spore: profile
id: fepm-aflas
spore_version: 0.2
family: fluoroelastomers
name: Tetrafluoroethylene-propylene rubber (FEPM, Aflas)
abbreviation: FEPM
role: Fluoroelastomer for seals and wire insulation in hot water, steam and base service
category: seals-adhesives
type: elastomers-and-o-rings
summary: |
  FEPM is an alternating copolymer of tetrafluoroethylene and propylene, sold by AGC under the trade name AFLAS (AGC technical brochure). AGC gives a continuous service temperature of 200 degC and a maximum peak exposure of 250 degC for AFLAS. Kalsi Engineering says FEPM resists hot water, steam, bases and brine better than FKM, but has poor compression set when used in rotary seals. ERIKS gives a tensile strength of 16 MPa and an elongation at break of 240 percent for its 75 IRHD O-ring compound 223002 (ISO 37).
best_for: Seals and insulation that must resist hot water, steam and bases at up to 200 degC, where FKM is weaker
weakest_at: 'Compression set: AGC gives 46 percent for conventional AFLAS 150P against 30 percent for an FKM terpolymer in the same table, and Kalsi calls FEPM compression set poor for rotary seals'
identity:
  formula: Alternating copolymer of tetrafluoroethylene and propylene, -(CF2-CF2)p-(CH2-CH(CH3))q-, with a TFE/P composition ratio of 55/45 as printed by AGC
  source: agc-intro
  where: AGC intro, Polymer Structure panel; AGC technical brochure, Heat Resistance section (composition ratio TFE/P=55/45)
  designations:
    - system: ASTM
      code: FEPM
      source: kalsi-b4
      where: Section 1, ASTM designation field
    - system: Trade name
      code: Aflas
      source: kalsi-b4
      where: Section 1, Trade names field
tags:
  environments: []
  stresses:
    - extreme-heat
    - extreme-cold
  applications:
    - mechanisms
    - electronics-and-chips
properties:
  - benchmark: density
    label: Density (ERIKS 223002, 75 IRHD compound)
    value: 1640
    unit: kg/m-3
    scope: material
    conditions:
      compound: ERIKS Aflas 75-compound 223002, peroxide cured, black
      test: ISO 2781
    method: Technical data sheet value, printed in kg/m-3
    status: ground
    source: eriks-aflas75
    where: Section 3, Physical Properties, Density row
  - benchmark: hardness
    label: Hardness (ERIKS 223002, 75 IRHD compound)
    value: 75
    unit: IRHD
    scope: material
    conditions:
      test: ISO 7619
      tolerance: printed as plus or minus 5
      compound: 223002
    method: Technical data sheet value
    status: ground
    source: eriks-aflas75
    where: Section 3, Physical Properties, Hardness row
  - benchmark: ultimate_tensile_strength
    label: Tensile strength at break (ERIKS 223002)
    value: 16
    unit: MPa
    scope: material
    conditions:
      test: ISO 37
      compound: 223002
    method: Technical data sheet value
    status: ground
    source: eriks-aflas75
    where: Section 3, Physical Properties, Tensile Strength at break row
  - benchmark: elongation
    label: Elongation at break (ERIKS 223002)
    value: 240
    unit: '%'
    scope: material
    conditions:
      test: ISO 37
      compound: 223002
    method: Technical data sheet value
    status: ground
    source: eriks-aflas75
    where: Section 3, Physical Properties, Elongation at break row
  - benchmark: ultimate_tensile_strength
    label: Tensile strength (AFLAS 150P, AGC standard formulation)
    value: 17
    unit: MPa
    scope: material
    conditions:
      grade: AFLAS 150P
      formulation: Polymer 100, MT carbon N990 30 phr, TAIC 5 phr, peroxide A 1 phr, sodium stearate 1 phr
      cure: 170 degC x 20 min press cure, 200 degC x 4 h post cure
    method: AGC standard formulation test result, not a commercial compound
    status: ground
    source: agc-tech
    where: Section 4, Standard Formulations and Properties table, 150P column
  - benchmark: ultimate_tensile_strength
    label: Tensile strength (AFLAS 400E, AGC standard formulation)
    value: 11
    unit: MPa
    scope: material
    conditions:
      grade: AFLAS 400E
      formulation: Polymer 100, MT carbon N990 30 phr, TAIC 5 phr, peroxide A 1.5 phr, calcium stearate 1 phr, processing aid 1 phr
      cure: 160 degC x 10 min press cure, 200 degC x 4 h post cure
    method: AGC standard formulation test result, not a commercial compound
    status: ground
    source: agc-tech
    where: Section 4, Standard Formulations and Properties table, 400E column
  - benchmark: ultimate_tensile_strength
    label: Tensile strength (AFLAS 600X, AGC standard formulation)
    value: 23
    unit: MPa
    scope: material
    conditions:
      grade: AFLAS 600X
      formulation: Polymer 100, MT carbon N990 30 phr, TAIC 3 phr, peroxide A 1 phr, calcium stearate 1 phr
      cure: 160 degC x 10 min press cure, 200 degC x 4 h post cure
    method: AGC standard formulation test result, not a commercial compound
    status: ground
    source: agc-tech
    where: Section 4, Standard Formulations and Properties table, 600X column
  - benchmark: elongation
    label: Elongation at break (AFLAS 400E, AGC standard formulation)
    value: 460
    unit: '%'
    scope: material
    conditions:
      grade: AFLAS 400E
      cure: 160 degC x 10 min press cure, 200 degC x 4 h post cure
    method: AGC standard formulation test result
    status: ground
    source: agc-tech
    where: Section 4, Standard Formulations and Properties table, 400E column, Tensile Elongation row
  - benchmark: elongation
    label: Elongation at break (AFLAS 600X, AGC standard formulation)
    value: 220
    unit: '%'
    scope: material
    conditions:
      grade: AFLAS 600X
      cure: 160 degC x 10 min press cure, 200 degC x 4 h post cure
    method: AGC standard formulation test result
    status: ground
    source: agc-tech
    where: Section 4, Standard Formulations and Properties table, 600X column, Tensile Elongation row
  - benchmark: hardness
    label: Hardness (AFLAS 400E, AGC standard formulation)
    value: 72
    unit: Shore A
    scope: material
    conditions:
      grade: AFLAS 400E
      cure: 160 degC x 10 min press cure, 200 degC x 4 h post cure
    method: AGC standard formulation test result
    status: ground
    source: agc-tech
    where: Section 4, Standard Formulations and Properties table, 400E column, Hardness row
  - benchmark: hardness
    label: Hardness (AFLAS 600X, AGC standard formulation)
    value: 70
    unit: Shore A
    scope: material
    conditions:
      grade: AFLAS 600X
      cure: 160 degC x 10 min press cure, 200 degC x 4 h post cure
    method: AGC standard formulation test result
    status: ground
    source: agc-tech
    where: Section 4, Standard Formulations and Properties table, 600X column, Hardness row
  - benchmark: max_service_temp
    label: Continuous service temperature (AFLAS, AGC)
    value: 200
    unit: degC
    scope: material
    conditions:
      basis: continuous service; AGC also gives a maximum peak exposure of 250 degC
    method: Statement by the manufacturer
    status: ground
    source: agc-tech
    where: Introduction (first pages), first paragraph
  - benchmark: max_service_temp
    label: Typical upper limit of quoted FEPM range (Kalsi)
    value: 232
    unit: degC
    scope: material
    conditions:
      basis: Kalsi prints the typically quoted range as -35 to 450 degF (-37 to 232 degC)
    method: Typical quoted range in Kalsi Seals Handbook
    status: ground
    source: kalsi-b4
    where: Section 1, General material description, first paragraph
  - benchmark: min_service_temp
    label: Temperature resistance lower limit (ERIKS 223002)
    value: -5
    unit: degC
    scope: material
    conditions:
      compound: 223002
      basis: ERIKS prints the range as -5 to +200 degC
    method: Technical data sheet statement
    status: ground
    source: eriks-aflas75
    where: Section 4, Temperature Resistance
  - benchmark: min_service_temp
    label: Typical lower limit of quoted FEPM range (Kalsi)
    value: -37
    unit: degC
    scope: material
    conditions:
      basis: Kalsi prints the typically quoted range as -35 to 450 degF (-37 to 232 degC)
    method: Typical quoted range in Kalsi Seals Handbook
    status: ground
    source: kalsi-b4
    where: Section 1, General material description, first paragraph
  - benchmark: min_service_temp
    label: Brittle point (Kalsi)
    value: -43
    unit: degC
    scope: material
    conditions:
      basis: Kalsi prints the brittle point as -45 degF (-43 degC)
    method: Brittle point stated in Kalsi Seals Handbook
    status: ground
    source: kalsi-b4
    where: Section 1, General material description, first paragraph
  - benchmark: low_temperature_tr10
    label: Low temperature resistance, TR10 (ERIKS 223002)
    value: 2
    unit: degC
    scope: material
    conditions:
      compound: 223002
      test: TR10
    method: Technical data sheet value
    status: ground
    source: eriks-aflas75
    where: Section 4, Temperature Resistance, TR10 row
  - benchmark: glass_transition_temperature
    label: Glass transition point (AFLAS 150P)
    value: -3
    unit: degC
    scope: material
    conditions:
      grade: AFLAS 150P
      basis: grade table, Glass Transition Point row
