Hexahydrophthalic anhydride

Hexahydrophthalic anhydride (CAS 85-42-7), abbreviated HHPA, is a cycloaliphatic anhydride used as a curing agent and reactive intermediate in epoxy and polyester systems.

Where is Hexahydrophthalic anhydride used?

• Electrical encapsulation and casting: primary hardener for epoxy resin systems
• Powder coatings: long pot life and controlled cure profiles
• Alkyd and polyester resin synthesis: monomer building block for industrial and can coatings
• Adhesives and sealants: reactive modifier that tunes flexibility and adhesion in structural bonding
• Specialty plasticizers: reactive modifier for polymer matrices
• Its cycloaliphatic backbone improves compatibility with PVC.

Good to know: Its saturated ring structure is preferred over aromatic anhydrides where UV stability and color retention matter. No FCC, USP, Ph. Eur., BP, EP or ACS grades are standard for this product.

Commercial specifications

• Standard commercial grades at high purity for resin and coating applications
• Typically handled and shipped in molten form for industrial volumes