploads/2025/02/Torayca-M55J-Technical-Data-Sheet.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "compressive_strength",
      "label": "Compressive strength of M55J composite, EU datasheet",
      "value": 880,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "Toray 2500 resin system, cured at 120°C",
        "temperature": "room temperature (RT)",
        "fibre_volume": "60 % (normalised)",
        "unit_in_source": "880 MPa (90 kgf/mm2)"
      },
      "method": "Nominal value printed in the Toray EU datasheet; the US datasheet prints 890 MPa",
      "status": "ground",
      "source": "toray-m55j-eu",
      "where": "Composite properties table, Compressive Strength row",
      "source_detail": {
        "title": "Torayca M55J Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers Europe, commercial documentation AQ. 866-13, July 2024",
        "url": "https://toray-cfe.com/wp-content/uploads/2025/02/Torayca-M55J-Technical-Data-Sheet.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "flexural_modulus",
      "label": "Flexural modulus of M55J composite, EU datasheet",
      "value": 280,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "Toray 2500 resin system, cured at 120°C",
        "temperature": "room temperature (RT)",
        "fibre_volume": "60 % (normalised)",
        "unit_in_source": "280 GPa (28.5 kgf/mm2 x 10^3)"
      },
      "method": "Nominal value printed in the Toray EU datasheet; the US datasheet prints 274 GPa",
      "status": "ground",
      "source": "toray-m55j-eu",
      "where": "Composite properties table, Flexural Modulus row",
      "source_detail": {
        "title": "Torayca M55J Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers Europe, commercial documentation AQ. 866-13, July 2024",
        "url": "https://toray-cfe.com/wp-content/uploads/2025/02/Torayca-M55J-Technical-Data-Sheet.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "interlaminar_shear_strength",
      "label": "Interlaminar shear strength of M55J composite, EU datasheet",
      "value": 70,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "Toray 2500 resin system, cured at 120°C",
        "temperature": "room temperature (RT)",
        "fibre_volume": "60 % (normalised)",
        "unit_in_source": "70 MPa (7 kgf/mm2)"
      },
      "method": "Nominal value printed in the Toray EU datasheet; the US datasheet prints 73.2 MPa",
      "status": "ground",
      "source": "toray-m55j-eu",
      "where": "Composite properties table, ILSS row",
      "source_detail": {
        "title": "Torayca M55J Carbon Fiber Data Sheet",
        "id": "Toray Carbon Fibers Europe, commercial documentation AQ. 866-13, July 2024",
        "url": "https://toray-cfe.com/wp-content/uploads/2025/02/Torayca-M55J-Technical-Data-Sheet.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "total_mass_loss",
      "label": "Total mass loss in vacuum, M55J/954-3 cyanate-ester laminate (ID GSC22345)",
      "value": 0.1,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "sample": "laminate, ID GSC22345, manufacturer HER",
        "resin": "954-3 cyanate ester",
        "test": "total mass loss in vacuum, NASA outgassing database",
        "unit_in_source": "none printed (the CSV has no unit row)"
      },
      "method": "Value read from the NASA legacy outgassing database. The CSV prints no unit row, so percent is assumed. This is not Toray #2500 epoxy and not M55J fibre alone.",
      "status": "ground",
      "source": "nasa-outgassing-db",
      "where": "Row LAMINATE M55J/954-3 CYANATE ESTER (GSC22345), column TML",
      "source_detail": {
        "title": "NASA outgassing database (legacy Outgassing_Db CSV)",
        "id": "NASA data.nasa.gov, legacy Outgassing_Db",
        "url": "https://data.nasa.gov/docs/legacy/Outgassing_Db/Outgassing_Db_rows.csv",
        "kind": "database",
        "license": "NASA open data"
      }
    },
    {
      "benchmark": "total_mass_loss",
      "label": "Total mass loss in vacuum, M55J/954-3 graphite/cyanate-ester laminate (ID GSC29125, lot P4304-5)",
      "value": 0.07,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "sample": "laminate, ID GSC29125, manufacturer HEX, lot P4304-5",
        "resin": "954-3 cyanate ester",
        "test": "total mass loss in vacuum, NASA outgassing database",
        "unit_in_source": "none printed (the CSV has no unit row)"
      },
      "method": "Value read from the NASA legacy outgassing database. The CSV prints no unit row, so percent is assumed. This is not Toray #2500 epoxy.",
      "status": "ground",
      "source": "nasa-outgassing-db",
      "where": "Row M55J/954-3 GRAPHITE/CYANATE ESTER LAMINATE (LOT P4304-5) (GSC29125), column TML",
      "source_detail": {
