Upilex-S polyimide film (BPDA) PI (Upilex-S)

spore: profile
id: pi-upilex-s
spore_version: 0.2
family: polyimides
name: Upilex-S polyimide film (BPDA)
abbreviation: PI (Upilex-S)
role: flexible insulating film
category: polymers
type: polyimides
summary: |
  Upilex-S is UBE's standard polyimide film, made from biphenyl tetracarboxylic dianhydride (BPDA) rather than the pyromellitic dianhydride used in Kapton. The UBE datasheet gives a tensile strength of 520 MPa and a density of 1.47 (x10^3 kg/m3) for 25 micrometre film at 25 degC. In low Earth orbit on MISSE 2 the film eroded at 9.22e-24 cm3/atom, about three times the Kapton HN rate in the same NASA table, so exposed Upilex-S needs a cover. The NASA erosion yield is from one flight record and the UBE values come from a manufacturer datasheet; no finished part was flown.
best_for: A thin, flexible, electrically insulating film with a very low coefficient of thermal expansion and no melting point, where dimensional stability over temperature matters more than atomic-oxygen resistance
weakest_at: Atomic-oxygen erosion in low Earth orbit (MISSE 2 erosion yield 9.22e-24 cm3/atom, the highest of the polyimides in the NASA table), so exposed film must be covered or coated
identity:
  formula: C22H10O4N2 (repeat unit, from NASA Table IV); BPDA-based polyimide
  cas: ''
  source: banks2008
  where: Table IV lists PI (Upilex-S) with formula C22H10O4N2 and molecular weight 366.3320; NASA Table V gives the atom counts. The CAS number is not read in this run and is left blank.
tags:
  environments:
    - low-earth-orbit
  stresses:
    - atomic-oxygen
    - uv
    - total-radiation-dose
    - thermal-cycling
    - vacuum-and-outgassing
  applications:
    - electronics-and-chips
    - thermal-control
properties:
  - benchmark: density
    label: Density (measured, MISSE 2 sample)
    value: 1.3866
    unit: g/cm3
    scope: material
    conditions:
      sample: MISSE 2 PEACE Polymers film, dehydrated before measurement
      temperature: not stated
      unit_in_source: g/cm3
    method: Measured density reported by NASA (ref. 12 density method)
    status: ground
    source: banks2008
    where: Table II, density column for PI (Upilex-S or US), value printed as 1.3866 g/cm3
  - benchmark: density
    label: Density (datasheet, 25 um film)
    value: 1.47
    unit: x10^3 kg/m3
    scope: material
    conditions:
      product: UPILEX-25S film, 25 micrometre
      temperature: 25 degC
      unit_in_source: x10^3 kg/m3
    method: ASTM D1505, as printed in the UBE datasheet
    status: ground
    source: ube_upilex_s
    where: Section (1) Mechanical properties, Density row; also repeated in Section (5) as 1.47 for UPILEX-25S
  - benchmark: ultimate_tensile_strength
    label: Tensile strength at 25 degC
    value: 520
    unit: MPa
    scope: material
    conditions:
      product: UPILEX-25S
      temperature: 25 degC
      film_thickness: 25 micrometre
    method: ASTM D882
    status: ground
    source: ube_upilex_s
    where: Section (1) Mechanical properties, Tensile strength row, 25 degC column for UPILEX-25S
  - benchmark: ultimate_tensile_strength
    label: Tensile strength at 300 degC
    value: 290
    unit: MPa
    scope: material
    conditions:
      product: UPILEX-25S
      temperature: 300 degC
    method: ASTM D882
    status: ground
    source: ube_upilex_s
    where: Section (1) Mechanical properties, Tensile strength row, 300 degC column for UPILEX-25S
  - benchmark: ultimate_tensile_strength
    label: Tensile strength at -269 degC
    value: 740
    unit: MPa
    scope: material
    conditions:
      product: UPILEX-25S
      temperature: '-269 degC'
    method: ASTM D882
    status: ground
    source: ube_upilex_s
    where: Section (1) Mechanical properties, Tensile strength row, -269 degC column for UPILEX-25S
