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Polymers & Resins

Caprolactone

CAS: 502-44-3

Overview

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.

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Physical Properties

Melting Point-18 °C
Boiling Point253 °C
Density1.030 g/cm³ (approx)
Flash Point229 °F
Appearanceclear liquid
ColorClear colorless, yellowing on aging
FormLiquid
Water Solubility>1000 MG/L (20 ºC)
Vapor Pressure0.01 mm Hg ( 20 °C)
Refractive Indexn 20/D 1.463(lit.)
Log P0.32 at 20℃

Safety & Handling

Warning GHS07 Hazard Statements H319 Causes serious eye irritation Precautionary Statements P280 Wear protective gloves/protective clothing/eye protection/face protection. P264+P265 Wash … thoroughly after handling. P337+P317 If eye irritation persists: Get medical advice/attention. Get emergency medical help. P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code29322090
WGK (Germany)2

Other Names

oxepan-2-one | hexanoic acidepsilon-lactone | hexan-6-olide | epsilon-caprolactone monomer | epsilon-caprolactone | 6-hydroxyhexanoic anhydride | 6-hydroxyhexanoic acidepsilon-lactone | 6-hydroxyhexanoic acid lactone | CL

Related Products

Chemical Properties

CAS Number
502-44-3
EC Number
207-938-1
Mol. Weight
114.14
HS Code
29322090

Industries

Documentation