        "title": "NASA outgassing database (legacy Outgassing_Db CSV)",
        "id": "NASA data.nasa.gov, legacy Outgassing_Db",
        "url": "https://data.nasa.gov/docs/legacy/Outgassing_Db/Outgassing_Db_rows.csv",
        "kind": "database",
        "license": "NASA open data"
      }
    },
    {
      "benchmark": "total_mass_loss",
      "label": "Total mass loss in vacuum, M55J/954-3 graphite/cyanate-ester laminate (ID GSC29122, lot P4477-5)",
      "value": 0.13,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "sample": "laminate, ID GSC29122, manufacturer HEX, lot P4477-5",
        "resin": "954-3 cyanate ester",
        "test": "total mass loss in vacuum, NASA outgassing database",
        "unit_in_source": "none printed (the CSV has no unit row)"
      },
      "method": "Value read from the NASA legacy outgassing database. The CSV prints no unit row, so percent is assumed. This is not Toray #2500 epoxy.",
      "status": "ground",
      "source": "nasa-outgassing-db",
      "where": "Row M55J/954-3 GRAPHITE/CYANATE ESTER LAMINATE (LOT P4477-5) (GSC29122), column TML",
      "source_detail": {
        "title": "NASA outgassing database (legacy Outgassing_Db CSV)",
        "id": "NASA data.nasa.gov, legacy Outgassing_Db",
        "url": "https://data.nasa.gov/docs/legacy/Outgassing_Db/Outgassing_Db_rows.csv",
        "kind": "database",
        "license": "NASA open data"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength of M55J composite, older Toray data sheet (350 F resin)",
      "value": 1860,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "Toray semi-toughened 350 °F epoxy resin",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D-3039",
        "unit_in_source": "270 ksi"
      },
      "method": "Value printed in Toray Carbon Fibers America data sheet No. CFA-017 under the ** footnote (350 °F resin). It differs from the 2025 US datasheet value of 2020 MPa (#2500 epoxy at 130 °C); both are kept side by side.",
      "status": "ground",
      "source": "toray-m55j-cfa017",
      "where": "M55J Composite Properties ** table, Tensile Strength row, metric column",
      "source_detail": {
        "title": "Torayca M55J Data Sheet No. CFA-017 (Toray Carbon Fibers America, undated older revision, hosted by Rockwest Composites)",
        "id": "Toray Carbon Fibers America, Inc., data sheet CFA-017, M55J",
        "url": "https://sfccdev.rockwestcomposites.com/on/demandware.static/-/Sites-rwc-master-catalog/default/dw9371cfa8/downloads/M55J.pdf",
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Tensile modulus of M55J composite, older Toray data sheet (350 F resin)",
      "value": 300,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "Toray semi-toughened 350 °F epoxy resin",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D-3039",
        "unit_in_source": "43.5 Msi"
      },
      "method": "Value printed in Toray data sheet No. CFA-017 under the ** footnote. The 2025 US datasheet prints 338 GPa for the",
      "status": "ground",
      "source": "toray-m55j-cfa017",
      "where": "M55J Composite Properties ** table, Tensile Modulus row, metric column",
      "source_detail": {
        "title": "Torayca M55J Data Sheet No. CFA-017 (Toray Carbon Fibers America, undated older revision, hosted by Rockwest Composites)",
        "id": "Toray Carbon Fibers America, Inc., data sheet CFA-017, M55J",
        "url": "https://sfccdev.rockwestcomposites.com/on/demandware.static/-/Sites-rwc-master-catalog/default/dw9371cfa8/downloads/M55J.pdf",
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "compressive_modulus",
      "label": "Compressive modulus of M55J composite, older Toray data sheet (350 F resin)",
      "value": 285,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "Toray semi-toughened 350 °F epoxy resin",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D-695",
        "unit_in_source": "41.5 Msi"
      },
      "method": "Value printed in Toray data sheet No. CFA-017 under the ** footnote. No canonical property name exists for compressive modulus in spores/property-canon.yaml, so a snake_case name is used.",
      "status": "ground",
      "source": "toray-m55j-cfa017",
      "where": "M55J Composite Properties ** table, Compressive Modulus row, metric column",
      "source_detail": {
        "title": "Torayca M55J Data Sheet No. CFA-017 (Toray Carbon Fibers America, undated older revision, hosted by Rockwest Composites)",
        "id": "Toray Carbon Fibers America, Inc., data sheet CFA-017, M55J",
        "url": "https://sfccdev.rockwestcomposites.com/on/demandware.static/-/Sites-rwc-master-catalog/default/dw9371cfa8/downloads/M55J.pdf",
