Caprolactone

Caprolactone (CAS 502-44-3), also known as ε-caprolactone or by the abbreviation CL, is a cyclic ester monomer used as a building block in polymer synthesis and as a reactive diluent in coating and resin systems.

Its ring-opening polymerization produces polycaprolactone and copolymer architectures that underpin a broad range of industrial and specialty applications. In plastics and coatings, CL is polymerized to produce polycaprolactone (PCL).

This biodegradable thermoplastic is used in packaging films, adhesives, and flexible molded parts. Printing ink and packaging formulators use caprolactone-based polyols to improve flexibility and adhesion.

These polyols also enhance solvent resistance in polyurethane systems. In personal care, it functions as a reactive ingredient in film-forming polymers and specialty esters used across skin and hair formulations.

At trace levels, caprolactone also appears as a flavoring agent in food applications. It contributes creamy, coconut-like notes to finished products and is often referenced by its FEMA code or E number where applicable.

Caprolactone is supplied as a colorless to pale yellow liquid. It is available in technical and polymer-grade specifications, with purity levels typically at 99% or higher to meet monomer quality requirements.

These standards ensure controlled polymerization for industrial use. While not typically listed under FCC, USP, Ph.Eur., BP, EP, or ACS, it meets rigorous industrial purity benchmarks.

Packaging ranges from drums to isotanks for bulk industrial supply. This ensures safe transport and storage for manufacturers requiring high-volume chemical precursors for large-scale resin production.