  - benchmark: elongation
    label: Elongation at 25 degC
    value: 40
    unit: '%'
    scope: material
    conditions:
      product: UPILEX-25S
      temperature: 25 degC
    method: ASTM D882
    status: ground
    source: ube_upilex_s
    where: Section (1) Mechanical properties, Elongation row, 25 degC column for UPILEX-25S
  - benchmark: elastic_modulus
    label: Tensile modulus at 25 degC
    value: 9.1
    unit: GPa
    scope: material
    conditions:
      product: UPILEX-25S
      temperature: 25 degC
    method: ASTM D882
    status: ground
    source: ube_upilex_s
    where: Section (1) Mechanical properties, Tensile modulus row, 25 degC column for UPILEX-25S
  - benchmark: cte
    label: Thermal linear expansion coefficient (50 to 200 degC)
    value: 12
    unit: ppm/degC
    scope: material
    conditions:
      product: UPILEX-25S
      temperature_range: 50 to 200 degC
      heating_rate: 5 degC/min
    method: Fine linear dilatometer
    status: ground
    source: ube_upilex_s
    where: Section (3) Thermal properties, Thermal linear expansion coefficient row, UPILEX-25S column
  - benchmark: heat_shrinkage
    label: Heat shrinkage
    value: 0.05
    unit: '%'
    scope: material
    conditions:
      product: UPILEX-25S
      temperature: 200 degC
      time: 2 h
    method: ASTM D1204
    status: ground
    source: ube_upilex_s
    where: Section (3) Thermal properties, Heat shrinkage row, UPILEX-25S column
  - benchmark: specific_heat
    label: Specific heat
    value: 1.13
    unit: kJ/(kg.K)
    scope: material
    conditions:
      product: UPILEX film (grade not stated in the row)
      temperature: not stated
    method: Differential scanning calorimeter
    status: ground
    source: ube_upilex_s
    where: Section (3) Thermal properties, Specific heat row
  - benchmark: thermal_conductivity
    label: Thermal conductivity (thickness direction)
    value: 0.29
    unit: W/(m.K)
    scope: material
    conditions:
      product: UPILEX-S film (grade not stated in the row)
      direction: thickness
    method: Laser flash method
    status: ground
    source: ube_upilex_s
    where: Section (3) Thermal properties, Thermal conductivity row
  - benchmark: heat_life_temperature
    label: Heat life (tensile strength basis, 20,000 h)
    value: 290
    unit: degC
    scope: material
    conditions:
      product: UPILEX-S film (grade not stated in the row)
      time: 20000 h
    method: Fixed temperature method, tensile strength basis as printed
    status: ground
    source: ube_upilex_s
    where: Section (3) Thermal properties, Heat life (Tensile strength) row
  - benchmark: oxygen_index
    label: Oxygen index
    value: 66
    unit: '%'
    scope: material
    conditions:
      product: UPILEX-S film (grade not stated in the row)
    method: JIS K7201
    status: ground
    source: ube_upilex_s
    where: Section (3) Thermal properties, Oxygen index row
  - benchmark: dielectric_strength
    label: Dielectric strength at 25 degC
    value: 6.8
    unit: kV
    scope: material
    conditions:
      product: UPILEX-25S
      temperature: 25 degC
      frequency: 60 Hz
    method: ASTM D149
    status: ground
    source: ube_upilex_s
    where: Section (2) Electrical properties, Dielectric strength row, UPILEX-25S 25 degC
  - benchmark: dielectric_constant
    label: Dielectric constant at 25 degC
    value: 3.5
    unit: '-'
    scope: material
    conditions:
      product: UPILEX-25S
      temperature: 25 degC
      frequency: 1 kHz
    method: ASTM D150
    status: ground
    source: ube_upilex_s
    where: Section (2) Electrical properties, Dielectric constant row, 1kHz, 25 degC
  - benchmark: dissipation_factor
    label: Dissipation factor at 25 degC
    value: 0.0013
    unit: '-'
    scope: material
    conditions:
