Overview
Tetrahydrophthalic anhydride (CAS 85-43-8 ), commonly abbreviated as THPA, is a cyclic dicarboxylic anhydride used as a curing agent and reactive intermediate in polymer manufacturing. It functions as a hardener for epoxy systems and a building block for polyester and alkyd resins.
This chemical is utilized across the coatings, adhesives, and plastics industries. In epoxy coating formulations, THPA acts as a stoichiometric curing agent, producing crosslinked networks with good mechanical performance and chemical resistance.
These properties make it ideally suited to industrial and protective coatings. Alkyd and unsaturated polyester resin producers use it as a monomer to control flexibility and reactivity in the final resin product.
In adhesive and sealant systems, THPA-cured epoxy formulations deliver the bond strength and thermal stability required for structural and assembly applications. This ensures long-term durability in demanding environments.
Printing ink manufacturers incorporate THPA-based resins where controlled cure response and adhesion to packaging substrates are required. This versatility makes it a staple in modern chemical manufacturing and processing.
THPA is supplied as a white to off-white crystalline solid or powder. Technical grade is the standard commercial form, with purity specifications typically at 98% or above to meet industrial requirements.
Bulk supply is available in bags or drums, with packaging options scaled to industrial procurement volumes. Our logistics network ensures reliable delivery for large-scale manufacturing operations and specialized chemical facilities.
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Physical Properties
| Melting Point | 102 °C |
| Boiling Point | 195 °C @ Press: 50 Torr |
| Density | 1.20 g/cm³ @ Temp: 105 °C |
| Flash Point | 157°C |
| Color | Off-White to Light Tan |
| Form | Solid |
| Water Solubility | 29.4g/L at 20℃ |
| Vapor Pressure | 0.021Pa at 20℃ |
| Refractive Index | 1.4810 (estimate) |
| pH | 2.1 (20°C, 10g/L in H2O) |
| Log P | 1.29 at 40℃ |
Safety & Handling
Danger GHS05 GHS08 GHS07 Hazard Statements H302 Harmful if swallowed H315 Causes skin irritation H317 May cause an allergic skin reaction H318 Causes serious eye damage H334 May cause allergy or asthma symptoms or breathing difficulties if inhaled H335 May cause respiratory irritation H412 Harmful to aquatic life with long lasting effects Precautionary Statements P233 Keep container tightly closed. P260 Do not breathe dust/fume/gas/mist/vapours/spray. P261 Avoid breathing dust/fume/gas/mist/vapours/spray. P264 Wash … thoroughly after handling. P270 Do not eat, drink or smoke when using this product. P271 Use only outdoors or in a well-ventilated area. P272 Contaminated work clothing should not be allowed out of the workplace. P273 Avoid release to the environment. P280 Wear protective gloves/protective clothing/eye protection/face protection. P284 In case of inadequate ventilation wear respiratory protection. P317 Get emergency medical help. P319 Get medical advice/attention if you feel unwell. P321 Specific treatment (see … on this label). P330 Rinse mouth. P403 Store in a well-ventilated place. P405 Store locked up. P501 Dispose of contents/container in accordance with local regulations. P264+P265 Wash … thoroughly after handling. P301+P317 Get emergency medical help. P302+P352 IF ON SKIN: Wash with plenty of water. P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing. P332+P317 Get emergency medical help. P333+P317 Get emergency medical help. P342+P316 Get emergency medical help immediately. P362+P364 Take off contaminated clothing and wash it before reuse. P403+P233 Store in a well-ventilated place. Keep container tightly closed. P305+P354+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
Other Names
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Chemical Properties
- CAS Number
- 85-43-8
- EC Number
- 201-605-4
- Mol. Weight
- 152.15
- Category
- Polymers & Resins