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "compressive_strength",
      "label": "Compressive strength of M55J composite, older Toray data sheet (350 F resin)",
      "value": 835,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "Toray semi-toughened 350 °F epoxy resin",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D-695",
        "unit_in_source": "120 ksi"
      },
      "method": "Value printed in Toray data sheet No. CFA-017 under the ** footnote. The 2025 US datasheet prints 890 MPa for the",
      "status": "ground",
      "source": "toray-m55j-cfa017",
      "where": "M55J Composite Properties ** table, Compressive Strength row, metric column",
      "source_detail": {
        "title": "Torayca M55J Data Sheet No. CFA-017 (Toray Carbon Fibers America, undated older revision, hosted by Rockwest Composites)",
        "id": "Toray Carbon Fibers America, Inc., data sheet CFA-017, M55J",
        "url": "https://sfccdev.rockwestcomposites.com/on/demandware.static/-/Sites-rwc-master-catalog/default/dw9371cfa8/downloads/M55J.pdf",
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "in_plane_shear_strength",
      "label": "In-plane shear strength of M55J composite, older Toray data sheet (350 F resin)",
      "value": 44,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "Toray semi-toughened 350 °F epoxy resin",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D-3518",
        "unit_in_source": "6.5 ksi"
      },
      "method": "Value printed in Toray data sheet No. CFA-017 under the ** footnote. The 2025 US datasheet prints 68 MPa for the",
      "status": "ground",
      "source": "toray-m55j-cfa017",
      "where": "M55J Composite Properties ** table, In-Plane Shear Strength row, metric column",
      "source_detail": {
        "title": "Torayca M55J Data Sheet No. CFA-017 (Toray Carbon Fibers America, undated older revision, hosted by Rockwest Composites)",
        "id": "Toray Carbon Fibers America, Inc., data sheet CFA-017, M55J",
        "url": "https://sfccdev.rockwestcomposites.com/on/demandware.static/-/Sites-rwc-master-catalog/default/dw9371cfa8/downloads/M55J.pdf",
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "transverse_tensile_strength",
      "label": "Tensile strength across the fibres of M55J composite, older Toray data sheet (350 F resin)",
      "value": 35,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "90 degree (transverse) specimens",
        "matrix": "Toray semi-toughened 350 °F epoxy resin",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D-3039",
        "unit_in_source": "5.0 ksi"
      },
      "method": "Value printed in Toray data sheet No. CFA-017 under the ** footnote (90 degree tensile row). The 2025 US datasheet prints 37 MPa; both are kept.",
      "status": "ground",
      "source": "toray-m55j-cfa017",
      "where": "M55J Composite Properties ** table, 90˚ Tensile Strength row, metric column",
      "source_detail": {
        "title": "Torayca M55J Data Sheet No. CFA-017 (Toray Carbon Fibers America, undated older revision, hosted by Rockwest Composites)",
        "id": "Toray Carbon Fibers America, Inc., data sheet CFA-017, M55J",
        "url": "https://sfccdev.rockwestcomposites.com/on/demandware.static/-/Sites-rwc-master-catalog/default/dw9371cfa8/downloads/M55J.pdf",
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Flexural strength of M55J composite, older Toray data sheet (250 F resin)",
      "value": 1230,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "layup": "not stated on the datasheet",
        "matrix": "Toray 250 °F epoxy resin",
        "fibre_volume": "60 % (normalised)",
        "test": "ASTM D-790",
        "unit_in_source": "180 ksi"
      },
      "method": "Value printed in Toray data sheet No. CFA-017 under the * footnote (250 °F resin). The 2025 US datasheet prints 1180 MPa for the",
      "status": "ground",
      "source": "toray-m55j-cfa017",
      "where": "M55J Composite Properties * table, Flexural Strength row, metric column",
      "source_detail": {
        "title": "Torayca M55J Data Sheet No. CFA-017 (Toray Carbon Fibers America, undated older revision, hosted by Rockwest Composites)",
        "id": "Toray Carbon Fibers America, Inc., data sheet CFA-017, M55J",
        "url": "https://sfccdev.rockwestcomposites.com/on/demandware.static/-/Sites-rwc-master-catalog/default/dw9371cfa8/downloads/M55J.pdf",
        "kind": "datasheet",
        "license": "manufacturer datasheet, values quoted for reference"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Vacuum outgassing of M55J/954-3 cyanate-ester laminates",
      "headline": "In the NASA outgassing database, three M55J laminates lost 0.07 % to 0.13 % of their mass in vacuum.",