      product: UPILEX-25S
      temperature: 25 degC
      frequency: 1 kHz
    method: ASTM D150
    status: ground
    source: ube_upilex_s
    where: Section (2) Electrical properties, Dissipation factor row, 1kHz, 25 degC
  - benchmark: moisture_absorption
    label: Water absorption (23 degC, 24 h immersion)
    value: 1.4
    unit: '%'
    scope: material
    conditions:
      temperature: 23 degC
      time: 24 h
      condition: water immersion
    method: ASTM D570
    status: ground
    source: ube_upilex_s
    where: Section (4) Chemical-resistant properties, Water absorption row, 23 degC 24h water immersion
  - benchmark: atomic_oxygen_erosion_yield
    label: Atomic oxygen erosion yield (LEO, MISSE 2)
    value: 9.22e-24
    unit: cm3/atom
    scope: material
    status: flight
    conditions:
      environment: low Earth orbit, ISS, MISSE 2 PEACE tray (outside Quest airlock)
      atomic_oxygen_fluence: 8.43e21 atoms/cm2
      exposure_duration: about 4 years (2001 to 2005)
    method: Mass loss with carefully dehydrated mass measurement, density from Table II, erosion yield per NASA TM-2008-215490
    source: banks2008
    where: Table I, MISSE 2 PEACE polymers erosion yield, row PI (Upilex-S or US); fluence from section 2.1
  - benchmark: ash_content
    label: Ash content (mass fraction, Na)
    value: 0.000482
    unit: '-'
    scope: material
    conditions:
      sample: MISSE 2 PEACE Polymers film
    method: RF plasma asher, as described in NASA TM-2008-215490
    status: ground
    source: banks2008
    where: Table II, mass fraction of polymer that is ash, row PI (Upilex-S or US)
corrosion:
  - environment: Low Earth orbit atomic oxygen (ISS, MISSE 2)
    headline: Atomic oxygen erodes Upilex-S at 9.22e-24 cm3/atom, the highest erosion yield among the polyimides in the NASA MISSE 2 table.
    effect: Over the MISSE 2 flight the polymer lost material at 9.22e-24 cm3/atom. For comparison, the NASA table gives 3.00e-24 for Kapton H and 2.81e-24 for Kapton HN. Exposed film must be covered or coated.
    rating: severe
    conditions:
      fluence: 8.43e21 atoms/cm2
      duration: about 4 years
    source: banks2008
    where: Table I row PI (Upilex-S or US); Table I rows PI (Kapton H) and PI (Kapton HN); section 2.1
  - environment: Solar and charged-particle exposure (MISSE 2)
    headline: NASA's ground-simulation comparison covers Upilex-S, but no Upilex-S absorptance number was read in this run.
    effect: NASA's comparison of proton, electron and ultraviolet simulation discusses Kapton and Upilex S together; the Upilex-S absorptance change is not reproduced here.
    rating: low
    conditions:
      exposure: ISS MISSE 2, total equivalent sun hours 5000 to 6700 ESH
    source: banks2008
    where: Section 2.1 (equivalent sun hours); the solar absorptance comparison is not reproduced here
  - environment: Chemical bath (acids, alkalis, hot water)
    headline: Strength falls to 80 percent after 5 days in 10 percent sodium hydroxide at 25 degC; hot water barely changes the film.
    effect: UBE reports strength retention of 80 percent in 10% sodium hydroxide, 25 degC, 5 days immersion, and 95 percent in pH 1.0 water at 100 degC for 2 weeks. The datasheet says the film is insoluble in organic solvents and resists virtually all chemicals.
    rating: low
    conditions:
      product: UPILEX-25S
      test: ASTM D882 retention after immersion
    source: ube_upilex_s
    where: Section (4) Chemical-resistant properties, strength retention table
risks:
  hazards:
    - text: Heated above 300 degC, the film gives off traces of residual DMAC, which forms carbon monoxide; above 500 degC it gives pyrolytic products. UBE advises ventilation so DMAC stays below 10 ppm and carbon monoxide below 100 ppm, and organic gas masks for fume exposure.
