CAP
A cellulosic ester offering a balance between CA and CAB with excellent clarity, low odor/taste, and good toughness; often specified for consumer and cosmetic products needing a premium glossy finish.
Reference datasheet — CAP 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.
Values for the MP condition
CAP grades and fills
CAP is supplied in 4 conditions, soft to hard. MP is the default FabDigit quotes; the values on this page are for it.
Compare all 4 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
High-plasticizer soft/high-flow grade | Pick when maximum flow, deep-draw toughness and a soft warm feel matter more than heat resistance or stiffness. | 18 | 20 | 80 | 68 Shore D |
MPDefault Medium-plasticizer standard injection-molding grade | General-purpose balance of stiffness, gloss and toughness for cosmetic caps, handles and housings. | 32 | 50 | 95 HRR | |
Pearlescent / transparent coloured eyewear & handle grade | Colour-matched, high-gloss compound for buffed eyewear frames, pen barrels and premium tool handles. | 32 | 34 | 45 | 79 Shore D |
Low-plasticizer rigid / high-heat grade | Pick for maximum rigidity, dimensional stability and the highest HDT available in CAP, at the cost of flow and notched impact. | 46 | 50 | 28 | 82 Shore D |
Supply forms, finishes and certifications
Ways CAP is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
SHT | Extrusion / thermoforming sheet & film grade | Surface finish |
FDA | Food-contact / cosmetic-packaging compliant grade | Certification |
UV | UV-stabilized / weatherable grade | Grade option |
What is CAP?
A cellulosic ester offering a balance between CA and CAB with excellent clarity, low odor/taste, and good toughness; often specified for consumer and cosmetic products needing a premium glossy finish. CAP has a density of 1.21 g/cm³ (0.0437 lb/in³), heavier than 60% of polymer grades. Its glass-transition temperature is 142°C (288 °F). CAP has a yield strength of 30 MPa (4.35 ksi) and a tensile strength of 32 MPa (4.64 ksi) — weaker than 70% of polymer grades. Elongation at break is 50% and the elastic modulus is 1.4 GPa (0.203 Msi).
What is CAP used for?
- cosmetic packaging
- pens and styluses
- eyewear components
- toothbrush handles
- decorative moldings
Advantages
- Polishes to a fine finish — 92/100, better than 97% of polymer grades
- Easy to machine — 78/100, better than 81% of polymer grades
- Good UV / weathering resistance — 55/100, better than 77% of polymer grades
- Low, predictable mold shrinkage — 0.45%, better than 77% of polymer grades
- Forms and bends easily — 80/100, better than 75% of polymer grades
Limitations
- Absorbs moisture — dry before molding — 1.8%, worse than 95% 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
CAP properties
Typical room-temperature values for CAP-MP; bars are the position among polymer grades.
Physical7
CAP has a density of 1.21 g/cm³ (0.0437 lb/in³), heavier than 60% of polymer grades. Its glass-transition temperature is 142°C (288 °F).
Mechanical12
CAP has a yield strength of 30 MPa (4.35 ksi) and a tensile strength of 32 MPa (4.64 ksi) — weaker than 70% of polymer grades. Elongation at break is 50% and the elastic modulus is 1.4 GPa (0.203 Msi).
Thermal11
CAP is rated for continuous service to 60°C (140 °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 130 µm/m·K (72.2 µin/in·°F).
Electrical7
CAP is an electrical insulator with a dielectric strength of 17 kV/mm (431.8 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 94% of polymer grades. UV resistance is good.
Sustainability4
Producing a kilogram of CAP takes about 100 MJ of energy and emits 4.5 kg of CO₂ — less than 61% of polymer grades. Typical recycled content is 0%.
Manufacturability8
CAP's machinability is very good (78/100, better than 81% of polymer grades); weldability good (60/100); formability very good (80/100).
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. CAP is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CAP
Is CAP easy to machine?