      "effect": "The database reports total mass loss (TML) only. The three laminates use 954-3 cyanate ester resin, not the #2500 epoxy in the Toray datasheets, and no outgassing value for M55J fibre alone was found.",
      "rating": "low",
      "conditions": {
        "test": "total mass loss in vacuum, NASA outgassing database",
        "units": "no unit row in the CSV; percent assumed"
      },
      "source": "nasa-outgassing-db",
      "where": "Rows for GSC22345, GSC29125 and GSC29122, column TML"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "The safety data sheet for high-purity carbon fibres (Rave Scientific, version 4.0, dated 5 October 2022) says the substance does not meet the criteria for classification under Regulation (EC) No 1272/2008. That sheet is generic and is not for M55J.",
        "ghs": [],
        "source": "rave-cf-sds",
        "where": "Section 2.1, classification under Regulation (EC) No 1272/2008"
      },
      {
        "text": "The same sheet says dust can cause eye irritation and that inhaling dust may irritate the respiratory system.",
        "ghs": [],
        "source": "rave-cf-sds",
        "where": "Section 11 (if in eyes; if inhaled)"
      },
      {
        "text": "Neither Toray datasheet gives a hazard statement. Both refer the reader to the safety data sheet for handling and disposal.",
        "ghs": [],
        "source": "toray-m55j-us",
        "where": "Packaging section, note under the bobbin table"
      }
    ],
    "failure_risks": [
      {
        "mode": "Loading across the fibres",
        "trigger": "Tensile load applied across the fibre direction of a unidirectional laminate",
        "consequence": "The US datasheet gives 37 MPa transverse tensile strength (5 Ksi) for the composite, against 2020 MPa for the composite tensile strength with the layup not stated.",
        "severity": "moderate",
        "source": "toray-m55j-us",
        "where": "Composite properties table, 90º Tensile Strength row and Tensile Strength row"
      },
      {
        "mode": "Brittle failure at low strain",
        "trigger": "Tensile load to failure",
        "consequence": "The fibre breaks at 0.8 % strain (US datasheet), so it stretches little before failure.",
        "severity": "moderate",
        "source": "toray-m55j-us",
        "where": "Fiber properties table, Strain at Failure row"
      }
    ],
    "side_effects": [
      {
        "text": "In vacuum, three M55J laminates in the NASA database lost 0.07 % to 0.13 % of their mass (total mass loss). The database does not say which nearby surfaces are affected.",
        "affects": "Sensitive optical or thermal surfaces near the part (not tested in the database)",
        "source": "nasa-outgassing-db",
        "where": "Rows for GSC22345, GSC29125 and GSC29122, column TML"
      }
    ],
    "handling": [
      {
        "text": "Refer to the safety data sheet for handling and disposal (printed on both Toray datasheets).",
        "source": "toray-m55j-us",
        "where": "Packaging section, note under the bobbin table"
      },
      {
        "text": "Shelf life is 24 months from the month of manufacture if stored under ambient conditions.",
        "source": "toray-m55j-eu",
        "where": "Requirements section"
      },
      {
        "text": "Each bobbin is protected against dust and packed to prevent damage during transport.",
        "source": "toray-m55j-eu",
        "where": "Packaging section"
      },
      {
        "text": "Strong oxidisers and peroxides are listed as incompatible for carbon fibre in the generic high-purity carbon fibre sheet. Avoid creating or accumulating dust.",
        "source": "rave-cf-sds",
        "where": "Sections 8.2, 10.3 and 10.5"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "structures",
      "device": "Antenna reflectors, from sandwich-panel sub-reflectors to large deployable reflectors",
      "example": "Toray's space guide says reflectors demand tight dimensional tolerances for accurate operation, and its fibre table lists M55J.",
      "source": "toray-space-guide",
      "where": "Antennas and reflectors section; fibre table on page 8"
    },
    {
      "application": "optics-and-cameras",
      "device": "Structural panels, deployable booms, struts and tubes that hold cameras and antennas",
      "example": "The space guide says tight dimensional tolerance requirements enable accurate pointing and clear spacecraft communications.",
      "source": "toray-space-guide",
      "where": "Supporting equipment section, page 3"
    },
    {
      "application": "structures",
      "device": "Rigid honeycomb-sandwich antenna reflector with composite skins",
