BTDA (3,3’, 4,4’-Benzophenone tetracarboxylic dianhydride) is a dianhydride that has been produced since the early 1970s. It has grown into a flagship product with a proven performance edge in the fields of epoxy and polyimide chemistry.

BTDA is a thermal curative that can improve temperature stability, dimensional stability, and dielectric properties of epoxy resins, particularly those based on DGEBA (Diglycidyl ether of Bisphenol A). It can improve glass transmission temperatures (Tg) and impart superior chemical, mechanical, and physical properties as compared to epoxies cured with other anhydride or dianhydride curatives. BTDA has been shown to increase Tg by as much as 20-30°C; resulting in a sustained high-temperature resistance which is unmatched in epoxy chemistry. This makes BTDA the ideal curative for a range of industries with increasingly complicated mechanical demands. It can be synthesized to varying purities and particle sizes to suit a range of requirements, while its adjustable pot life makes for ideal processing conditions.

BTDA is primarily utilized in powder coating applications where, after co-milling the epoxy and the BTDA the coating is applied using, for example, fluidized bed or electrostatic spray techniques. BTDA is a solid and it can be challenging to incorporate into viscous liquid epoxies. It requires careful monitoring during processing to insure that the BTDA is adequately dispersed prior to curing. Another option is to pre-blend BTDA into low viscosity monoanhydrides. The resulting pourable or pumpable paste is easier to incorporate into liquid resins. The result is an epoxy that benefits from the properties imparted by both the BTDA and the monoanhydride.

BTDA Applications

BTDA has a broad range of commercial applications as a thermal curative for epoxy resins. Historically it finds use in adhesive formulations to attach circuits to electronic components, or in powder coatings to improve chemical resistance and insulation efficiency. It is also utilized in wire enamels, motor varnishes, and LED encapsulants.

BTDA can also be used a curative for the epoxy formulation used in syntactic foams for applications that require high compressive strength and temperature stability, particularly in off-shore drilling operations and increasing depths required to reach identified oil reserves.

BTDA and BTDA blends have been used as curatives in epoxy systems used for interior and exterior coatings and primers for petroleum, crude oil, and shale gas piping where the improved physical and mechanical properties are critical for performance and service life.

Solutions from CABB

CABB’s Jayhawk team has a proven history of manufacturing BTDA for use in a range of applications, including BTDA Microfine, BTDA Polymer Fine, BTDA Flake, and BTDA Ultrapure.

To learn more about fine chemical solutions, read our previous article: What is a Polyimide?

If you would like any more information, please do not hesitate to contact us.

[BTDA is a registered trademark of Jayhawk Fine Chemicals Corporation or its subsidiaries]