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.
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'
  source: toray-m55j-us
  where: Chemical Composition row of the Functional properties table; Product Designation table
  impurities: Na + K below 50 ppm (Toray US datasheet, Chemical Composition row)
  sizing: Sizing type B, sizing 50B at 1.0 % (Toray US datasheet, Product Designation table)
  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
tags:
  environments: []
  stresses:
    - vacuum-and-outgassing
  applications:
    - structures
    - optics-and-cameras
properties:
  - benchmark: density
    label: Density of the M55J fibre
    value: 1.91
    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
  - benchmark: elastic_modulus
    label: Tensile modulus of the M55J fibre
    value: 540
    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
  - benchmark: ultimate_tensile_strength
    label: Tensile strength of the M55J fibre
    value: 4020
    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
  - benchmark: elongation
    label: Strain at failure of the M55J fibre
    value: 0.8
    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
  - benchmark: specific_heat
    label: Specific heat of the M55J fibre
    value: 0.732
    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
  - benchmark: cte
    label: Coefficient of thermal expansion of the M55J fibre
    value: -1.1
    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
  - benchmark: ultimate_tensile_strength
    label: Tensile strength of M55J composite, US datasheet
    value: 2020
    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
  - benchmark: elastic_modulus
    label: Tensile modulus of M55J composite, US datasheet
    value: 338
    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
  - benchmark: elongation
    label: Tensile strain of M55J composite, US datasheet
    value: 0.61
    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
  - benchmark: flexural_strength
    label: Flexural strength of M55J composite, US datasheet
    value: 1180
    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
  - benchmark: flexural_modulus
    label: Flexural modulus of M55J composite, US datasheet
    value: 274
    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
  - benchmark: compressive_strength
    label: Compressive strength of M55J composite, US datasheet
    value: 890
    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
  - benchmark: interlaminar_shear_strength
    label: Interlaminar shear strength of M55J composite, US datasheet
    value: 73.2
    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
  - benchmark: in_plane_shear_strength
    label: In-plane shear strength of M55J composite, US datasheet
    value: 68
    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
  - benchmark: transverse_tensile_strength
    label: Tensile strength across the fibres of M55J composite, US datasheet
    value: 37
    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
  - benchmark: ultimate_tensile_strength
    label: Tensile strength of M55J composite, EU datasheet
    value: 2010
    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
  - benchmark: elastic_modulus
    label: Tensile modulus of M55J composite, EU datasheet
    value: 340
    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
  - benchmark: compressive_strength
    label: Compressive strength of M55J composite, EU datasheet
    value: 880
    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
  - benchmark: flexural_modulus
    label: Flexural modulus of M55J composite, EU datasheet
    value: 280
    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
  - benchmark: interlaminar_shear_strength
    label: Interlaminar shear strength of M55J composite, EU datasheet
    value: 70
    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
  - benchmark: total_mass_loss
    label: Total mass loss in vacuum, M55J/954-3 cyanate-ester laminate (ID GSC22345)
    value: 0.1
    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
  - 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
    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
  - 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
    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
  - benchmark: ultimate_tensile_strength
    label: Tensile strength of M55J composite, older Toray data sheet (350 F resin)
    value: 1860
    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
  - benchmark: elastic_modulus
    label: Tensile modulus of M55J composite, older Toray data sheet (350 F resin)
    value: 300
    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
  - benchmark: compressive_modulus
    label: Compressive modulus of M55J composite, older Toray data sheet (350 F resin)
    value: 285
    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
  - benchmark: compressive_strength
    label: Compressive strength of M55J composite, older Toray data sheet (350 F resin)
    value: 835
    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
  - benchmark: in_plane_shear_strength
    label: In-plane shear strength of M55J composite, older Toray data sheet (350 F resin)
    value: 44
    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
  - benchmark: transverse_tensile_strength
    label: Tensile strength across the fibres of M55J composite, older Toray data sheet (350 F resin)
    value: 35
    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
  - benchmark: flexural_strength
    label: Flexural strength of M55J composite, older Toray data sheet (250 F resin)
    value: 1230
    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
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
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: []
    manufacture: Toray does not print its precursor on the datasheets. Wikipedia lists polyacrylonitrile (PAN), rayon and petroleum pitch as precursors for carbon filaments.
    source: wiki-carbon-fibre
    where: Synthesis section
  - subject: Torayca M55J manufacturing locations
    abundance: Not applicable
    producers: []
    manufacture: Torayca M55J is manufactured in Japan (US datasheet) and in France and Japan (EU datasheet). No production shares by country were read.
    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.
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
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.'
story:
  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
        share: '>99% by mass (Toray US datasheet, Chemical Composition row)'
        role: Makes up the fibre. The datasheet does not describe the crystal structure.
      - name: Sizing
        share: 1.0 % (sizing type 50B, Toray US datasheet)
        role: A coating on the tow. The datasheet gives its type and amount but not its chemistry.
      - name: Sodium and potassium
        share: below 50 ppm (Na + K, Toray US datasheet)
        role: Impurities. The datasheet reports only the combined total.
      - name: 'Toray #2500 epoxy (test matrix)'
        share: Not stated. The normalised composite values assume 60 % fibre volume.
        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
      level: 0
      verdict: No hazard classification for M55J found
      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.
    - 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.
  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
      benchmark: elastic_modulus
      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).'
    - label: Strength
      benchmark: ultimate_tensile_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.
    - label: Thermal expansion
      benchmark: cte
      value: '-1.1 ×10⁻⁶/°C'
      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.
  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
    - label: Tensile modulus
      benchmark: elastic_modulus
    - label: Density
      benchmark: density
  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.