      ghs: []
      source: ube_upilex_s
      where: Section (6) Packing and handling precautions, handling note
    - text: UBE says the film is flame resistant (UL94 V-0, oxygen index 66 percent) but advises checking the supplier safety data sheet before use.
      ghs: []
      source: ube_upilex_s
      where: Section (3) Thermal properties, flammability row; Section (6) handling note
  failure_risks:
    - source: banks2008
      where: Table I
      mode: Atomic oxygen in low Earth orbit removes the film at 9.22e-24…
      consequence: Atomic oxygen in low Earth orbit removes the film at 9.22e-24 cm3/atom, so bare Upilex-S film does not survive a long LEO mission.
  side_effects: []
  handling:
    - text: Use good ventilation when heating the film, because of residual DMAC and pyrolysis products above 300 degC.
      source: ube_upilex_s
      where: Section (6) handling precautions
  mitigations:
    - text: Cover or coat the film in LEO. The erosion yield in the NASA table is the reason; no cover or coating was tested in the fetched sources.
      source: banks2008
      where: Table I
uses:
  - application: electronics-and-chips
    device: Flexible printed circuit and TAB-tape substrates
    example: UBE says Upilex-S changes little in size when heated, which suits minute circuits in flexible printed circuit and TAB-tape substrates.
    source: ube_upilex_s
    where: Section (3) Thermal properties, intro paragraph
  - application: thermal-control
    device: Carrier base and release film for high-temperature processing
    example: UBE lists Upilex-S as a carrier base and releasing material because its outgassing is low.
    source: ube_upilex_s
    where: Section (6) Smooth surface, application examples
  - application: electronics-and-chips
    device: Electrical insulation in high-temperature circuits
    example: UBE says the electrical properties hardly change at 200 degC, with a dielectric strength of 6.8 kV at 25 degC and 60 Hz.
    source: ube_upilex_s
    where: Section (2) Electrical properties
supply:
  - subject: Polyimide film (Upilex)
    abundance: Monomer feedstock abundance was not read in a fetched page.
    producers:
      - name: UBE Corporation
        note: Makes UPILEX polyimide film from BPDA monomers (UBE datasheet)
        country: Japan
    critical_lists: []
    recycling: Not sourced.
    source: ube_upilex_s
    where: 'Cover page: UBE''s BPDA monomer and UPILEX film grades'
gaps:
  - Atomic oxygen erosion for Upilex-S is one MISSE 2 flight value; the NASA predicted-vs-measured table (Table VII) prints 9.22e-25 for Upilex-S, which conflicts with Table I (9.22e-24). Table I is used here; the conflict is not resolved.
  - Glass transition temperature for Upilex-S was not found in any fetched page.
  - Density for the UBE datasheet row is printed as x10^3 kg/m3; the value is kept as printed and not converted.
  - Supply country shares, production volumes and critical-mineral lists were not reached in this run.
  - Hazard classification (GHS) and the supplier SDS were not read in this run.
  - Story media and outgassing (NASA Goddard database) were not read in this run.
  - Only three sources were reached in this run; the lithium standard asks for eight.