Machines and turns easily with sharp positive-rake tools and coolant/air blast; keep speeds moderate to avoid smearing and plasticizer sweat-out.
Can CAP be welded?
Joins well by solvent cementing (acetone/MEK blends) and by ultrasonic or hot-plate welding; avoid overheating which causes acid odour and discolouration.
Can CAP be formed, bent or molded?
Dry 2–3 h at 65–75 °C before molding; melt 185–240 °C, mold 35–75 °C, low-to-moderate injection pressure with generous gates — over-shear causes brown streaks and burnt-sugar odour.
CAP 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 |
|---|---|---|
| propionyl contentprimary ester substituent (per ASTM D817 assay) | 39 – 48 | 45 |
| acetyl contentminor ester substituent | 0.5 – 3.5 | 2 |
| hydroxyl contentfree OH, governs polarity and moisture pickup | 1 – 3 | 1.8 |
| plasticizer (e.g. DOA / DEP / citrate essets LP / MP / HP grade class per ASTM D1562 | 0 – 20 | 10 |
| stabilizers, UV absorbers, colourants | 0 – 2 | 0.5 |
| cellulose backbone (anhydroglucose unitswood pulp / cotton linter derived | ≥ 45 (balance) |
What surface finishes work on CAP?
Ash-buffs to an exceptional mirror gloss; accepts hot stamping, vacuum metallising and printing after suitable priming, but avoid ketone/ester based paints and cleaners.
Equivalent designations
Standards and trade names that resolve to CAP in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- D1562
How much does CAP cost?
CAP 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.
CAP — frequently asked
What is CAP used for?
CAP is typically used for cosmetic packaging, pens and styluses, eyewear components, toothbrush handles and decorative moldings. In short: highest gloss cellulosic; low odour and taste; between CA and CAB.
What is the yield strength of CAP?
CAP has a typical yield strength of 30 MPa (4.35 ksi) and a tensile strength of 32 MPa (4.64 ksi) — weaker than 70% of polymer grades. Strength varies by condition: see the 4 listed tempers.
Is CAP easy to machine?
Yes — machinability is rated very good (78/100, better than 81% of polymer grades). Machines and turns easily with sharp positive-rake tools and coolant/air blast; keep speeds moderate to avoid smearing and plasticizer sweat-out.
Can CAP be welded?
Yes — weldability is rated good (60/100). Joins well by solvent cementing (acetone/MEK blends) and by ultrasonic or hot-plate welding; avoid overheating which causes acid odour and discolouration.
What surface finishes work on CAP?
Ash-buffs to an exceptional mirror gloss; accepts hot stamping, vacuum metallising and printing after suitable priming, but avoid ketone/ester based paints and cleaners.
Can CAP be formed, bent or molded?
Dry 2–3 h at 65–75 °C before molding; melt 185–240 °C, mold 35–75 °C, low-to-moderate injection pressure with generous gates — over-shear causes brown streaks and burnt-sugar odour.
What is the maximum service temperature of CAP?
CAP 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.
What is the difference between CAP MP and CAP LP?
MP is the default condition — general-purpose balance of stiffness, gloss and toughness for cosmetic caps, handles and housings. LP: pick for maximum rigidity, dimensional stability and the highest HDT available in CAP, at the cost of flow and notched impact. Yield strength is 30 MPa in MP versus 46 MPa in LP.
How much does CAP cost?
CAP 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
- ASTM D1562 — Standard Specification for Cellulose Acetate Propionate Molding and Extrusion Compounds — ASTM International (2021)
- ASTM D817 — Test Methods for Cellulose Acetate Propionate and Cellulose Acetate Butyrate — ASTM International (2020)
- Tenite Propionate molding and extrusion compounds — property and processing data — Eastman Chemical Company (2022)
- Engineered Materials Handbook Vol. 2: Engineering Plastics (cellulosics section) — ASM International (1988)
- CAMPUS / UL Prospector cellulose ester grade data — CWFG / UL Solutions (2024)
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.