Cellulose Acetate Phthalate (CAP)
Cellulose Acetate Phthalate (CAP) is a cellulose derivative obtained by esterification of cellulose with acetic acid and phthalic anhydride. It appears as a white to off-white, free-flowing powder that is insoluble in water but soluble in alkaline solutions and certain organic solvents. CAP is primarily used as an enteric coating agent in pharmaceutical formulations, providing resistance to acidic gastric fluids and enabling targeted release of drugs in the intestines. Due to its film-forming, pH-sensitive solubility, and protective properties, CAP is also applied in food, cosmetics, and specialty industrial uses.
Cellulose Acetate Phthalate (CAP) Uses
- Primary Uses
Pharmaceutical Industry
- Widely used as an enteric coating polymer for tablets and capsules to prevent dissolution in stomach acid and enable targeted release in the intestines.
- Provides protection for acid-sensitive drugs and reduces gastric irritation.
- Acts as a controlled-release film former in oral dosage forms.
Food Industry
- Used as a coating agent for confectionery and food products to provide gloss and protective barriers.
- Functions as a controlled-release matrix for flavor and nutrient encapsulation.
Cosmetics
- Employed in nail polish formulations and other cosmetics for film-forming and gloss-enhancing properties.
- Provides water-resistant coatings.
Secondary Uses
Packaging Industry
- Utilized in specialty coatings for biodegradable films and packaging materials for controlled permeability.
Adhesives & Sealants
- Applied as a component in water-resistant adhesives and sealants.
Printing Industry
Used in inks and coatings to improve film durability and chemical resistance.
- Basic Identification Attributes
- Chemical Name (IUPAC): Cellulose, acetate, phthalate
- Common/Trade Name: Cellulose Acetate Phthalate, CAP
- CAS Number: 9004-35-7
- HS Code: 3912.10.00
- Molecular Formula: Variable (cellulose backbone with acetate and phthalate ester substitutions)
- Synonyms:
- CAP
- Cellulose acetate phthalate polymer
- Phthalylated cellulose acetate
- Physical & Chemical Properties
- Physical State: White to off-white powder
- Color & Odor: White/off-white; virtually odorless
- Melting Point: Decomposes before melting
- Boiling Point: Not applicable
- Density: Approximately 1.3–1.4 g/cm³
- Solubility:
- Insoluble in water and gastric acid (pH <3)
- Soluble in alkaline conditions (pH >6)
- Soluble in acetone, ethanol, and certain organic solvents
- pH Sensitivity: Dissolves at intestinal pH (around 6.8 and above)
- Stability: Stable under dry, cool storage conditions; sensitive to strong acids and bases
- Safety & Hazard Attributes
- Hazard Class (GHS): Not classified as hazardous under normal use
- NFPA Ratings:
- Health: 0
- Flammability: 1 (combustible dust risk)
- Reactivity: 0
- Exposure Limits: No specific occupational exposure limits; general dust precautions advised
- Toxicity: Non-toxic; widely regarded as safe for pharmaceutical and food uses
- Reactivity: Stable under normal conditions; avoid strong oxidizers and acids
- Storage & Handling Attributes
- Storage Conditions: Store in a cool, dry place away from moisture and direct sunlight
- Container Type: Sealed, moisture-proof containers or bags (plastic or foil-lined)
- Shelf Life: Typically 2–3 years if stored properly
- Special Handling: Avoid dust generation and inhalation; use PPE when handling powders
- Regulatory & Compliance Attributes
- FDA Status: Approved as a pharmaceutical excipient and food additive in regulated uses
- REACH Status: Registered
- Transportation: Not regulated as hazardous material
- Waste Disposal: Dispose according to local regulations; biodegradable under industrial composting
- Environmental & Health Impact
- Ecotoxicity: Low environmental impact; biodegradable under aerobic conditions
- Persistence: Moderate biodegradability; slow in some conditions
- Bioaccumulation: Not expected to bioaccumulate
- Carcinogenicity/Mutagenicity: Not classified as carcinogenic or mutagenic
Biodegradability: Biodegradable, but may require controlled conditions
Safety Handling Precautions
Personal Protective Equipment (PPE):
- Dust mask or respirator for powder handling
- Safety goggles
- Gloves recommended
Handling Measures:
- Avoid dust formation and accumulation
- Use in well-ventilated areas
- Prevent contact with strong acids or oxidizers
Storage Measures:
- Keep containers tightly sealed and dry
- Store away from heat and ignition sources
Hygiene Practices:
- Wash hands after handling
- Avoid eating, drinking, or smoking while handling product
First Aid Measures
- Inhalation: Remove to fresh air; seek medical attention if irritation occurs
- Skin Contact: Wash with soap and water; seek medical advice if irritation persists
- Eye Contact: Flush with water for 15 minutes; seek medical attention if irritation continues
- Ingestion: Non-toxic; rinse mouth and seek medical advice if large quantities ingested
Firefighting Measures
- Fire Hazards: Combustible powder; may produce dust explosion hazard
- Extinguishing Media: Use water spray, foam, dry chemical, or CO₂
- Special Precautions: Avoid dust accumulation; firefighters should wear protective equipment and respiratory protection
- Decomposition Products: Carbon oxides, phthalic anhydride, and acetic acid vapors under thermal decomposition

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