sources:
  banks2008:
    title: 'NASA/TM-2008-215490: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit (Banks, Backus, de Groh)'
    id: NASA/TM-2008-215490
    url: https://ntrs.nasa.gov/citations/20090011780
    year: 2008
    kind: report
    license: public domain (US government work)
  ube_upilex_s:
    title: UBE UPILEX-S polyimide film datasheet (English)
    id: ube.com/upilex/catalog/pdf/upilex_s_e.pdf
    url: https://ube.com/upilex/catalog/pdf/upilex_s_e.pdf
    kind: datasheet
    license: manufacturer document, linked not reproduced
  wiki_polyimide:
    title: 'Wikipedia: Polyimide (composition and history only)'
    id: en.wikipedia.org/wiki/Polyimide
    url: https://en.wikipedia.org/wiki/Polyimide
    kind: web
    license: CC-BY-SA-4.0
documents:
  - title: 'NASA/TM-2008-215490: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit'
    type: report
    url: https://ntrs.nasa.gov/citations/20090011780
    year: 2008
  - title: UBE UPILEX-S polyimide film datasheet
    type: datasheet
    url: https://ube.com/upilex/catalog/pdf/upilex_s_e.pdf
license: CC-BY-4.0
updated: '2026-10-20'
review:
  status: draft
  method: assistant
  checked_values: 19
  unreachable: 6
  caveats: 3
  note: Written by an AI assistant on 2026-10-20 from text extracted from the NASA TM-2008-215490 PDF and the UBE Upilex-S datasheet PDF, both fetched in this run. Wikipedia was read for composition and history only. Only three sources were reached; the rest of the lithium standard is listed in gaps.
story:
  risk_groups:
    - title: Electronics and space engineers who need a thin, insulating film…
  why: Upilex-S is a polyimide made from biphenyl tetracarboxylic dianhydride (BPDA), a different monomer from the pyromellitic dianhydride used in Kapton. The NASA table gives the repeat unit as C22H10O4N2 with a molecular weight of 366.3320. UBE says the film has no melting point and the highest heat resistance of any plastic film it lists. The MISSE 2 flight erosion yield of 9.22e-24 cm3/atom is the largest of the polyimides NASA lists, so this is a film for ground or covered use.
  recipe:
    line: Repeat unit C22H10O4N2 from BPDA-based polycondensation (formula and molecular weight from NASA Table IV). The synthesis route and the monomer ratio were not read in this run.
    parts:
      - name: Carbon
        symbol: C
        atoms: 22
        atomic_weight: 12.011
        role: Backbone of the aromatic imide rings and the biphenyl units.
      - name: Hydrogen
        symbol: H
        atoms: 10
        atomic_weight: 1.008
        role: Ring hydrogens on the aromatic units.
      - name: Oxygen
        symbol: O
        atoms: 4
        atomic_weight: 15.999
        role: Carbonyl oxygens in the imide rings.
      - name: Nitrogen
        symbol: 'N'
        atoms: 2
        atomic_weight: 14.007
        role: Imide nitrogen linking the carbonyl pairs.
  supply: Only one manufacturer, UBE Corporation, is named in the fetched datasheet. No supply shares were read in this run.
  compare: In the NASA MISSE 2 table, Upilex-S eroded at 9.22e-24 cm3/atom against 3.00e-24 for Kapton H and 2.81e-24 for Kapton HN. For exposed LEO use, Upilex-S should not be chosen over Kapton HN on this evidence. No metal or composite is compared in the fetched sources.
  compare_rows:
    - label: Atomic oxygen erosion yield
      benchmark: atomic_oxygen_erosion_yield
    - label: Density
      benchmark: density
    - label: Thermal linear expansion coefficient
      benchmark: cte
  handling:
    - Keep the film covered in orbit. When heating above 300 degC, ventilate so DMAC and carbon monoxide stay below the UBE limits of 10 ppm and 100 ppm. Check the supplier safety data sheet before use.
  can_do:
    - label: Strength
      line: Insulate and carry fine circuits at temperatures from -269 degC to 300 degC, keep its size when heated (thermal linear expansion of 12 ppm/degC from 50 to 200 degC), and serve as a low-outgassing carrier film. It cannot protect itself from atomic oxygen in low Earth orbit.
  good_for:
    - Thin, flexible, electrically insulating layers that must keep their size over a wide temperature range, with a low coefficient of thermal expansion and low outgassing.
  watch_out:
    - Atomic oxygen in LEO erodes Upilex-S faster than Kapton, so bare film does not last. The 9.22e-24 value is one flight, and the NASA predicted-vs-measured table prints a conflicting figure.
  verdict: Upilex-S is a heat-stable polyimide insulator with a strong datasheet and a fast MISSE 2 erosion record. It is useful on the ground and under cover, and it is a poor choice for bare LEO exposure.