CTA
A fully acetylated cellulose ester distinct from the more common secondary cellulose acetate (CA); valued for its high clarity, dimensional stability and low birefringence, historically used as photographic and cinematic film base.
Reference datasheet — CTA is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
CTA grades and fills
CTA is supplied in 3 conditions, soft to hard.
Compare all 3 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Membrane grade | High-purity, tightly controlled DS/molecular-weight flake for asymmetric RO, NF and dialysis hollow-fibre casting; chlorine tolerant but pH-limited (4–7). | 6 | 10 | 30 | |
Plasticized injection-moulding / extrusion grade | Plasticizer-modified compound (usually with CA/CAB blending) when melt processing rather than solvent casting is required. | 45 | 40 | 100 HRR | |
Optical polarizer protective film grade | Choose for LCD polarizer protective film and optical compensation film where retardation must be near zero and haze <0.5 %. | 75 | 105 | 20 | 70 HRM |
Supply forms, finishes and certifications
Ways CTA is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FIBER | Triacetate textile filament grade | Supply form |
FILM-PHOTO | Photographic / cine safety film base | Supply form |
NATDefault | Unplasticized natural CTA flake/resin | Standard supply |
What is CTA?
A fully acetylated cellulose ester distinct from the more common secondary cellulose acetate (CA); valued for its high clarity, dimensional stability and low birefringence, historically used as photographic and cinematic film base. CTA has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 185°C (365 °F). CTA has a yield strength of 55 MPa (7.98 ksi) and a tensile strength of 70 MPa (10.2 ksi) — stronger than 62% of polymer grades. Elongation at break is 25% and the elastic modulus is 3.2 GPa (0.464 Msi).
What is CTA used for?
- photographic/motion-picture film base
- polarizer protective film
- optical filters
- textile fibers
Advantages
- Polishes to a fine finish — 80/100, better than 89% of polymer grades
- Stiff — 3.2 GPa (0.464 Msi), better than 77% of polymer grades
Limitations
- Absorbs moisture — dry before molding — 2.5%, worse than 98% of polymer grades
CTA properties
Typical room-temperature values; bars are the position among polymer grades.
Physical7
CTA has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 185°C (365 °F).
Mechanical13
CTA has a yield strength of 55 MPa (7.98 ksi) and a tensile strength of 70 MPa (10.2 ksi) — stronger than 62% of polymer grades. Elongation at break is 25% and the elastic modulus is 3.2 GPa (0.464 Msi).
Thermal11
CTA is rated for continuous service to 95°C (203 °F). It conducts heat at 0.21 W/m·K (0.121 BTU/hr·ft·°F), better than 55% of polymer grades. Thermal expansion is 80 µm/m·K (44.4 µin/in·°F).
Electrical7
CTA is an electrical insulator with a dielectric strength of 16 kV/mm (406.4 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental2
UV resistance is fair.
Sustainability4
Producing a kilogram of CTA takes about 105 MJ of energy and emits 4.5 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 2%.
Manufacturability7
CTA's machinability is good (65/100, better than 66% of polymer grades); weldability good (60/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. CTA is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CTA
Is CTA easy to machine?
Machines like acrylic with sharp positive-rake tools and air cooling; avoid water-soluble coolants (moisture pickup) and any chlorinated/ketone cutting fluids that will craze or dissolve the surface.
Can CTA be welded?
Not weldable by hot-gas in practice — join by solvent bonding (dichloromethane/acetone blends) or pressure-sensitive/acrylic adhesives after corona or saponification treatment.
Can CTA be formed, bent or molded?
Predominantly solvent cast from dichloromethane–methanol dope; melt processing needs plasticizer and a narrow 220–265 °C window with pre-drying to <0.05 % moisture, since the polymer degrades and yellows above ~280 °C.
CTA chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| cellulose triacetate (acetyl content)wt % combined acetic acid basis ≈ 60–62.5 %; degree of substitution 2.8–3.0 | 43 – 44.8 | 43.9 |
| plasticizer (triphenyl phosphate / diethfilm-base and moulding grades only; optical TAC film uses low or non-phthalate plasticizer | 0 – 15 | 10 |
| residual free acid / moisture | 0 – 1 | 0.3 |
| cellulose backbone (biobased, wood/cottobalance of the anhydroglucose repeat unit | balance |
What surface finishes work on CTA?
Takes high-gloss polish and vacuum-deposited hardcoats/AR stacks; alkaline saponification is used to make TAC film surfaces hydrophilic for PVA polarizer lamination — avoid strong alkali on load-bearing parts.
How much does CTA cost?
CTA is a premium-cost polymer ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
CTA — frequently asked
What is CTA used for?
CTA is typically used for photographic/motion-picture film base, polarizer protective film, optical filters and textile fibers. In short: highest-clarity cellulosic; low-birefringence optical film; solvent-cast, not moulded.
What is the yield strength of CTA?
CTA has a typical yield strength of 55 MPa (7.98 ksi) and a tensile strength of 70 MPa (10.2 ksi) — stronger than 62% of polymer grades. Strength varies by condition: see the 3 listed tempers.
Is CTA easy to machine?
Reasonably — machinability is rated good (65/100, better than 66% of polymer grades). Machines like acrylic with sharp positive-rake tools and air cooling; avoid water-soluble coolants (moisture pickup) and any chlorinated/ketone cutting fluids that will craze or dissolve the surface.
Can CTA be welded?
Yes — weldability is rated good (60/100). Not weldable by hot-gas in practice — join by solvent bonding (dichloromethane/acetone blends) or pressure-sensitive/acrylic adhesives after corona or saponification treatment.
What surface finishes work on CTA?
Takes high-gloss polish and vacuum-deposited hardcoats/AR stacks; alkaline saponification is used to make TAC film surfaces hydrophilic for PVA polarizer lamination — avoid strong alkali on load-bearing parts.
Can CTA be formed, bent or molded?
Predominantly solvent cast from dichloromethane–methanol dope; melt processing needs plasticizer and a narrow 220–265 °C window with pre-drying to <0.05 % moisture, since the polymer degrades and yellows above ~280 °C.
What is the maximum service temperature of CTA?
CTA is rated for continuous use to about 95°C (203 °F), and briefly to 140°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does CTA cost?
CTA is a premium-cost polymer ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- Engineered Materials Handbook Vol. 2: Engineering Plastics (cellulosics section) — ASM International (1988)
- Polymer Handbook, 4th ed. (cellulose ester thermal/optical data) — Wiley (1999)
- Cellulose ester product literature (cellulose acetate / triacetate flake) — Eastman Chemical (2022)
- ASTM D871 — Testing Cellulose Acetate (acetyl content, viscosity) — ASTM (2020)
- ISO 1875 / GB/T 1043, D638, D790, D256, D648 test methods referenced for typical values — ISO/ASTM/GB (2021)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.