      "example": "The English abstract of the 2018 Acta Materiae Compositae Sinica study compares a reflector with M55J skins against one with T300 skins, and reports that the M55J skin reflector had smaller thermal deformation.",
      "source": "buaa-reflector-2018",
      "where": "English abstract, article page (fhclxb.buaa.edu.cn)"
    }
  ],
  "supply": [
    {
      "subject": "Carbon fibre precursor (polymer feedstock)",
      "abundance": "No crustal abundance applies: the fibre is made from a synthetic polymer precursor.",
      "producers": [],
      "critical_lists": [],
      "substitutes": [],
      "source": "wiki-carbon-fibre",
      "where": "Synthesis section"
    },
    {
      "subject": "Torayca M55J manufacturing locations",
      "abundance": "Not applicable",
      "producers": [],
      "critical_lists": [],
      "substitutes": [],
      "source": "toray-m55j-us",
      "where": "Product Notes section (US datasheet); product description (EU datasheet)"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet (Toray Carbon Fibers America, rev. 04/22/2025)",
      "type": "datasheet",
      "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
      "year": 2025
    },
    {
      "title": "Torayca M55J Carbon Fiber Data Sheet (Toray Carbon Fibers Europe, July 2024)",
      "type": "datasheet",
      "url": "https://toray-cfe.com/wp-content/uploads/2025/02/Torayca-M55J-Technical-Data-Sheet.pdf",
      "year": 2024
    },
    {
      "title": "Toray Space, Satellite and Launch Advanced Composite Materials Selector Guide",
      "type": "datasheet",
      "url": "https://www.toraytac.com/media/0d07df99-1e4b-4c8a-91f7-0fb10e9e1eea/yRI1Vg/TAC/Documents/Selector%20Guides/Toray_Space-Satellite-Launch_Advanced-Composite-Materials_Selector-Guide.pdf",
      "year": 2024
    },
    {
      "title": "NASA legacy outgassing database (Outgassing_Db rows)",
      "type": "database",
      "url": "https://data.nasa.gov/docs/legacy/Outgassing_Db/Outgassing_Db_rows.csv",
      "year": 2026
    },
    {
      "title": "Rave Scientific safety data sheet, high purity carbon fibers SDS00170CC1016 version 4.0 (generic, not M55J)",
      "type": "sds",
      "url": "https://ravescientific.com/images/pdf/SDS00170CC1016-01_Carbon_Fibre.pdf",
      "year": 2022
    },
    {
      "title": "Torayca M55J Data Sheet No. CFA-017 (Toray Carbon Fibers America, older revision with 250 F and 350 F resin composite data)",
      "type": "datasheet",
      "url": "https://sfccdev.rockwestcomposites.com/on/demandware.static/-/Sites-rwc-master-catalog/default/dw9371cfa8/downloads/M55J.pdf"
    },
    {
      "title": "Thermal distortion for honeycomb sandwich construction rigid reflector of satellite antenna",
      "type": "paper",
      "url": "https://fhclxb.buaa.edu.cn/en/article/doi/10.13801/j.cnki.fhclxb.20171020.001",
      "year": 2018
    }
  ],
  "gaps": [
    "No M55J-specific safety data sheet found. Hazard and handling lines come from a generic high-purity carbon fibre sheet (Rave Scientific), which is not for M55J.",
    "No humidity, UV, heat-ageing or chemical-resistance result for M55J fibre or M55J composite found in any source we hold.",
    "No vacuum outgassing value for M55J fibre alone or for a Toray #2500 epoxy composite found. The three NASA rows are 954-3 cyanate-ester laminates.",
    "The NASA outgassing CSV has no unit row: percent is assumed for the TML values.",
    "Production shares by country for M55J not found. Toray names only the manufacturing countries (Japan; France and Japan).",
    "Electrical resistivity of the M55J fibre (0.8 x 10-3 Ω·cm, US datasheet) is not included: the printed exponent form could not be matched to the stored value, so the property was removed rather than written with a guessed notation.",
    "Thermal conductivity not included. The US datasheet prints 1.556 J/cm·s·°C and the EU datasheet prints 0.372 Cal/cm.S.°C; neither unit is in the importer's unit table, and converting would create a number that is not printed.",
    "Specific heat on the EU datasheet is printed as 0.17 Cal/g.°C (nominal). It is not converted and not used; the US value (0.732 J/g·°C) is used.",
    "Compressive strength, compressive modulus, in-plane shear and transverse tensile strength have no canonical name in spores/property-canon.yaml; snake_case names are used.",
    "The older Toray data sheet CFA-017 is hosted on a Rockwest Composites development subdomain (a reseller), and it has no revision date printed. Its values are used only with the resin named in each row. Toray's own copy of this revision was not found.",
    "The BUAA 2018 reflector study is read from its English abstract only. The full text was not reachable, so no numbers from the study are used; the use entry only states the abstract's comparison.",
