Amivion ANH-MHHPA is methylhexahydrophthalic anhydride (MHHPA), a fully saturated cyclic anhydride epoxy curing agent produced by complete hydrogenation of methylphthalic anhydride. The full saturation of the cyclohexane ring—distinguishing MHHPA from its partially hydrogenated counterpart methyltetrahydrophthalic anhydride (MTHPA)—eliminates residual double bonds and significantly improves UV and photostability in the cured system. Amivion ANH-MHHPA is a colorless, low-viscosity liquid that reacts with epoxy resins in the presence of an accelerator at elevated temperatures, producing cured systems with high transparency, high glass transition temperature, excellent electrical insulation properties, and superior resistance to UV-induced yellowing. It is the preferred anhydride hardener in optical epoxy applications including LED encapsulation, optical lens casting, and UV-stable electrical insulation systems.
Key Features
- Superior UV and Photo-Stability: The fully saturated ring structure of Amivion ANH-MHHPA eliminates the chromophoric double bond present in MTHPA, resulting in significantly improved resistance to UV-induced yellowing in cured epoxy systems. This enhanced photostability makes MHHPA the preferred anhydride hardener in LED encapsulants, optical lenses, and light-transmitting epoxy components where maintaining optical clarity and color neutrality under light exposure is critical to product performance.
- High Optical Clarity in Cured Systems: Epoxy formulations cured with Amivion ANH-MHHPA and compatible cycloaliphatic or bisphenol-type epoxy resins produce cured materials with high light transmittance and low haze. This optical clarity supports applications in LED optics, optical fiber coatings, transparent encapsulants for photovoltaic modules, and clear casting resins where optical performance is a primary specification.
- Excellent Electrical Insulation Properties: Like other anhydride-cured epoxy systems, Amivion ANH-MHHPA produces cured networks with high dielectric strength, low dielectric constant, and low dissipation factor. These properties support its use in transformer and motor impregnation, high-voltage component potting, and insulation systems for power electronics where maintaining dielectric performance under thermal and electrical stress is required.
- Low Viscosity for Processing: Amivion ANH-MHHPA has low viscosity at ambient and moderately elevated processing temperatures, facilitating vacuum pressure impregnation (VPI) of electrical windings, casting of optical components, and automated potting operations. The low-viscosity formulating window it provides supports uniform impregnation of fibrous insulation structures and filling of complex encapsulant mould geometries.
- High Tg and Thermal Stability: Anhydride-cured epoxy systems based on Amivion ANH-MHHPA develop high glass transition temperatures and retain good mechanical and electrical properties after thermal aging. These characteristics support classification at elevated thermal ratings for electrical insulation systems and enable use in applications where long-term service at elevated temperatures is required.
Typical Applications
Amivion ANH-MHHPA is the preferred anhydride hardener in epoxy systems where UV stability, optical clarity, and thermal performance must be combined. Primary applications include LED encapsulant resins for high-brightness and high-power LED packages, where resistance to photodegradation and yellowing is critical to maintaining luminous efficacy over the product lifetime. In optical components, MHHPA-cured cycloaliphatic epoxy resins are used for casting optical lenses, prisms, and light guides. Transformer and motor winding impregnation systems benefit from the combination of low viscosity for VPI processing and high Tg for thermal class compliance.
Additional applications include encapsulation resins for photovoltaic junction boxes and solar panel edge sealing, where UV exposure and outdoor weathering resistance are required; potting compounds for automotive lighting modules and under-hood electronic assemblies subject to elevated temperature and UV radiation; optical fiber primary and secondary coating systems; and transparent casting resins for decorative, artistic, and industrial visual inspection applications requiring long-term color stability. Amivion ANH-MHHPA is also evaluated in UV-stable insulating varnishes for outdoor-rated electrical equipment.
Technical Specifications
- Chemical Name: Methylhexahydrophthalic anhydride (MHHPA; methyl-1,2,3,4,5,6-hexahydrophthalic anhydride)
- CAS No.: To be confirmed based on the final specification sheet. (Commercial grade is typically a mixture of isomers.)
- Molecular Formula: C₉H₁₂O₃
- Molecular Weight: 168.19 g/mol
- Appearance: To be confirmed based on the final specification sheet.
- Anhydride Content / Purity: To be confirmed based on the final specification sheet.
- Acid Value: To be confirmed based on the final specification sheet.
- Viscosity at 25°C: To be confirmed based on the final specification sheet.
- Color (APHA): To be confirmed based on the final specification sheet.
- Water Content: To be confirmed based on the final specification sheet.
Thermal Stability
- Amivion ANH-MHHPA is thermally stable under recommended storage and handling conditions.
- Avoid contact with water, strong bases, amines, and alcohols. Moisture hydrolyzes the anhydride to the corresponding dicarboxylic acid, reducing curing reactivity. Decomposition above recommended storage temperature may produce irritating vapors.
Storage Recommendations
- Recommended maximum storage temperature: To be confirmed based on the final specification sheet.
- Store in a cool, dry, well-ventilated area away from moisture, heat sources, and direct sunlight.
- Keep containers tightly sealed — MHHPA is hygroscopic and moisture ingress degrades curing performance.
- Avoid contact with water, strong bases, amines, and reactive hydroxyl compounds outside of intended use.
Packaging & Transport
- Standard Packaging: To be confirmed based on the final specification sheet.
- UN Number: To be confirmed based on the final specification sheet.
- Transport Class: To be confirmed based on the final specification sheet.
Amivion ANH-MHHPA: Safety & Handling
Amivion ANH-MHHPA should be handled in accordance with applicable safety procedures for cyclic organic anhydrides. MHHPA is a known respiratory sensitizer and skin sensitizer; inhalation of vapor or mist must be avoided and controlled to levels at or below relevant occupational exposure limits. Appropriate respiratory protection, chemical-resistant gloves, safety goggles, and protective clothing must be worn during all handling, mixing, and heated processing operations. Local exhaust ventilation is required at dispensing and processing workstations. Users must review the Safety Data Sheet prior to use and implement the engineering controls, personal protective equipment, and medical surveillance appropriate for anhydride-handling operations as specified therein.
Safety Data Sheet and destination-compliant labeling information are available upon request. For related products, see also Amivion METHPA and Amivion DETA.