Why is MTHPA preferred over amine hardeners for electrical potting and encapsulation?

MTHPA gives a controlled, low-exotherm cure, which reduces cracking and internal stress in large castings compared with fast room-temperature amine systems. It also provides good electrical insulation, heat resistance, and mechanical strength after heat curing.

Does MTHPA require an accelerator when curing epoxy resin?

Yes. MTHPA reacts slowly with epoxy by itself, so a tertiary amine accelerator such as BDMA or DMP-30 is normally used. Typical accelerator loading is about 0.5-3%, with curing usually carried out at elevated temperature.

Why are different MTHPA isomer ratios offered?

The isomer ratio influences crystallization tendency, freezing point, viscosity, and handling in different climates. Suppliers can adjust the ratio to provide a stable liquid that is easier to pump and impregnate into coils, transformers, and complex electrical components.

What are the main applications of MTHPA CAS 11070-44-3?

It is used for epoxy casting, potting, and encapsulation in electrical and electronic components such as transformers, coils, capacitors, and LED packages. It is also suitable for filament winding, pultrusion, and vacuum impregnation.

Methyltetrahydrophthalic Anhydride (MTHPA) CAS 11070-44-3

Methyltetrahydrophthalic Anhydride, also called MTHPA, CAS 11070-44-3, is a liquid anhydride curing agent supplied for epoxy casting, potting and electrical insulation. Confirm the required grade and isomer ratio, then request a quotation with COA/TDS/SDS for bulk supply.

CAS: 11070-44-3
Synonyms: MTHPA, Methyl tetrahydrophthalic anhydride, 4-Methyl-1,2,3,6-tetrahydrophthalic anhydride, Epoxy Anhydride Hardener, Liquid Anhydride Curing Agent
Einecs: 234-290-7
Molecular Formula: C₉H₁₀O₃
Grade: Electronic Grade, Electrical Potting Grade.
Package: 220kg Iron Drum or 1200kg IBC Tank.

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Product Description

Methyltetrahydrophthalic Anhydride CAS 11070-44-3 is a liquid alicyclic anhydride curing agent, also known as MTHPA, with molecular formula C9H10O3, molecular weight about 166.17 and EINECS 234-290-7.

Synonyms: MTHPA; Methyl tetrahydrophthalic anhydride; 4-Methyl-1,2,3,6-tetrahydrophthalic anhydride; Epoxy anhydride hardener; Liquid anhydride curing agent.

CAS: 11070-44-3.

It has the molecular formula C9H10O3 and a molecular weight of about 166.17 g/mol.

It appears as a pale yellow transparent liquid with low viscosity at room temperature.

A standard electronic grade typically has purity of at least 99.0% by GC and anhydride content of about 41.0–42.0%.

Viscosity at 25 °C is about 20–50 mPa·s, and color (APHA/Pt-Co) is typically no more than 100.

The isomer ratio can be adjusted to control the freezing point and viscosity for different climates and production environments.

It provides a controlled, low-exotherm cure, which reduces cracking and internal stress in large castings.

When cured with epoxy resin, it imparts good electrical insulation, high heat resistance (high Tg) and mechanical strength.

It is used for epoxy casting, potting and encapsulation of transformers, coils, capacitors and LED packages.

It also suits filament winding, pultrusion and vacuum impregnation.

It is normally used with a tertiary amine accelerator such as BDMA or DMP-30 at about 0.5–3%, cured at elevated temperature.

Store in a cool, dry, well-ventilated area in tightly closed containers away from moisture, heat and ignition sources.

Protect from moisture and keep containers closed when not in use.

Confirm appearance, purity, anhydride content, viscosity, color, freezing point and isomer ratio as required.

Use suitable eye and skin protection during handling, and wash skin contact with soap and water.

The page is an RFQ entry point and does not state stock, price, MOQ or fixed lead time.

For an RFQ, state the intended application, required grade, isomer ratio, quantity, packaging, destination and document needs.

FAQ - Technical & Supply Chain

Q:
What is Methyltetrahydrophthalic Anhydride MTHPA CAS 11070-44-3?

A: MTHPA is a liquid alicyclic anhydride curing agent for epoxy resin systems. Its molecular formula is C9H10O3, with a molecular weight of about 166.17 g/mol.
Q:
Why is MTHPA preferred over amine hardeners for electrical potting and encapsulation?

A: MTHPA gives a controlled, low-exotherm cure, which reduces cracking and internal stress in large castings compared with fast room-temperature amine systems. It also provides good electrical insulation, heat resistance, and mechanical strength after heat curing.
Q:
Does MTHPA require an accelerator when curing epoxy resin?

A: Yes. MTHPA reacts slowly with epoxy by itself, so a tertiary amine accelerator such as BDMA or DMP-30 is normally used. Typical accelerator loading is about 0.5-3%, with curing usually carried out at elevated temperature.
Q:
Why are different MTHPA isomer ratios offered?

A: The isomer ratio influences crystallization tendency, freezing point, viscosity, and handling in different climates. Suppliers can adjust the ratio to provide a stable liquid that is easier to pump and impregnate into coils, transformers, and complex electrical components.
Q:
What are the main applications of MTHPA CAS 11070-44-3?

A: It is used for epoxy casting, potting, and encapsulation in electrical and electronic components such as transformers, coils, capacitors, and LED packages. It is also suitable for filament winding, pultrusion, and vacuum impregnation.

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