    "Ceramic-matrix M55J composites (SiC matrix, JECS 2024; SiC/Si3N4 matrix, Ceramics International 2025) were found but are not polymer-matrix data, so they are not used.",
    "A 2019 Materials paper with an M55J fibre table (MDPI, doi 10.3390/ma12040579) was blocked on fetch (HTTP 403), so it is not used.",
    "Interlaminar shear strength (ILSS) in the older CFA-017 sheet is printed only in ksi and kgf/mm2, so it is not added; the 2025 US and EU rows stay as they were.",
    "The two composite datasheets disagree: 2020 MPa and 338 GPa (US, cured at 130 °C) against 2010 MPa and 340 GPa (EU, Toray 2500 at 120 °C). Both are kept side by side and neither is averaged.",
    "Laminate layup, laminate density and fibre volume beyond the 60 % normalisation are not stated on either datasheet.",
    "Atomic oxygen, UV and thermal-cycling numbers for M55J not found.",
    "No space flight or thermal-vacuum result for M55J found. A search snippet described a 1.2 m spaceborne reflector study with M55J skins; its journal page blocked automated access, so it is not used.",
    "The Vanguard antenna use of M55J with cyanate-ester prepreg came from a search snippet only and was not read in a fetched page, so it is not used.",
    "Critical-mineral status not checked. The fibre is made from a synthetic polymer precursor, not a mineral ore."
  ],
  "story": {
    "why": "Torayca M55J is a high-modulus carbon fibre that Toray sells for structures that must hold their shape. The US datasheet gives a fibre tensile modulus of 540 GPa and a fibre density of 1.91 g/cm3. Toray's EU datasheet says the fibre meets dimensional stability requirements of demanding aerospace applications. The composite values are lower than the fibre values because they include the resin and the test conditions.",
    "uses": [
      {
        "where": "Antenna reflectors",
        "line": "Toray's space guide says reflectors demand tight dimensional tolerances for accurate operation, and its fibre table lists the M55J fibre."
      },
      {
        "where": "Structures that hold cameras and antennas",
        "line": "The space guide says structural panels, deployable booms, struts and tubes hold cameras and antennas, and that tight dimensional tolerance requirements enable accurate pointing."
      }
    ],
    "can_do": [
      {
        "label": "Stiffness",
        "line": "The fibre has a tensile modulus of 540 GPa (US datasheet). The composite gives 338 GPa at 60 % fibre volume with #2500 epoxy (US datasheet), and 340 GPa for the Toray 2500 system (EU datasheet).",
        "benchmark": "elastic_modulus",
        "scope": "material"
      },
      {
        "label": "Strength",
        "line": "The fibre tensile strength is 4020 MPa (US datasheet). The composite tensile strength is 2020 MPa in the US datasheet and 2010 MPa in the EU datasheet. The two datasheets cite different cure temperatures for the 2500 resin, 130 °C and 120 °C.",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material"
      },
      {
        "label": "Thermal expansion",
        "line": "The fibre has a coefficient of thermal expansion of -1.1 ×10⁻⁶/°C (US datasheet, Functional properties). A negative value means the fibre shrinks slightly as it warms.",
        "benchmark": "cte",
        "scope": "material",
        "value": "-1.1 ×10⁻⁶/°C"
      }
    ],
    "compare": "Within the M55J data, the fibre is far stiffer than the composite is strong across the fibres: 540 GPa fibre modulus against 37 MPa transverse tensile strength. The two Toray datasheets agree on fibre density and modulus. They differ on composite strength (2020 MPa against 2010 MPa) and on the cure temperature of the 2500 resin (130 °C against 120 °C), so both values are kept. The datasheets give no other carbon fibre to compare against directly.",
    "compare_rows": [
      {
        "label": "Tensile strength",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material"
      },
      {
        "label": "Tensile modulus",
        "benchmark": "elastic_modulus",
        "scope": "material"
      },
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      }
    ],
    "handling": [
      "Keep the fibre dry and closed, away from strong oxidisers and peroxides (generic carbon fibre sheet).",
      "Avoid creating or accumulating dust. Use ventilation when you cut, sand or machine composites made with it.",
      "Check the safety data sheet for the exact product before handling or disposal, as both Toray datasheets advise.",
      "Keep bobbins sealed and used within the 24-month shelf life from manufacture (Toray EU datasheet)."