    method: AGC grade table value
    status: ground
    source: agc-tech
    where: Section 2, Grade range table, Glass Transition Point row, 150P column
  - benchmark: glass_transition_temperature
    label: Glass transition point (AFLAS 400E)
    value: -3
    unit: degC
    scope: material
    conditions:
      grade: AFLAS 400E
      basis: grade table, Glass Transition Point row
    method: AGC grade table value
    status: ground
    source: agc-tech
    where: Section 2, Grade range table, Glass Transition Point row, 400E column
  - benchmark: glass_transition_temperature
    label: Glass transition point (AFLAS 600X)
    value: -3
    unit: degC
    scope: material
    conditions:
      grade: AFLAS 600X
      basis: grade table, Glass Transition Point row
    method: AGC grade table value
    status: ground
    source: agc-tech
    where: Section 2, Grade range table, Glass Transition Point row, 600X column
  - benchmark: specific_gravity
    label: Specific gravity (AFLAS 400E)
    value: 1.55
    unit: '-'
    scope: material
    conditions:
      grade: AFLAS 400E
      basis: grade table, printed without unit; AGC physical table prints 1.6 for 400E compound (see gaps)
    method: AGC grade table value
    status: ground
    source: agc-intro
    where: Grade table, Specific Gravity row, 400E and 600X columns
  - benchmark: electrical_resistivity
    label: Volume resistivity (AFLAS 400E)
    value: 30000000000000000
    unit: Ω.cm
    scope: material
    conditions:
      grade: AFLAS 400E compound
      cure: 170 degC x 10 min press, 220 degC x 4 h post cure
    method: AGC physical and electrical performance table, printed as 3 x 10^16
    status: ground
    source: agc-intro
    where: 'AFLAS 400E: Physical and Electrical Performance table, Volume Resistivity row'
  - benchmark: dielectric_constant
    label: Dielectric constant at 1 kHz (AFLAS 400E)
    value: 2.8
    unit: '-'
    scope: material
    conditions:
      frequency: 1 kHz
      grade: AFLAS 400E compound
    method: AGC physical and electrical performance table
    status: ground
    source: agc-intro
    where: 'AFLAS 400E: Physical and Electrical Performance table, Dielectric Constant row'
  - benchmark: dielectric_strength
    label: Dielectric breakdown (AFLAS 400E)
    value: 23
    unit: kV/mm
    scope: material
    conditions:
      grade: AFLAS 400E compound
    method: AGC physical and electrical performance table
    status: ground
    source: agc-intro
    where: 'AFLAS 400E: Physical and Electrical Performance table, Dielectric Breakdown row'
  - benchmark: dissipation_factor
    label: Dielectric loss tangent at 1 kHz (AFLAS 400E)
    value: 0.03
    unit: '-'
    scope: material
    conditions:
      frequency: 1 kHz
      grade: AFLAS 400E compound
    method: AGC physical and electrical performance table
    status: ground
    source: agc-intro
    where: 'AFLAS 400E: Physical and Electrical Performance table, Dielectric Loss Tangent row'
  - benchmark: compression_set
    label: Compression set (conventional AFLAS 150P)
    value: 46
    unit: '%'
    scope: material
    conditions:
      cure: 170 degC x 10 min press, 220 degC x 4 h post cure
      test_condition: 200 degC and 25 percent compression, as printed beside the AGC 600X compression chart
      time: not printed in the table row
    method: AGC physical table, compared with an FKM terpolymer in the same row
    status: ground
    source: agc-intro
    where: 'AFLAS 600X: Physical and Electrical Performance table, Compression Set row, 150P column'
  - benchmark: compression_set
    label: Compression set (AFLAS 600X compound A)
    value: 29
    unit: '%'
    scope: material
    conditions:
      cure: 170 degC x 10 min press, 220 degC x 4 h post cure
      test_condition: 200 degC and 25 percent compression, as printed beside the AGC 600X compression chart
      compound: 600X compound A
    method: AGC physical table, same row as the 150P value
    status: ground
    source: agc-intro
    where: 'AFLAS 600X: Physical and Electrical Performance table, Compression Set row, compound A column'
  - benchmark: fluorine_content
    label: Fluorine content (AFLAS 150P)
    value: 57
    unit: '%'
    scope: material
    conditions:
      grade: AFLAS 150P
    method: AGC grade table value
    status: ground
    source: agc-tech
    where: Section 2, Grade range table, Fluorine Content row, 150P column
corrosion:
  - environment: Hot air, 200 degC, 70 h
    headline: Heat ageing for 70 h at 200 degC changes hardness and strength only slightly.
