CAST-SHT
Finish state
Choose for eyewear fronts and temples where layered/patterned aesthetics, CNC milling and tumble polishing are required.
Values for the CAST-SHT condition
Other CA grades and fills
CA is listed in 3 conditions; see the grade overview at CA.
Compare all 3 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
High-plasticizer CA (20–30% plasticizer), soft/tough | Pick when maximum toughness, easy flow and warm hand feel matter (eyewear frames, tool handles, cast sheet); heat resistance and stiffness drop. | 26 | 30 | 50 | 66 Shore D |
CAST-SHTThis page cast/block eyewear sheet (block-pressed, patterned) | Choose for eyewear fronts and temples where layered/patterned aesthetics, CNC milling and tumble polishing are required. | 32 | 42 | 35 | 75 Shore D |
Low-plasticizer CA (≤12% plasticizer), rigid/heat-resistant | Pick when stiffness, dimensional stability and higher HDT are needed (rigid housings, sheet, technical film); flow is poor and impact strength lower. | 52 | 58 | 18 | 83 Shore D |
What is CAST-SHT?
CAST-SHT is CA supplied in the CAST-SHT condition — choose for eyewear fronts and temples where layered/patterned aesthetics, CNC milling and tumble polishing are required. CAST-SHT has a yield strength of 32 MPa (4.64 ksi) and a tensile strength of 42 MPa (6.09 ksi) — weaker than 69% of polymer grades. Elongation at break is 35% and the elastic modulus is 1.5 GPa (0.218 Msi). CAST-SHT has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 120°C (248 °F).
Advantages
- Polishes to a fine finish — 92/100, better than 97% of polymer grades
- Easy to machine — 85/100, better than 88% of polymer grades
- Forms and bends easily — 85/100, better than 81% of polymer grades
Limitations
- Absorbs moisture — dry before molding — 2.5%, worse than 98% of polymer grades
- Needs corrosion protection — 55/100, worse than 94% of polymer grades
- Limited service temperature — 60°C (140 °F), worse than 87% of polymer grades
CAST-SHT properties
Typical room-temperature values for CAST-SHT; 22 are specific to this condition. Other listed values are CA reference data and may not represent this condition. Bars are the position among polymer grades.
Physical6
CAST-SHT has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 120°C (248 °F).
Mechanical16
CAST-SHT has a yield strength of 32 MPa (4.64 ksi) and a tensile strength of 42 MPa (6.09 ksi) — weaker than 69% of polymer grades. Elongation at break is 35% and the elastic modulus is 1.5 GPa (0.218 Msi).
Thermal11
CAST-SHT is rated for continuous service to 60°C (140 °F). It conducts heat at 0.22 W/m·K (0.127 BTU/hr·ft·°F), better than 60% of polymer grades. Thermal expansion is 130 µm/m·K (72.2 µin/in·°F).
Electrical7
CAST-SHT is an electrical insulator with a dielectric strength of 18 kV/mm (457.2 V/mil) and a resistivity of 1×10¹⁰ Ω·m.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 94% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of CAST-SHT takes about 100 MJ of energy and emits 4 kg of CO₂ — less than 61% of polymer grades. Typical recycled content is 2%.
Manufacturability7
CAST-SHT's machinability is excellent (85/100, better than 88% of polymer grades); weldability poor (30/100); formability excellent (85/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CAST-SHT
Is CA easy to machine?
Machines and routs cleanly with sharp positive-rake tools and high speed; avoid heat build-up (plasticizer sweats, edges soften) and use air blast rather than water-based coolant.
Can CA be welded?
Solvent bonding (acetone/methyl acetate/ethyl acetate mixes) and adhesive joints are standard; ultrasonic works on rigid low-plasticizer grades, hot-plate welding tends to scorch.
Can CA be formed, bent or molded?
Dry 2–4 h at 65–75 °C before molding; melt 175–230 °C with mold 35–75 °C, keep residence time short as CA degrades and releases acetic acid above ~240 °C; excellent thermoforming and bending in hot air or oil.
What surface finishes work on CA?
Barrel/tumble polishing with wood chips and wax gives the classic high-gloss eyewear finish; flame or vapor polishing works but must be brief, and hard coats or UV-stabilized lacquers are advised for outdoor use.
CA 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 |
|---|---|---|
| plasticizer (diethyl phthalate, triaceticontent sets the High/Low plasticizer grade split | 8 – 30 | 15 |
| heat/light stabilizer + antioxidant | 0.1 – 1 | 0.4 |
| residual free acetic acid / moisturemust be dried before molding | 0 – 0.5 | 0.2 |
| colorant / pearlescent pigment (optional | 0 – 3 | 0.5 |
| cellulose acetate polymer (acetyl contenwood pulp / cotton linter cellulose esterified with acetic anhydride | ≥ 70 (balance) | — |
CAST-SHT — frequently asked
What is CAST-SHT used for?
CAST-SHT is typically used for eyeglass frames, tool handles, photographic film base, packaging film, toys and cosmetic packaging. In short: biobased high-gloss cellulosic; standard eyewear sheet material; easiest cellulosic to polish.
What is the yield strength of CAST-SHT?
CAST-SHT has a typical yield strength of 32 MPa (4.64 ksi) and a tensile strength of 42 MPa (6.09 ksi) — weaker than 69% of polymer grades. Strength varies by condition: see the 3 listed tempers.
Is CAST-SHT easy to machine?
Yes — machinability is rated excellent (85/100, better than 88% of polymer grades). Machines and routs cleanly with sharp positive-rake tools and high speed; avoid heat build-up (plasticizer sweats, edges soften) and use air blast rather than water-based coolant.
Can CAST-SHT be welded?
Not readily — weldability is rated poor (30/100). Solvent bonding (acetone/methyl acetate/ethyl acetate mixes) and adhesive joints are standard; ultrasonic works on rigid low-plasticizer grades, hot-plate welding tends to scorch.
What surface finishes work on CAST-SHT?
Barrel/tumble polishing with wood chips and wax gives the classic high-gloss eyewear finish; flame or vapor polishing works but must be brief, and hard coats or UV-stabilized lacquers are advised for outdoor use.
Can CAST-SHT be formed, bent or molded?
Dry 2–4 h at 65–75 °C before molding; melt 175–230 °C with mold 35–75 °C, keep residence time short as CA degrades and releases acetic acid above ~240 °C; excellent thermoforming and bending in hot air or oil.
What is the maximum service temperature of CAST-SHT?
CAST-SHT is rated for continuous use to about 60°C (140 °F), and briefly to 90°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM D706 — Cellulose Acetate Molding and Extrusion Compounds — ASTM International (2019)
- ISO 20200 — Determination of degree of disintegration of plastic materials under composting conditions — ISO (2023)
- ASM Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
- Polymer Handbook, 4th ed. (cellulose esters section) — Wiley (1999)
- Cellulose ester molding compound and film technical literature (Eastman, Daicel, Mazzucchelli) — producers (2023)
- CAMPUS / UL Prospector cellulosic thermoplastic datasets — CWFG / UL (2024)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.