    ],
    "good_for": [
      "Stiff structures that must keep their shape: 540 GPa fibre tensile modulus (US datasheet), and a space guide that cites reflectors and booms.",
      "Low thermal expansion: -1.1 ×10⁻⁶/°C fibre coefficient of thermal expansion (US datasheet)."
    ],
    "watch_out": [
      "Transverse strength: 37 MPa across the fibres in the composite (US datasheet).",
      "Low strain at failure: 0.8 % for the fibre (US datasheet).",
      "Composite numbers depend on the resin and cure. The two Toray datasheets cite 130 °C and 120 °C for the 2500 system, and the vacuum data come from other resins (954-3 cyanate ester)."
    ],
    "verdict": "Torayca M55J is a stiff fibre that Toray presents for dimensionally stable structures and reflectors, but it is weak across the fibres and its composite numbers depend on the resin and cure. Check the layup and the resin before you use the 2020 MPa figure.",
    "recipe": {
      "line": "Torayca M55J is a carbon fibre of more than 99% carbon, supplied as untwisted 6,000 filament tows with a sizing. Wikipedia describes the general route for carbon fibre as spinning a precursor polymer, oxidising it in air and carbonising it. Toray does not print its precursor or process on the datasheets.",
      "parts": [
        {
          "name": "Carbon",
          "role": "Makes up the fibre. The datasheet does not describe the crystal structure."
        },
        {
          "name": "Sizing",
          "role": "A coating on the tow. The datasheet gives its type and amount but not its chemistry."
        },
        {
          "name": "Sodium and potassium",
          "role": "Impurities. The datasheet reports only the combined total."
        },
        {
          "name": "Toray #2500 epoxy (test matrix)",
          "role": "Holds the fibres in place and carries load between them. The datasheets name only the resin system and its cure temperature (130 °C in the US datasheet, 120°C in the EU datasheet)."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "No safety data sheet for M55J itself was found. The hazard lines below come from a generic high-purity carbon fibre sheet, which says the substance does not meet the criteria for classification under Regulation (EC) No 1272/2008.",
        "points": [
          {
            "label": "The fibre",
            "line": "The generic sheet (version 4.0, dated 5 October 2022) gives no hazard classification for the carbon fibre."
          },
          {
            "label": "Dust",
            "line": "Cutting, sanding or machining makes dust. The sheet says dust can cause eye irritation and that inhaling dust may irritate the respiratory system."
          }
        ],
        "level": 0,
        "verdict": "No hazard classification for M55J found"
      },
      {
        "title": "If it fails",
        "lead": "The weak direction is across the fibres. The datasheet gives a transverse number far below the composite tensile strength.",
        "points": [
          {
            "label": "Loading across the fibres",
            "line": "The US datasheet gives 37 MPa tensile strength across the fibres (90 degree row, 5 Ksi), against 2020 MPa for the composite tensile strength with the layup not stated."
          },
          {
            "label": "Strain at failure",
            "line": "The fibre breaks at 0.8 % strain (US datasheet), so there is little stretch before failure."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Storage",
            "line": "Shelf life is 24 months from the month of manufacture when stored under ambient conditions (Toray EU datasheet)."
          },
          {
            "label": "Incompatibility",
            "line": "Strong oxidisers and peroxides are listed as incompatible for carbon fibre in the generic sheet."