    effect: 'ERIKS 223002 after 70 h at 200 degC (ISO 188): hardness +2 points, tensile strength -10 percent, elongation at break -15 percent.'
    rating: low
    conditions:
      time: 70 h
      temperature: 200 degC
      standard: ISO 188
    source: eriks-aflas75
    where: Section 3, Heat Ageing 70h/200 degC rows
  - environment: Steam, 180 degC, 70 h
    headline: Steam at 180 degC cuts tensile strength by 18 percent in 70 h, more than hot-air ageing does.
    effect: 'ERIKS 223002 after 70 h at 180 degC steam (ISO 1817): hardness -5 points, tensile strength -18 percent, elongation at break -22 percent, volume +6.5 percent.'
    rating: moderate
    conditions:
      time: 70 h
      temperature: 180 degC
      standard: ISO 1817
    source: eriks-aflas75
    where: Section 3, Steam Resistance 70h/180 degC rows
  - environment: Steam, 170 degC, 720 h (AFLAS 600X)
    headline: AFLAS 600X keeps most of its strength after 720 h in 170 degC steam.
    effect: After 720 h at 170 degC steam, AFLAS 600X hardness changed by -1 point, elongation by -7 percent, tensile strength by -7 percent, and volume by 2 percent (rating A).
    rating: low
    conditions:
      time: 720 h
      temperature: 170 degC
    source: agc-intro
    where: 'AFLAS 600X: Steam Resistance table, 170 degC Steam Resistance, 720 hours'
  - environment: Hot water, 40 and 80 degC, 720 h (AFLAS 600X)
    headline: Hot water swells AFLAS 600X by less than half a percent in 720 h.
    effect: 'AFLAS 600X volume change after 720 h: 0.3 percent at 40 degC and 0.4 percent at 80 degC (both rating A).'
    rating: low
    conditions:
      time: 720 h
      temperature: 40 degC and 80 degC
    source: agc-intro
    where: 'AFLAS 600X: Steam and Hot Water resistance table, 720 hours'
  - environment: Sodium hydroxide 48 percent, 70 degC, 720 h (AFLAS 600X)
    headline: Strong caustic soda has little effect on AFLAS 600X.
    effect: AFLAS 600X volume change 0.4 percent after 720 h at 70 degC in 48 percent NaOH (rating A).
    rating: low
    conditions:
      time: 720 h
      temperature: 70 degC
    source: agc-intro
    where: 'AFLAS 600X: Chemical Resistance table, NaOH (48%) row'
  - environment: Aqueous ammonia 28 percent, 70 degC, 720 h (AFLAS 600X)
    headline: Aqueous ammonia swells AFLAS 600X by under 3 percent in 720 h.
    effect: AFLAS 600X volume change 2.7 percent after 720 h at 70 degC in 28 percent ammonia (rating A).
    rating: low
    conditions:
      time: 720 h
      temperature: 70 degC
    source: agc-intro
    where: 'AFLAS 600X: Chemical Resistance table, Aq. Ammonium (28%) row'
  - environment: Hydrochloric acid 20 percent, 70 degC, 720 h (AFLAS 600X)
    headline: Hydrochloric acid at 20 percent swells AFLAS 600X by 3.1 percent in 720 h.
    effect: AFLAS 600X volume change 1.2 percent after 168 h and 3.1 percent after 720 h at 70 degC in 20 percent HCl (rating A).
    rating: low
    conditions:
      time: 720 h
      temperature: 70 degC
    source: agc-intro
    where: 'AFLAS 600X: Chemical Resistance table, HCl (20%) row'
  - environment: ASTM Fuel C, acetone, MEK and related solvents
    headline: FEPM is poor in fuel C, acetone and MEK, but good in oil and water.
    effect: ERIKS rates ASTM Fuel C, acetone and MEK as unsatisfactory, MTBE as fair, and ASTM oil No. 3, crude oil, kerosine, water and steam at 200 degC as very good (qualitative table).
    rating: severe
    conditions:
      basis: qualitative table rating, no test time given
    source: eriks-aflas75
    where: Section 5, Chemical Resistance table
  - environment: Acetates, ethers, ketones, halohydrocarbons and toluene
    headline: Kalsi says to avoid these media with FEPM seals.
    effect: Kalsi lists acetates, ethers, ketones (MEK, acetone), halohydrocarbons (carbon tetrachloride, trichlorethylene) and toluene as known media limitations for FEPM.
    rating: severe
    conditions:
      basis: qualitative statement in Kalsi handbook
    source: kalsi-b4
    where: Section 1, Known media limitations
risks:
  hazards:
    - text: No safety data sheet for an FEPM compound is among the sources. The GHS entries below are for the two monomers, not the compound.
