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Tetrahydrophthalic anhydride (THPA)

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Tetrahydrophthalic anhydride (THPA)

Synonyms：Cis-1,2,3,6-Tetrahydrophthalic anhydride; 3a,4,7,7a-Tetrahydroisobenzofuran-1,3-dione

CAS No.：85-43-8

EINECS No.：213-308-7

Molecular Formula：C₈H₈O₃

Molecular Weight：152.1473

Structural Formula：

Standard：

Items	Specifications
Appearance	White flakes
Content	≥99.0%
Melting point	98.0℃ ~ 102.0℃
Melt color（Pt-Co）	≤80Hazen

Properties：THPA is a white flake solid. Soluble in general organic solvents, slightly soluble in petroleum ether. Melting point: 100℃, Density 1.35g/ml.

Applications：As a high-performance alicyclic acid anhydride-based chemical raw material, Tetrahydrophthalic Anhydride (THPA, CAS 85-43-8) excels with low toxicity, high stability, and light color. It plays a core role in multiple industries and is an indispensable key material for industrial production. Specific applications are as follows:

1.) Epoxy Resin Curing Agent

As a preferred anhydride-based epoxy resin curing agent, THPA reacts with epoxy groups to form a dense three-dimensional network structure. The cured product boasts excellent electrical insulation, heat resistance, and mechanical strength. Widely used in high-end scenarios such as insulation packaging of electronic components, LED encapsulants, casting insulation of power equipment, generator coil impregnation, and transformer casting; it is also suitable for electrical casting, powder coatings, and Epoxy Resin Transfer Molding (RTM) processes. Its low yellowing property makes it more suitable for transparent or light-colored epoxy floors and high-end coatings.

2.) Key Raw Material for Resin Modification

In the field of polymer synthesis, THPA is a core modifier for unsaturated polyester resins and alkyd resins. It introduces alicyclic structures into the resin main chain through esterification reactions, significantly enhancing product flexibility, chemical resistance, and weather resistance. It improves resin air-drying performance and shortens drying time, serving as a key component in high-grade putty, air-drying coatings, and automotive refinish paints. It optimizes coating adhesion, elasticity, gloss, and water resistance, extending the service life of architectural coatings and industrial anti-corrosion paints.

3.) Environmentally Friendly Plasticizer & Functional Additive

As a non-toxic and environmentally friendly plasticizer, THPA enhances the cold resistance and heat resistance of PVC products, complying with high-safety standards for scenarios such as food packaging and medical devices. Meanwhile, it acts as a surfactant for emulsifiers and wetting agents to improve coating leveling, a fiber treatment agent to enhance antistatic properties, and a lubricating oil additive to optimize performance.

4.) Core Intermediate for Fine Chemicals

In the pesticide industry, THPA is a key building block for synthesizing high-efficiency, low-toxicity pyrethroid insecticides and herbicides. In the pharmaceutical field, its derivatives have biological activity, applicable to the synthesis of various drug molecules and preparation of active ingredients. Additionally, it is widely used in textile treatment agents and composite material modification, covering industries such as electronics, coatings, plastics, pharmaceuticals, and agriculture.

Storage：Store in a cool, ventilated, moisture-proof and light-proof place. Keep container sealed and away from fire.

Packing：25kg plastic woven bag, or 500kg jumbo bag

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