          }
        ]
      }
    ]
  },
  "updated": "2026-11-01",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 30,
    "unreachable": 1,
    "caveats": 4,
    "note": "Written 2026-11-01 from the Toray US and EU datasheets, the Toray space selector guide, the NASA outgassing database rows, a generic high-purity carbon fibre SDS and Wikipedia. Deepened 2026-11-02 with the older Toray CFA-017 data sheet (350 F and 250 F resin composite rows), a 2018 BUAA reflector abstract (use entry only) and the existing sources. Caveats: the two composite datasheets disagree on strength, modulus and cure temperature (both kept); the outgassing rows are other resin systems; the hazard data are generic carbon fibre, not M55J; thermal conductivity is left out because its printed unit is not in the unit table."
  },
  "sources": {
    "toray-m55j-us": {
      "title": "Torayca M55J High Modulus Carbon Fiber Data Sheet",
      "id": "Toray Carbon Fibers America, TORAYCA M55J Rev. 04/22/2025",
      "url": "https://www.toraycma.com/wp-content/uploads/M55J-Data-Sheet.pdf",
      "year": 2025,
      "kind": "datasheet",
      "license": "manufacturer datasheet, values quoted for reference"
    },
    "toray-m55j-eu": {
      "title": "Torayca M55J Carbon Fiber Data Sheet",
      "id": "Toray Carbon Fibers Europe, commercial documentation AQ. 866-13, July 2024",
      "url": "https://toray-cfe.com/wp-content/uploads/2025/02/Torayca-M55J-Technical-Data-Sheet.pdf",
      "year": 2024,
      "kind": "datasheet",
      "license": "manufacturer datasheet, values quoted for reference"
    },
    "toray-space-guide": {
      "title": "Toray Space, Satellite and Launch Advanced Composite Materials Selector Guide",
      "id": "Toray Advanced Composite Materials, Space Product Overview (copyright 2024 Toray Industries)",
      "url": "https://www.toraytac.com/media/0d07df99-1e4b-4c8a-91f7-0fb10e9e1eea/yRI1Vg/TAC/Documents/Selector%20Guides/Toray_Space-Satellite-Launch_Advanced-Composite-Materials_Selector-Guide.pdf",
      "year": 2024,
      "kind": "datasheet",
      "license": "manufacturer selector guide, quoted for reference"
    },
    "nasa-outgassing-db": {
      "title": "NASA outgassing database (legacy Outgassing_Db CSV)",
      "id": "NASA data.nasa.gov, legacy Outgassing_Db",
      "url": "https://data.nasa.gov/docs/legacy/Outgassing_Db/Outgassing_Db_rows.csv",
      "kind": "database",
      "license": "NASA open data"
    },
    "rave-cf-sds": {
      "title": "Safety data sheet: High purity carbon fibers in carbon fiber threads, document SDS00170CC1016 version 4.0",
      "id": "Rave Scientific, Regulation (EC) No 1907/2006 Art. 31, dated October 5th 2022",
      "url": "https://ravescientific.com/images/pdf/SDS00170CC1016-01_Carbon_Fibre.pdf",
      "year": 2022,
      "kind": "datasheet",
      "license": "supplier safety data sheet, quoted for reference"
    },
    "wiki-carbon-fibre": {
      "title": "Carbon fiber (Wikipedia article, Carbon fibers)",
      "id": "Wikipedia, article Carbon fibers",
      "url": "https://en.wikipedia.org/wiki/Carbon_fibers",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0"
    },
    "toray-m55j-cfa017": {
      "title": "Torayca M55J Data Sheet No. CFA-017 (Toray Carbon Fibers America, undated older revision, hosted by Rockwest Composites)",
      "id": "Toray Carbon Fibers America, Inc., data sheet CFA-017, M55J",
      "url": "https://sfccdev.rockwestcomposites.com/on/demandware.static/-/Sites-rwc-master-catalog/default/dw9371cfa8/downloads/M55J.pdf",
      "kind": "datasheet",
      "license": "manufacturer datasheet, values quoted for reference"
    },
    "buaa-reflector-2018": {
      "title": "Thermal distortion for honeycomb sandwich construction rigid reflector of satellite antenna (Acta Materiae Compositae Sinica)",
      "id": "ZHOU Tao, YE Zhoujun, SHI Yaohui, LIANG Yanmin, HAO Xufeng, QIAN Yuan; Acta Materiae Compositae Sinica 35(8), 2065-2073, 2018; DOI 10.13801/j.cnki.fhclxb.20171020.001",
      "url": "https://fhclxb.buaa.edu.cn/en/article/doi/10.13801/j.cnki.fhclxb.20171020.001",
      "year": 2018,
      "kind": "paper",
      "license": "journal abstract, quoted for reference"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/toray-m55j/"
}