      ghs: []
      source: agc-tech
      where: Notice, item 2 (refer to the SDS)
    - text: Propylene is an extremely flammable gas. PubChem aggregates 2232 reports, with H220 in more than 99.9 percent and H280 in 55.3 percent of them.
      ghs:
        - H220
        - H280
      source: pubchem-propylene
      where: GHS Classification, aggregated notifications (2232 reports)
    - text: 'Tetrafluoroethylene is an extremely flammable gas that may explode if heated. PubChem aggregates 811 reports: H220 (30.7 percent), H280 (36.6 percent), H350 (36 percent) and H371 (32.2 percent). 59.3 percent of reports say the chemical does not meet GHS hazard criteria.'
      ghs:
        - H220
        - H280
        - H350
        - H371
      source: pubchem-tfe
      where: GHS Classification, aggregated notifications (811 reports)
  failure_risks:
    - mode: Poor compression set in rotary seals
      trigger: Solid cross-section FEPM rotary seals exposed to shaft deflection or runout
      consequence: The seal loses recovery and can leak, so Kalsi recommends spring preload or isolation from shaft runout
      severity: moderate
      source: kalsi-b4
      where: Section 1, FEPM has poor compression set resistance
    - mode: Stiffening at low temperature
      trigger: Operation below the brittle point of -43 degC (Kalsi)
      consequence: Seal loses flexibility and may crack or leak
      severity: moderate
      source: kalsi-b4
      where: Section 1, General material description
    - mode: Fuel swelling and loss of strength
      trigger: Exposure to ASTM Fuel C at room temperature
      consequence: ERIKS rates ASTM Fuel C as unsatisfactory for this compound
      severity: moderate
      source: eriks-aflas75
      where: Section 5, Chemical Resistance table
    - mode: Attack by ketones, ethers and halohydrocarbons
      trigger: Service in acetone, MEK, acetates, ethers, carbon tetrachloride, trichlorethylene or toluene
      consequence: Kalsi says to avoid these media, which can degrade the seal
      severity: high
      source: kalsi-b4
      where: Section 1, Known media limitations
  side_effects:
    - text: No side-effect data for FEPM appear in the sources used.
      affects: Not sourced
      source: agc-tech
      where: Not stated
  handling:
    - text: Refer to the safety data sheet for the specific FEPM compound before handling, as AGC asks.
      source: agc-tech
    - text: Keep propylene away from heat and ignition sources; PubChem gives precautionary codes P210 and P410+P403 for propylene.
      source: pubchem-propylene
  mitigations:
    - text: Preload homogeneous FEPM rotary seals with a spring and washer, as Kalsi recommends, to offset compression set.
      source: kalsi-b4
      where: Section 1, FEPM has poor compression set resistance
    - text: Use a molding grade with lower compression set, such as AFLAS 600X (29 percent) instead of conventional AFLAS 150P (46 percent) in the AGC table.
      source: agc-intro
      where: 'AFLAS 600X: Physical and Electrical Performance table, Compression Set row'
uses:
  - application: mechanisms
    device: Rotary shaft seals in drilling and downhole equipment (Kalsi Seals)
    example: Kalsi tested 2.75 in (69.85 mm) spring-loaded FEPM rotary seals in an 80 Shore A compound at a drilling fluid temperature of 275 degF (135 degC), for about 235 hours at 522 ft/min (2.652 m/s).
    source: kalsi-b4
    where: Section 1, Testing of homogeneous FEPM seals
  - application: mechanisms
    device: O-rings and gaskets from AFLAS 600X or AFLAS 400E
    example: AGC says AFLAS 600X is a high-speed molding grade similar to 400E, and is suitable for sealing materials such as O-rings and gaskets. No space mission is named.
    source: agc-tech
    where: Section 2, Commercial Polymer Types and AFLAS Grades, 600X description
  - application: electronics-and-chips
    device: Wire and cable insulation
    example: AGC says AFLAS has been finding new applications in wire and cable as an elastomeric insulating material with the highest heat resistance, with electrical resistivity of the order of 10^15 to 10^16 ohm cm.
    source: agc-tech
    where: Introduction, wire and cable paragraph
supply:
  - subject: Fluorspar (calcium fluoride), the fluorine feedstock for fluoropolymers
    abundance: 'World mine production was 10,000 thousand t in 2025 (rounded) and world reserves were 330,000 thousand t (USGS). 2025 mine production in thousand t: China 6,000; Mexico 1,500; Mongolia 1,500; South Africa 410; Vietnam 160 (USGS). Aqueous HF is the primary feedstock for fluorine-bearing chemicals, particularly refrigerants and fluoropolymers (USGS). The United States was 100 percent net import reliant (USGS).'
    producers: []
    critical_lists: []
    recycling: Synthetic fluorspar may be produced from neutralization of waste from uranium enrichment, petroleum alkylation and stainless-steel pickling, but impurities constrain its use. Primary aluminum producers recycle HF and fluorides from smelting operations (USGS).
    substitutes:
      - Fluorosilicic acid has been used as an alternative to fluorspar in making AlF3 and HF (USGS).
    source: usgs-fluorspar
    where: Domestic Production and Use; World Mine Production and Reserves table; Recycling; Substitutes
  - subject: FEPM (AFLAS) producer
    abundance: AGC introduced the TFE-propylene copolymer family in 1975 under the trade name AFLAS (AGC brochure). The brochure names AGC Inc. (Tokyo, Japan) as manufacturer and lists AGC regional companies in the Americas, Europe, Asia Pacific and China. No production share or capacity figure for FEPM was found.
    producers: []
    critical_lists: []
    recycling: Not stated in the sources.
    substitutes: []
    source: agc-tech
    where: Introduction, first section; Manufacturer/distributor block
media: []
documents:
  - title: AFLAS Technical Brochure, AGC
    type: datasheet
    url: https://agcce.com/wp-content/uploads/2023/10/AFLAS_Technical.pdf
  - title: Introduction to AFLAS 400E and 600X Grades, AGC Chemicals Americas
    type: datasheet
    url: https://www.agcchem.com/wp-content/uploads/wpfd/preview_files/Introduction-to-AFLAS-400E-and-600X-Grades(52d2752b150f9c35ccb6869cbf074e48).pdf
  - title: ERIKS technical data sheet, Aflas 75-compound 223002
    type: datasheet
    url: https://o-ring.info/en/datasheets%20o-ring/aflas/ERIKS%20-%20Datasheet%20-%20Aflas%2075-compound%20223002.pdf
    year: 2010
  - title: Kalsi Seals Handbook, Chapter B4, FEPM seal material
    type: report
    url: https://www.kalsi.com/handbook/B04_FEPM_seal_material.pdf
    year: 2020
  - title: USGS Mineral Commodity Summaries 2026, Fluorspar
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf
    year: 2026
  - title: PubChem, Propylene (CID 8252)
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/8252
  - title: PubChem, Tetrafluoroethylene (CID 8301)
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/8301
gaps:
  - 'Outgassing to ASTM E595 (total mass loss and CVCM) for FEPM: no value found. A search for Aflas outgassing returned only the ASTM E595 method text, and the NASA outgassing database was not checked in this run.'
  - No spacecraft, vacuum or radiation flight use is named for FEPM in the sources used. All figures are ground results.
  - 'Composition basis: AGC prints TFE/P=55/45 without saying whether the ratio is by mole or by mass. Fluorine content for AFLAS 400E and 600X is printed in parentheses, and the explanation is not given in the table text.'
  - Specific gravity for AFLAS 400E and 600X is 1.55 in the AGC grade table but 1.6 in the AGC physical table for the test compounds. The profile uses the grade-table value and keeps the physical-table value here.
  - 'Low-temperature limits disagree: ERIKS gives -5 degC for compound 223002, Kalsi gives a typical lower limit of -37 degC and a brittle point of -43 degC. All three are kept with their source.'
  - AGC standard formulation values (N990 carbon, TAIC, peroxide) are for AGC test compounds, not a commercial product. AFLAS 400E intro values (tensile 12 MPa, elongation 490 percent, hardness 73 Shore A) differ from the brochure standard formulation values (11 MPa, 460 percent, 72 Shore A) and are not mixed into the same property.
  - Grade-level compression set for the 150P, 400E and 600X standard formulations was not parsed cleanly from the brochure table, so the only compression set values used come from the AGC intro table (test time not printed in that row).
  - Monomer composition by mass fraction and the cure system of commercial grades were only partly stated; the brochure gives TFE/P=55/45 and peroxide cure, with no mass fraction.
  - 'ASTM D1418 or ISO 1629 designation for FEPM: not stated in the Wikipedia Fluoroelastomer page, which gives those for FKM. Kalsi prints ASTM designation FEPM, listed in identity.designations.'
  - Critical-mineral status of fluorspar is not stated in the USGS 2026 fluorspar summary.
  - FEPM producer production shares, capacity, and propylene and TFE feedstock suppliers were not found in any source used.
  - 'Non-canonical benchmark names used: hardness, compression_set, specific_gravity, fluorine_content, low_temperature_tr10. Canonical names exist for density, tensile strength, elongation, glass transition and the dielectric properties.'
  - 'Decomposition: the AGC brochure says the copolymer only starts to decompose in nitrogen at 400 degC. A thermogravimetric curve in the same section gives 415 degC without naming the grade, so 415 degC is not used as a value.'
  - No safety data sheet for an FEPM compound was used. The GHS data are for propylene and tetrafluoroethylene from PubChem.
  - ERIKS data sheet is dated 12.01.2010 and may predate current AGC grades.
story:
  recipe:
    line: FEPM is an alternating copolymer of tetrafluoroethylene (TFE) and propylene, introduced by AGC under the trade name AFLAS in 1975 (AGC brochure). The composition ratio is TFE/P=55/45 as printed, with the basis not stated. AGC cures AFLAS with peroxide; the Kalsi handbook calls FEPM a fluorocarbon polymer, and Wikipedia describes it as tetrafluoroethylene/propylene rubber.
    parts:
      - name: Tetrafluoroethylene (TFE, C2F4)
        share: 55 (TFE/P composition ratio as printed by AGC; mole or mass basis not stated)
        role: The fluorinated unit that gives the chain its heat and chemical resistance. ERIKS says the propylene units sit between neighbouring TFE units, which gives excellent heat resistance even at a lower fluorine content.
      - name: Propylene (C3H6)
        share: 45 (TFE/P composition ratio as printed by AGC; mole or mass basis not stated)
        role: The hydrocarbon unit that makes the polymer alternate with TFE. AGC says the TFE/P=55/45 composition gives excellent heat stability.
  risk_groups:
    - title: For people
      lead: No safety data sheet for an FEPM compound is among the sources. The hazard figures below are for the monomers.
      points:
        - label: Safety data
          line: Refer to the safety data sheet for the specific FEPM compound before handling.
    - title: For the monomers
      verdict: Flammable gases with suspected cancer hazards
      lead: PubChem classifies the two monomer gases, not the FEPM compound.
      points:
        - label: Propylene
          line: PubChem lists it as an extremely flammable gas (H220, more than 99.9 percent of reports) that may explode if heated (H280, 55.3 percent).
        - label: Tetrafluoroethylene
          line: PubChem lists it as an extremely flammable gas (H220), a gas under pressure (H280), a suspected or confirmed cancer hazard (H350) and a hazard to organs (H371), in 30.7 to 36.6 percent of reports.
  why: FEPM (AFLAS) is a fluoroelastomer that Kalsi says outperforms FKM in hot water, steam, explosive decompression, brine and bases. It has slightly less oil resistance and substantially less high-temperature compression set resistance than FKM. AGC gives a continuous service temperature of 200 degC.
  uses:
    - where: Rotary shaft seals in drilling and downhole equipment
      line: Kalsi tested spring-loaded FEPM rotary seals in an 80 Shore A compound for about 235 hours with drilling fluid at 135 degC. Kalsi recommends spring preload to offset compression set.
    - where: O-rings and gaskets
      line: AGC describes AFLAS 600X as a molding grade suitable for sealing materials such as O-rings and gaskets, with improved compression set. No space mission is named.
    - where: Wire and cable insulation
      line: AGC says AFLAS is finding new applications in wire and cable as an elastomeric insulating material with the highest heat resistance.
  can_do:
    - label: Temperature
      value: '-5 to 200 degC'
      line: ERIKS gives -5 to +200 degC for compound 223002, and AGC gives 200 degC continuous service with a 250 degC peak. The copolymer only starts to decompose in nitrogen at 400 degC (AGC brochure).
    - label: Strength
      value: 16 MPa (ISO 37)
      line: ERIKS gives 16 MPa tensile strength and 240 percent elongation for compound 223002. AGC standard formulations give 11 to 23 MPa, depending on grade and formulation.
    - label: Steam and bases
      value: 2 percent volume change
      line: After 720 h in 170 degC steam, AFLAS 600X swells by 2 percent (AGC). After 720 h in 28 percent ammonia at 70 degC, it swells by 2.7 percent.
    - label: Electrical insulation
      value: 3 x 10^16 ohm cm
      line: AFLAS 400E has a volume resistivity of 3 x 10^16 ohm cm and a dielectric constant of 2.8 at 1 kHz (AGC intro, compound values).
  compare: Against FKM, AGC gives a compression set of 30 percent for an FKM terpolymer and 46 percent for conventional AFLAS 150P in the same table. Kalsi says FEPM has substantially less high-temperature compression set resistance and slightly less oil resistance than FKM, but about the same resistance to acids and better resistance to hot water, steam, bases and brine.
  compare_rows:
    - scope: material
      label: Compression set
      benchmark: compression_set
    - scope: material
      label: Continuous service temperature
      benchmark: max_service_temp
    - scope: material
      label: Low-temperature limit
      benchmark: min_service_temp
  handling:
    - Refer to the safety data sheet for the specific FEPM compound before handling.
    - Avoid acetates, ethers, ketones, halohydrocarbons and toluene in service, as Kalsi advises.
    - Keep propylene away from heat, as PubChem precautionary codes P210 and P410+P403 advise.
  good_for:
    - 'Hot water and steam service: AFLAS 600X swells by 0.3 to 0.4 percent in hot water after 720 h, and by 2 percent in 170 degC steam (AGC).'
    - 'Base and amine service: AFLAS 600X swells by 0.4 percent in 48 percent NaOH and by 2.7 percent in 28 percent ammonia after 720 h at 70 degC (AGC).'
    - Heat service at 200 degC continuous (AGC) and electrical insulation with volume resistivity of 3 x 10^16 ohm cm for AFLAS 400E (AGC).
  watch_out:
    - 'Compression set: 46 percent for conventional AFLAS 150P and 29 percent for AFLAS 600X compound A, against 30 percent for an FKM terpolymer (AGC table).'
    - 'Cold: Kalsi gives a brittle point of -43 degC, and ERIKS gives a TR10 value of +2 degC for compound 223002.'
    - 'Fuel and solvents: ERIKS rates ASTM Fuel C, acetone and MEK as unsatisfactory, and Kalsi says to avoid ketones, ethers, halohydrocarbons and toluene.'
  verdict: FEPM (Aflas) is a fluoroelastomer for hot water, steam and strong base service where FKM is weaker, rated to 200 degC continuous by AGC. Its compression set is high in rotary and solid-seal use. No outgassing, space flight, producer share or critical-mineral data for FEPM were found in the sources used.
sources:
  kalsi-b4:
    title: Kalsi Seals Handbook, Chapter B4, FEPM seal material, Revision 3
    id: Kalsi Document 3054, Chapter B4
    url: https://www.kalsi.com/handbook/B04_FEPM_seal_material.pdf
    year: 2020
    kind: handbook
    license: Kalsi Engineering handbook chapter, cited
  eriks-aflas75:
    title: ERIKS technical data sheet, Aflas 75-compound 223002
    id: ERIKS Aflas 75-compound 223002 data sheet
    url: https://o-ring.info/en/datasheets%20o-ring/aflas/ERIKS%20-%20Datasheet%20-%20Aflas%2075-compound%20223002.pdf
    year: 2010
    kind: datasheet
    license: Manufacturer data sheet, cited
  agc-tech:
    title: AFLAS Technical Brochure, AGC Chemicals and AGC Inc.
    id: AFLAS Technical Brochure (agcce.com)
    url: https://agcce.com/wp-content/uploads/2023/10/AFLAS_Technical.pdf
    kind: datasheet
    license: Manufacturer brochure, cited
  agc-intro:
    title: Introduction to AFLAS 400E and 600X Grades, AGC Chemicals Americas
    id: AGC intro, AFLAS 400E and 600X
    url: https://www.agcchem.com/wp-content/uploads/wpfd/preview_files/Introduction-to-AFLAS-400E-and-600X-Grades(52d2752b150f9c35ccb6869cbf074e48).pdf
    kind: datasheet
    license: Manufacturer presentation, cited
  usgs-fluorspar:
    title: Mineral Commodity Summaries 2026, Fluorspar, U.S. Geological Survey
    id: USGS MCS 2026, fluorspar
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf
    year: 2026
    kind: report
    license: U.S. Government work, public domain
  pubchem-propylene:
    title: PubChem, Propylene (CID 8252)
    id: PubChem CID 8252
    url: https://pubchem.ncbi.nlm.nih.gov/compound/8252
    kind: database
    license: PubChem, public database
  pubchem-tfe:
    title: PubChem, Tetrafluoroethylene (CID 8301)
    id: PubChem CID 8301
    url: https://pubchem.ncbi.nlm.nih.gov/compound/8301
    kind: database
    license: PubChem, public database
  wikipedia-fluoroelastomer:
    title: Wikipedia, Fluoroelastomer
    id: Wikipedia Fluoroelastomer; describes FEPM as tetrafluoroethylene/propylene rubber and gives standard designations for FKM only
    url: https://en.wikipedia.org/wiki/Fluoroelastomer
    kind: web
    license: CC BY-SA 4.0
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 28
  note: Written on 2026-11-01 from the AGC brochure and AGC intro, the ERIKS 223002 data sheet, Kalsi Seals Handbook Chapter B4, USGS fluorspar 2026, PubChem REST records for propylene and tetrafluoroethylene, and Wikipedia Fluoroelastomer, all read in this run.